JP7189832B2 - Functional titanium member and method for producing functional titanium member - Google Patents

Description

The present invention relates to a titanium member and a method for manufacturing a titanium member.

Patent Literature 1 describes a method for manufacturing titanium products including primary age hardening treatment, crystal precipitation treatment and secondary age hardening treatment. Specifically, in the primary age hardening treatment, the titanium alloy molding is held at a temperature of 350 to 600° C. for a certain period of time in the air, vacuum or inert gas atmosphere. In the crystal precipitation treatment, titanium crystals are precipitated on the surface of the molding by heating the molding that has undergone the primary age hardening treatment to 1000 to 1400° C. in a vacuum furnace. In the secondary age hardening treatment, the above-mentioned molding that has undergone the above-mentioned crystal precipitation treatment is held at 350 to 600° C. for a certain period of time in the process of allowing it to cool in the air, vacuum or inert gas atmosphere.

JP-A-11-61366

However, the titanium product of Patent Document 1 is described to have a Vickers hardness of HV750 or higher. This was verified experimentally, but the hardness of titanium products only heated in an inert gas atmosphere did not increase to this level.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing a titanium member having a high hardness and a fine uneven pattern appearing on the surface.

A titanium member according to the present invention is a titanium member containing pure titanium or a titanium alloy, at least one surface of which is rough, the surface of the rough surface has an uneven pattern, and has a Vickers hardness of HV500 or more. be.

The titanium member according to the present invention has high hardness and a fine uneven pattern on the surface.

FIG. 1 is a diagram for explaining a method of manufacturing a titanium member. FIG. 2 is a diagram for explaining a method of manufacturing a titanium member. FIG. 3 is a schematic cross-sectional view showing the structure of the functional titanium member 10 of Example 1-1. FIG. 4 is a microscope image of a JIS type 2 pure titanium plate material that has been polished to #800. FIG. 5 is a microscope image of a blasted titanium substrate. 6 is a microscope image of the titanium member 11 obtained under the heat treatment condition 1. FIG. FIG. 7 is a microscope image of the titanium member 11 obtained under the heat treatment condition 2. FIG. FIG. 8 is a diagram for explaining the crystallinity of the pure titanium plate material, the blasted titanium substrate, and the titanium member 11. FIG. FIG. 9 is a schematic cross-sectional view showing the structure of the functional titanium member 20 of Example 1-2. FIG. 10 is a microscope image of the titanium member 21 obtained under heat treatment condition 3. FIG. FIG. 11 is a diagram for explaining the crystallinity of the pure titanium plate material, the blue crystal portion, the white crystal portion, and the black crystal portion. FIG. 12 is a schematic cross-sectional view showing the structure of the functional titanium member 30 of Example 2. FIG. FIG. 13 is a microscope image of the blasted titanium substrate. FIG. 14 is a microscope image of the titanium member 31 obtained under the heat treatment condition 4. FIG. FIG. 15 is a microscope image of the titanium member 31 obtained under heat treatment condition 5. FIG. FIG. 16 is a diagram for explaining the crystallinity of the pure titanium plate, the blasted titanium substrate, and the titanium member 31. FIG. FIG. 17 is a schematic cross-sectional view showing the structure of the functional titanium member 40 of Example 3. As shown in FIG. FIG. 18 is a microscope image of the blasted titanium substrate. FIG. 19 is a microscope image of the titanium member 41 obtained under the heat treatment condition 6. FIG. FIG. 20 is a diagram for explaining the crystallinity of the pure titanium plate, the blasted titanium substrate, and the titanium member 41. As shown in FIG. FIG. 21 is a schematic cross-sectional view showing the structure of the functional titanium member 50 of Example 4. FIG. FIG. 22 is a microscope image of a blasted titanium substrate. 23 is a microscope image of the titanium member 51 obtained under heat treatment condition 7. FIG. FIG. 24 is a diagram for explaining the crystallinity of the pure titanium plate material, the blasted titanium substrate, and the titanium member 51. FIG. 25 is a schematic cross-sectional view showing the structure of the functional titanium member 60 of Example 5. FIG. FIG. 26 is a microscope image of the titanium member 61 obtained under heat treatment condition 8. FIG. FIG. 27 is a diagram for explaining the crystallinity of the pure titanium plate material and the titanium member 61. FIG. 28 is a schematic cross-sectional view showing the structure of the functional titanium member 70 of Example 6. FIG. 29 is a microscope image of the titanium member 71 obtained under the heat treatment condition 9. FIG. FIG. 30 is a diagram for explaining the crystallinity of the pure titanium plate material and the titanium member 71. FIG. FIG. 31 is a diagram showing the relationship between composite hardness and measurement results of scratch resistance.

A form (embodiment) for carrying out the present invention will be described in detail. The present invention is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

<Functional titanium member>
A functional titanium member of an embodiment is a functional titanium member including a titanium member containing pure titanium or a titanium alloy, and a functional layer provided on the titanium member, wherein the titanium member has a It has an uneven pattern, the functional layer has an uneven pattern on its surface derived from the uneven pattern of the titanium member, and the functional titanium member has a Vickers hardness of HV500 or higher. That is, the titanium member includes a surface having an uneven pattern, a functional layer is provided on the surface so as to follow the uneven pattern, and the uneven pattern is held on the surface of the functional layer. ing. Note that the titanium member may have an uneven pattern on at least one surface of the member. In addition, it is sufficient that at least part of the surface has an uneven pattern.

The titanium member included in the functional titanium member is a titanium member containing pure titanium or a titanium alloy, has an uneven pattern on the surface, exhibits the original color of titanium, and has a Vickers hardness of HV30 higher than that of the raw material titanium member. Bigger than that. The details of the uneven pattern, color, and Vickers hardness will be described later in the method for manufacturing a titanium member. In addition, details of the uneven pattern and functions of the functional titanium member will be described later in the manufacturing method of the functional titanium member.

The functional titanium member of the embodiment can be used for ornaments. Examples of accessories include clocks such as wristwatches; accessories such as spectacles and accessories; and decorative members such as sporting goods. More specifically, watch constituent members such as a case and a piece of a band can be mentioned. The clock may be a photovoltaic clock, a thermoelectric clock, a standard time radio wave receiving self-correcting clock, a mechanical clock, or a general electronic clock. Such a timepiece is manufactured by a known method using the functional titanium member.

<Method for manufacturing titanium member>
First, a method for manufacturing a titanium member included in the functional titanium member will be described. Examples of the method for manufacturing the titanium member include a method for manufacturing a first titanium member to a method for manufacturing a third titanium member.

[Method for producing first titanium member]
A first titanium member manufacturing method (first manufacturing method) includes a blasting step, a first heating step, and a second heating step. According to the first manufacturing method, a titanium member having an uneven pattern on its surface is obtained. Also, the titanium member has at least one rough surface, and the surface of the rough surface has an uneven pattern.

The fine structure (uneven pattern) that appears in the titanium member appears when heated above the phase transition temperature (885° C.) from the α phase to the β phase of titanium. Pure titanium has an α phase and a hexagonal close-packed structure (HCP) at room temperature, but changes to a β phase and a face-centered cubic lattice structure (FCC) above the phase transition temperature. When pure titanium is heated above the phase transition temperature, metal crystals slide from the close-packed hexagonal close-packed structure (HCP) to the face-centered cubic lattice structure (FCC) during the temperature rise, and the crystal grows. The size of the obtained crystals can be controlled by the heating conditions (heating start temperature, temperature rising rate, reaching temperature, holding time, etc.) in the steps described later.

The uneven pattern is formed, for example, by arranging small pieces in a mosaic pattern. In addition, it may look like a surface pattern of rocks such as sedimentary rocks, igneous rocks, and metamorphic rocks. In this specification, the uneven pattern is also referred to as a crystal pattern. Moreover, as will be described later in Examples, when there are two or more types of regions with a difference in L ^* of 50 or more, it is possible to visually recognize that the crystal pattern certainly exists.

In addition, the obtained titanium member exhibits the original color of titanium. That is, it exhibits a gray color without a specific tint, specifically an achromatic color. The original color of titanium can be confirmed from the difference of 10 or less in the R, G, and B values obtained by RGB measurement, as will be described later in Examples.

Further, the obtained titanium member has a Vickers hardness of HV240 or higher, preferably HV280 or higher. Specifically, the Vickers hardness is HV30 or more higher than that of the material titanium member. In addition, the resulting titanium member generally has a root-mean-square roughness Rq of about 3000 Å as determined by the scratch resistance measurement described in the Examples.

In the blasting step, the raw material titanium member containing pure titanium or a titanium alloy is blasted to form a rough surface, thereby obtaining a blasted titanium member. As pure titanium used for raw material titanium members, industrial pure titanium corresponding to JIS type 1, JIS type 2, JIS type 3 or JIS type 4 can be specifically mentioned. Specific examples of titanium alloys used for raw material titanium members include alpha alloys such as 5Al-2.5 and Sn1.5Al (JIS class 50). The shape of the raw material titanium member is not particularly limited as long as it is a shape suitable for the application. For example, when it is used for watch components such as cases and band pieces, it has the shape of such watch components.

Blasting is usually performed by spraying special media such as alumina or glass beads at high speed on metal products. It is possible to change the surface characteristics of metal products such as surface texture and touch, and to improve physical hardness, toughness, and residual compressive stress. When the special media collides with the metal at high speed, the growth of cracks is suppressed due to the refinement of crystals on the metal surface, the fatigue strength is improved due to the addition of compressive residual stress, and the surface becomes hard and scratch resistant. Such as, you can give the effect of increasing strength. It is possible to create various surface conditions depending on the media conditions and injection pressure conditions during blasting. In addition, various crystal patterns can be imparted by variously adjusting the heat treatment conditions in the first heating step and the second heating step, which will be described later. If only the heat treatment is performed to enlarge the crystals, the surface hardness usually decreases. On the other hand, by applying blasting treatment before heat treatment as in the first manufacturing method, the surface hardness can be maintained at a high level and a wide variety of crystal patterns can be imparted.

Specifically, sandblasting is suitably used as the blasting treatment. In this specification, blasting treatment also includes WPC treatment (registered trademark) (FPB (Fine Particle Bombarding)), which is a type of shot peening. This WPC treatment (registered trademark) is also preferably used.

In sandblasting, media materials include alumina, diamond sand, silica sand, glass, silicon carbide, titanium oxide, zirconia, and diamond. Among these, alumina and glass are preferred. In the WPC treatment (registered trademark), media materials include steel, stainless steel, glass, ceramics, indium lead, tin, silver, molybdenum disulfide, tungsten disulfide, boron nitride, and fluororesin. Of these, steel is preferred.

The discharge pressure is preferably 0.10 MPa or more and 0.5 MPa or less, since high hardness and uneven pattern can be realized in the obtained titanium member. If it is less than 0.10 MPa, the surface change due to blasting is small, and the degree of increase in hardness due to compressive stress may be small. If it exceeds 0.5 MPa, the compressive stress may increase excessively and the substrate may warp greatly. In addition, the media may not be removed due to being struck, and may form a mixture with titanium when crystallized.

In addition, conditions such as the amount of media to be ejected and the ejection time can be appropriately set.

The resulting blasted titanium member generally has a Vickers hardness of HV280 or higher. Generally, it becomes harder than the material titanium member by HV30 or more. Also, the blasted titanium member has at least one surface roughened by blasting.

FIG. 1 is a diagram for explaining a method of manufacturing a titanium member. As shown by the solid line in FIG. 1, in the first heating step, the blasted titanium member is heated under reduced pressure to a temperature T1 from room temperature (for example, 10° C. or higher and 30° C. or lower) to 835° C. or higher and 935° C. or lower (within the above range). The temperature is raised to the predetermined temperature T1) set in 1) and heated. Thus, it is desirable that the temperature T1 (heating start temperature, reached temperature 1) be in the range of 885° C.±50° C. at which the phase transitions from the α phase to the β phase. If the temperature T1 is less than 835°C, the crystal growth may not be so effective. Moreover, when the temperature T1 exceeds 950° C., both the visible amount of crystals and the crystal pattern may decrease.

Although the first heating step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less. Further, the heating time HT1 (heating time 1) in the first heating step is, specifically, the time required to reach a predetermined temperature T1 set within the above range from room temperature, for example, 30 minutes or more. 3 hours or less.

As shown by the solid line in FIG. 1, in the second heating step, the blasted titanium member that has undergone the first heating step is heated under reduced pressure from a temperature T1 to a temperature T2 of 950° C. or more and 1150° C. or less (within the above range The titanium member is obtained by raising the temperature to the set predetermined temperature T2) over a period of time HT2 of 30 minutes or more and 8 hours or less. Specifically, the time HT2 (heating time 2) is the time required for the predetermined temperature T1 set within the above range to reach the predetermined temperature T2 set within the above range. Time HT2 is the most important condition for producing crystal patterns. If the time HT2 is too short and the heating rate is too high, slippage due to phase transition occurs rapidly, which tends to make it difficult to form fine uneven structures and crystal patterns. Further, when the time HT2 exceeds 8 hours, no significant difference is observed in the obtained crystals. The temperature T2 (reaching temperature 2) is an important condition for controlling the crystal size. For example, the temperature is around 950° C. when the crystal size is to be reduced, and around 1150° C. when the crystal size is to be increased. If the temperature T2 is less than 950°C, the crystal tends to be too small. On the other hand, if the temperature T2 exceeds 1150° C., the crystals grow excessively and enlarge, and the crystal pattern may disappear.

The second heating step is performed under reduced pressure, preferably at a pressure of 8.0×10 ⁻³ Pa or less.

Usually, the heating rate S2 in the second heating step is lower than the heating rate S1 in the first heating step. The temperature increase rate S1 (° C./hour) is obtained by (temperature T1−room temperature)/heating time HT1, and the temperature increase rate S2 (° C./hour) is (temperature T2−temperature T1)/heating time HT2. Desired. If the heating rate S2 is too high, it tends to be difficult to form a crystal pattern.

In addition, the temperature increase rate in the first heating step and the second heating step may be constant or may be changed. Furthermore, the first heating step and the second heating step may have a so-called jagged heating pattern. In other words, the first heating step may be a step of raising the temperature as a whole while repeating temperature rise and fall within the range of room temperature to temperature T1 or less. Further, the second heating step may be a step of raising the temperature as a whole while repeating the temperature rise and fall within the range of temperature T1 or higher and temperature T2 or lower.

A cooling step is usually performed following the second heating step. In the cooling step, the titanium member obtained in the second heating step is cooled by lowering the temperature from the temperature T2 to a temperature lower than the temperature T2. It is preferably cooled to a temperature between room temperature and 150°C. The cooling rate in the cooling step is a condition for crystals that have transitioned to the β phase to return to the α phase, and is preferably as low as possible. No significant change in crystal pattern and crystal size is observed whether the crystal is cooled slowly or rapidly. However, in the case of rapid cooling, a serrated structure may appear at the crystal interface. Even if such a structure is formed, the mechanical properties hardly change, but the ductility may decrease.

In addition, the cooling rate in the cooling step may be constant or may be changed. A certain temperature may be held for a certain period of time during the cooling process. Also, the cooling step is performed under atmospheric pressure or under reduced pressure. When it is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

The first manufacturing method may further include a first holding step and a second holding step, as indicated by broken lines in FIG. Moreover, either one of the first holding step and the second holding step may be included.

Specifically, in the first manufacturing method, the blasted titanium member that has undergone the first heating step is further held under reduced pressure at a temperature T1 for a time KT1 of 30 minutes or more and 3 hours or less. A process may be included. In this case, the second heating step is a step of heating the blasted titanium member that has undergone the first holding step to obtain a titanium member. By providing the time KT1 (holding time 1), the entire blasted titanium member can be reliably brought to the temperature T1. Therefore, it becomes easier to control the formation of the crystal pattern.

Although the first holding step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

Further, specifically, the first manufacturing method further includes a second holding step of holding the titanium member that has undergone the second heating step under reduced pressure at a temperature T2 for a time KT2 of 30 minutes or more and 6 hours or less. may contain In this case, the cooling step is a step of cooling the titanium member that has undergone the second holding step from the temperature T2 to a temperature lower than the temperature T2. It is preferably cooled to a temperature between room temperature and 150°C. Time KT2 (holding time 2) can control the crystal size, crystal pattern, and surface state of the entire surface. For example, increasing the time KT2 can increase the crystal size.

Although the second holding step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

Thus, in the titanium member obtained through the blasting process, a fine uneven pattern is formed on the surface of the rough surface.

[Second Method for Manufacturing Titanium Member]
A second titanium member manufacturing method (second manufacturing method) includes a first heating step and a second heating step. According to the second manufacturing method, a titanium member having an uneven pattern on its surface is obtained. In addition, the resulting titanium member exhibits the original color of titanium, and has a Vickers hardness higher than that of the starting titanium member by HV30 or more. The details of the obtained titanium member are the same as those described in the first manufacturing method.

FIG. 2 is a diagram for explaining a method of manufacturing a titanium member. As shown by the solid line in FIG. 2, in the first heating step, a raw material titanium member containing pure titanium or a titanium alloy is heated from room temperature (for example, 10° C. or higher and 30° C. or lower) to a temperature of 835° C. or higher and 935° C. or lower under reduced pressure. The temperature is raised to T1 (predetermined temperature T1 set within the above range) and heated. Details of the raw material titanium member containing pure titanium or a titanium alloy are the same as those described in the first manufacturing method. Thus, it is desirable that the temperature T1 (heating start temperature, reached temperature 1) be in the range of 885° C.±50° C. at which the phase transitions from the α phase to the β phase. If the temperature T1 is less than 835°C, the crystal growth may not be so effective. Moreover, when the temperature T1 exceeds 950° C., both the visible amount of crystals and the crystal pattern may decrease.

Although the first heating step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less. Further, the heating time HT1 (heating time 1) in the first heating step is, specifically, the time required to reach a predetermined temperature T1 set within the above range from room temperature, for example, 30 minutes or more. 3 hours or less.

As shown by the solid line in FIG. 2, in the second heating step, the raw material titanium member that has undergone the first heating step is heated under reduced pressure from a temperature T1 to a temperature T2 of 950° C. or more and 1150° C. or less (set within the above range). It is heated to a predetermined temperature T2) over a period of time HT2 of 30 minutes to 8 hours to obtain a titanium member. Specifically, the time HT2 (heating time 2) is the time required for the predetermined temperature T1 set within the above range to reach the predetermined temperature T2 set within the above range. Time HT2 is the most important condition for producing crystal patterns. If the time HT2 is too short and the heating rate is too high, slippage due to phase transition occurs rapidly, which tends to make it difficult to form fine uneven structures and crystal patterns. Further, when the time HT2 exceeds 8 hours, no significant difference is observed in the obtained crystals. The temperature T2 (reaching temperature 2) is an important condition for controlling the crystal size. For example, the temperature is around 950° C. when the crystal size is to be reduced, and around 1150° C. when the crystal size is to be increased. If the temperature T2 is less than 950°C, the crystal tends to be too small. On the other hand, if the temperature T2 exceeds 1150° C., the crystals grow excessively and enlarge, and the crystal pattern may disappear.

The second heating step is performed under reduced pressure, preferably at a pressure of 8.0×10 ⁻³ Pa or less.

In the second heating step, nitrogen gas or water vapor is introduced so that the pressure is 6.7 Pa or more and 67 Pa or less for 30 minutes or more and 8 hours or less during the time HT2. That is, nitrogen gas or water vapor is introduced for at least part of the time HT2. By introducing nitrogen gas or water vapor in this way, the resulting titanium member can have a high hardness and an uneven pattern. Furthermore, the resulting titanium member exhibits the inherent color of titanium. In addition, in the second heating step, the pressure is preferably 8.0×10 ⁻³ Pa or less when nitrogen gas or water vapor is not introduced.

Regarding the introduction of nitrogen gas or water vapor, it is preferable to appropriately adjust the introduction amount and introduction time. For example, when the introduction amount is large, the introduction time may be shortened, and when the introduction amount is small, the introduction time may be lengthened. More specifically, in the case of 6.7 Pa, it may be about 5 hours, and in the case of 67 Pa, it may be about 0.5 hours.

Moreover, water vapor may introduce argon gas as a carrier.

Usually, the heating rate S2 in the second heating step is lower than the heating rate S1 in the first heating step. The temperature increase rate S1 (° C./hour) is obtained by (temperature T1−room temperature)/heating time HT1, and the temperature increase rate S2 (° C./hour) is (temperature T2−temperature T1)/heating time HT2. Desired. If the heating rate S2 is too high, it tends to be difficult to form a crystal pattern.

The details of the heating rate in the first heating step and the second heating step are the same as those described in the first manufacturing method. Moreover, following the second heating step, a cooling step is usually performed. The details of the cooling step are the same as those described in the first manufacturing method.

The second manufacturing method may further include a first holding step and a second holding step. Moreover, either one of the first holding step and the second holding step may be included.

Specifically, the second manufacturing method further includes a first holding step of holding the raw titanium member that has undergone the first heating step under reduced pressure at a temperature T1 for a time KT1 of 30 minutes or more and 3 hours or less. may contain. In this case, the second heating step is a step of heating the material titanium member that has undergone the first holding step to obtain a titanium member. By providing the time KT1 (holding time 1), the entire raw material titanium member can be reliably brought to the temperature T1. Therefore, it becomes easier to control the formation of the crystal pattern.

Although the first holding step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

Further, specifically, the second manufacturing method further includes a second holding step of holding the titanium member that has undergone the second heating step under reduced pressure at a temperature T2 for a time KT2 of 30 minutes or more and 6 hours or less. may contain In this case, the cooling step is a step of cooling the titanium member that has undergone the second holding step from the temperature T2 to a temperature lower than the temperature T2. It is preferably cooled to a temperature between room temperature and 150°C. Time KT2 (holding time 2) can control the crystal size, crystal pattern, and surface state of the entire surface. For example, increasing the time KT2 can increase the crystal size.

Although the second holding step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

[Third Method for Manufacturing Titanium Member]
A third titanium member manufacturing method (third manufacturing method) includes a first heating step, a second heating step, and a second holding step. According to the third manufacturing method, a titanium member having an uneven pattern on its surface is obtained. In addition, the resulting titanium member exhibits the original color of titanium, and has a Vickers hardness higher than that of the starting titanium member by HV30 or more. The details of the obtained titanium member are the same as those described in the first manufacturing method.

FIG. 2 is a diagram for explaining a method of manufacturing a titanium member. As indicated by the dashed line in FIG. 2, in the first heating step, a raw material titanium member containing pure titanium or a titanium alloy is heated from room temperature (for example, 10° C. or higher and 30° C. or lower) to a temperature of 835° C. or higher and 935° C. or lower under reduced pressure. The temperature is raised to T1 (predetermined temperature T1 set within the above range) and heated. Details of the raw material titanium member containing pure titanium or a titanium alloy are the same as those described in the first manufacturing method. Thus, it is desirable that the temperature T1 (heating start temperature, reached temperature 1) be in the range of 885° C.±50° C. at which the phase transitions from the α phase to the β phase. If the temperature T1 is less than 835°C, the crystal growth may not be so effective. Moreover, when the temperature T1 exceeds 950° C., both the visible amount of crystals and the crystal pattern may decrease.

Although the first heating step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less. Further, the heating time HT1 (heating time 1) in the first heating step is, specifically, the time required to reach a predetermined temperature T1 set within the above range from room temperature, for example, 30 minutes or more. 3 hours or less.

As shown by the dashed line in FIG. 2, in the second heating step, the raw material titanium member that has undergone the first heating step is heated under reduced pressure from temperature T1 to temperature T2 (set within the above range) from temperature T1 to temperature T2 (set within the above range). It is heated to a predetermined temperature T2) over a period of time HT2 of 30 minutes to 8 hours. Specifically, the time HT2 (heating time 2) is the time required for the predetermined temperature T1 set within the above range to reach the predetermined temperature T2 set within the above range. Time HT2 is the most important condition for producing crystal patterns. If the time HT2 is too short and the heating rate is too high, slippage due to phase transition occurs rapidly, which tends to make it difficult to form fine uneven structures and crystal patterns. Further, when the time HT2 exceeds 8 hours, no significant difference is observed in the obtained crystals. The temperature T2 (reaching temperature 2) is an important condition for controlling the crystal size. For example, the temperature is around 950° C. when the crystal size is to be reduced, and around 1150° C. when the crystal size is to be increased. If the temperature T2 is less than 950°C, the crystal tends to be too small. On the other hand, if the temperature T2 exceeds 1150° C., the crystals grow excessively and enlarge, and the crystal pattern may disappear.

The second heating step is performed under reduced pressure, preferably at a pressure of 8.0×10 ⁻³ Pa or less.

Usually, the heating rate S2 in the second heating step is lower than the heating rate S1 in the first heating step. The temperature increase rate S1 (° C./hour) is obtained by (temperature T1−room temperature)/heating time HT1, and the temperature increase rate S2 (° C./hour) is (temperature T2−temperature T1)/heating time HT2. Desired. If the heating rate S2 is too high, it tends to be difficult to form a crystal pattern.

As indicated by the dashed line in FIG. 2, in the second holding step, the raw material titanium member that has undergone the second heating step is held under reduced pressure at a temperature T2 for a time KT2 (holding time 2) of 30 minutes or more and 6 hours or less. to obtain a titanium member.

In the second holding step, nitrogen gas or water vapor is introduced so that the pressure is 6.7 Pa or more and 67 Pa or less for 10 minutes or more and 5 hours or less within the time KT2. That is, nitrogen gas or water vapor is introduced during at least part of the time KT2. By introducing nitrogen gas or water vapor in this way, the resulting titanium member can have a high hardness and an uneven pattern. Furthermore, the resulting titanium member exhibits the inherent color of titanium. In addition, in the second holding step, the pressure is preferably 8.0×10 ⁻³ Pa or less when nitrogen gas or water vapor is not introduced.

Regarding the introduction of nitrogen gas or water vapor, it is preferable to appropriately adjust the introduction amount, the introduction time, and the temperature T2, which is the heating temperature in the second holding step. For example, when the introduction amount is large, the introduction time may be shortened or the heating temperature may be lowered, and when the introduction amount is small, the introduction time may be lengthened or the heating temperature may be raised. More specifically, in the case of 6.7 Pa, it may be about 5 hours, and in the case of 67 Pa, it may be about 0.5 hours.

Moreover, water vapor may introduce argon gas as a carrier.

The details of the heating rate in the first heating step and the second heating step are the same as those described in the first manufacturing method. Moreover, following the second holding step, a cooling step is usually performed. The details of the cooling step are the same as those described in the first manufacturing method.

The third manufacturing method may further include a first holding step.

Specifically, the third manufacturing method further includes a first holding step of holding the raw material titanium member that has undergone the first heating step under reduced pressure at temperature T1 for a time KT1 of 30 minutes or more and 3 hours or less. You can stay. In this case, the second heating step is a step of heating the raw material titanium member that has undergone the first holding step. By providing the time KT1 (holding time 1), the entire raw material titanium member can be reliably brought to the temperature T1. Therefore, it becomes easier to control the formation of the crystal pattern.

Although the first holding step is performed under reduced pressure, the pressure is preferably 8.0×10 ⁻³ Pa or less.

<Manufacturing method of functional titanium member>
Next, a method for manufacturing a functional titanium member will be described. The method for producing a functional titanium member includes, for example, a functional layer forming step of forming a functional layer on the titanium member obtained by the first to third production methods to obtain a functional titanium member. including. That is, the method for producing a functional titanium member is a method for producing a functional titanium member including a titanium member containing pure titanium or a titanium alloy and a functional layer provided on the titanium member. According to the method for producing a functional titanium member, a functional titanium member having an uneven pattern on the surface and a Vickers hardness of HV500 or higher can be obtained. Specifically, the titanium member has an uneven pattern on its surface, and the functional layer has an uneven pattern on its surface derived from the uneven pattern of the titanium member. The details of the titanium member included in the functional titanium member, ie, the details of the uneven pattern, color, Vickers hardness, etc., are the same as those described in the first manufacturing method. Further, the details of the concave-convex pattern of the functional titanium member are the same as those described in the first manufacturing method.

The functional layer has, for example, a curing function. In this case, the functional titanium member is hardened according to the hardness of the functional layer. That is, the functional titanium member has a Vickers hardness of HV500 or higher. Moreover, the functional layer may have a coloring function as well as a curing function. In this case, the functional titanium member is hardened according to the hardness of the functional layer and exhibits a color according to the color of the functional layer. The titanium member does not have crystals such as white, blue, and pink like the titanium product of Patent Document 1, but has the original color of titanium. Therefore, even in the functional titanium member, crystals such as white, blue, and pink derived from the titanium product do not appear, and the color corresponding to the color of the functional layer is exhibited.

The functional layer specifically contains a metal or semiconductor combined with at least one element of carbon, nitrogen and oxygen. Examples of the metal or semiconductor include titanium (Ti), tungsten (W), tantalum (Ta), zirconium (Zr), hafnium (Hf), niobium (Nb), boron (B), and silicon (Si). For example, when the metal or semiconductor is titanium, the functional layer is titanium carbide, which is titanium bonded with carbon, titanium nitride, which is titanium bonded with nitrogen, titanium nitrocarbide, which is titanium bonded with carbon and nitrogen, and the like. including. The same applies to other metals or semiconductors mentioned above. As the functional layer, more specifically, metal nitride films such as TiN, ZrN, and HfN exhibiting gold color, and metal carbonitrides such as TiCN, ZrCN, HfCN, TiON, ZrON, and HfON exhibiting pink to brown color. and metal oxynitride films, and gray-colored metal carbide films such as TiC. In addition, the film may contain elements other than those described above as long as the object of the embodiment is not impaired. Alternatively, the functional layer contains black diamond-like carbon (DLC). In order to exhibit an excellent hardening function, a compound film of metal and non-metal having higher hardness is preferably used.

The functional layer may be one layer or a laminate of two or more layers.

The thickness of the functional layer is preferably 0.02 μm or more and 3.0 μm or less, more preferably 0.02 μm or more and 2.0 μm or less so that the crystal pattern appears. When the functional layer is formed following the unevenness forming the pattern on the titanium member and has the same unevenness, a crystal pattern appears. When the thickness of the functional layer is within the above range, a crystal pattern usually appears, which is preferable.

In the functional layer forming step, for example, a layer containing a metal or semiconductor combined with at least one element of carbon, nitrogen and oxygen or a layer containing diamond-like carbon is formed as the functional layer. Specifically, the functional layer can be formed by dry film formation such as a sputtering method, a CVD method, or an ion plating method.

In addition, the manufacturing method of the functional titanium member may further include an adhesion layer forming step. That is, it includes an adhesion layer forming step of forming an adhesion layer on the titanium member obtained by the first to third production methods, and the functional layer forming step includes the adhesion layer forming step. may be a step of forming a functional layer on the titanium member having the above to obtain a functional titanium member. The adhesion layer is a film of titanium, silicon, or the like.

Moreover, the method for producing a functional titanium member may further include a colored layer forming step. That is, it may further include a colored layer forming step of forming a colored layer on the obtained functional titanium member. For example, as a laminate, a TiC film exhibiting a hardening function may be formed on a titanium member, and then a white noble metal film such as Pt, Pd, Rh, etc. exhibiting a coloring function may be further formed.

When the adhesion layer or the colored layer is formed, the total thickness of the adhesion layer, the functional layer and the colored layer is preferably 0.02 μm or more and 3.0 μm or less so that the crystal pattern appears. The adhesion layer forming step and the colored layer forming step can be formed by a sputtering method, a CVD method, an ion plating method, or the like.

As described above, the titanium members obtained by the first to third manufacturing methods have high hardness, have the original color of titanium, and have a fine uneven pattern on the surface. In addition, the functional titanium member obtained by the method for producing a functional titanium member described above has a high degree of hardness and a fine uneven pattern on the surface.

By the way, in order to create a crystal pattern unique to titanium, it is necessary to apply a temperature higher than the β-phase transition temperature (885°C). When a temperature higher than the phase transition temperature is applied, the crystal structure undergoes phase conversion from the α phase to the α + β phase, and a unique pattern appears as the crystal grows. However, when the crystal changes from the α phase to the α + β phase, the Young's modulus decreases and the hardness decreases, and inhomogeneous diffraction crystals may appear due to the growth of needle crystals due to crystal slippage accompanying the phase transition. When titanium is used as an ornament, this reduction in hardness is a factor in reducing scratch resistance. Incidentally, according to the vacuum carburizing treatment, the hardness can be increased by reacting gases such as oxygen and nitrogen during the heat treatment. However, this method tends to cause coloring and cannot impart a unique pattern. On the other hand, in the manufacturing method described above, the reduction in hardness due to crystal transformation can be suppressed by using blasting or providing a specific gas introduction step. Furthermore, a unique crystal pattern can be deposited on titanium to improve the design.

<Other functional titanium members and manufacturing methods thereof>
The functional titanium members of other embodiments have high hardness, exhibit a highly decorative blue color, and have a fine uneven pattern on the surface. It is the same as the functional titanium member except that it exhibits a blue color that is excellent in decorativeness. Specifically, as described above, the uneven pattern of the titanium member is formed by, for example, small pieces lined up in a mosaic pattern, but in other embodiments, some of the small pieces exhibit a blue color. This blue color can also be visually recognized in the functional titanium member provided with the functional layer. In the present specification, the term "excellent in decorativeness" means that the material looks beautifully shining in a glittering and mother-of-pearl style.

In the titanium member, small pieces showing blue color are considered to have irregularities of a specific height regularly arranged at a specific pitch. It is presumed that the specific concave-convex structure and pitch interval are factors that strongly reflect blue light, and that blue color is exhibited. This uneven structure and pitch interval can be confirmed by AFM measurement. Since blue color develops according to the principle described above, sparkling blue color can be visually recognized even when a functional layer is provided.

Functional titanium members of other embodiments are obtained, for example, by the following manufacturing method. That is, in another embodiment of the method for producing a functional titanium member, a raw material titanium member containing pure titanium or a titanium alloy is heated from room temperature to a temperature T1 of 835° C. or higher and 935° C. or lower under reduced pressure. After the first heating step and the first heating step, the raw material titanium member is heated under reduced pressure from a temperature T1 to a temperature T2 of 950° C. or more and 1150° C. or less for a time HT2 of 30 minutes or more and 8 hours or less. A second heating step of heating to obtain a titanium member, and a functional layer forming step of forming a functional layer on the titanium member obtained in the second heating step to obtain a functional titanium member. including. Here, the titanium member has an uneven pattern on the surface, the functional layer has an uneven pattern on the surface derived from the uneven pattern of the titanium member, and the functional titanium member has a Vickers hardness. HV500 or more. Thus, the production of the titanium member is the same as the first production method, except that the blasting process is not performed. Moreover, the functional layer forming step is the same as the method for manufacturing the functional titanium member of the above-described embodiment.

According to this method for producing a functional titanium member, a titanium member having a high hardness, a highly decorative blue color, and a fine uneven pattern on the surface can be obtained.

As described above, the present invention relates to the following.
[1] A titanium member containing pure titanium or a titanium alloy, wherein at least one surface is rough, the surface of the rough surface has an uneven pattern, and has a Vickers hardness of HV500 or more.
[2] The titanium member according to [1], having a functional layer provided on the titanium member, wherein the functional layer has an uneven pattern derived from the uneven pattern.
[3] The titanium member according to [2], wherein the functional layer is a layer containing a metal or semiconductor combined with at least one element selected from carbon, nitrogen and oxygen, or a layer containing diamond-like carbon.
[4] A blasting step of performing a blasting treatment to form a rough surface on the surface of a raw titanium member containing pure titanium or a titanium alloy to obtain a blasted titanium member, and reducing the pressure of the blasted titanium member. a first heating step in which the temperature is raised from room temperature to a temperature T1 of 835° C. or higher and 935° C. or lower and heated, and the blasted titanium member that has undergone the first heating step is heated from the temperature T1 under reduced pressure, a second heating step of heating to a temperature T2 of 950° C. or more and 1150° C. or less over a period of time HT2 of 30 minutes or more and 8 hours or less to obtain a titanium member; A method for manufacturing a titanium member, which forms an uneven pattern.
[5] Further comprising a functional layer forming step of forming a functional layer on the titanium member, wherein the functional layer forming step forms an uneven pattern derived from the uneven pattern of the titanium member on the surface. The method for manufacturing a titanium member according to [4].
[6] The functional layer forming step forms, as the functional layer, a layer containing a metal or semiconductor bonded to at least one element selected from carbon, nitrogen and oxygen, or a layer containing diamond-like carbon; [5] A method for manufacturing the titanium member according to 1.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[Example]
<Analysis method and evaluation method>
(Hardness measurement of pure titanium plate material)
The hardness of the pure titanium plate material was measured using a micro-indentation hardness tester (manufactured by FISCHER, H100) with a load of 5 mN.
(Hardness measurement of titanium member)
The hardness of the titanium member was measured using a micro-indentation hardness tester (manufactured by FISCHER, H100).
Blasting or introduction of nitrogen gas or water vapor significantly changes the state of the surface and affects the hardness measurement results from the surface. For this reason, a focused ion beam (FIB) apparatus was used to cut perpendicularly to the surface, and the cut surfaces were polished and measured. The hardness in the vicinity of the surface was measured at a position of 10 μm±5 μm in the depth direction from the outermost surface under a load of 5 mN at intervals of 100 μm or more in the horizontal direction. The measurement was performed at 12 points, and the average was used as the hardness of the sample.

(Hardness measurement of hard film)
The hardness of the hard film was measured using a micro-indentation hardness tester (manufactured by FISCHER, H100) with a load of 5 mN. The hardness measurement of the hard film was carried out using the Si wafer included in the film formation.

(Crystallinity measurement)
Amartlab manufactured by Rigaku Corporation was used to measure the crystal orientation. Measurement conditions were performed under the following conditions.
Overall qualitative analysis conditions X-ray output: 40 kV, 30 mA, scan axis: 2θ/θ, scan range: 5° to 120°, 0.02 step, solar slit: 5 deg, longitudinal limit slit: 15 mm
Micropart qualitative analysis conditions X-ray output: 40 kV, 30 mA, scan axis: 2θ/θ, scan range: 5° to 120°, 0.02 step, solar slit: 2.5 deg, longitudinal limit slit: 15 mm

(Crystal surface observation)
• RGB measurement A VHX-5000 microscope manufactured by Keyence Corporation was used for surface observation of the crystal. The measurement was carried out using an epi-illumination method of white light ring illumination at a brightness of 70, a gain of 30, and a magnification of 20 times. Color tone measurement was performed by RGB measurement of the same device. For crystal grains that appear to have different color tones on a microscope, 8 or more RGB measurements were performed for each different color tone, and the average values of R, G, and B were calculated. For each different color tone, a value obtained by subtracting the minimum average value of R, G, and B from the maximum average value of R, G, and B was used to judge the tint. For example, in a certain color tone, if the average value of R is 100, the average value of G is 100, and the average value of B is 120, 120−100=20.
Color Tone Judgment When the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B was 10 or less, it was judged that there was no color tone such as blue or pink. In other words, it is white, gray, and black (achromatic), and it can be confirmed that it does not look like mother-of-pearl work and has the original metallic color of titanium.
Determination of Concavo-convex Pattern Luminance L ^* was calculated from the average values of R, G, and B for each different color tone using the following formula. A difference of 50 or more in L ^* between different color tones can be said to correspond to the presence of a crystal pattern (uneven pattern). This is because if a crystal pattern exists and can be visually recognized, at least the appearance (brightness) is different.
L ^* =0.299×R+0.587×G+0.114×B (maximum luminance value: 255)

(Composite hardness calculation)
The composite hardness _Hc of the manufactured titanium member and functional titanium member was calculated. Specifically, the composite hardness _Hc was calculated using the following formula (1).

Ｈ_f：薄膜硬度、Ｈ_s：基材硬度、Ｅ_f：薄膜ヤング率、ｎ＝２、ｔ：薄膜の膜厚、ｄ：ビッカース圧痕サイズ、θ：ビッカース圧子の対面角度の１／２＝６８度。

H _f : thin film hardness, H _s : substrate hardness, E _f : thin film Young's modulus, n=2, t: thickness of thin film, d: Vickers indentation size, θ: ½ of facing angle of Vickers indenter=68 Every time.

(Measurement of scratch resistance)
The scratch resistance test was performed as follows. Abrasive paper in which alumina particles were uniformly dispersed was brought into contact with the test sample under a constant load, and the test sample was rubbed a constant number of times to generate scratches. The scratched surface of the test sample was scanned in the direction perpendicular to the scratch to measure the surface roughness, and the root-mean-square roughness was obtained. The scratch resistance was evaluated from this root-mean-square roughness. The larger the number of scratches and the deeper the scratches, the larger the mean square roughness value. becomes smaller. From this, the scratch resistance can be evaluated numerically.

(Film thickness measurement)
In the film thickness measurement, the masked Si wafer was introduced into the film forming apparatus together with the base material, the mask was removed after film formation, and the step between the masked and unmasked portions was measured.

[Example 1-1]
FIG. 3 is a schematic cross-sectional view showing the structure of the functional titanium member 10 of Example 1-1. In Example 1-1, JIS-specified pure titanium was sandblasted and then subjected to vacuum heat treatment to obtain a titanium member 11 having crystal patterns deposited thereon. A hardened layer (functional layer) 12 made of TiC was formed on this titanium member 11 to obtain a functional titanium member 10 . In the schematic cross-sectional view, the uneven pattern on the titanium member and the functional titanium member is omitted.

A #800-polished JIS class 2 pure titanium plate material was used for the production of the titanium member 11 . A WA Fujirandom #46 media (alumina media) is sprayed onto the pure titanium plate at a discharge pressure of 0.4 MPa using a pneumatic blaster sandblasting device manufactured by Fuji Seisakusho Co., Ltd. to form a blasted titanium substrate. Obtained. Subsequently, using a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of −4 Pa, the blasted titanium substrate is heated to a temperature range equal to or higher than the phase transition temperature, A titanium member 11 was produced by depositing crystals.

Subsequently, the titanium member 11 was set in an ion plating apparatus capable of adjusting the amount of reaction gas, and a hardened layer (TiC hard film) 12 was formed on the titanium member 11 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 10 was produced.

In Example 1-1, heat treatment conditions 1 and 2 shown in Table 1 were applied after setting the blasted titanium substrate in a vacuum heat treatment furnace and evacuating the furnace to 9.0E-4Pa. That is, the temperature reached 1, the temperature rising time 1, the holding time 1, the reaching temperature 2, the temperature rising time 2, the holding time 2, and the cooling time to lower the temperature to 150° C. were carried out as shown in Table 1.

FIG. 4 is a microscope image of a JIS type 2 pure titanium plate material that has been polished to #800. 5 to 7 show microscope images of the titanium surface shape during the production process of the titanium member 11. FIG. That is, FIG. 5 is a microscope image of the blasted titanium substrate. 6 is a microscope image of the titanium member 11 obtained under the heat treatment condition 1. FIG. FIG. 7 is a microscope image of the titanium member 11 obtained under the heat treatment condition 2. FIG. The pure titanium plate material is glossy and exhibits a smooth surface that reflects the ring illumination light used for photographing. When the pure titanium plate material is sandblasted, the surface is scraped as a whole and changes to a satin surface with irregularities. The hardness of the blasted titanium substrate increased to HV302 compared to HV240 of pure titanium due to the increase in internal stress due to surface scraping and the application of compressive residual stress due to high-speed hitting of the media against the surface. .

It is believed that the increase in hardness of the blasted titanium substrate is also caused by changes in the crystal structure. FIG. 8 is a diagram for explaining the crystallinity of the pure titanium plate material, the blasted titanium substrate, and the titanium member 11. FIG. Crystals of pure titanium usually form an α phase having an hcp structure. As shown in FIG. 8, it exhibits a crystal structure oriented mainly in the [100] plane around 35°, the [002] plane around 39°, and the [101] plane around 41°. It can be seen that the blast treatment results in a crystal structure preferentially oriented in the [101] plane near 41°. This is a crystal change accompanying an increase in residual compressive stress due to blasting, and this crystal change is presumed to be one of the factors for the increase in hardness.

By heating the titanium member 11 obtained under the heat treatment condition 1 at 1050° C. for 3 hours, titanium crystals precipitated on the entire surface, forming a tasteful pattern like Japanese paper. The hardness of the titanium member 11 obtained under heat treatment condition 1 is HV292, which is slightly lower than that of the blasted titanium substrate but higher than that of the pure titanium plate. In addition, it was found that the crystals of the titanium member 11 preferentially grow [101] around 41° compared to the blasted titanium substrate. This change in crystal orientation is a clear proof that crystals have grown and a crystal pattern has appeared on the entire titanium base material. It is speculated that the difference in preferred orientation from pure titanium sheet material contributes to the increase in hardness due to compressive residual stress. Also, the titanium member 11 obtained under the heat treatment condition 2 was heated at 1100° C. for 3 hours, and a crystal pattern similar to that of the heat treatment condition 1 was precipitated. The crystal size was larger than that of heat treatment condition 1. It was thought that the higher the temperature, the faster the crystal growth and the larger the crystal size obtained.

The hardened layer (TiC hard film) 12 is formed by setting the titanium member 11 in an ion plating apparatus, evacuating the titanium member 11 to 3.0E-3Pa, and then adding CH ₄ gas as a reaction gas while evaporating the titanium film material. and made. The hardened layer 12 had a film hardness of HV1100 and a film thickness of 1.0 μm. The color tone of the TiC hard film was gray like that of pure titanium, and the color tone of the functional titanium member 10 was gray.

Even when the hardened layer 12 was formed on the titanium member 11, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the cured layer 12 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 12, the composite hardness of the functional titanium member 10 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 10, since the hardened layer 12 is formed on the titanium member 11 with good adhesion, scratch resistance that can withstand the actual use environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 10 having the hardened layer 12 is significantly improved. Table 2 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 11 produced under the heat treatment condition 1 and the functional titanium member 10 produced using this. The functional titanium member 10 exhibited approximately four times the scratch resistance as compared with the titanium member 11 . By forming the hardened layer 12, while maintaining the unique crystal pattern of titanium, scratch resistance that can withstand actual use was obtained. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

Regarding the color tone of the titanium member 11 obtained in Example 1-1, the average values of R, G, and B in the bright portion were 235, 231, and 235, respectively, and the luminance L ^* was 232 (maximum 255 ). Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 4, and it can be seen that the color is neutral gray. The average values of R, G, and B in the dark portion were 161, 161, and 160, respectively, and the luminance L ^* was 161 (maximum 255). Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 1, and it can be seen that the color is neutral gray. The difference in brightness between a portion that looks bright and a portion that looks dark is 72, which is large. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

[Example 1-2]
FIG. 9 is a schematic cross-sectional view showing the structure of the functional titanium member 20 of Example 1-2. In Example 1-2, vacuum heat treatment was performed on JIS-defined pure titanium to obtain a titanium member 21 in which a crystal pattern was precipitated. A hardened layer (functional layer) 22 made of TiC was formed on this titanium member 21 to obtain a functional titanium member 20 .

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 21 . Using a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of −4 Pa, the pure titanium plate material is heated to a temperature range equal to or higher than the phase transition temperature to precipitate crystals. A titanium member 21 was produced.

Subsequently, the titanium member 21 is set in an ion plating apparatus capable of adjusting the amount of reaction gas, and a hardened layer (TiC hard film) 22 is formed on the titanium member 21 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 20 was produced.

In Example 1-2, the pure titanium plate material was placed in a vacuum heat treatment furnace, and heat treatment conditions 3 shown in Table 3 were applied after exhausting the atmosphere to 9.0E-4Pa. That is, it was carried out as shown in Table 3 with respect to reaching temperature 1, heating time 1, holding time 1, reaching temperature 2, heating time 2, holding time 2, and cooling time to lower the temperature to 150°C.

FIG. 10 shows a microscope image of the titanium surface profile during the production process of the titanium member 21 . 10 is a microscope image of the titanium member 21 obtained under the heat treatment condition 3. FIG. In the titanium member 21 obtained under heat treatment condition 3, blue, white, and black crystals are sparsely observed on the titanium surface. The hardness of the titanium member 21 obtained under heat treatment condition 3 was HV219, which was slightly lower than that of the pure titanium plate material.

FIG. 11 is a diagram for explaining the crystallinity of the pure titanium plate material, the blue crystal portion, the white crystal portion, and the black crystal portion. As shown in FIG. 11, in the titanium member 21, the crystal of the blue crystal portion exhibited a crystal structure in which the (103) plane was preferentially oriented near 71°. In addition, crystals in the white crystal part exhibited a crystal structure preferentially oriented to the (102) plane near 53° and the (200) plane attributed to the β crystal near 56°. In addition, the crystals of the black crystal portion exhibited a crystal structure in which the (102) plane near 53° and the (110) plane near 63° were preferentially oriented. It is believed that the change in the crystal structure brought about a difference in strength parameters such as Young's modulus and reduced the hardness of the titanium member 21 . Furthermore, the β-crystal appearing around 56° has a larger mobility of dislocations responsible for deformation than the α-crystal, and is soft. For this reason, it is considered that the hardness of the titanium member 21 is lower than that of the pure titanium plate.

The hardened layer (TiC hard film) 22 is formed by setting the titanium member 21 in an ion plating apparatus, evacuating the titanium member 21 to 3.0E-3Pa, and adding CH ₄ gas as a reaction gas while evaporating the titanium film material. and made. The hardened layer 22 had a film hardness of HV 1100 and a film thickness of 1.0 μm. The color tone of the TiC hard film was gray similar to that of pure titanium except for the blue crystal portion, white crystal portion and black crystal portion. Further, the color tone of the functional titanium member 20 was gray in portions other than the blue crystal portion, the white crystal portion, and the black crystal portion.

Even when the hardened layer 22 was formed on the titanium member 21, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the hardened layer 22 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 22, the composite hardness of the functional titanium member 20 is remarkably improved. In the functional titanium member 20, since the hardened layer 22 is formed on the titanium member 21 with good adhesion, scratch resistance that can withstand the actual use environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 20 having the hard film 22 formed thereon is remarkably improved. Table 4 shows the measurement results of the scratch resistance performance of the titanium member 21 and the functional titanium member 20 produced under heat treatment condition 3. For comparison, the calculated values and measurement results of the composite hardness of a pure titanium plate material and a hard film-treated pure titanium plate material obtained by applying a hard film treatment to a pure titanium plate material are also shown. The functional titanium member 20 exhibited approximately four times the scratch resistance as compared with the titanium member 21 . However, compared with the functional titanium member 10 of Example 1-1, the scratch resistance was lowered by about 12%. Furthermore, it was 5% lower than that of the hard-film-treated pure titanium plate material. This is probably because the base material hardness of the titanium member 21 is lower than that of the titanium member 11 and the pure titanium plate material of Example 1-1.

As for the color tone of the titanium member 21 obtained in Example 1-2, the average values of R, G, and B were 108, 113, and 219, respectively, and the luminance L ^* was 122 in the portion that looked blue. Among R, G, and B, since B is higher than R and G by 100 or more, this crystal phase is visually recognized as blue. The average values of R, G, and B in the portion that looked white were 201, 204, and 201, respectively, and the luminance L ^* was 202. The value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 3, and it can be seen that the color is bright gray with no tint. The average values of R, G, and B in the black portion were 43, 41, and 45, respectively, and the luminance L ^* was 42. The value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 4, and it can be seen that the color is a dull dark gray color. The luminance difference between the blue portion, the white portion, and the black portion is as large as 50 or more. From this, it can be seen that there is a clear crystal pattern on the substrate. In particular, only the B value of the blue portion is higher than 100, indicating that the crystal phase exhibits a strong blue color.

[Example 2]
FIG. 12 is a schematic cross-sectional view showing the structure of the functional titanium member 30 of Example 2. FIG. In Example 2, JIS-specified pure titanium was sandblasted and then subjected to vacuum heat treatment to obtain a titanium member 31 having crystal patterns deposited thereon. A hardened layer (functional layer) 32 made of DLC was formed on this titanium member 31 to obtain a functional titanium member 30 . The cured layer 32 made of DLC has a function of coloring as well as curing.

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 31 . A media of glass beads #300 was sprayed onto the pure titanium plate material using a Pneumatic Blaster sandblasting apparatus manufactured by Fuji Seisakusho Co., Ltd. at a discharge pressure of 0.4 MPa to obtain a blasted titanium substrate. Subsequently, using a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of −4 Pa, the blasted titanium substrate is heated to a temperature range equal to or higher than the phase transition temperature, A titanium member 31 was produced by depositing crystals.

Subsequently, a titanium member 31 was set in a CVD apparatus, and a hardened layer (DLC hard film) 32 was formed on the titanium member 31 using benzene gas as a reaction gas, thereby producing a functional titanium member 30 .

Example 2 was carried out under heat treatment conditions 4 and 5 shown in Table 5 after setting the blasted titanium substrate in a vacuum heat treatment furnace and evacuating to 9.0E-4Pa. That is, the temperature reached 1, the temperature rising time 1, the holding time 1, the reaching temperature 2, the temperature rising time 2, the holding time 2, and the cooling time to lower the temperature to 150° C. were carried out as shown in Table 5.

13 to 15 show microscope images of the titanium surface profile during the fabrication process of the titanium member 31. FIG. That is, FIG. 13 is a microscope image of the blasted titanium substrate. FIG. 14 is a microscope image of the titanium member 31 obtained under the heat treatment condition 4. FIG. FIG. 15 is a microscope image of the titanium member 31 obtained under heat treatment condition 5. FIG. When a pure titanium plate material is sandblasted, the surface is scraped as a whole and changes to a satin surface with irregularities. The hardness of the blasted titanium substrate increased to HV316 from HV240 of pure titanium by imparting compressive residual stress by hitting the media against the surface at high speed. The glass beads used in the blasting process are bead-like spheres compared to the WA Fujirandom used in Example 1-1. For this reason, although the effect of scraping the base material is reduced, the effect of striking the base material is increased accordingly, and it is considered that the hardness is higher than that of the blasted titanium substrate of Example 1-1.

It is believed that the increase in hardness of the blasted titanium substrate is also caused by changes in the crystal structure. FIG. 16 is a diagram for explaining the crystallinity of the pure titanium plate, the blasted titanium substrate, and the titanium member 31. FIG. It can be seen that when the blasting treatment is performed, the crystal structure is preferentially oriented in the [101] plane near 41°, as in Example 1-1. This is a crystal change accompanying an increase in residual compressive stress due to blasting, and this crystal change is presumed to be the cause of the increase in hardness.

By heating the titanium member 31 obtained under the heat treatment condition 4 at 1050° C. for 3 hours, titanium crystals precipitated on the entire surface, forming an interesting pattern like a quay wall. The hardness of the titanium member 31 obtained under heat treatment condition 4 is HV301, which is slightly lower than that of the blasted titanium substrate but higher than that of the pure titanium plate. It was also found that the crystals of the titanium member 31 preferentially grow [101] around 41° compared to the blasted titanium substrate. This change in crystal orientation is a clear proof that crystals have grown and a crystal pattern has appeared on the entire titanium base material. It is speculated that the difference in preferred orientation from pure titanium sheet material contributes to the increase in hardness due to compressive residual stress. Also, the titanium member 31 obtained under the heat treatment condition 5 was heated at 1100° C. for 3 hours, and a crystal pattern similar to that of the heat treatment condition 4 was precipitated. The crystal size was large compared to heat treatment condition 4. It is believed that the higher the temperature, the more the crystal growth is promoted and the larger the crystal size obtained.

The hardened layer (DLC hard film) 32 is formed by setting the titanium member 31 in a combined CVD and sputtering apparatus, evacuating to 3.0E-3Pa, and sputtering a titanium adhesion layer of 0.1 μm and a silicon adhesion layer of 0.1 μm in this order. After forming, it was fabricated using benzene gas. The hardened layer 32 had a film hardness of HV1580 and a film thickness of 0.8 μm. In addition, the film thickness was 1.0 μm as a whole. The color tone of the DLC hard film was black, and the color tone of the functional titanium member 30 was black.

Even when the hardened layer 32 was formed on the titanium member 31, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the entire film thickness of the hardened layer 32 and the like is as thin as 1.0 μm, and in dry film formation such as CVD and sputtering, the film is formed along the unevenness of the surface.

By forming the hardened layer 32, the composite hardness of the functional titanium member 30 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 30, since the hardened layer 32 is formed on the titanium member 31 with good adhesion, scratch resistance that can withstand the actual use environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 30 having the hard film 32 formed thereon is remarkably improved. Table 6 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 31 produced under the heat treatment condition 4 and the functional titanium member 30 produced using this. The functional titanium member 30 exhibited approximately 8.5 times higher scratch resistance than the titanium member 31 . By forming the hardened layer 32, scratch resistance that can withstand actual use was obtained while maintaining the unique crystal pattern of titanium. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

Although the heat treatment conditions of Example 2 are exactly the same as those of Example 1-1, it can be seen that the obtained crystal patterns are different due to the difference in the substrate surface state due to the blasting treatment.

Regarding the color tone of the titanium member 31 obtained in Example 2, the average values of R, G, and B in the bright portion were 235, 234, and 234, respectively, and the luminance L ^* was 234. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 1, and it can be seen that the color is a bright gray color with no tint. The average values of R, G, and B in the dark portion were 49, 48, and 47, respectively, and the luminance L ^* was 48. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 2, and it can be seen that the color is a dull dark gray color. The average values of R, G, and B were 125, 125, and 122, respectively, and the luminance L ^* was 124 in the middle portion between the bright portion and the dark portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 3, and it can be seen that the color is neutral gray. The difference in brightness between the portion that looks bright and the portion that looks dark and the intermediate portion is as large as 50 or more. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

[Example 3]
FIG. 17 is a schematic cross-sectional view showing the structure of the functional titanium member 40 of Example 3. As shown in FIG. In Example 3, JIS-specified pure titanium was sandblasted and then subjected to vacuum heat treatment to obtain a titanium member 41 on which a crystal pattern was deposited. A hardened layer (functional layer) 42 made of TiC was formed on this titanium member 41 to obtain a functional titanium member 40 .

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 41 . Alumina #150 media was sprayed onto the pure titanium plate at a discharge pressure of 0.2 MPa using a pneumatic blaster sandblaster manufactured by Fuji Seisakusho Co., Ltd. to obtain a blasted titanium substrate. Subsequently, using a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of −4 Pa, the blasted titanium substrate is heated to a temperature range equal to or higher than the phase transition temperature, and crystals are formed. was deposited to produce a titanium member 41 .

Subsequently, the titanium member 41 is set in an ion plating apparatus capable of adjusting the amount of reaction gas, and a hardened layer (TiC hard film) 42 is formed on the titanium member 41 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 40 was produced.

In Example 3, the blasted titanium substrate was placed in a vacuum heat treatment furnace, and heat treatment conditions 6 shown in Table 7 were applied after the furnace was evacuated to 9.0E-4Pa. That is, the temperature reached 1, the temperature rising time 1, the holding time 1, the reaching temperature 2, the temperature rising time 2, the holding time 2, and the cooling time to lower the temperature to 150° C. were carried out as shown in Table 7.

18 and 19 show microscope images of the titanium surface profile during the production process of the titanium member 41. FIG. That is, FIG. 18 is a microscope image of the blasted titanium substrate. FIG. 19 is a microscope image of the titanium member 41 obtained under the heat treatment condition 6. FIG. When a pure titanium plate material is sandblasted, the surface is scraped as a whole and changes to a satin surface with irregularities. The hardness of the blasted titanium substrate increased to HV300 compared to HV240 of pure titanium due to the increase in internal stress due to surface scraping and the application of compressive residual stress due to high-speed hitting of the media against the surface. .

It is believed that the increase in hardness of the blasted titanium substrate is also caused by changes in the crystal structure. FIG. 20 is a diagram for explaining the crystallinity of the pure titanium plate, the blasted titanium substrate, and the titanium member 41. As shown in FIG. Crystals of pure titanium usually form an α phase having an hcp structure. As shown in FIG. 20, it exhibits a crystal structure oriented mainly in the [100] plane around 35°, the [002] plane around 39°, and the [101] plane around 41°. It can be seen that the blast treatment results in a crystal structure preferentially oriented in the [101] plane near 41°. This is a crystal change accompanying an increase in residual compressive stress due to blasting, and this crystal change is presumed to be the cause of the increase in hardness.

It is believed that the titanium member 41 obtained under the heat treatment condition 6 had the temperature rise time 2 extended to 3 hours compared to the heat treatment conditions of Example 1-1, and therefore crystal growth was accelerated and a tasteful marble pattern appeared. be done. Titanium is α-phase, hexagonal close-packed structure (HCP) at room temperature, but at 885° C. or higher, it undergoes a phase transition to β-phase, face-centered cubic lattice structure (FCC). When pure titanium is heated above this phase transition temperature, metal crystals slide from the close-packed hexagonal close-packed structure (HCP) to the face-centered cubic lattice structure (FCC) during the temperature rise, and needle-like crystals grow. In Example 3, the crystal growth accompanied by this sliding process occurred slowly, so it is thought that the crystal growth was accelerated and crystals appeared clearer than in Example 1-1. The hardness of the titanium member 41 obtained under the heat treatment condition 6 is HV289, which is slightly lower than that of the blasted titanium substrate but higher than that of the pure titanium plate. In addition, it was found that the crystals of the titanium member 41 preferentially grow [101] around 41° compared to the blasted titanium substrate. This change in crystal orientation is a clear proof that crystals have grown and a crystal pattern has appeared on the entire titanium base material. It is speculated that the difference in preferred orientation from pure titanium sheet material contributes to the increase in hardness due to compressive residual stress.

The hardened layer (TiC hard film) 42 is formed by setting the titanium member 41 in an ion plating apparatus, evacuating the titanium member 41 to 3.0E-3Pa, and then introducing CH ₄ gas as a reaction gas while evaporating titanium, which is the film material. and made. The hardened layer 42 had a film hardness of HV1100 and a film thickness of 1.0 μm. The color tone of the TiC hard film was gray like that of pure titanium, and the color tone of the functional titanium member 40 was gray.

Even when the hardened layer 42 was formed on the titanium member 41, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the hardened layer 42 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 42, the composite hardness of the functional titanium member 40 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 40, since the hardened layer 42 is formed on the titanium member 41 with good adhesion, scratch resistance that can withstand the actual usage environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 40 having the hardened layer 42 is significantly improved. Table 8 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 41 produced under the heat treatment condition 6 and the functional titanium member 40 produced using this. The functional titanium member 40 exhibited approximately four times the scratch resistance as compared with the titanium member 41 . By forming the hardened layer 42, while maintaining the unique crystal pattern of titanium, scratch resistance that can withstand actual use was obtained. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

As for the color tone of the titanium member 41 obtained in Example 3, the average values of R, G, and B in the bright portion were 235, 235, and 235, respectively, and the luminance L ^* was 234. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 0, and it can be seen that the color is bright gray with no tint. The average values of R, G, and B in the dark portion were 73, 71, and 67, respectively, and the luminance L ^* was 71. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 6, and it can be seen that the color is a dull dark gray color. The average values of R, G, and B were 139, 141, and 138, respectively, and the luminance L ^* was 140 in the intermediate portion between the bright portion and the dark portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 3, and it can be seen that the color is neutral gray. The difference in brightness between the portion that looks bright and the portion that looks dark and the intermediate portion is as large as 50 or more. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

[Example 4]
FIG. 21 is a schematic cross-sectional view showing the structure of the functional titanium member 50 of Example 4. FIG. In Example 4, JIS-specified pure titanium was sandblasted and then subjected to vacuum heat treatment to obtain a titanium member 51 having crystal patterns deposited thereon. A hardened layer (functional layer) 52 made of TiC was formed on this titanium member 51 to obtain a functional titanium member 50 .

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 51 . Steel beads having a particle size of 200 μm or less were sprayed onto a pure titanium plate using a pneumatic sandblasting apparatus manufactured by Fuji Seisakusho Co., Ltd. at a discharge pressure of 0.45 MPa to obtain a blasted titanium substrate. Subsequently, using a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of −4 Pa, the blasted titanium substrate is heated to a temperature range equal to or higher than the phase transition temperature, and crystals are formed. was deposited to produce a titanium member 51 .

Subsequently, the titanium member 51 was set in an ion plating apparatus capable of adjusting the amount of reaction gas, and a hardened layer (TiC hard film) 52 was formed on the titanium member 51 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 50 was produced.

In Example 4, the blast-treated titanium substrate was placed in a vacuum heat treatment furnace, and heat treatment conditions 7 shown in Table 9 were applied after the furnace was evacuated to 9.0E-4Pa. That is, it was carried out as shown in Table 9 with respect to reaching temperature 1, heating time 1, holding time 1, reaching temperature 2, heating time 2, holding time 2, and cooling time to lower the temperature to 150°C.

22 and 23 show microscope images of the titanium surface profile during the production process of the titanium member 51. FIG. That is, FIG. 22 is a microscope image of the blasted titanium substrate. 23 is a microscope image of the titanium member 51 obtained under heat treatment condition 7. FIG. When a pure titanium plate is sandblasted, the surface is scraped as a whole and changes to a satin surface with irregularities. The hardness of the blasted titanium substrate increased to HV416, compared to HV240 of pure titanium, due to the increase in internal stress due to surface scraping and the application of compressive residual stress due to high-speed hitting of the media against the surface. . When metal powder such as steel or zircon is sprayed at high pressure during blasting, the weight is heavier than alumina or glass beads, and the compressive residual stress applied to the substrate surface is high, so the hardness is significantly improved.

It is believed that the increase in hardness of the blasted titanium substrate is also caused by changes in the crystal structure. FIG. 24 is a diagram for explaining the crystallinity of the pure titanium plate material, the blasted titanium substrate, and the titanium member 51. FIG. Crystals of pure titanium usually form an α phase having an hcp structure. As shown in FIG. 24, it exhibits a crystal structure oriented mainly in the [100] plane around 35°, the [002] plane around 39°, and the [101] plane around 41°. It can be seen that the blast treatment results in a crystal structure preferentially oriented in the [101] plane near 41°. This is a crystal change accompanying an increase in residual compressive stress due to blasting, and this crystal change is presumed to be the cause of the increase in hardness.

In the titanium member 51 obtained under the heat treatment conditions 7, the temperature rise time 2 was extended to 5 hours compared to the heat treatment conditions of Example 1-1, so it is thought that crystal growth was promoted and a pattern with a large crystal size appeared. be done. Titanium has an α phase and a hexagonal close-packed structure (HCP) at room temperature, but at 885° C. or higher, it undergoes a phase transition to a β phase and a face-centered cubic lattice structure (FCC). When pure titanium is heated above this phase transition temperature, metal crystals slide from the close-packed hexagonal close-packed structure (HCP) to the face-centered cubic lattice structure (FCC) during the temperature rise, and needle-like crystals grow. In Example 4, the crystal growth accompanied by this slipping process occurred slowly, so it is thought that the crystal growth was accelerated and crystals appeared clearer than in Example 1-1. The hardness of the titanium member 51 obtained under the heat treatment condition 7 is HV400, which is slightly lower than that of the blasted titanium substrate but higher than that of the pure titanium plate. In addition, it was found that the crystals of the titanium member 51 preferentially grow [101] around 41° compared to the blasted titanium substrate. This change in crystal orientation is a clear proof that crystals have grown and a crystal pattern has appeared on the entire titanium base material. It is speculated that the difference in preferred orientation from pure titanium sheet material contributes to the increase in hardness due to compressive residual stress.

The hardened layer (TiC hard film) 52 is formed by setting the titanium member 51 in an ion plating apparatus, evacuating the titanium member 51 to 3.0E-3Pa, and then introducing CH ₄ gas as a reaction gas while evaporating titanium, which is the film material. and made. The hardened layer 52 had a film hardness of HV1100 and a film thickness of 1.0 μm. The color tone of the TiC hard film was gray like that of pure titanium, and the color tone of the functional titanium member 50 was gray.

Even when the hardened layer 52 was formed on the titanium member 51, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the hardened layer 52 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 52, the composite hardness of the functional titanium member 50 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 50, since the hardened layer 52 is formed on the titanium member 51 with good adhesion, scratch resistance that can withstand the actual usage environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 50 having the hardened layer 52 is remarkably improved. Table 10 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 51 produced under heat treatment condition 7 and the functional titanium member 50 produced using this. The functional titanium member 50 exhibited approximately four times the scratch resistance as compared with the titanium member 51 . By forming the hardened layer 52, scratch resistance that can withstand actual use was obtained while maintaining the unique crystal pattern of titanium. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

As in Examples 1-1 to 1-4, by variously changing the blasting conditions and heat treatment conditions, a crystal pattern unique to titanium can be imparted. Also, depending on the blasting conditions, the residual compressive stress of the titanium base material can be increased, and the hardness of the base material can be increased. Increased hardness of the substrate also improves scratch resistance.

Table 11 summarizes the measurement results of titanium member hardness, hard film hardness, composite hardness and scratch resistance of Examples 1-1 to 1-4. In Example 2, since the hardened layer is made of DLC with high hardness, the scratch resistance is remarkably high. Comparing the results excluding Example 2, it can be seen that as the hardness of the titanium member increases, the composite hardness increases and the scratch resistance improves. This is because the scratch resistance is determined by the hardness of the laminated hard film, the hardness of the substrate, the thickness of the hard film, and the adhesion to the substrate. That is, it is considered that the blasting treatment increased the hardness of the base material.

From the above results, it can be understood that by subjecting the titanium base material to blasting treatment and further vacuum heat treatment, it is possible to provide a decorative part having excellent scratch resistance while imparting a unique pattern.

Regarding the color tone of the titanium member 51 obtained in Example 4, the average values of R, G, and B were 246, 244, and 246, respectively, and the luminance L ^* was 244 in the bright portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 2, and it can be seen that the color is bright gray with no tint. The average values of R, G, and B in the dark portion were 69, 70, and 71, respectively, and the luminance L ^* was 71. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 2, and it can be seen that the color is a dull dark gray color. The average values of R, G, and B were 148, 149, and 148, respectively, and the luminance L ^* was 148 in the intermediate portion between the bright portion and the dark portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 1, and it can be seen that the color is neutral gray. The difference in brightness between the portion that looks bright and the portion that looks dark and the intermediate portion is as large as 50 or more. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

[Example 5]
In Examples 1-1 to 1-4, the case where a titanium base material is subjected to blasting treatment to increase the hardness and to produce a crystal pattern has been described. In Examples 5 and 6, the case where the hardness is increased and the crystal pattern is imparted without performing the blasting treatment is shown.

25 is a schematic cross-sectional view showing the structure of the functional titanium member 60 of Example 5. FIG. In Example 5, pure titanium specified by JIS was subjected to vacuum heat treatment while water was introduced to obtain a titanium member 61 in which a crystal pattern was precipitated. A hardened layer (functional layer) 62 made of TiC was formed on this titanium member 61 to obtain a functional titanium member 60 .

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 61 . A pure titanium plate material is put into a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of -4 Pa. The pure titanium plate material is heated to a temperature range above the phase transition temperature and mixed with water. A titanium member 61 was produced by reacting and depositing crystals.

Subsequently, the titanium member 61 was set in an ion plating apparatus capable of adjusting the amount of reaction gas, and a hardened layer (TiC hard film) 62 was formed on the titanium member 61 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 60 was produced.

In Example 5, the pure titanium plate material was placed in a vacuum heat treatment furnace, and heat treatment conditions 8 shown in Table 12 were applied after exhausting the atmosphere to 9.0E-4Pa. That is, the temperature reached 1, the temperature rising time 1, the holding time 1, the reaching temperature 2, the temperature rising time 2, the holding time 2, and the cooling time to lower the temperature to 150° C. were carried out as shown in Table 12.

Also, at the timing when holding time 2 started, water vapor was introduced using Ar gas as a carrier until the pressure reached 0.25 Torr (33 Pa) and was supplied for 1 hour. After that, the water supply was stopped and the mixture was kept for 1 hour. After that, using Ar gas as a carrier again, water vapor was introduced to 0.25 Torr (33 Pa) and supplied for 1 hour. Thus, water vapor was supplied for 2 hours out of 3 hours of holding time 2.

FIG. 26 is a microscope image of the titanium member 61 obtained under heat treatment condition 8. FIG. When a pure titanium plate was subjected to vacuum heat treatment while steam was introduced, a stone-like rugged pattern appeared. The hardness of the titanium member 61 was HV799. Compared with HV240 of pure titanium, it increased about 3.3 times.

FIG. 27 is a diagram for explaining the crystallinity of the pure titanium plate material and the titanium member 61. FIG. Crystals of pure titanium usually form an α phase having an hcp structure. As shown in FIG. 27, it exhibits a crystal structure oriented mainly in the [100] plane around 35°, the [002] plane around 39°, and the [101] plane around 41°. It can be seen that when heat treatment is performed while reacting with water, the crystal structure transforms into a crystal structure in which only the [101] plane near 41° is strongly preferentially oriented. This crystal change is presumed to be one of the factors for the increase in hardness. It is also possible that the reaction with water precipitated crystals such as titanium dioxide and increased the hardness. However, since titanium dioxide crystals have a crystal structure with preferential orientation at around 25°, it is difficult to say that titanium dioxide is formed. In addition, it is also possible that the hydrogen that forms water penetrates into the interior of titanium and distorts the crystal spacing due to the action with water, increasing the compressive stress and increasing the hardness. In any case, it is considered that the change in the crystal structure and the increase in compressive stress due to the distortion of the crystal greatly contribute to the increase in hardness.

The hardened layer (TiC hard film) 62 is formed by setting the titanium member 61 in an ion plating apparatus, evacuating the titanium member 61 to 3.0E-3Pa, and then introducing CH ₄ gas as a reaction gas while evaporating titanium, which is the film material. and made. The hardened layer 62 had a film hardness of HV1100 and a film thickness of 1.0 μm. The TiC hard film had a gray color similar to that of pure titanium, and the functional titanium member 60 had a gray color.

Even when the hardened layer 62 was formed on the titanium member 61, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the hardened layer 62 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 62, the composite hardness of the functional titanium member 60 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 60, since the hardened layer 62 is formed on the titanium member 61 with good adhesion, scratch resistance that can withstand the actual use environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 60 having the hardened layer 62 is significantly improved. Table 13 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 61 produced under heat treatment condition 8 and the functional titanium member 60 produced using this. The functional titanium member 60 exhibited approximately three times the scratch resistance as compared with the titanium member 61 . By forming the hardened layer 62, scratch resistance that can withstand actual use was obtained while maintaining the unique crystal pattern of titanium. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

In addition, when the amount of water supplied was too large, and when the supply time was too long, the hardness was significantly improved, but the crystal pattern was disturbed and the surface of the titanium was rough in some places. rice field. Conversely, when the amount of water supplied was too small or the supply time was too short, a crystal pattern was obtained, but blue, white, and black crystals were sparsely deposited as in Example 1-2. However, the increase in hardness was sometimes slight. The amount of water to be introduced, water supply time, heat treatment temperature, introduction timing, etc. are important.

Regarding the color tone of the titanium member 61 obtained in Example 5, the average values of R, G, and B in the bright portion were 229, 227, and 228, respectively, and the luminance L ^* was 228. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 2, and it can be seen that the color is bright gray with no tint. The average values of R, G, and B in the dark portion were 65, 68, and 68, respectively, and the luminance L ^* was 67. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 3, and it can be seen that the color is a dull dark gray color. The average values of R, G, and B were 135, 138, and 138, respectively, and the luminance L ^* was 148 in the intermediate portion between the bright portion and the dark portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 3, and it can be seen that the color is neutral gray. The difference in brightness between the portion that looks bright and the portion that looks dark and the intermediate portion is as large as 50 or more. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

[Example 6]
28 is a schematic cross-sectional view showing the structure of the functional titanium member 70 of Example 6. FIG. In Example 6, pure titanium specified by JIS was subjected to vacuum heat treatment while nitrogen was introduced to obtain a titanium member 71 in which a crystal pattern was precipitated. A hardened layer (functional layer) 72 made of TiC was formed on this titanium member 71 to obtain a functional titanium member 70 .

A #800-polished JIS class 2 pure titanium plate material was used to manufacture the titanium member 71 . A pure titanium plate material is put into a vacuum heat treatment apparatus (FHH-30GHS manufactured by ULVAC, Inc.) equipped with a diffusion pump and capable of evacuating to a high vacuum of -4 Pa, and nitrogen is added while heating the pure titanium plate material to a temperature range above the phase transition temperature. A titanium member 71 was produced by reacting and depositing crystals.

Subsequently, the titanium member 71 was set in an ion plating apparatus capable of adjusting the reaction gas amount, and a hard layer (TiC hard film) 72 was formed on the titanium member 71 using Ti as an evaporation source and CH ₄ gas as a reaction gas. was formed, and a functional titanium member 70 was produced.

In Example 6, the pure titanium plate material was set in a vacuum heat treatment furnace, and heat treatment conditions 9 shown in Table 14 were applied after the vacuum was exhausted to 9.0E-4Pa. That is, the temperature reached 1, the temperature rising time 1, the holding time 1, the reaching temperature 2, the temperature rising time 2, the holding time 2, and the cooling time to lower the temperature to 150° C. were carried out as shown in Table 14.

Further, at the timing when the heating period 2 started, nitrogen gas was introduced to 0.3 Torr (40 Pa) and supplied for 1.5 hours, after which the supply of nitrogen was stopped. In this way, nitrogen gas was supplied during the heating time 2 of 1.5 hours.

29 is a microscope image of the titanium member 71 obtained under the heat treatment condition 9. FIG. When pure titanium plate material was subjected to vacuum heat treatment while introducing nitrogen, a rugged pattern resembling igneous rock appeared. The hardness of the titanium member 71 was HV446. Compared with HV240 of pure titanium, it increased about 1.9 times.

FIG. 30 is a diagram for explaining the crystallinity of the pure titanium plate material and the titanium member 71. FIG. Crystals of pure titanium usually form an α phase having an hcp structure. As shown in FIG. 27, it exhibits a crystal structure oriented mainly in the [100] plane around 35°, the [002] plane around 39°, and the [101] plane around 41°. It can be seen that when heat treatment is performed while introducing nitrogen, the crystal structure is transformed into a crystal structure strongly preferentially oriented to the [002] plane near 39°. Furthermore, crystals thought to be titanium nitride (TiN) were confirmed. It is believed that the hardness increased due to the formation of mixed crystals of titanium nitride and titanium.

The hardened layer (TiC hard film) 72 is formed by setting the titanium member 71 in an ion plating apparatus, evacuating the titanium member 71 to 3.0E-3Pa, and then introducing CH ₄ gas as a reaction gas while evaporating titanium, which is the film material. and made. The hardened layer 72 had a film hardness of HV1100 and a film thickness of 1.0 μm. The TiC hard film had a gray color similar to that of pure titanium, and the functional titanium member 70 had a gray color.

Even when the hardened layer 72 was formed on the titanium member 71, the crystal pattern did not disappear and showed the same state as before the film formation. This is probably because the film thickness of the hardened layer 72 is as thin as 1.0 μm, and in dry film formation such as ion plating, the film is formed along the unevenness of the surface.

By forming the hardened layer 72, the composite hardness of the functional titanium member 70 is remarkably improved. Titanium material has low hardness in the first place, and when it is applied to accessories such as eyeglasses, accessories, watches, etc., or exterior parts such as decorations, sports equipment, etc., it may be scratched immediately depending on the usage environment, and it can withstand the actual usage environment. Hard to say. On the other hand, in the functional titanium member 70, since the hardened layer 72 is formed on the titanium member 71 with good adhesion, scratch resistance that can withstand the actual use environment is ensured.

The scratch resistance is roughly determined by the hard film hardness of the entire cured layer laminated on the substrate, the substrate hardness, the hard film thickness, and the adhesion to the substrate (composite hardness). Therefore, the scratch resistance of the functional titanium member 70 having the hardened layer 72 is remarkably improved. Table 14 shows the calculated values of the composite hardness and the measurement results of the scratch resistance of the titanium member 71 produced under heat treatment condition 9 and the functional titanium member 70 produced using this. The functional titanium member 70 exhibited approximately four times the scratch resistance as compared with the titanium member 71 . By forming the hardened layer 72, scratch resistance that can withstand actual use was obtained while maintaining the unique crystal pattern of titanium. Furthermore, compared with the comparative example in which a hardened layer was formed on a pure titanium plate material that had been polished to #800, an effect was seen in that scratches were less noticeable due to the existence of the crystal pattern.

In addition, when the amount of nitrogen supplied is too large, when the supply time is too long, and when nitrogen is introduced during the holding time 2, the crystal pattern disappears and the overall gold color is exhibited (so-called nitriding titanium). FIG. 30 also shows the crystal structure when nitrogen was introduced during the holding time 2, which was the crystal structure of titanium nitride. Conversely, if the supply amount of nitrogen is too small, or if the supply time is too short, blue, white, and black crystals like those in Example 1-2 are sparsely precipitated, and the increase in hardness is slight. something happened. The amount of nitrogen introduced, nitrogen supply time, heat treatment temperature, introduction timing, etc. are important.

As for the color tone of the titanium member 71 obtained in Example 6, the average values of R, G, and B were 237, 236, and 241, respectively, and the luminance L ^* was 237 in the bright portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 5, and it can be seen that the color is bright gray with no tint. The average values of R, G, and B in the dark portion were 57, 61, and 57, respectively, and the luminance L ^* was 59. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 4, and it can be seen that the color is a dull dark gray color. The average values of R, G, and B were 135, 137, and 136, respectively, and the luminance L ^* was 136 in the middle portion between the bright portion and the dark portion. Also, the value obtained by subtracting the minimum value from the maximum value of the average values of R, G, and B is 2, and it can be seen that the color is neutral gray. The difference in brightness between the portion that looks bright and the portion that looks dark and the intermediate portion is as large as 50 or more. The presence of this luminance difference makes it possible to visually recognize the presence of the pattern.

FIG. 31 is a diagram showing the relationship between composite hardness and measurement results of scratch resistance. It can be seen that the scratch resistance is exponentially improved with an increase in composite hardness due to an increase in substrate hardness. By performing blasting or gas treatment, the hardness of the substrate increases and a crystal pattern peculiar to titanium can be imparted. As a result, it is possible to provide a functional titanium member having excellent scratch resistance and high designability.

10, 20, 30, 40, 50, 60, 70 Functional titanium member 11, 21, 31, 41, 51, 61, 71 Titanium member 12, 22, 32, 42, 52, 62, 72 Hardened layer

Claims (4)

A functional titanium member comprising a titanium member made of pure titanium and a functional layer provided on the titanium member ,
The titanium member has at least one rough surface, and the surface of the rough surface has an uneven pattern,
The functional layer has an uneven pattern derived from the uneven pattern,
The functional titanium member has a Vickers hardness of HV500 or more,
Functional titanium material. wherein the functional layer is a layer containing a metal or semiconductor bonded to at least one element selected from carbon, nitrogen and oxygen, or a layer containing diamond-like carbon;
The functional titanium member according to claim 1 . a blasting step of performing blasting to form a rough surface on the surface of a raw material titanium member made of pure titanium to obtain a blasted titanium member;
a first heating step of heating the blasted titanium member from room temperature to a temperature T1 of 835° C. or more and 935° C. or less under reduced pressure;
The blasted titanium member that has undergone the first heating step is heated under reduced pressure from temperature T1 to temperature T2 of 950° C. or more and 1150° C. or less over a time HT2 of 30 minutes or more and 8 hours or less. a second heating step of heating to obtain a titanium member;
a functional layer forming step of forming a functional layer on the titanium member obtained in the second heating step to obtain a functional titanium member;
forming an uneven pattern on the surface of the titanium member;
In the functional layer forming step, an uneven pattern derived from the uneven pattern of the titanium member is formed on the surface,
The functional titanium member has a Vickers hardness of HV500 or more,
A method for producing a functional titanium member. In the functional layer forming step, a layer containing a metal or semiconductor combined with at least one element selected from carbon, nitrogen and oxygen or a layer containing diamond-like carbon is formed as the functional layer.
The method for manufacturing the functional titanium member according to claim 3 .

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