JP4452089B2 - Hard film with excellent wear resistance and method for producing the same - Google Patents

Description

  The present invention relates to an improvement in a hard film having wear resistance formed on the surface of a cutting tool, a sliding member for automobiles, and the like.

  In recent years, there has been a growing need for improvement in wear resistance of cutting tools and sliding members for automobiles, etc., and a hard film (hereinafter simply referred to as “film”) having wear resistance formed and used on the surface of these members. Improvement) is being considered. For example, in the case of a cutting tool, it has been reported that by adding Si or B to the TiAlN film, the oxidation resistance is improved and the crystal grains are refined to obtain high hardness (see Patent Documents 1 and 2). ). In addition, in the case of a sliding member typified by an automobile piston ring, it has been reported that high hardness can be obtained by adding B to the CrN film (see Patent Document 3).

In all of the above prior arts, a specific element is uniformly added to a film, and a single layer film having a single chemical composition is formed. The film formed in this way has a higher hardness and improved wear resistance due to the refinement of the crystal grains constituting the film, but the friction coefficient on the film surface is insufficiently reduced and the resistance to wear is reduced. There remains room for further improvements such as insufficient improvement in wear and lubricity, and increased attack on the mating member as the hardness increases.
JP 7-310174 A Japanese Patent No. 2793696 JP 2000-144391 A

  Therefore, an object of the present invention is to provide a hard coating and a method for producing the same that are more excellent in wear resistance and lubricity than conventional hard coatings.

The invention described in claim 1 is a film formed by alternately laminating layers A and B having the chemical composition shown below on the surface of the substrate, and the thicknesses of the layers A and B are dA respectively. , DB,
dB / dA ≦ 0.5, 0.5 nm ≦ dB, dA ≦ 200 nm
It is a hard film excellent in wear resistance characterized by satisfying
Layer _{A: (Cr 1-α X} α) (B a C b N 1-a-b-c O c) e
X is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al and Si, and 0 ≦ α ≦ 0.9, 0 ≦ a ≦ 0.15, 0 ≦ b ≦ 0.3, 0 ≦ c ≦ 0.1, 0.2 ≦ e ≦ 1.1 (α represents the atomic ratio of X, and a, b, and c represent B , C, O. The same applies hereinafter.
Layer B: B _1−s−t C _s N _t
However, 0.1 <= s <= 0.25, (1-s-t) / t <= 1.5 (s and t show the atomic ratio of C and N, respectively, and so on.)
Or Si _1-xy C _x N _y
However, it is 0.05 <= x <= 0.25, 0.5 <= (1-xy) / y <= 1.4 (x and y show the atomic ratio of C and N, respectively, and so on ) . .

  The invention according to claim 2 is the hard film having excellent wear resistance according to claim 1, wherein the α is 0.

  The invention according to claim 3 is the hard coating having excellent wear resistance according to claim 1, wherein the α is 0.05 or more.

  The invention according to claim 4 is characterized in that the layer A has a rock salt cubic structure and is observed by an X-ray diffraction pattern obtained by measurement by a θ-2θ method using CuKα rays and a (111) plane; The hard film having excellent wear resistance according to any one of claims 1 to 3, wherein at least one of the half-value widths of the diffraction lines from the (200) plane is 0.3 ° or more.

  The invention according to claim 5 is a film forming apparatus comprising the hard film according to any one of claims 1 to 4 and at least one arc evaporation source and sputtering evaporation source each having a magnetic field application function. The component A of the layer A is evaporated by the arc evaporation source, and the component of the layer B is evaporated by the sputtering evaporation source, whereby the layer A and the layer are formed on the substrate. It is a method for producing a hard coating having excellent wear resistance, characterized by alternately laminating B.

According to the present invention, conventional hard layers are formed by alternately laminating high hardness layers A and lubricating layers B on the surface of the substrate to suppress and refine the growth of crystal grains constituting the layer A. It is possible to provide a hard coating and a method for producing the same that are more excellent in wear resistance and lubricity than the coating.

[Configuration of hard coating]
The present inventors make the film thicknesses dA and dB of the layer A made of a chemical composition satisfying the following formula (1) and the layer B made of a chemical composition satisfying the following formula (2) satisfy the following formula (3). Further, the inventors have found that a hard film excellent in wear resistance and lubricity can be obtained by forming a film in which layers A and B are alternately laminated on a substrate, and the present invention has been completed.

Layer _{A: Cr (B a C b} N 1-abc O c) e
0 ≦ a ≦ 0.15, 0 ≦ b ≦ 0.3, 0 ≦ c ≦ 0.1, 0.2 ≦ e ≦ 1.1 (1)
Layer B: B _1-st CsNt
0 ≦ s ≦ 0.25, (1-s−t) /t≦1.5 (2)
dB / dA ≦ 0.5, 0.5 nm ≦ dB, dA ≦ 200 nm (3)

  The reason why the composition and thickness of the layer A and the layer B are defined as described above will be described in detail below.

[Composition of layer A]
First, the layer A is a Cr (B, C, N, O) film, and the ratio of B, C, N, O is set to a ratio as shown in the above formula (1) for the following reason. That is, the layer A has a composition containing chromium nitride (CrN, Cr ₂ N) having a high hardness as a main component in order to maintain the wear resistance of the film. Further, the addition of C, B, O to chromium nitride further increases the hardness and improves the wear resistance. However, excessive addition of these elements causes a decrease in the hardness, so that a (that is, B) The upper limit is 0.15, preferably 0.1, the upper limit of b (ie C) is 0.3, preferably 0.2, and the upper limit of c (ie O) is 0.1, preferably 0. 0.07 or less.

The total ratio e of B, C, N, and O with respect to Cr is preferably in the range of 0.2 to 1.1. In this range, the structure of the crystals constituting the layer A is Cr ₂ N structure or CrN. It corresponds to the range of the composition that becomes the structure. Note that the crystal structure of the layer A can be confirmed by a cross-sectional TEM and electron beam diffraction, as will be described later.

[Composition of layer B]
Next, the layer B is a BN compound that functions as a solid lubricant in order to impart lubricity to the coating. Here, in order to form the BN compound, the ratio of B to N (1-st) / t needs to be 1.5 or less, and preferably 1.2 or less. And, by adding C to this BN compound, it is possible to increase the hardness while imparting lubricity to the layer B. However, excessive addition reduces the hardness and loses the lubricity. Is set to 0.25. Preferably, the ratio of C to B, s / (1-s−t), is 0.25 or less, more preferably 0.1 or less.

[Thickness of layer A and layer B]
Next, the reason why the thicknesses of the layer A and the layer B (hereinafter also referred to as “film thickness”) are defined as in the above formula (3) will be described below. The layer A defined by the above formula (1) is crystalline (Cr ₂ N type or CrN type), and the layer B is amorphous. By forming the film by alternately laminating two layers having different crystal states in this way, the growth of the crystal grains in the layer A in the thickness direction of the film is interrupted by the insertion of the layer B, and the layer A The crystal grain size is about the same as the thickness of the film. As a result, the crystal grains become finer and the hardness of the film is further increased as compared with the case where there is no interruption of the growth of crystal grains as in the prior art.

  If the thickness of the layer B is too small, the growth of crystal grains cannot be effectively interrupted, so that it is 0.5 nm or more, preferably 1 nm or more. Further, if the thickness of the layer A is too large, the effect of refining the crystal grains is small, and there is almost no difference in properties such as hardness and wear resistance with the above-described conventional film, so the thickness of the layer A is 200 nm or less, Preferably it is 100 nm or less, More preferably, it is 50 nm or less.

  In addition, in the present invention, the layer A has a role of improving wear resistance and the layer B has a role of improving lubricity, but the layer B with respect to the thickness of the layer A is used. This is because if the thickness ratio is too large, the hardness of the film is lowered and the wear resistance is lowered. Preferably, dB / dA ≦ 0.2.

  In addition, the thickness of the layer A and the layer B can be calculated | required as an average value of the value measured from each of 2 visual fields of the magnification of 500 to 1,500,000 by observation by cross-sectional TEM.

  Moreover, although the thickness of the whole film formed by laminating layer A and layer B varies depending on the use of the substrate on which the film is formed, it is generally in the range of 1 to 3 μm for cutting tools, and for sliding parts. It is in the range of 3 to 100 μm.

[Modification of composition of layer A]
As described above, the layer A is a layer that has a high hardness and plays a role of exhibiting wear resistance, and is intended to further improve the characteristics by refining crystal grains by inserting the layer B. By replacing a part of Cr in layer A with another element, the hardness of layer A is further increased, and the wear resistance can be further improved.

  One or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, and Si are recommended as the other elements. Among these, Al, Si, W, and Ti are preferable as the one element, and combinations of Al and Si, Al and Ti, W and Si, and Ti and Si are preferable as the two elements.

  The substitution ratio α for the other element is set to 0.9 or less because if the ratio is too large, the ratio of the original Cr becomes too small and the effect of increasing the hardness is lost. The lower limit of the substitution ratio α is not particularly limited, but is preferably 0.05 or more in order to obtain a certain effect by substitution with another element. The more preferable range of the substitution ratio α varies depending on the type and combination of elements to be substituted, but is generally about 0.4 to 0.8.

  In addition, when two elements of Ti and Al are combined and replaced with Cr, if the Al is increased, the oxidation resistance of the film is improved. Therefore, the Al ratio is preferably larger than the Ti ratio, but the Al ratio is too large. Therefore, the ratio of Al to the total amount of Cr, Ti and Al is preferably 0.8 or less.

  Further, when Si is contained in the substitution element, if the proportion of Si is too large, the layer A tends to be amorphous. Therefore, the proportion of Si with respect to the total amount of Cr and substitution elements should be 0.5 or less. preferable.

[Modified example of composition of layer B]
Even if an SiCN-based or CN-based coating is used as the layer B in addition to the BCN-based coating, a coating excellent in wear resistance can be obtained.

When a SiCN-based film is used for layer B, generally, a low coefficient of friction like that of a BCN-based film cannot be obtained and the aggression against the counterpart material cannot be reduced. However, since it is harder than the BCN-based film, The wear resistance is improved, and the coating is suitable for a cutting tool that does not require consideration of the aggressiveness against the counterpart material. Furthermore, the oxidation resistance is excellent. In addition, since hardness will decline when C is added excessively, the upper limit of the addition ratio of C shall be 0.25 .

  In addition, CN-based coatings are unstable at high temperatures and generally cannot be used in high-temperature sliding environments. However, as a guideline, they are used because they exhibit the same sliding characteristics as BCN-based coatings in sliding environments below 400 ° C. Is possible. The standard of the addition ratio of N is 0.6 or less, preferably 0.4 or less.

[Degree of refinement of layer A crystal grains]
The layer A can have a hexagonal Cr ₂ N type structure or a cubic rock salt type CrN type structure depending on the ratio of the total amount of Cr and B, C, N, and O as described above. Since the CrN type structure is superior, the rock salt cubic structure is preferred as the crystal structure of the layer A.

  Further, in the present invention, the layer A and the layer B are laminated at the film thickness and the film thickness ratio shown in the above formula (3), whereby the crystal grain growth of the layer A is interrupted by the layer B, and as a result The gist is that refinement of crystal grains occurs.

  Here, the degree of refinement of the crystal grains is determined by the half width (FWHM: Full Width Half) of diffraction lines from the (111) plane and the (200) plane of the rock salt cubic structure of the layer A observed in the X-ray diffraction pattern. (Maximum) can be evaluated as an index. In general, the half width of the diffraction line has a certain relationship with the crystal grain size of the material to be measured, and the half width increases as the crystal grain size decreases. However, it is known that the half width of the diffraction line varies depending on other factors such as non-uniform stress generated in the film, and the relationship between the half width and the crystal grain size is not necessarily linearly proportional.

  Based on these considerations, the present inventors investigated the relationship between the half-width of the diffraction line and the film hardness or wear resistance, and as a result, the half-width of the diffraction line from the (111) and (200) planes. It has been found that when at least one of them is 0.3 ° or more, the properties of the film are further improved. A more preferable lower limit value of the half width is 0.4 °. The upper limit of the half width is not particularly limited, but is substantially about 1 °.

  In the present invention, the half width of the diffraction line was evaluated by X-ray diffraction by the θ-2θ method using CuKα ray (40 kV-40 mA). As other X-ray optical system conditions, divergence, scattering slit is 1 °, receiving slit is 0.15 mm, graphite monochromator is used, receiving slit before counter is 0.8 °, scanning speed is 2 ° / min. (Continuous scan), the step width was 0.02 °.

[Method of manufacturing hard coating]
As described above, the hard coating according to the present invention has characteristics such as wear resistance, lubricity, and oxidation resistance by alternately laminating two or more different coatings on the substrate as layer A and layer B. To be expressed.

  The hard film having such a structure is a film forming apparatus (see FIG. 1; hereinafter referred to as “sputtering film forming apparatus”) including a plurality of sputtering evaporation sources or a film forming apparatus including a plurality of electron beam evaporation sources (see FIG. 1). (See FIG. 2; hereinafter referred to as an “electron beam deposition apparatus”), and by alternately switching the evaporation source to which targets having different compositions are attached, the layers A and B are alternately formed on the substrate. Although it can be formed, the following method is recommended.

  The method of manufacturing a hard coating recommended in this embodiment is a film forming apparatus (see FIG. 3; hereinafter referred to as “composite film forming apparatus”) that includes one or more arc evaporation sources and sputter evaporation sources each having a magnetic field application mechanism. In the mixed gas of sputtering gas such as Ar, Ne, and Xe and reactive gas such as nitrogen, methane, acetylene, oxygen, etc. In this method, layers A and B are alternately laminated by performing reactive film formation by alternately evaporating the constituent components of B with a sputtering evaporation source.

  The reason for changing the evaporation source method between layer A and layer B is as follows. That is, in the present invention, as described in the above section [Thickness of layer A and layer B], the film thickness of layer B is 0.5 times or less, preferably 0.2 times or less that of layer A. In general, film formation using a sputtering evaporation source has a higher film formation speed than film formation using an arc evaporation source. A sputter evaporation source is used.

  On the other hand, when the arc evaporation source is used for both the layer A and the layer B film formation, the arc evaporation source has a lower limit value in the discharge power at which discharge occurs below a certain input power. Even if the input power to the targets attached to both evaporation sources is adjusted, it is difficult to adjust the film thickness ratio of the layer B to the layer A to 0.5 or less, which is a particularly preferable range of 0.2. It is more difficult to adjust to: The lower limit of the film thickness ratio that can be adjusted by adjusting the input power is about 0.5.

Further, when forming a layer made of (B, N), (Si, C, N) or (C, N) as the layer B, the layer B is formed using a B, BN, B ₄ C, Si, C target or the like. Although it is necessary to form a film, B and BN are insulative substances, and no discharge occurs in the arc evaporation source, so that the film cannot be formed, and B ₄ C, Si, and C are conductive substances, but the discharge is not stable. Film formation is difficult with an arc evaporation source.

  On the other hand, when a sputter evaporation source is used for both layer A and layer B film formation, the sputter evaporation source operates at a low input power, unlike the arc evaporation source, but the film formation rate is comparable to the arc evaporation source. In addition, the hardness of the formed film is inferior to that of the arc evaporation source.

Accordingly, in this embodiment, the layer A is formed by using an arc evaporation source as a target with Cr or CrX (where X is a group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, and Si). 1 or 2 or more selected elements), and a B, BN, B ₄ C, Si or C target is used as a sputter evaporation source for forming the layer B, and a mixture of a sputtering gas and a reactive gas is used. A preferred mode is to form a film by alternately laminating the layers A and B while rotating the substrate in the gas.

In addition, since there is no conductivity when using a B or BN target, an RF sputtering method is used as a sputter evaporation source. However, when a B ₄ C, Si, or C target is used, it has conductivity. As the sputtering evaporation source, both DC and RF systems can be used.

  Further, when forming layer A, metal Cr or CrX (where X is one or more selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al and Si) Cr (B, C, O, N) or (Cr, X) (B, C, O) using a target to which at least one element selected from B, C, O, and N is added. , N) can also be formed.

  Then, by adjusting the ratio of the electric power supplied to both the arc evaporation source and the sputtering evaporation source and the rotation speed of the substrate, the film thickness of the layer A or the layer B and the film thickness ratio can be easily within the above preferable range. It can be adjusted.

  The partial pressure of the reaction gas in the mixed gas composed of the sputtering gas and the reaction gas during film formation is preferably 0.6 Pa or more, and more preferably 1 Pa or more. The total pressure of the mixed gas is not particularly limited, but it is about 1 Pa or more when it is considered that a sputter gas substantially equal to the reaction gas is supplied. However, under high pressure, abnormal discharge is likely to occur in both the sputtering evaporation source and the arc evaporation source, so 5 Pa or less is a standard.

  As shown in FIG. 3, when using the sputtering evaporation source 1 and the arc evaporation source 2 having both magnetic field application mechanisms, the polarities are reversed so that the magnetic field lines A of the adjacent evaporation sources 1 and 2 are connected. It is preferable. Thereby, it becomes possible to trap the secondary electrons that maintain the discharge in the vicinity of the substrate 3, and as a result, ion irradiation to the substrate 3 increases, and a denser and harder film can be formed.

  Using the sputter deposition apparatus provided with two sputter evaporation sources shown in FIG. 1 or the composite film formation apparatus provided with two sputter evaporation sources and arc evaporation sources shown in FIG. The film which has was formed.

As the substrate, a cemented carbide (mirror polishing) for hardness measurement was used. Regardless of whether a sputtering film forming apparatus or a composite film forming apparatus is used, the substrate is charged into the apparatus and heated to maintain the substrate temperature at about 400 to 500 ° C., and 3 × 10 ^−3. After evacuating to a vacuum state of Pa or less and cleaning with Ar ions (pressure 0.6 Pa, substrate voltage 500 V, treatment time 5 minutes), film formation was performed.

  In the case of using a sputter deposition apparatus, carbon is formed in a pure Ar atmosphere when forming a metal film during film formation, and in a mixed gas (volume mixing ratio 65:35) atmosphere of Ar and nitrogen when forming a nitride. In the case of forming a nitride, the film is formed in an atmosphere of a mixed gas of Ar, nitrogen, and methane (volume mixing ratio 65: 30: 5) under a total pressure of 0.6 Pa. Adjustment was made by changing the time to activate each evaporation source. Metal Cr and B were used for the target.

  In the case of using a composite film forming apparatus, a mixed gas of Ar and nitrogen (volume mixing ratio 50:50), in the case of carbonitride, a mixed gas of Ar, nitrogen and methane (volume mixing ratio 50: 45: 5), total pressure The film was formed under the condition of 2.66 Pa, the film thickness ratio of layer A and layer B was adjusted by the ratio of the input electric power to each evaporation source, and the thickness of layer A and layer B was adjusted by the rotation speed of the substrate.

The total thickness of the formed film was kept constant at approximately 3 μm. The layer A was formed with an arc evaporation source, and the layer B was formed with a sputter evaporation source. As a target, metal Cr was used as an arc evaporation source, and conductive B ₄ C was used as a sputtering evaporation source.

First, using a sputter film forming apparatus and a composite film forming apparatus, the layer A has a composition of CrN, the layer B has a composition of B _0.45 C _0.1 N _0.45 , the thickness of the layer A is constant at 30 nm, and the thickness of the layer B is 0. Films were formed with various changes in the range of 2 to 50 nm (test numbers 2 to 7 and 9 to 14). For comparison, only the layer A was formed as a conventional method (test numbers 1 and 8).

Furthermore, using only the composite film forming apparatus, the layer A was changed to a Cr ₂ N composition, and film formation was performed under the same conditions as described above (test numbers 15 to 21).

  As a result of performing cross-sectional TEM observation on the test material after film formation, the effect of refining crystal grains as seen in FIG. 4 was confirmed. When the size of the crystal grains was the same as that of the conventional film having no laminated structure, the evaluation was x, and when it was smaller than the conventional film, the evaluation was ○.

  Moreover, the thickness of each layer A and B after film formation was measured by observing two fields of view at a magnification of 500 to 1,500,000.

  The ratio of metal elements and elements such as N, C, O, etc. in each film was obtained by calculation from the composition profile in the depth direction collected by sputtering with Ar ions from the surface by Auger electron spectroscopy.

  The hardness of the obtained film was measured with a micro Vickers hardness tester (load 25 gf [≈0.245 N], holding time 15 seconds).

  Further, the wear resistance of the film and the aggressiveness to the mating material were evaluated using a ball-on-plate type reciprocating sliding friction tester. Using bearing steel (SUJ2, HRC60) with a diameter of 9.53 mm as the mating material (ball), a sliding test was conducted in a dry environment at a sliding speed of 0.1 m / s, a load of 2 N, and a sliding distance of 250 m. The friction coefficient during sliding and the wear rate of each ball and film were measured to evaluate the characteristics of the film.

  Moreover, the X-ray-diffraction measurement of (theta) -2 (theta) using a Cuk (alpha) ray was implemented, and the half value width of the (111) and (200) plane was measured.

  The results of the above test are shown in Table 1. The number of layers shown in Table 1 is the number of layers A and B stacked one by one (the same applies to Tables 2 to 4).

  From these test results, the following is clear. That is, when the thickness of the layer B is less than 0.5 nm, the effect of crystal grain refinement cannot be obtained, and the degree of increase in the hardness of the coating is small (see test numbers 1, 2, 8, 9, 15, and 16). On the other hand, if the thickness of the layer B is too large, although the crystal grains are refined, the ratio of the thickness of the low-hardness layer B to the thickness of the high-hardness layer A becomes excessive. Shows a tendency to decrease (see test numbers 7, 14, and 21). Therefore, the film thickness of the layer B is preferably 0.5 times or less of the film thickness of the layer A (see test numbers 3 to 6, 10 to 13, and 17 to 20).

The coefficient of friction of the film shows a tendency similar to that of the hardness, but the wear rate of the film hardly changes when the thickness of the layer B is smaller than the thickness of the layer A (test numbers 1 to 6, 8 to 13 and 15 to 20), when the thickness is larger than the thickness of the layer A, it shows a tendency to rapidly increase, suggesting a decrease in wear resistance (see Test Nos. 7, 14, and 21).

In addition to satisfying the formulas (1) to (3), the layer A is formed of CrN having a rock salt cubic structure, and at least of the half-widths of diffraction lines from the (111) plane and the (200) plane When one side is 0.3 degree or more, it turns out that the film | membrane which is high hardness and was excellent in abrasion resistance is obtained (refer test number 3-6, 10-13).

In this example, the same composite film forming apparatus as used in Example 1 was used, and the composition of layer A was CrN and layer B was B _0.45 C _0.1 N _0.45 as in Example 1, Film formation was performed by keeping the thickness of the layer B constant at 2 nm and varying the thickness of the layer A in the range of 1 to 300 nm. The other test conditions are the same as in Example 1.

  The results of the above test are shown in Table 2. From these test results, the following is clear.

When the thickness of the layer A is smaller than the thickness of the layer B, the degree of increase in the hardness of the film is small because the characteristics of the relatively low hardness layer B are dominant (see test number 31). On the other hand, when the thickness of the layer A exceeds 300 nm, the effect of dividing and refining the crystal grains by the layer B is reduced, and on the contrary, the hardness of the film tends to decrease (see test number 36). Therefore, the thickness of the layer A is preferably 200 nm or less, and the thickness of the layer B is preferably 0.5 times or less of the thickness of the layer A.

  In the present embodiment, the same sputter deposition apparatus or composite film deposition apparatus as used in the first embodiment is used, the thickness of layer A is constant at 30 nm, and the thickness of layer B is constant at 2 nm. Film formation was performed with various changes in the composition of B. When C or O was contained in the layer A, methane or oxygen gas was added to the reaction gas, and when B was contained, a Cr—B alloy target containing B in the target was used. The other test conditions are the same as in Example 1.

  The results of the above test are shown in Tables 3 and 4. From these test results, it was found that a film having high hardness and excellent wear resistance can be obtained by making the layers A and B have compositions satisfying the above formulas (1) and (2), respectively.

  When layer B has a SiCN-based composition, the friction coefficient of the film is relatively high and the wear rate of the ball is slightly higher than that of the BCN-based composition, but the film hardness is the same or slightly higher. It was found that a high value was obtained and the film was suitable for a cutting tool or the like that did not require consideration of the aggressiveness against the counterpart material.

This means that when the layer B is a composition other than the SiCN-based composition in the composition defined in the present invention, the effect of reducing the aggressiveness against the counterpart material can be obtained as compared with the conventional film.

It is a schematic explanatory drawing which shows an example of the sputtering film-forming apparatus which forms the hard film concerning this invention. It is a schematic explanatory drawing which shows an example of the electron beam film-forming apparatus which forms the hard film concerning this invention. It is a schematic explanatory drawing which shows an example of the composite film-forming apparatus which forms the hard film concerning this invention. It is a figure which shows the microstructure of the thickness direction cross section of the hard film which concerns on this invention, (a) is a schematic diagram, (b) is a longitudinal cross-sectional view.

Explanation of symbols

1: Sputter evaporation source 2: Arc evaporation source 3: Substrate A: Magnetic field lines

Claims (5)

When the surface of the base material is a film formed by alternately laminating layers A and B having the chemical composition shown below, and the thicknesses of the layers A and B are dA and dB, respectively,
dB / dA ≦ 0.5, 0.5 nm ≦ dB, dA ≦ 200 nm
Hard film with excellent wear resistance characterized by satisfying
Layer _{A: (Cr 1-α X} α) (B a C b N 1-a-b-c O c) e
X is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al and Si, and 0 ≦ α ≦ 0.9, 0 ≦ a ≦ 0.15, 0 ≦ b ≦ 0.3, 0 ≦ c ≦ 0.1, 0.2 ≦ e ≦ 1.1 (α represents the atomic ratio of X, and a, b, and c represent B , C, O. The same applies hereinafter.
Layer B: B _1−s−t C _s N _t
However, 0.1 <= s <= 0.25, (1-s-t) / t <= 1.5 (s and t show the atomic ratio of C and N, respectively, and so on.)
Or Si _1-xy C _x N _y
However, it is 0.05 <= x <= 0.25, 0.5 <= (1-xy) / y <= 1.4 (x and y show the atomic ratio of C and N, respectively, and so on ) . .   The hard film having excellent wear resistance according to claim 1, wherein α is 0.   The hard film having excellent wear resistance according to claim 1, wherein α is 0.05 or more.   The layer A has a rock salt cubic structure, and the diffraction lines from the (111) plane and the (200) plane are observed in the X-ray diffraction pattern obtained by measuring by the θ-2θ method using CuKα rays. The hard film having excellent wear resistance according to any one of claims 1 to 3, wherein at least one of the half-value widths is 0.3 ° or more.   A method of forming the hard film according to any one of claims 1 to 4 with a film forming apparatus provided with at least one arc evaporation source and a sputtering evaporation source each having a magnetic field application function, A component of A is evaporated by the arc evaporation source, and a component of the layer B is evaporated by the sputtering evaporation source, whereby the layers A and B are alternately stacked on the substrate. A method for producing a hard coating having excellent wear resistance.