JP7631412B2 - Ceramic sealing parts and manufacturing method thereof - Google Patents

Description

The embodiments generally relate to a ceramic sealed component (hereinafter referred to as a ceramic sealed component) in which a ceramic component and a metal component are joined together, such as for use in electric power pipes.

As ceramic sealing parts for magnetrons, power tubes, and electron tubes, metallization layers mainly composed of high melting point metals such as molybdenum (Mo) are coated with alumina (aluminum oxide: AlO
In the ceramic sealing part, a ceramic sealing part formed on a ceramic part such as ceramic parts (3) is used. The ceramic sealing part can protect the inside from the external environment and electrically insulate the inside by bonding the ceramic and metal to block the outside air and hermetically seal the inside of the part. For example, in the ceramic sealing part shaped as shown in FIG. 1, a metallized layer mainly composed of molybdenum is formed on the ring parts of the upper and lower end surfaces of a cylindrical ceramic part made of an alumina sintered body. A nickel (Ni) layer of a predetermined thickness is formed on the surface of this metallized layer to improve the bonding strength with other metal parts and to perform sealing. This nickel part and the cylindrical metal part are bonded with silver solder (e.g. BAg-8).

As a ceramic sealed part, an electron tube having a vacuum airtight structure in which a ceramic cylinder is formed with a metal surface made of molybdenum and an iron metal cylinder is joined with a brazing material has been disclosed (Patent Document 1). According to Patent Document 1, by replacing the metal cylinder with iron instead of Kovar, it is possible to manufacture a low-cost electron tube.

Also, a vacuum switch outer tube has been disclosed in which a nickel-based alloy is bonded to ceramics by an active metal, without using a high-melting-point metal such as molybdenum (Patent Document 2). According to Patent Document 2, a vacuum switch outer tube with high bonding strength can be manufactured without forming intermetallic compounds that cause an unstable bonding state.

Japanese Patent Application No. 1-46978 JP 2001-220253 A

When metallizing the ceramic surface with a high melting point metal such as molybdenum,
A furnace was required to heat the material to a high temperature of 400° C. or higher, and energy costs were incurred to perform the treatment at high temperatures. In addition, it was difficult to braze the formed high-melting-point metallized layer to a metal part as is, and plating of nickel or the like was required on the surface, making the process complicated.

In order to ensure sealing (airtightness) when joining active metal brazing materials, a certain joining width is necessary.
The thermal expansion coefficients of ceramics and metals are different (for example, the thermal expansion coefficient of alumina is 7.2 x 10
-6/°C for copper, 16.5×10-6/°C for iron, 11.7×10-6/°C for iron), and cracks are likely to occur due to the difference in thermal expansion. Active metal brazing can be used at a lower temperature of 850°C compared to metallization using high melting point metals, making it possible to mitigate the difference in thermal expansion. When joining metal parts with active metal brazing material or silver brazing material, it is advantageous to join at a high temperature to increase the joining strength, but if the joining temperature is increased, the silver and copper components in the silver brazing material will melt and separate, which can reduce the joining strength with ceramic parts.

In addition, when joining to a metal part using an active metal brazing material, a joining layer with the ceramic is formed with an active metal brazing material paste, and then the joining layer with the metal is formed with the active metal brazing material at a higher temperature than that for brazing. For this reason, the melting point of the active metal brazing material paste is higher than that of the brazing material. In order to increase the melting point of this active metal brazing material paste, it is necessary to contain a large amount of metals with high melting points such as copper (Cu) and silver (Ag), which is prone to melting and separating from other brazing material metal components during the heating process. This melting and separating can cause uneven joining and lead to leak defects and crack defects. In addition, the brazing material is often processed into a foil shape, etc., and in the case of small quantities and a wide variety of products, it is necessary to process the brazing material parts many times, which is a cause of cost.

The embodiments are intended to solve such problems, and relate to a highly productive ceramic sealed part and a manufacturing method thereof that suppresses poor joining and leak defects when a ceramic part and a metal part are joined with an active metal brazing material.

In the embodiment, a ceramic sealed component in which a ceramic component and a metal component are bonded by a bonding layer containing silver, copper, and an active metal has silver and copper melted in the bonding layer. When the cross section of the central part of the bonding layer is divided into 20 or more layers, the mass percentages of silver, copper, and the active metal are measured, and the mass percentages of the bonding layer are plotted from the ceramic component side to the metal component side, the maximum value (Wm) of the active metal mass percentage is
The second largest maximum value of the active metal mass% is 0.7 times or less than the maximum value (Wm), the minimum value of the copper mass% is 0.3 times or more than the maximum value (Wc), and the silver mass% up to 1/4 of the ceramic part side is 0.7 times or less than the maximum value (Wm).
The maximum value of is 0.3 times or more and 0.5 times or less of the maximum value (Wa)

In addition, in the ceramic sealing part of the embodiment, in the plot of copper mass%, 0.5Wc
The range below is 40% or less, and in the plot of silver mass, the range below 0.5 Wa is 5
It is below 0%.

In the ceramic sealed component of the embodiment, the active metal brazing material is one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing material metals selected from copper and silver.

Furthermore, in the ceramic sealed component of the embodiment, the thickness of the bonding layer is 70 μm or more.

In the ceramic sealing component of the embodiment, the metal component is iron or an iron alloy, an iron-nickel alloy, or copper or a copper alloy.

In addition, in the ceramic sealing part of the embodiment, the ceramic part is alumina.

In addition, in an embodiment of a manufacturing method for a ceramic sealed part that joins a ceramic part and a metal part, a paste made of an active metal brazing material containing copper is printed on the ceramic part, dried, and heated to form an active metal brazing material layer on the end face of the ceramic part, a paste made of a brazing material containing silver is printed and dried on the formed active metal brazing material layer, and then the metal part is placed on it and heat-treated to form a brazing material layer, thereby joining the ceramic part and the metal part.

In addition, in the embodiment of the manufacturing method for a ceramic sealed part that joins a ceramic part and a metal part, the heating temperature (T1) of the active metal brazing material layer is 800°C or less, the heating temperature (T2) of the brazing material layer is 820°C or less, and the difference in heating temperatures (T2-T1) is 20°C or more.

In addition, in the embodiment of the manufacturing method for a ceramic sealed part that joins a ceramic part and a metal part, the printing thickness of the paste made of the active metal brazing material is 20 μm or more, and the thickness of the paste made of the silver-containing brazing material is 50 μm or more.

In addition, in the manufacturing method of the embodiment for joining a ceramic part and a metal part, a paste made of a brazing material containing silver is printed on the entire surface of the active metal brazing material layer made of the active metal brazing material.

FIG. 1 is a perspective view showing an example of a ceramic sealing component according to an embodiment; FIG. 1 is a cross-sectional view of a ceramic sealing component according to an embodiment of the present invention; FIG. 1 is a cross-sectional view showing an example of a joint portion of a ceramic sealing component according to an embodiment; FIG. 1 is a diagram showing an example of a manufacturing process for a ceramic sealing component according to an embodiment. FIG. 1 is an enlarged view of an example of a cross section of a joint of a ceramic sealed component according to an embodiment; FIG. 1 is a diagram showing a mass percentage of an example of a cross section of a joint of a ceramic sealing component according to an embodiment. FIG. 1 is a diagram showing a mass percentage of an example of a cross section of a joint of a ceramic sealing part according to a comparative example. FIG. 1 is a diagram showing a mass percentage of an example of a cross section of a joint of a ceramic sealing part according to a comparative example.

In the embodiment, a ceramic sealed component in which a ceramic component and a metal component are bonded by a bonding layer containing silver, copper, and an active metal has silver and copper melted in the bonding layer. When the cross section of the central part of the bonding layer is divided into 20 or more layers, the mass percentages of silver, copper, and the active metal are measured, and the mass percentages of the bonding layer are plotted from the ceramic component side to the metal component side, the maximum value (Wm) of the active metal mass percentage is
The second largest maximum value of the active metal mass% is 0.7 times or less than the maximum value (Wm), the minimum value of the copper mass% is 0.3 times or more than the maximum value (Wc), and the silver mass% up to 1/4 of the ceramic part side is 0.7 times or less than the maximum value (Wm).
The maximum value of is 0.3 to 0.5 times the maximum value (Wa).

In addition, in an embodiment of a manufacturing method for a ceramic sealed part that joins a ceramic part and a metal part, a paste made of an active metal brazing material containing copper is printed on the ceramic part, dried, and heated to form an active metal brazing material layer on the end face of the ceramic part, a paste made of a brazing material containing silver is printed and dried on the formed active metal brazing material layer, and then the metal part is placed on it and heat-treated to form a brazing material layer, thereby joining the ceramic part and the metal part.

FIG. 1 shows an example of a perspective view of a ceramic sealing part 1 according to an embodiment. 3 is a cylindrical ceramic part, and 2 is a cylindrical metal part. FIG. 1 shows an example in which a metal part 2 is joined to the upper end face and the lower (opposite) end face of the ceramic part 3. The embodiment is not limited to this shape, and may be a ceramic part or a metal part in a rectangular tube shape, a form in which the lower bottom face is a ceramic part and only the upper side (one side) is joined to a metal part, or a ceramic part having two or more openings on one side to which a metal part is joined.

In the ceramic sealing part 1 according to the embodiment, for example, the ceramic part 3 is a cylindrical ceramic part made of alumina, and a bonding layer is provided on a part of the surface of the ceramic part. The bonding layer here is made of copper (Cu) on the ceramic part side,
Metals such as silver (Ag) and titanium (Ti), zirconium (Zr), and hafnium (
The metal part 2 is a mixture of an active metal such as kovar (
It is a cylindrical metal part made of Fe--Ni--Co or copper (Cu).

FIG. 2 shows an example of a cross-sectional view of a ceramic sealing part according to an embodiment. 1 is a ceramic sealing part, 2 is a metal part, and 3 is a ceramic part. The ceramic part 3 is preferably one of alumina, aluminum nitride, silicon nitride, and zirconia-added alumina (Alzir). Alumina includes alumina-based ceramics in which other ceramics are added to alumina. For example, zirconia-added alumina is a sintered body in which alumina and zirconium oxide are mixed. In addition, a sintering aid other than zirconia may be added to alumina. This is because the added sintering aid forms a grain boundary phase made of a glass phase to densify the alumina sintered body. Examples of sintering aids include compounds of manganese (Mn), silicon (Si), magnesium (Mg), calcium (Ca), and the like. These are referred to as Mn, Si,
It is preferable to add at least one of Mg and Ca in a total amount of 1 to 15 mass % calculated as a single metal element. Also, it is preferable that the ceramic part is alumina, which has good cost performance as an insulating sealed part.

The material of the metal part 2 to be joined to the ceramic part 3 is preferably iron (Fe) and iron alloys, iron-nickel alloys, copper (Cu) and copper alloys, tungsten (W), and molybdenum (Mo). The iron alloys include carbon steels such as rolled steel, and alloy steels such as chromium steel.
Nickel-based alloys include 42 alloy (Ni 42 mass%, Mn 0.8 mass% or less, balance Fe), Kovar (Ni 29 mass%, Co 17 mass%, balance Fe), etc. Iron and iron alloys are excellent in cost performance, while iron-nickel alloys are excellent in physical properties such as thermal expansion coefficient. Copper and copper alloys are easily deformed to relieve stress due to thermal expansion difference, and it is preferable to form metal parts from copper and copper alloys when the influence of heat is large. Copper alloys include pure copper such as oxygen-free copper, tough pitch copper, and deoxidized copper, and high copper alloys such as beryllium copper and titanium copper. For this reason, it is preferable to form metal parts from iron and iron alloys, iron-nickel alloys, copper and copper alloys depending on the application.
In addition, it is possible to use two or more types of metal parts, such as Kovar on one side and copper on the other side. Metal parts are manufactured by processing them into a desired shape through pressing, cutting, bending, etc. Furthermore, plating with nickel or other metals is possible to improve corrosion resistance and wettability.

Fig. 3(a) is an enlarged view of part A in Fig. 2, showing an example of a cross section of a joint of a ceramic sealed component according to an embodiment. In Fig. 3(a), the tip of the metal component is bent and is joined to the ceramic component in a flat plane via a joining layer. Fig. 3(b) is an enlarged view of part A in Fig. 2.
In this case, the tip of the metal part is joined to the ceramic part in a line (end surface) in the circumferential direction via a joining layer.

The joint is formed at a low temperature using a brazing material containing an active metal that easily wets the ceramics. To prevent a decrease in strength due to the dissolution of silver and copper, copper is selected, which is more cost-effective than silver, and components such as tin (Sn), which has a low melting point, are added to lower the melting point of copper. In addition, since the active metal of the active brazing layer reacts with hydrogen and becomes embrittled, which is prone to leak defects, the active brazing layer is printed so as to cover it with silver brazing paste, and the metal parts are joined by heating in a nitrogen-hydrogen atmosphere. If the heating temperature is too high, the silver in the silver brazing material will diffuse too much into the active brazing layer, so it is set to be below the brazing temperature +50°C.
Moreover, if the heating temperature is too low, the brazing paste will not wet the active brazing metal layer, so the temperature is set to be 20° C. higher than the brazing temperature.

The active metal brazing material 4 uses an active metal such as Ti (titanium). Examples of active metals other than Ti include Zr (zirconium) and Hf (hafnium). Examples of the active metal brazing material include a mixture of Ti and copper (Cu). For example, Ti is 0.1 to 10 mass%, and Cu is the remainder. Examples of other active metal brazing materials include a mixture of Ti, Ag, and Cu. Ti is 0.1 to 10 mass%, Cu is 10 to 60 mass%, and Ag is the remainder. In addition, when controlling the diffusion of the active metal brazing material during bonding, 1 to 15 mass% of one or more selected from indium (In), tin (Sn), aluminum (Al), silicon (Si), carbon (C), and magnesium (Mg) may be added as necessary. The active metal brazing material paste is printed on the surface of the ceramic part and then dried. Thereafter, the ceramic part is heated at 750 to 800°C in a vacuum or in a non-oxidizing gas to form a metallized layer (bonding layer) on the surface of the ceramic part. Next, a silver brazing paste is printed on the surface of the metallized layer and then dried. After that, a metal part is placed in contact with the printed and dried paste surface, and the ceramic part and the metal part are joined by heating at 780 to 820°C in a vacuum or in a non-oxidizing gas.

4 shows a process diagram of the manufacturing method of the ceramic sealing part of FIG. 3(b) according to the embodiment. FIG. 4(a) is a cross-sectional view of the ceramic part 3. In FIG. 4(a), chamfers are formed on the outer and inner peripheries. Although it is possible to manufacture the ceramic part without chamfering, the end faces of the ceramic part are easily chipped due to external impacts, etc., and this is effective in preventing chipping.
4(b) shows the state in which an active metal brazing material paste is printed on a ceramic part 3, dried, and then heated in a vacuum or in a non-oxidizing gas to form an active metal brazing material layer 4. The surface of the active metal brazing material layer 4 before joining is approximately flat because the paste is printed on the flat end surface of the ceramic part. In FIG. 4(b), the active metal brazing material paste is printed only on the flat portion of the end, but it is also possible to print the active metal brazing material on the chamfered portion as well.

FIG. 4(c) shows the state in which the brazing paste 6 is printed and dried on the surface of the joining layer. Since the active metal brazing paste contains an active metal that is prone to hydrogen embrittlement, it is preferable that the brazing paste covers the entire surface of the active metal brazing paste after joining. When printing the same print pattern as the active metal brazing paste, it is possible to spread and cover the entire surface during printing by making the viscosity of the brazing paste slightly lower than that of the active metal paste. It is also possible to print a print pattern larger (wider) than the print pattern of the brazing paste so as to cover the entire surface of the active metal brazing layer. If the print pattern is made too large, the brazing paste will not react with the ceramic parts when heated and will gather on the active metal brazing layer or the metal parts. At this time, if the brazing paste is present in the form of a mass around the active metal brazing layer or the metal parts, it will cause stress concentration. For this reason, when making the print pattern of the brazing paste larger, it is preferable to make it 0.1 mm or less larger than the print pattern of the active metal brazing paste.

Fig. 4(d) shows the state where the metal part 2 is placed on the surface of the printed and dried brazing paste 6. When joining multiple metal parts 2 as in Fig. 2, they are placed at the same time. In this state, the metal parts 2 are joined by heating.

4(e) shows the state where the metal part 2 is joined. The brazing filler metal layer 5 creeps up onto the side surface of the metal part 2 to form a strong joint. In this way, the brazing filler metal layer 5 covers the metal part 2, enabling leak-free sealing inside and outside the part.

Next, a method for manufacturing the ceramic sealing part according to the embodiment will be described. As long as the ceramic sealing part has the above-mentioned configuration, the manufacturing method is not particularly limited.
The following methods can be used to obtain a high yield.

An example of the ceramic part according to the embodiment has a cylindrical shape, for example, an outer diameter of 50 mm, an inner diameter of 38 mm, and a height of 50 mm. Ceramic parts are prone to chipping and cracking at their corners due to external impacts. For this reason, it is preferable to chamfer the outer and inner peripheries of the end faces. The shape of the chamfer may be, for example, C-chamfer or R-chamfer, and the size of the chamfer is preferably 0.1 to 2 mm.

The materials of the metal parts according to the embodiment include iron and iron alloys, copper and copper alloys, iron-nickel alloys such as 42 alloy and Kovar, tungsten, molybdenum, etc. Kovar has excellent physical properties such as thermal expansion coefficient, while copper and copper alloys are easily deformed to relieve stress caused by the difference in thermal expansion. For this reason, it is preferable to form metal parts from Kovar, copper, and copper alloys.

An example of the shape of the metal part according to the embodiment is a substantially cylindrical shape. For example, the height is 20 mm, and in the case of FIG. 3(a), the part without the tip machined has an outer diameter of 48 mm and an inner diameter of 46 mm. The tip is a flange shape that is bent inwardly and substantially perpendicularly, and has a length of 4 mm. The metal part having the above shape is formed into a cylindrical shape by pressing or the like, and then the tip is formed into a flange shape by pressing or drawing. It is also possible to obtain a bent shape by punching out the bottomed cylindrical shape with a press, leaving the bent part. Also, in the case of FIG. 3(b), the outer diameter is 46 mm, the inner diameter is 4
These metal parts can be plated with nickel or other materials to improve corrosion resistance and wettability.

The active metal brazing material and brazing material are in the form of a paste. Sheets and wires require a process in which the active metal brazing material is melted and processed into a sheet or wire shape, and then processed to the specified dimensions to match the product shape. In contrast, pastes, although there is a process for manufacturing the paste, are easy to handle, as they can be printed in the required locations to match the product shape. In addition,
If the amount of active metal brazing material is too small, unjoined areas will occur, resulting in braze breaks, while if there is too much, braze puddles will occur, which can lead to stress fractures. Therefore, it is possible to adjust the amount of active metal brazing material used according to the brazing area.

The active metal brazing paste is prepared by mixing active metal powder with brazing metal powder, to which an organic binder and an organic solvent are added. There are no particular limitations on the organic binder, so long as it is burned away during the drying process or the joining (heating) process. A preferred example is ethyl cellulose. There are no particular limitations on the organic solvent, so long as it is burned away during the drying process or the firing process. Preferred examples are terpineol and butyl carbitol. The active metal brazing paste is prepared, for example, by crushing and mixing active metal powder and brazing metal powder, and then mixing them with an organic binder and an organic solvent. In addition,
The ratio of the active metal contained in the active metal brazing material component is 0.1 to 15 mass %, preferably 0.5
Up to 10% by mass.

The printing thickness of the active metal brazing paste is preferably 20 to 100 μm. If the printing thickness is less than 20 μm, the thickness of the active metal brazing layer varies, lowering the joining strength. On the other hand, if it exceeds 100 μm, no further effect can be obtained. The paste is printed in a uniform thickness on the end surface of the ceramic component by screen printing or the like. If the printing thickness is not uniform, the active metal brazing material will be excessive in the thick parts, causing brazing material to accumulate and cracks due to thermal stress. In addition, in the thin parts, leakage defects will occur due to breakage of the active metal brazing material. For this reason, it is preferable that the difference in printing thickness between the thick and thin parts is 15 μm or less, and more preferably 10 μm or less.

The paste printed on the ceramic parts is dried in the air or the like. If the drying temperature is low and the drying time is short, the solution components of the paste are not sufficiently volatilized, and voids may occur during bonding. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface may progress, and the bonding temperature may change. For this reason, the drying temperature is 50 to 100°C, preferably 60 to 80°C. The drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

After the paste is dried, the metal parts are placed on the dried paste surface and heated to bond. The bonding temperature is 600 to 850°C, preferably 700 to 800°C. The bonding time is preferably in the range of 5 to 60 minutes after the bonding temperature is reached. If the bonding temperature is low and the bonding time is short, the active metal brazing material may not melt sufficiently and bonding may not be performed. Conversely, if the bonding temperature is high and the bonding time is long, the active metal brazing material may melt too much and spread, causing voids. The active metal bonding atmosphere is, as necessary, in a vacuum or a non-oxidizing atmosphere. When performing in a vacuum, it is preferable that the pressure is 1×10 ⁻² Pa or less. Examples of the non-oxidizing atmosphere include a nitrogen atmosphere and an argon atmosphere. By performing in a vacuum or a non-oxidizing atmosphere, the active metal brazing material layer can be prevented from being oxidized. This improves the bonding strength. A continuous furnace or a batch furnace is used as the furnace used for brazing. A continuous furnace is superior in terms of mass production, and a batch furnace is easier to control the temperature and atmosphere. The active metal brazing material layer is formed by heating for a predetermined time in the above atmosphere.

Brazing paste is composed of metal parts, active metal brazing material, and metal with good wettability. The brazing material most often used to join ceramics and metal parts is silver brazing. Silver brazing is mainly composed of silver and copper, but may also contain other metal components such as zinc and nickel. Silver brazing (BAg-8), which is made of 72% silver and 28% copper, is often used to join ceramics and metal parts.
In BAg-8 according to "Silver solder (JIS Z3261:1998)", silver (A
g) 71-73%, copper (Cu) 27-29%, and total of other elements 0.15% or less. The brazing paste is a mixture of brazing metal powders to which an organic binder and an organic solvent are added. There are no particular limitations on the organic binder as long as it is burned away during the drying process or the joining (heating) process. A preferred example is ethyl cellulose. There are no particular limitations on the organic solvent as long as it is burned away during the drying process or the firing process.
Preferred examples include terpineol and butyl carbitol. The brazing paste is prepared, for example, by crushing and mixing metal powder, and then mixing it with an organic binder and an organic solvent.

The printing thickness of the brazing paste is preferably 50 to 200 μm. If the printing thickness is less than 50 μm, the thickness of the brazing paste layer varies, reducing the joining strength. On the other hand, if it exceeds 200 μm, no further effect can be obtained. The paste is printed in a uniform thickness on the end surface of the ceramic component by a screen printing method or the like. If the printing thickness is not uniform, the brazing paste will be excessive in the thick parts, causing brazing paste pools and cracks due to thermal stress. In addition, in the thin parts, leakage defects will occur due to breakage of the active metal brazing paste. For this reason, it is preferable that the difference in printing thickness between the thick and thin parts is 20 μm or less, and more preferably 15 μm or less.

The brazing paste printed on the active brazing metal layer is dried in the air or other atmosphere. If the drying temperature is low and the drying time is short, the solution components of the paste are not sufficiently volatilized, and voids may occur during bonding. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface may progress, and the bonding temperature conditions may change. For this reason, the drying temperature is set to 50 to 100
The drying time is 5 to 30 minutes, preferably 10 to 20 minutes.
It is 0 minutes.

After the brazing paste is dried, the metal part is placed on the dried paste surface and heated to bond the parts. The bonding temperature is 650 to 900°C, preferably 750 to 820°C. The bonding time is preferably 5 to 60 minutes after the bonding temperature is reached.
) the brazing material layer 5 melts and wets and spreads over the surface of the metal part 2 to form a bond, resulting in a bond with a seal. If the bonding temperature is low and the bonding time is short, the active metal brazing material may not melt sufficiently to form a bond. Conversely, if the bonding temperature is high and the bonding time is long, the brazing material may melt too much and wet and spread, resulting in brazing failure and voids.

Furthermore, the brazing and joining atmosphere is a non-oxidizing atmosphere as necessary. Examples of non-oxidizing atmospheres include a nitrogen atmosphere and a hydrogen nitrogen atmosphere. By using a non-oxidizing atmosphere, the joining layer can be prevented from being oxidized. This improves the joining strength. A continuous furnace or a batch furnace is used for brazing. A continuous furnace is superior in terms of mass production, while a batch furnace allows for easy control of the temperature and atmosphere. Brazing is performed by heating the parts in the above atmosphere for a specified period of time.

The thickness of the bonding layer that bonds the ceramic part and the metal part is preferably 70 μm or more. This is because, as described above, the bonding layer is formed from an active metal brazing material layer of 20 μm or more and a brazing material layer of 50 μm or more. The thickness of the bonding layer at this time indicates the distance between the bonding surface of the metal part and the ceramic part. For example, in FIG. 3(a), the tip of the metal part 2 is bent into a flange shape and is bonded to the ceramic part 3 on a flat surface. Therefore, the thickness of the bonding layer is approximately the center part of the bent part. Also, in FIG. 3(b), the end face of the metal part 2 is bonded to the ceramic part 3. Therefore, the thickness of the bonding layer is approximately the center part of the end face of the metal part 2. Furthermore, if the tip of the metal part 2 is pointed, such as U-shaped or V-shaped, the thickness of the bonding layer is the pointed tip part.

FIG. 5 shows an enlarged view of the portion B in FIG. 3(b). In FIG. 5, the portion B is 20 mm thick.
The divided state is shown in schematic form. The mass percentage of the constituent elements of each divided portion is measured using an energy dispersive X-ray fluorescence analyzer (EDX). When the mass percentage of the bonding layer is plotted from the ceramic part side to the metal part side, the maximum value of the active metal mass percentage (Wm),
There is a maximum value of copper mass % (Wc) and a maximum value of silver mass % (Wa). When there are two or more maximum values, the larger value is regarded as each maximum value.

In one example of a ceramic sealed component according to the embodiment, the central 200 μm of the cross section of the joint was divided into 3.6 μm widths (heights), and the following was measured by an energy dispersive X-ray fluorescence analyzer (EDX):
The mass percentage of the constituent elements is measured. FIG. 6 shows a plot of mass percentage of elements for an example of a cross section of a joint of a ceramic sealed component according to an embodiment. In FIG. 6, (a) titanium (
The graph plots the mass % (wt %) values of (a) Ti), (b) copper (Cu), and (c) silver (Ag) at each location (distance) from the ceramic side to the metal side. The plots are on the smaller side, for example, values of 0 to 3.6 μm are plotted at 0 μm on the X-axis.

In FIG. 6, the second largest maximum value of active metal mass% (Wm2) is 6.0 mass%.
Wm) 12.2 mass%, which is 0.49 times or less than 0.7 times. When the active metal brazing material is heated, the active metal reacts with the ceramics to form a bonding layer, so the maximum value of the active metal exists on the ceramic side. When the brazing material paste is printed and heated (heating temperature (T2)), part of the active metal diffuses into the brazing material layer. At this time, if the heating temperature (T2) is low, the effect on the active metal bonding layer is small, and therefore the effect on the magnitude of the maximum value is small. Heating temperature (T
When 2) is high, the active metal layer of the brazing material layer diffuses widely, so that the maximum value of the active metal in the brazing material layer becomes larger than 0.7 times the maximum value (mass). In this case, if the active metal required for bonding is insufficient, the bonding strength decreases.

In Figure 6, the minimum value of copper mass % is 21.1 mass %, which is 0.37 times the maximum value (Wc) of 56.6 mass %, and is more than 0.3 times. For example, when the brazing material used is BAg-8 brazing material, the copper content is 28%, so when an active metal brazing material containing more copper is used as the active metal brazing material, the maximum value of copper is on the ceramic part side. Heating temperature (T
When the heating temperature (T 2) is low, the effect on the active brazing metal layer is small, so that the minimum value as shown in FIG. 6 does not exist, or the effect on the maximum value is small, being 0.3 times or less.
When 2) is high, the silver and copper in the brazing material melt and separate, so the joint strength is greater than 50%. When the metals in the brazing material melt and separate, the joint strength decreases. If there are two or more minimum values, the smallest value is taken as the minimum value.

In addition, in FIG. 6, the maximum mass percent of silver up to 1/4 of the distance on the ceramic part side was 28.7
The maximum value (Wa) of 63.0 mass% is 0.46 times, which is 0.3 times or more and 0.5 times or less. This is a state in which the brazing material containing silver is moderately diffused into the active metal brazing material layer. When the brazing material is moderately diffused into the active metal brazing material layer, the active metal brazing material and the brazing material layer are firmly bonded to each other.

In addition, in the plot of copper mass % in FIG. 6, the range of 0.5Wc or less is 6 out of 27 points, or 22.2%, which is within the range of 40% or less. If the range of 0.5Wc or less is 40% or less,
There is a sufficient amount of copper that contributes to bonding and sealing. If the range of 0.5Wc or less exceeds 40%, there will be areas where constituent elements other than copper are excessive, which will cause bonding failure and leakage failure.

In addition, in the plot of silver mass % in Fig. 6, 13 out of 27 points, or 48.1%, are in the range of 0.5Wa or less. This is within the range of 50% or less. If the range of 0.5Wc or less is 40% or less, there is sufficient silver that contributes to bonding and sealing. If the range of 0.5WC or less exceeds 40%, there will be areas where constituent elements other than silver are excessive, which will cause bonding failure and leak failure.

FIG. 7 is a plot of mass % active metal when the heating temperature (T2) is low.
The second largest maximum value was 4.9 mass%, which is 0.7 times the maximum value (Wm) of 9.4 mass%. However, the minimum value of the copper mass% was 10.1 mass%, which is 57.3 mass%.
This is smaller than 0.18 and 0.3 times. This indicates that there are places in the bonding layer where copper is not present in sufficient amounts, which can cause bonding failures and leak failures. In addition, the maximum mass percent of silver up to 1/4 of the distance from the ceramic part side is 20.3 mass%, which is 0.27 times the maximum value (Wa) of 75.0 mass. This is because the brazing material containing silver is not sufficiently diffused into the active metal brazing material layer. If the brazing material is not sufficiently diffused, the bond between the active metal brazing material and the brazing material will be weak, which can cause bonding failures and leak failures.

In addition, in Fig. 7, in the plot of copper mass%, 10 out of 24 points, 41.1%, are in the range of 0.5Wc or less, which is outside the range of 40% or less. If the range of 0.5Wc or less exceeds 40%, there will be parts where the constituent elements other than copper are excessive, which will cause poor bonding and leaks. In addition, in the plot of silver mass, 13 out of 27 points, 48.1%, are in the range of 0.5Wa or less.
If the range of 0.5Wc or less is 40% or less, there is a sufficient amount of silver that contributes to bonding and sealing. If the range of 0.5Wc or less exceeds 40%, there will be areas where constituent elements other than silver are excessive, which will cause bonding failure or leakage failure.

FIG. 8 is a plot of mass% when the heating temperature (T2) is high. In FIG. 8(a), the second largest maximum value of active metal mass% is 12.0 mass%, which is larger than 0.85 and 0.7 times the maximum value (Wm) of 14.1 mass%. This indicates that a bonding layer of a sufficient amount of active metal cannot be formed near the surface of the ceramic parts. If there is a small amount of active metal that contributes to the bonding of the ceramic parts, it will cause poor bonding and leak failure near the ceramic parts. In addition, the minimum value of copper mass% is 3.6 mass%, which is 0.05 times the maximum value (Wc) of 79.2 mass%, which is smaller than 0.3 times. This indicates that there are places in the bonding layer where copper is not sufficiently present, which will cause poor bonding and leak failure. In addition, the maximum value of silver mass% up to 1/4 of the ceramic part side is 0.6 mass%, which is 0.01 times the maximum value (Wa) of 86.9 mass%, which is small. This is because the brazing material containing silver is not sufficiently diffused into the active metal brazing material layer. If the brazing material is not sufficiently diffused, the bond between the active metal brazing material and the brazing material will be weak, causing poor bonding and leaks.

In addition, in FIG. 8, in the plot of copper mass%, 10 out of 22 points are in the range of 0.5Wc or less, which is 45.5%, and is outside the range of 40% or less. If the range of 0.5Wc or less exceeds 40%, parts with excess of constituent elements other than copper will occur, which will cause poor bonding and leaking. In addition, in the plot of silver mass, 15 out of 22 points are in the range of 0.5Wa or less, which is 68.2%, and is outside the range of 50% or less. If the range of 0.5Wc or less exceeds 50%, parts with excess of constituent elements other than silver will occur, which will cause poor bonding and leaking.

According to the method for manufacturing a ceramic sealed component in the embodiment of the present invention, a ceramic sealed component excellent in cost performance can be obtained while maintaining the airtightness of the sealed component.

(Examples 1 to 8, Comparative Examples 1 to 8)
Alumina was added with manganese oxide (MnO ₂ ), silicon oxide (silica: SiO ₂ ), and magnesium oxide (magnesia: MgO) as auxiliary agents to prepare granulated powder having a composition of 92% alumina by mass. The granulated powder was molded with a die press and sintered in air at 1500°C to obtain a cylindrical ceramic part with an outer diameter of 50 mm, an inner diameter of 40 mm, a height of 50 mm, an outer diameter C chamfer of 0.5 mm, and an inner diameter C chamfer of 0.5 mm. Aluminum nitride granulated powder was also prepared by adding 3% by mass of yttria (yttrium oxide: Y ₂ O ₃ ) as auxiliary agent to aluminum nitride (AlN). The granulated powder was molded with a die press and sintered in nitrogen at 1800°C to obtain a cylindrical ceramic part with the same dimensions as the alumina part.

The metal parts were obtained by pressing copper, kovar, and iron into a cylindrical shape with an outer diameter of 46 mm, an inner diameter of 44 mm, and a height of 20 mm, as shown in Table 1. The surfaces of the processed iron parts were plated with nickel to a thickness of 2 μm.

Next, a mixture of copper powder, tin powder, and titanium hydride (TiH) powder was mixed in a ratio of 60:1 by weight.
The mixture was mixed with ethyl cellulose and terpineol to make a paste in a kneader to prepare an active metal brazing paste. The active metal paste was printed to a thickness of 30 μm on the upper and lower ends (ring portions) of the ceramic part by screen printing using a 100 mesh screen with an outer diameter of 48 mm and an inner diameter of 42 mm, and dried at 100° C. in air. The ceramic part with the dried active metal brazing paste was heated in a continuous furnace in a nitrogen atmosphere at a heating temperature (T1).
By heating for the above 10 minutes, an active metal brazing material layer was formed on the end face of the ceramic part.

Next, silver powder and copper powder were mixed so that the metal powder compounding ratio was 72:28 by weight percent, and the mixture was made into a paste in the same manner as in the active metal brazing paste, to prepare a silver brazing paste.
A brazing paste was printed to a thickness of 100 μm by screen printing using a 2 mm 100 mesh screen, and then dried at 100° C. in air.
The metal parts are placed on the jig in the correct order and heated in a hydrogen nitrogen atmosphere continuous furnace for 10 minutes at a heating temperature (T2).
By heating for 10 minutes, the metal part and the ceramic part were joined to produce a ceramic sealed part.

In addition, for measuring the bonding strength, a metal plate measuring 10 mm x 100 mm x 0.1 mm was used instead of the metal part, and the metal plate, ceramic part, and metal plate were set in a jig in that order and bonded by heating to prepare a bonding strength test sample.

As can be seen from Table 1, in the examples, the heating temperature (T1), the brazing material printing thickness, and the heating temperature (T
2) The temperature difference (T2-T1) was within the preferred range, whereas in the comparative example, it was outside the preferred range.

Next, the ceramic sealed part was cut at the center as shown in Figure 2, the joint was polished, and the center of the joint was divided into 200 μm parts with a width (height) of 3.6 μm as shown in Figure 5, and the mass percentages of the constituent elements were measured using an energy dispersive X-ray fluorescence analyzer (WDX). The elements of titanium, copper, and silver were plotted on graphs as shown in Figures 7 to 9, and the maximum values of the active metal mass percentages (
Wm), the second maximum value of active metal mass% (Wm2), the maximum value of copper mass% (Wc), and copper mass%
The minimum value of active metal mass % (Wcl), the maximum value of silver mass % (Wa), the maximum value of silver mass % up to 1/4 of the ceramic part side (Waq), the range of 0.5Wc or less in the plot of copper mass %, and the range of 0.5Wa or less in the plot of silver mass were obtained from the obtained values.
the second maximum value of active metal mass% (Wm2/Wm) relative to the maximum value of active metal mass%, the minimum value of copper mass% (Wcl/Wc) relative to the maximum value of copper mass%, the maximum value of silver mass% up to 1/4 of the ceramic part side relative to the maximum value of silver mass%, and the 0.5% value in the plot of copper mass%.
The percentage of the range below Wc and the percentage of the range below 0.5Wa in the plot of silver mass were calculated. The results are shown in Table 2.

As can be seen from Table 2, the bonding strength of the examples was a good value of 60 MPa or more. In contrast, the bonding strength of the comparative examples was 55 MPa or less. Under the bonding conditions of the examples, the ceramics and the active metal brazing material, the active metal brazing material and the brazing material, and the brazing material and the metal part reacted with each other to form a strong bonding layer. In contrast, under the bonding conditions of the comparative examples, the reaction did not proceed as much as in the examples, leading to a decrease in bonding strength.

Next, the metal plate of the bonding strength test sample was bent at a right angle and pulled upward with an Instron tensile tester to determine the bonding strength. In addition, the upper part of the ceramic sealed part after the test was pressed down with silicone applied with a circular jig made of Viton rubber, and the lower part was fixed to a helium leak detector and sucked to perform a helium leak test. The helium leak test was performed in accordance with the vacuum spray method (spray method) of "Helium Leak Test Method" (JIS Z2331:2006), and the case where no leakage of 1×10 ⁻⁹ Pa·m ³ /s or more occurred at a vacuum degree of 1.3 μPa was judged as pass (◯), and the case where leakage occurred was judged as fail (×).

Furthermore, the ceramic sealed parts that passed the helium leak test were subjected to TCT (Thermal Conductivity Test).
After performing 80 cycles of a temperature cycle test (temperature cycle test) at a low temperature of -40°C for 30 minutes and a high temperature of 125°C for 30 minutes, a helium leak test was performed. If no leakage occurred, it was evaluated as a pass (o), and if leakage occurred, it was evaluated as a fail (x). The test results for the examples and comparative examples are shown in Table 3.

As can be seen from Table 2, the bonding strength of the examples was a good value of 0.60 MPa or more. In contrast, the bonding strength of the comparative examples was 0.55 MPa or less. Under the bonding conditions of the examples, the ceramics and the active metal brazing material, the active metal brazing material and the brazing material, and the brazing material and the metal part reacted with each other to form a strong bonding layer. In contrast, under the bonding conditions of the comparative examples, the reaction did not proceed as much as in the examples, leading to a decrease in bonding strength.

Furthermore, the ceramic sealed parts according to the examples did not suffer from leak defects in the helium leak test. This is because the joint distance between the ceramic parts and the metal parts was sufficient, and because the joint strength was ensured by the joint layer consisting of the active metal brazing material layer and the brazing material layer, and the thermal expansion difference was reduced. In contrast, leak defects occurred in the comparative examples. This is because the joint strength was not high enough, and because the joint part was damaged due to the thermal expansion difference between the ceramic parts and the metal parts, and airtightness could not be maintained.

In addition, the ceramic sealed parts according to the examples did not have any leak failures in the helium leak test after TCT. This is because the bonding distance between the ceramic parts and the metal parts was sufficient, the bonding strength was ensured by the bonding layer consisting of the active metal brazing material layer and the brazing material layer, and the low bonding temperature reduced damage to the bonding layer due to the thermal stress of heating and cooling. In contrast, in the comparative example, a helium leak failure occurred after TCT. This is because the bonding strength was sufficiently ensured by the bonding layer consisting of the active metal brazing material layer and the brazing material layer, and the thermal expansion difference was not sufficiently alleviated, so that the bonding layer was damaged by the thermal stress of heating and cooling, creating a leak path.

As is clear from the results shown above, the examples have improved leak characteristics and TCT compared to the comparative examples.
An improvement in reliability was observed.

Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments include:
The present invention can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. In addition, the above-mentioned embodiments can be implemented in combination with each other.

1...ceramic sealed part 2...metal part 3...ceramic part 4...active metal brazing material layer 5...brazing material layer 6...brazing material paste

Claims (10)

In a ceramic sealed component in which a ceramic part and a metal part are bonded with a bonding layer containing silver, copper, and an active metal,
Silver and copper are molten in the bonding layer,
When the cross section of the central portion of the bonding layer is divided into 20 or more layers, the mass percentages of silver, copper, and active metal are measured, and the mass percentages are plotted from the ceramic component side to the metal component side of the bonding layer, there is a maximum value of the active metal mass percentage (Wm), a maximum value of the copper mass percentage (Wc), and a maximum value of the silver mass percentage (Wa),
A ceramic sealed component, characterized in that the second largest maximum value of the active metal mass% is 0.7 times or less the maximum value (Wm), the minimum value of the copper mass% is 0.3 times or more the maximum value (Wc), and the maximum value of the silver mass% up to a distance of 1/4 of the ceramic component side is 0.3 to 0.5 times the maximum value (Wa). The ceramic sealed component described in claim 1, characterized in that in the plot of copper mass percentage, the range of 0.5Wc or less is 40% or less, and in the plot of silver mass, the range of 0.5Wa or less is 50% or less. The ceramic sealing part according to claim 1 or 2, characterized in that the active metal brazing material is one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing metals selected from copper and silver. A ceramic sealed part according to claim 1 or 2, characterized in that the thickness of the bonding layer is 70 μm or more. The ceramic sealed part according to claim 1 or 2, characterized in that the metal part is one or more metal parts selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys. The ceramic sealed part according to claim 1 or 2, characterized in that the ceramic part is alumina, aluminum nitride, silicon nitride, or aluminium. A method for manufacturing a ceramic sealed part that joins a ceramic part and a metal part, comprising the steps of: printing and drying a paste made of an active metal brazing material containing copper on an end surface of the ceramic part, and heating the printed paste at a heating temperature (T1) of 800°C or less to form an active metal brazing material layer on the end surface of the ceramic part; printing and drying a paste made of a brazing material containing silver so as to cover the entire surface of the formed active metal brazing material layer; placing the metal part on the ceramic part and heating the printed paste at a temperature (T2) of 820°C or less to form a brazing material layer; and joining the ceramic part and the metal part with a heating temperature difference (T2-T1) of 20°C or more . 8. The method for producing a ceramic sealed part according to claim 7, wherein the active metal brazing material is one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing metals selected from copper and silver . The method for manufacturing a ceramic sealed part according to claim 7 or 8, characterized in that the printing thickness of the paste made of active metal brazing material is 20 μm or more, and the thickness of the paste made of silver-containing brazing material is 50 μm or more. 9. The method for producing a ceramic sealed part according to claim 7 , wherein the metal part is one or more metal parts selected from the group consisting of iron, iron alloys, iron-nickel alloys, copper, and copper alloys .

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