JPH04331779A - Method for metallizing oxide based ceramics - Google Patents

Abstract

PURPOSE:To improve strength of oxide based ceramics without changing characteristics by forming a specific layer to the surface of an oxide based ceramic sintered body to form a specific layer and then forming the second layer thereon and then sintering these layers in an atmosphere such as hydrogen. CONSTITUTION:A paste obtained by mixing 100 pts. wt. mixed powder consisting of 70-95 pts. wt. tungsten powder having <=10mum average particle diameter and 30-5 pts. wt. glass powder having <=10mum particle diameter with 0.1-20 pts. wt. powder obtained by combining one or more kind of compound among pure substance, oxide and salt of Ni, Co, Pd, Fe, etc., and having <=50mum maximum particle diameter and kneading the mixture with an organic vehicle is applied to the surface of ceramic sintered compact 2 and dried to form a metallized lower layer 31 which is the first layer. Then an upper alloy layer 32 consisting of nickel, etc., is formed on the layer 31. Then the above-mentioned formed body is sintered at sintering temperature corresponding to the composition of the sintered compact 2 and layers 31 and 32 under atmosphere controlled so that ratio (r) of hydrogen and steam may have desired correlation to produce oxide based ceramics in which a metallized layer 3 is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for metallizing ceramics, and more particularly, to a method for metallizing oxide-based ceramics that has excellent vacuum sealing properties, brazing properties, and bonding strength.

0002

2. Description of the Related Art Electron tubes such as magnetron insulators for microwave ovens and vacuum switch envelopes are examples of devices that utilize the bonding of metals and oxide ceramics. When using metal and ceramic bonding for these,
The bonding interface must maintain vacuum sealing properties, and the bonding method that meets this condition is generally to metalize ceramics and then braze the ceramics with the mating metal after metallization. There is.

[0003] Many proposals regarding such metallization have been made in the past. However, conventional methods often require complicated processing and a long time to form a metallized layer that has both vacuum sealability and brazing properties, which poses major problems in terms of economy and work efficiency. . Therefore, the present applicant invented a metallization method that efficiently solved this problem, and filed an application earlier. This prior invention has been published as Japanese Patent Application Laid-Open No. 2-124787, and its outline is as follows. Furthermore, this Unexamined Patent Publication No. 2-12
The technique disclosed in Japanese Patent No. 4787 is hereinafter referred to as the Ni-W method.

Now, in the Ni-W method, a paste made by kneading a mixed powder of tungsten powder and glass powder in an organic vehicle is applied to the surface of an oxide-based ceramic sintered body, and then dried. One layer is formed, and then a paste made by kneading any one or a combination of two or more of nickel, nickel oxide, and nickel salt in the organic vehicle is applied to the top surface of the first layer. and then drying to form a second layer.

The mixed powder forming the first layer is 70 to 95 tungsten powder whose average particle size is adjusted to 10 μm or less.
The mixed powder forming the second layer contains one or two of nickel, nickel oxide, and nickel salt adjusted to an average particle size of 10 μm. It is a powder that is a combination of more than one species.

As mentioned above, after forming the first layer and the second layer on the ceramic surface, the ceramic sintered body is heated for 12 hours.
Firing is performed in the range of 00 to 1,400°C under atmospheric conditions in which the ratio of hydrogen to water vapor in the atmosphere is adjusted to be 1<(H2/H2O)<100000. During this firing, the tungsten powder of the first layer is sintered with an appropriate amount of voids. On the other hand, the glass powder in the paste melts, a part of which flows onto the surface of the ceramic sintered body and reacts with the ceramic. The remaining glass fills the voids in the tungsten without any gaps, forming a mixed layer of tungsten and glass (metallized lower layer).

On the other hand, nickel, nickel oxide, and nickel salt in the second layer are reduced to a metallic state in the firing atmosphere, are sufficiently sintered, and cover the metallized lower layer, forming a nickel layer by themselves. FIG. 2 shows a cross section of the metallized layer 3 formed on the surface of the ceramic sintered body 2 in this way. A nickel layer 32 is formed on the upper surface of this mixed layer 31,
It constitutes the metallized layer 3. In this case, tungsten can be dissolved in the nickel layer 32 up to its solid solubility limit;
Does not affect brazing properties. In this way, a strongly bonded metallized layer 3 is formed on the ceramic sintered body 2. After cooling, alumina and glass become a continuous phase, and tungsten and glass firmly adhere due to the anchor effect. In this way, the oxide ceramic and tungsten are bonded to each other through glass, and the tungsten and nickel are bonded to each other by mutual diffusion, and the metallized alumina body 1 is completed.

The Ni-W method was invented for the purpose of improving the conventionally used metallization method called the refractory metal method, and compared with the refractory metal method, it has better brazing properties and vacuum It has many excellent features such as good sealing performance, approximately half the manufacturing cost, and no inferior bonding strength.

[0009]

[Problems to be Solved by the Invention] The properties produced by the Ni-W method are very high and can be used satisfactorily, but in terms of strength, by increasing the strength of the metallized lower layer, Furthermore, there was a possibility that the strength of the joined body could be increased. The reason for this is explained below. In the Ni-W method, it is important that the tungsten in the metallized lower layer has an appropriate amount of voids; when tungsten is oversintered, the tungsten voids decrease, so the strength of the metalized lower layer itself increases; The anchoring effect of tungsten and glass is reduced and the overall strength is reduced. Conversely, if the sintering state of tungsten in the lower metallized layer is insufficient, there will be more voids in the tungsten, and although a sufficient anchoring effect between glass and tungsten can be obtained, the strength of the lower metallized layer itself will decrease. However, the overall bonding strength still decreases. That is, if the metallized lower layer could be strengthened without reducing the anchoring effect, there was a possibility that strength even higher than the Ni-W method could be obtained.

[0010] Furthermore, the firing temperature in the Ni-W method is 12
00 to 1400°C, but it was possible to reduce the firing temperature by adding a metal that promotes sintering of tungsten to the first layer and adjusting the atmosphere at the same time. That is, depending on the components of the ceramic, the characteristics of the base material may deteriorate if fired at a temperature of 1200° C. or higher. For example, when a barium titanate capacitor fired at 1100° C. was metalized at 1200° C. or higher, the dielectric properties were significantly deteriorated. Therefore, there has been a desire for a method that allows metallization even at temperatures below 1200°C.

The present invention aims to further improve the Ni-W method, and includes a trace amount of Ni, Co, Pd, Fe, Pt,
By adding one or more of Ru, Ir, Rh, and Re and adjusting the atmosphere, it is possible to reduce the firing temperature and further improve the bonding strength.

0012

[Means for Solving the Problems] The present invention, which solves the above-mentioned problems, includes adding 70 to 95 parts by weight of tungsten powder with an average particle size of 10 μm or less and a particle size of 10 μm on the surface of an oxide-based ceramic sintered body. For 100 parts by weight of a mixed powder consisting of 30 to 5 parts by weight of the following glass powders,
0.1 to 20 parts by weight of powder with a maximum particle size of 50 μm or less, which is a combination of any one or two or more of pure substances, oxides, and salts of d, Fe, Pt, Ru, Ir, Rh, and Re. After applying a paste made by mixing and kneading this with an organic vehicle, it is dried to form a first layer, and then a pure substance or oxide of nickel or cobalt with an average particle size of 10 μm or less is applied on the first layer. Apply a paste made by kneading powder of one or more salts in an organic vehicle and dry it to form a second layer, or apply a paste of nickel or cobalt with an average particle size of 10 μm or less. A powder containing one or more of pure copper substances, oxides, and salts, and a powder containing one or more of pure copper substances, oxides, and salts in an organic vehicle. The paste kneaded with is applied and dried to form a second layer, and then the firing temperature is set according to the components of the ceramic sintered body and the powder composition of the first and second layers, and the firing temperature is set at a temperature determined in advance. Oxide-based ceramics with excellent vacuum sealability, brazing properties, and bonding strength, characterized in that the ratio r is controlled based on the correlation between the firing temperature and the ratio r of hydrogen to water vapor in the atmosphere. The gist is the metallization method.

[0013]

[Operation] The steps of the Ni-W method described above are as follows. First, tungsten powder 70 adjusted to an average particle size (hereinafter simply referred to as particle size unless otherwise specified) of 10 μm or less
~95% by weight and 30~5% by weight of glass powder are mixed to form a paste, and the paste is applied to the upper surface of the oxide ceramic sintered body to form the first layer. After drying this first layer, a powder of one or more of nickel, nickel oxide, and nickel salt adjusted to a particle size of 10 μm is made into a paste and applied to the top surface of the first layer. to form a second layer and dry again. After forming the first and second layers on the ceramic in this way, the ceramic sintered body is heated in the range of 1200 to 1400°C so that the ratio of hydrogen to water vapor in the atmosphere is 1<H2 /H2O<100000. Firing under controlled atmospheric conditions.

During this firing, the tungsten powder of the first layer is sintered to some extent as shown in FIG. On the other hand,
The glass powder in the paste melts, and a portion of it flows onto the surface of the ceramic sintered body and reacts with the alumina. The remaining glass fills the voids in the tungsten without any gaps, forming a tungsten and glass mixed layer. on the other hand,
Nickel, nickel oxide, and nickel salt in the second layer are reduced to nickel in the firing atmosphere, are sufficiently sintered, cover the tungsten layer, and form the nickel layer themselves.

[0015] In this way, on the ceramic sintered body,
A strongly bonded metallized layer is formed. After cooling, alumina and glass become a continuous phase, and tungsten and glass firmly adhere due to the anchor effect. Thus,
Alumina and tungsten are bonded together through glass, and tungsten and nickel are bonded together through mutual diffusion.
The metallized ceramic body is completed. In this way, metallized ceramics can be firmly bonded to metals.

Furthermore, the present inventors filed Japanese Patent Application No. 1-246736 for a method of using cobalt as a substitute material for nickel as a metal having brazing properties equivalent to nickel. Furthermore, patent application No. 2-3188 discloses a method of adding copper to the nickel layer on the surface of the metallized layer to improve solderability.
The application was filed as No.

[0017] In the Ni-W method, the present invention adds the above-mentioned additive to the metallized lower layer, further improves the bonding strength obtained by the Ni-W method, and further lowers the firing temperature of the metallized layer, thereby improving the performance of ceramics. The aim is to enable the selection of firing temperatures suitable for the ingredients. As mentioned above, in the Ni-W method, it is important that the tungsten in the metallized lower layer has an appropriate amount of voids, and when tungsten is oversintered, the tungsten voids decrease, so the strength of the metalized lower layer itself decreases. increases, but the anchoring effect of tungsten and glass decreases, and the overall strength decreases. Conversely, if the sintering state of tungsten in the lower metallized layer is insufficient, there will be more voids in the tungsten, and although a sufficient anchoring effect between glass and tungsten can be obtained, the strength of the lower metallized layer itself will decrease. However, the overall bonding strength still decreases. That is, the bonding strength is maximized under conditions where the strength of the lower metallized layer and the strength of the anchor effect are each at their optimum values, as shown by the solid line in FIG.

That is, if the lower metallized layer can be strengthened without reducing the anchoring effect, it is possible to obtain strength that is even higher than the Ni--W method in the cited example, as shown by the broken line in FIG. In order to improve the strength of the metallized lower layer while maintaining the anchor effect, the tungsten in the metallized lower layer may be partially oversintered while leaving an appropriate amount of tungsten voids. By partially oversintering the metallized lower layer, the strength of the metallized lower layer is improved, and since the voids are not lost, the anchoring effect is also maintained.

[0019] Furthermore, the firing temperature in the Ni-W method is 12
However, when low-temperature sintered oxide ceramics (e.g. glass-added barium titanate capacitors fired at 1100°C) are metallized at temperatures above 1100°C, their characteristics as capacitors change. These metallizations had to be carried out at firing temperatures below 1100°C. Therefore, a metallization method that provides high strength at low firing temperatures has been desired. By adding a metal that promotes sintering of tungsten to the first layer and adjusting the atmosphere at the same time, it is possible to reduce the firing temperature and increase the number of applicable ceramic species.

Therefore, as a result of repeated research, Ni, Co, Pd, Fe, Ni, Co, Pd, Fe,
It has been found that addition of Ru, Ir, Pt, Rh, and Re improves the strength of the metallized lower layer, increases the bonding strength, and can reduce the firing temperature to 900°C. The present invention uses trace amounts of Ni, Co, Pd, Fe, Pt,
By adding Ru, Ir, Rh, and Re, the bonding strength obtained by the cited Ni-W method can be further improved, and the firing temperature can be significantly reduced. Ni, Co, Pd, Fe, Pt added to the first layer,
Ru, Ir, Rh, and Re are hereinafter referred to as additives.

FIG. 4 is a schematic diagram for explaining the basic mechanism of the present invention. First, as shown in FIG. 4(a), Ni, Co, Pd, F,
e, Pt, Ru, Ir, Rh, Re pure substances, oxides,
A paste made by kneading a mixed powder of one or more salts, tungsten powder, and glass powder using an organic vehicle is applied and then dried to form the first layer 301 . The particle sizes of the tungsten powder and the glass powder are each adjusted to 10 μm or less. Glass can be used as long as it is an oxide and melts at the firing temperature and is not reduced to metal in the firing atmosphere. One example is Al2 O3 -MnO-SiO2
system can be used. Further, as an example of the organic vehicle, a mixture of an organic binder such as ethyl cellulose and an organic solvent such as terpineol to obtain an appropriate viscosity can be used. Next, on the top surface of the first layer 301, a particle size of 10 μm is applied.
pure nickel or cobalt substances, oxides,
A paste made by kneading powder of one or more salts in an organic vehicle, or a pure substance of nickel or cobalt with a particle size of 10 μm or less,
A paste made by kneading a powder containing one or more of oxides and salts and a powder containing one or more of pure copper, oxides and salts in an organic vehicle. After coating, dry and apply the second layer 3.
Form 02. FIG. 4(b) schematically shows these.

In this way, the first layer 301 and the second layer 30
After forming the ceramic sintered body 2, the firing temperature is selected depending on the ceramic component and the powder composition of the first layer and the second layer, and the ceramic sintered body 2 is fired under atmospheric conditions corresponding to the firing temperature. At this time, as shown in the schematic diagram of FIG.
Tungsten powder is sintered with a suitable amount of voids. At this time, the additive added to the first layer is hardly dissolved in the tungsten, and a very small amount is diffused onto the surface of the tungsten powder. That is, the movement of tungsten atoms necessary for sintering of tungsten occurs through the additive diffused on the surface. The diffusion coefficient of tungsten in the additive is
This is significantly larger than the diffusion coefficient of tungsten in the absence of additives (for example, the diffusion coefficient of tungsten in nickel is 2.2 x 10-
14 m2/s, much higher than the diffusion coefficient of 5.8 x 10-24 m2/s in the absence of nickel). That is, the firing temperature can be significantly lowered by the addition of an additive that diffuses in a very small amount. However, if the hydrogen/steam ratio is too low, a thin oxide film will form on the tungsten surface, which will inhibit the surface diffusion of additives to the tungsten grain surface. It is necessary to keep the ratio high.

[0023] Furthermore, since tungsten can form a solid solution in the additive, tungsten diffuses into the additive. This phenomenon caused tungsten to gather around the additive, resulting in the same phenomenon as when the metal was partially oversintered around the additive. This increases the strength of the metallized lower layer. The glass powder in the paste is melted, and a portion of it flows onto the surface of the ceramic sintered body 2 and reacts with alumina. The remainder of the glass fills the voids in the tungsten without any gaps.
Form a metallized lower layer containing three types of coexistence: tungsten, glass, and additives.

On the other hand, the pure substances of nickel, cobalt, and copper in the second layer 302 or their oxides and salts are reduced to nickel, cobalt, and copper in the firing atmosphere, and are sufficiently sintered.
It covers the lower layer of metallization and itself forms the upper alloy layer. FIG. 1 shows a cross section of the metallized layer 3 generated on the surface of the ceramic sintered body 2 in this way.
1, and an upper alloy layer 32 is formed on the upper surface of this lower metallized layer 31, constituting the metallized layer 3. In this case, tungsten can be dissolved in the upper alloy layer 32 up to its solid solubility limit (approximately 35% by weight), but this does not affect the brazing properties. In this way, a strongly bonded metallized layer 3 is formed on the ceramic sintered body 2. After cooling, alumina and glass become a continuous phase, and tungsten and glass firmly adhere due to the anchor effect. In this way, alumina and tungsten are bonded to each other through glass, and tungsten and the upper alloy are bonded to each other by mutual diffusion, and a metalized alumina body 1 is completed.

[0025] The tungsten grains are limited to those having a grain size of 10 μm or less. Outside this range, the difference in distance between tungsten grains becomes too large, and glass moves to areas with narrow intergranular diameters due to capillary action, making it impossible for glass to exist in areas with wide intergranular diameters. Sealing properties cannot be obtained. The glass particle size is also limited to 10 μm or less for the same reason as the above-mentioned reason for limiting the tungsten particle size. In other words, when glass having a particle size of 10 μm or more is melted, the glass is absorbed into the area where the tungsten particle size is small, and the area where the glass was present becomes a void.

The mixing ratio of tungsten powder and glass powder is 70 to 95% by weight of tungsten and 30 to 5% by weight of glass.
% by weight. If the ratio deviates from the side with more tungsten, the absolute amount of glass becomes too small, the glass cannot fill the tungsten network, and vacuum sealability cannot be guaranteed. On the other hand, if the amount of tungsten is shifted to the side where there is less tungsten, the tungsten will not be able to form a network and sufficient strength will not be obtained.

The thickness of the nickel source, cobalt source, and copper source, that is, the pure substances, oxides, and salts of nickel, cobalt, and copper, is limited to 10 μm or less. If this is not the case, sintering will not proceed sufficiently.
Since the surface of the metallized lower layer 31 cannot be completely covered,
Brazing properties deteriorate. The amount of additive is 0 parts by weight per 100 parts by weight of the total weight of tungsten and glass.
．． It is limited to 1 to 20 parts by weight. If it deviates from the above-mentioned limited range to the small side, the effect as an additive cannot be obtained, and if it deviates to the large side, the oversintered portion will cover the entire area and the anchor effect will disappear.

The particle size of the additive is limited to a maximum particle size of 50 μm. This is because if the particle size exceeds 50 μm, the particles will not pass through the screen during screen printing. The firing temperature is set between 900 and 1450°C based on the ceramic components and the powder compositions of the first and second layers. For example, when the ceramic is alumina with a purity of about 92%, metallization is possible at a firing temperature of 900 to 1450°C. However, for materials such as sapphire, which have poorer reactivity with glass than alumina with a purity of 92%, the metallized layer must be fired at a high firing temperature, whereas glass-added barium titanate, which is fired at a low temperature, The metallized layer must be fired at a temperature of 1100°C or lower. At that time, the relationship between firing temperature and atmosphere is determined as follows. The ratio r of hydrogen to water vapor in the atmosphere with respect to the firing temperature T must fall within the range shown in the table below. The copper source in the second layer is particularly necessary when making the metallized layer compatible with soldering, but the correlation between the firing temperature and the atmosphere is different depending on whether the second layer contains the copper source or not. The reason for this is that at temperatures above 1150°C, copper melts and penetrates into the pores of tungsten, producing the effect of liquid phase sintering. When the firing temperature was less than 1150°C, no effect of copper addition was observed. ■When the second layer does not contain a copper source Firing temperature T (°C) Ratio of hydrogen to water vapor in the atmosphere r 900≦T<10
00℃ 50≦(H2/H2O)≦1000
00 1000≦T<1100℃ 10≦(H
2/H2O)≦100000 1100≦T<1
200℃ 5≦(H2/H2O)≦10
0000 1200≦T<1450℃ 1
≦(H2 /H2 O)≦100000 ■When the second layer contains a copper source Firing temperature T (°C) Ratio of hydrogen to water vapor in the atmosphere r 900≦T<10
00℃ 50≦(H2/H2O)≦1000
00 1000≦T<1100℃ 10≦(H
2/H2O)≦100000 1100≦T<1
150℃ 5≦(H2/H2O)≦10
0000 1150≦T<1450℃ 1
≦(H2/H2O)≦100000 Among the above firing temperatures, if the temperature range is less than 900°C, sintering of tungsten will be insufficient no matter how much the atmosphere is adjusted.
When the temperature exceeded 50°C, the metallized layer was oversintered and the bonding strength decreased in both cases.

[0029] When the atmosphere r deviates from the set range, an oxide film is formed on the tungsten surface, which inhibits sintering of the tungsten. In particular, when r is less than 1, the entire tungsten is oxidized. If r exceeds 100,000, the glass will be reduced and metal will precipitate, and the alumina will become more discolored. As described above, as long as hydrogen and water vapor are within a predetermined range, an inert gas such as nitrogen, argon, helium, etc. can be mixed.

As described above, in the Ni-W method, in addition to alumina (Al2O3) in the experimental example, it was also possible to metalize mullite, steatite, forsterite, and cordierite. In addition to the oxide-based ceramics mentioned above, the method also makes it possible to prevent property deterioration due to the low firing temperature of the metallized layer for functional ceramics such as capacitors, which are fired at a low temperature of about 1100°C, such as barium titanate. This makes it possible to form a metallized layer with high strength.

[0031]

【Example】

Example 1 Inner diameter 12 mmφ×outer diameter 16 mmφ× shown in the perspective view of FIG.
The present invention was carried out when an iron pipe 6 was joined to a cylindrical body 20, which is a ceramic sintered body having a height of 10 mm, as shown in FIG.

[0032] The cylindrical body 20 has an Al2O3 content of 92%.
The upper end 20a of this cylindrical body 20 is first coated with Al2O3:M, each of which has a particle size of 5 μm or less.
nO:SiO2=10:45:45 weight ratio Al2O3
A mixed powder obtained by mixing -MnO-SiO2 glass powder and tungsten powder in a ratio of 85:15% by weight, and further adding 5 parts by weight of nickel oxide powder was kneaded in an organic vehicle. The paste was applied by screen printing. However, when the glass powder was fired at a temperature lower than 1200° C., boric acid was added to the glass to lower the melting point. After applying the paste, a drying process was performed in an oven for 200×120 minutes to form a first layer 311 as shown in FIG. Next, the first layer 311
A mixture of nickel oxide powder and cobalt oxide powder adjusted to a particle size of 5 μm or less in various ratios was kneaded in the above-mentioned organic vehicle, and the resulting paste was applied to the surface 311a by screen printing. After coating, a second layer 321 was formed by drying in an oven for 200×120 minutes. The thickness of both the first layer 311 and the second layer 321 is 2
It is 0 μm. Thereafter, firing was performed in a mixed atmosphere of nitrogen, hydrogen, and water vapor in which H2/H2O was adjusted to 1, 5, 10, 50, and 100, respectively. The dew point can be obtained by bubbling a mixed gas of hydrogen and nitrogen into water at a predetermined water temperature. Specifically, when H2/H2O is 1, hydrogen is 5% by volume, nitrogen is 95% by volume, water temperature is 30°C, H2
When /H2O is 5, hydrogen is 10% by volume, nitrogen is 90% by volume, water temperature is 20℃, and when H2 /H2O is 10,
Hydrogen 13% by volume, nitrogen 87% by volume, water temperature 10°C, H2
/H2O is 50, hydrogen is 50% by volume, nitrogen is 50%
When % by volume, water temperature is 7°C, and H2/H2O is 100, hydrogen is 70% by volume, nitrogen is 30% by volume, and water temperature is 2°C. Tables 1 to 5 at a heating rate of 10°C/min in the mixed gas flow
The mixture was heated to the temperature shown in and held for 60 minutes. Then 10℃
The alumina body 10 was obtained by cooling at a rate of 1/2 min to form a metallized layer 30.

An iron pipe 6 was bonded to this alumina body 10 as shown in FIG. 7, and the vacuum sealability and bonding strength were measured. For joining with the iron pipe 6, a brazing material 5 (in this example, JIS Z 3261 B) is used between the metallized layer 30 and the iron pipe 6.
A bonded body was obtained by brazing in a hydrogen atmosphere. After obtaining the bonded body, an iron jig was attached to the bottom surface 20b of the alumina body using an adhesive that maintains sufficient sealing properties.

Vacuum sealability was determined by measuring the amount of leakage from the tip of the iron tube 6 using a helium leak detector. The criteria for evaluation was that those exhibiting a sealing performance of 1×10 −10 Torr·L/sec or less were passed. The bonding strength was measured by fixing an iron jig and pulling the iron pipe 6 upward. Tables 1 to 5
shows an example of the results of an investigation using the mixing ratio of the glass powder and tungsten powder and the firing temperature as parameters.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5]

Example 2 In Example 1, a mixed powder of 50% by weight of nickel oxide and 50% by weight of cobalt oxide was used as the substance forming the second layer 321, and the mixed powder was mixed with copper oxide powder. The ratio is 8
The same treatment as in Example 1 was performed using a weight ratio of 0:20. Table 6 shows the results.

[0041]

[Table 6]

Example 3 In Example 1, the additives added to the first layer 321 were Co, Pd, Fe, Pt, Ru, Ir, Rh, and F.
e, Re, mixed powder of tungsten and glass 10
An experiment was conducted by adding 5 parts by weight of each additive to 0 parts by weight. The firing temperature is 900 to 1450°C, the atmosphere is H2/H2O=50, and the material forming the second layer 322 is a mixed powder of nickel oxide:cobalt oxide in a weight ratio of 50:50. Table 7 below shows the results.

[0043]

[Table 7]

Example 4 In Example 1, the additive added to the first layer 321 is nickel oxide, and the amount added is 0.05 to 30 parts by weight per 100 parts by weight of the mixed powder of tungsten and glass. An experiment was conducted with the addition of Firing temperature is 900-145
0°C, atmosphere H2/H2O=50, second layer 322
The substance that forms is nickel oxide: cobalt oxide = 5
It is a mixed powder with a weight ratio of 0:50. Table 8 below shows the results. When the amount was 0.1 to 20 parts by weight, higher strength was obtained than when no additive was added.

[0045]

[Table 8]

Example 5 The ceramic to be metalized was barium titanate,
As an additive in the first layer, 5% by weight of nickel oxide is added to 100 parts by weight of mixed powder of tungsten and glass.
The second layer was made of 80% by weight of nickel oxide and 20% by weight of copper oxide, and metallization was performed at a firing temperature of 1000° C. and a hydrogen-steam ratio r of 15 in the atmosphere. After firing, the surface of the metallized layer is soldered to a thickness of 0.5 m.
m iron wires were joined and characteristic values such as dielectric constant were investigated. As a result, no deterioration of the properties (permittivity) of the base material was observed.
Further, during the tensile test, the solder part was destroyed, and no destruction was observed from the metallized layer or the base material.

[0047]

[Effects of the Invention] As explained above, according to the present invention, N
The strength obtained by the i-W method can be further improved, and the firing temperature can be set according to the ceramic components, so it is suitable for functional ceramics whose base material properties change when fired at high temperatures. However, it is possible to metalize it without changing its properties.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a metallized layer formed according to the present invention.

FIG. 2 is a cross-sectional view of a metallized phase metallized by the cited Ni-W method.

FIG. 3 is a graph showing the relationship between the degree of sintering of tungsten and bonding strength.

Fig. 4 shows the state in which paste is applied to the surface of the alumina ceramic sintered body, (a) is a cross-sectional view, (b)
) is a schematic diagram.

FIG. 5 is a schematic diagram showing a state in which the paste applied to the surface of the alumina ceramic sintered body is baked.

FIG. 6 is a perspective view of a cylindrical alumina ceramic sintered body showing a specific embodiment of the present invention.

7 is a sectional view showing a state in which an iron pipe is joined to the alumina body of FIG. 6; FIG.

8 is a cross-sectional view showing a metallized layer in the alumina body of FIG. 7. FIG.

[Explanation of symbols]

1, 10 Alumina body 2, 20
Alumina ceramic sintered body 3, 3
0 metallized layer 31
Metallized lower layer 32
Upper alloy layer 301, 311 first
Layers 302, 321 2nd layer

Claims (1)

[Scope of Claims] [Claim 1] Tungsten powder 70-9 having an average particle size of 10 μm or less is coated on the surface of an oxide-based ceramic sintered body.
5 parts by weight and 30 to 5 parts by weight of glass powder with a particle size of 10 μm or less,
Powder 0.1 to 20 with a maximum particle size of 50 μm or less, which is a combination of any one or two or more of pure substances, oxides, and salts of O, Pd, Fe, Pt, Ru, Ir, Rh, and Re.
After applying a paste made by mixing parts by weight and kneading this in an organic vehicle, it is dried to form a first layer, and then a pure substance of nickel or cobalt with an average particle size of 10 μm or less is applied on the first layer. A paste made by kneading powder of one or more of the following: oxides, salts, etc. in an organic vehicle is applied and dried to form a second layer, and then the components of the ceramic sintered body and the 1st layer, 2nd layer
Vacuum sealing characterized in that the firing temperature is set according to the powder composition of the layer, and the firing is performed while controlling the ratio r based on the correlation between the firing temperature determined in advance and the ratio r of hydrogen to water vapor in the atmosphere. A method for metallizing oxide-based ceramics that has excellent fastening properties, brazing properties, and bonding strength. [Claim 2] Claim 1, wherein the firing temperature and the ratio r of hydrogen and water vapor in the atmosphere satisfy the following conditions.
The metallization method for oxide ceramics described. Firing temperature T (°C) Ratio of hydrogen to water vapor in the atmosphere r 900≦T<
1000℃ 50≦(H2/H2O)≦10
0000 1000≦T<1100℃ 10≦
(H2 /H2 O)≦100000 1100≦T
<1200℃ 5≦(H2/H2O)≦
100000 1200≦T<1450℃
1≦(H2/H2O)≦100000 [Claim 3
] The second layer is made of any one of pure substances, oxides, and salts of nickel or cobalt with an average particle size of 10 μm or less.
A pure substance of copper, a powder of seeds or a combination of two or more kinds,
The oxide-based ceramic according to claim 1, wherein the oxide-based ceramic is formed by applying a paste made by kneading powder of one or more of oxides and salts in an organic vehicle and drying the paste. Metallization method. 4. Claim 3, characterized in that the firing temperature and the ratio r of hydrogen to water vapor in the atmosphere satisfy the following conditions:
The metallization method for oxide ceramics described. Firing temperature T (°C) Ratio of hydrogen to water vapor in the atmosphere r 900≦T<
1000℃ 50≦(H2/H2O)≦10
0000 1000≦T<1100℃ 10≦
(H2 /H2 O)≦100000 1100≦T
<1150℃ 5≦(H2/H2O)≦
100000 1150≦T<1450℃
1≦(H2/H2O)≦100000