JPH01111784A - Production of airtight ceramic vessel - Google Patents

Abstract

PURPOSE:To obtain the above vessel having excellent adhesive strength and airtightness maintenability by placing a metallic solder layer on the active metal layer formed on the open end face of a ceramic barrel, placing a metallic lid thereon to close the opening, and carrying out brazing to join both barrel and lid without previously metallizing the open end face. CONSTITUTION:An active metal paste prepared by kneading the active metal consisting of the Ti powder and/or Zr powder having <=5mu particle diameter (e.g., mixed powder of Ti/Zr=9/1) with a soln. of ethyl cellulose in ethanol is applied at 0.1-10mg/cm<2> (expressed in terms of metal) on both open end faces of the ceramic barrel 1 made of Al2O3, etc., and having 60mm outer diameter, 50mm inner diameter, and 60mm height, and an active metal layer is formed. Metallic solder is placed thereon, the metallic lid 2 of covar, etc., is arranged on the solder to close the open end face, the assembly is put in a vacuum furnace and heated, for example, at about 850 deg.C for about 5min, and both barrel and lid are joined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing an airtight ceramic container and a method for manufacturing a vacuum valve using the airtight ceramic container.

(Prior Art) Ceramics have excellent heat resistance and insulation properties, and therefore are used as materials for various electrical components by taking advantage of these characteristics. An example is an airtight container used for electrical components such as vacuum valves. In the case of such an airtight container, the inside is used in an atmosphere filled with an inert gas or in a vacuum state. Therefore, in order to maintain this internal atmosphere,
It must be possible to maintain strict airtightness.

A conventional airtight ceramic container (object to be manufactured in the present invention) has a structure in which the open end of a ceramic cylindrical body 1 is sealed with a metal lid 2, as shown in FIG. 1(A). ing. When manufacturing such an airtight ceramic container, a conventional method (brazing) is to apply metallization to the open end surface of the ceramic cylindrical body 1 and then join a metal lid thereon via metal solder. It is used. In this case, since the ceramic cylindrical body 1 and the metal lid body 2 have different coefficients of thermal expansion, thermal stress is generated at the joint during brazing. If this thermal stress is large, the ceramic cylindrical body 2
Cracks will occur and the airtightness will be compromised. Therefore,
In order to reduce this thermal stress and prevent the occurrence of cracks, the following measures have been taken.

The first is to use a metal with a small coefficient of thermal expansion, such as Mo or W, or an alloy with a small coefficient of thermal expansion, such as Invar or Kovar, as the metal lid.

The second method is to bend the end of the metal lid body 2 as shown in FIG.
This is because the bonding area between the two is reduced by (end surface bonding). Since the magnitude of the thermal stress generated at the joint is proportional to the joint area between the two, this end face bonding contributes to reducing the thermal stress.

In addition, in order to obtain sufficient joint strength and sufficient airtightness in such end surface joints, as shown in FIG. It is necessary to have a structure that widens outward over the entire length.

Next, the metallizing method used to manufacture the above-mentioned airtight ceramic container will be explained.

The conventional metallizing method is as follows.

■ Apply a powder containing MO or W as the main component to the surface of the ceramic base material, and reduce the
A method of metallizing by heating to 00°C and reacting with the ceramic base material. If necessary, apply N on the metallized layer.
Perform plating processing such as i. This method has problems with complicated processes, such as the need for metallizing treatment at extremely high temperatures.

■ A method of metallizing by placing Au or PT on the surface of a ceramic base material and heating it while applying pressure. Since this method uses expensive precious metals, it is not economical for vacuum valves with large joint areas. Moreover, since high pressure is required to improve adhesion,
Application to electronic parts that do not like deformation is not preferred.

■ Active metals such as Ti and Zr on the ceramic base material,
This is a method in which transition metals such as Ni and Cu are arranged and metallized by heat treatment at a temperature higher than the melting point of the alloy (Japanese Patent Application Laid-open No. 183093/1983).

This method uses TL and Zr as active metals, and when an alloy is formed between the active metals and transition metals such as Cu and Ni,
We focused on the fact that in the eutectic composition region, the alloy exhibits a melting point several 100 degrees Celsius lower than the melting point of either element. In this method, since the active metal wets the ceramic matrix, metallization can be carried out with almost no need for pressurization. In addition, it has the advantage that it can be metallized with strong adhesion to the ceramic base material due to the effect of the active metal.

No matter which metallizing method from ■ to ■ is used, in order to manufacture an airtight ceramic container using the above method,
After metallizing the end face of the ceramic cylindrical body, the lid must be further brazed. That is, the metallizing process and the brazing of the lid to ensure the airtightness of the container must be performed separately, which has the disadvantage of complicating the process. Therefore, a method of manufacturing an airtight ceramic container by brazing a metal lid to the open end surface of a ceramic cylindrical body without performing the above-mentioned metallization in advance has been studied.

On the other hand, the following one-step joining method has been proposed as a method for joining ceramic members and metal members without prior metallization (Japanese Patent Laid-Open No. 59-3282
No. 8). That is, a joining method using a low melting point brazing material (particularly Ag brazing material) containing Ti and/or Zr as an active metal,
Alternatively, there is a joining method in which the thin plate of the active metal and the Ag brazing material layer are laminated, and this is inserted between the ceramic member and the metal member and heated. Since this one-step bonding method does not require metallization, the process can be simplified.

However, in the case of the above-mentioned one-step joining method, Fig. 1 (B
) The preferable bonding structure as explained in 2.) cannot be obtained. Therefore, if the bonding area between the ceramic member and the metal member is sufficiently large, substantially satisfactory bonding characteristics can be obtained, but if the bonding area is small, sufficient bonding characteristics cannot be obtained. Therefore, it is inappropriate to apply it to the production of airtight ceramic containers as described above. That is, even if brazing is performed using a thin brazing material plate 3 that is larger than the end surface of the lid body 2 as shown in FIG. 1(C), the wettability of the ceramic surface by the molten brazing material is not sufficient. ) As shown in
The brazing material layer is formed only directly under the end face of the the result,
A gap is likely to be formed at the joint, and even a small external force may cause the lid 2 to peel off.

Next, a conventional vacuum valve using the above-mentioned airtight ceramic container will be explained.

An example of the structure of a vacuum valve is shown in FIG. In the figure, 1 is a ceramic cylinder. A metal lid 2 is attached to both open ends of the cylindrical body via silver solder 8a, 8b.
a and 2b are hermetically joined to form a vacuum container whose interior is maintained in vacuum.

Inside this vacuum container, there is a fixed conductive shaft 5a and a movable conductive shaft 5.
b are opposed to each other and are provided so as to penetrate through the lids 2a and 2b. As shown in the figure, the fixed conductive shaft 5a is connected to the lid body 2a.
The movable conductive shaft 5b is movable in the axial direction. A pair of contacts 3a, 3b are provided at opposing ends of both conductive shafts 5a, 5b. Contact 3a is a fixed contact, and contact 3b is a movable contact. The contact 3b is brazed directly to the conductive shaft 5b, or is brazed to the conductive shaft 5b via an electrode (not shown). Further, the other end of the fixed conductive shaft 5a is a fixed terminal 4a, and the other end of the movable conductive shaft 5b is a movable terminal 4b. Therefore, due to the axial movement of the movable conductive shaft 5b, the contact point 3a.

3b is opened and closed. Further, a bellows 7 is attached to the movable conductive shaft 5b, and the bellows allows the movable conductive shaft 5b to move in the axial direction while keeping the inside of the container vacuum-tight. Further, a metal arc shield (not shown) is provided above the bellows 7 to prevent the bellows 7 from being covered with arc vapor. Further, a metal arc shield 6 is provided in the vacuum container so as to cover the contacts 3a and 3b, and the ceramic cylindrical body 1
This prevents the area from being covered with arc vapor. This prevents the evaporated contact material from adhering to the inner surface of the ceramic cylinder 1 and causing a short circuit.

By the way, in the above vacuum valve, the arc shield must be fixed at a predetermined position in the vacuum container. For this purpose, the ceramic cylindrical body 1 has a convex portion 1' as shown in the figure.
is formed. This convex portion 1' is connected to the arc shield 6
The arc shield 6 is disposed so as to mesh with a recess 6' provided in the arc shield 6, thereby preventing the arc shield 6 from falling off or moving. In some cases, the ceramic cylindrical body 1 is formed with four parts, and the arc shield 6 is provided with a convex part to engage the two parts. This fixing method has an economical advantage since no metallization is required to attach the ceramic cylinder 1 and the arc shield 6. However, since a gap inevitably occurs between the two, vibration or movement of the arc shield 6 is unavoidable when the vacuum valve is subjected to vibration. Furthermore, if there is a problem with the concave portion 6' of the arc shield 6, the arc shield 6 may fall out of the specified position, resulting in a disadvantage that the withstand voltage characteristics and the interrupting characteristics are deteriorated.

As a second method of fixing the arc shield 6 to the ceramic cylindrical body 1, a method is also known in which the inner surface of the cylindrical body 1 is metallized and then the arc shield 6 is soldered to the inner surface of the cylindrical body 1.

As the metallizing method, the methods (1) to (4) described above are used. According to this method, troubles such as falling off or movement of the arc shield 6 can be prevented. However, no matter which method (1) to (3) is used, the problems associated with metallization as described above arise. That is, the method (2) has a problem in that it requires complicated steps such as high-temperature treatment. Method (2) not only has problems in terms of economy, but also has problems in productivity because brazing the parts required to obtain sufficient pressure occupies a certain amount of space in the furnace. (3)
With this method, it is difficult to obtain desired bonding strength.

As a third means for attaching the arc shield 6 to the cylindrical body 1, the one shown in FIG. 11 is known. That is, the sixth
Two ceramic members 1a obtained by dividing the cylindrical body in the figure
, lb is prepared, and metallizing 9a is applied to the opposite end surface.
Apply step 9b. Then, a flange provided on the arc shield 6a is inserted between the end faces 9a and 9b, and the end faces 9a and 9b are hermetically sealed.

In this case as well, the metallizing method is as described above.
The method of ~■ is used. Since this method also uses a metallizing method, it has the same drawbacks as the second method. In addition, since the number of metalized parts increases, it is disadvantageous in terms of economy. Furthermore, since the number of locations requiring airtight sealing increases, reliability in maintaining airtightness is also disadvantageous.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and the first problem is that metallization is not applied to the open end face of the ceramic cylindrical body without metallizing the open end face in advance. The purpose of the present invention is to manufacture an airtight ceramic container having sufficient joint strength and high ability to maintain airtightness by end-face joining the peripheral edge of a lid.

The second problem of the present invention is that when manufacturing a vacuum valve using the airtight ceramic container, a part of the inner surface and the arc shield can be easily connected without metallizing the inner surface of the ceramic cylindrical body in advance. An object of the present invention is to provide a method for manufacturing a vacuum valve that can be directly joined with sufficient strength by a method.

(Means for Solving the Problems) In the method for manufacturing an airtight ceramic container according to the present invention, 0.1 to 10 II of an active metal consisting of Ti and/or Zr is applied to the open end surface of a ceramic cylindrical body. a step of forming an active metal layer by depositing an amount of i/d, a step of placing a metal brazing layer on the active metal layer, and a step of sealing the opening of the ceramic cylindrical body. metal lid body,
a step of arranging the peripheral edge end surface to be in contact with the metal solder layer, and a step of melting the metal solder layer by heating and brazing the metal lid body to the opening end surface of the ceramic cylindrical body. It is characterized by the following:

A method for manufacturing a vacuum valve according to the present invention includes an airtight ceramic container obtained by the above method, which is penetrated from the outside to the inside of the container, and is disposed facing the container, and at least one of which is movable in the axial direction. a pair of contact shafts that can be opened and closed by this, a metal contact member provided at the tip of each of the pair of contact shafts, and movement of the contact shafts in the axial direction while maintaining a vacuum in the vacuum container. and a metal arc shield disposed surrounding the contact member to prevent metal evaporated from the contact member from adhering to the inner surface of the ceramic cylindrical body. When manufacturing, the inner surface of the ceramic cylindrical body is polished in advance so that the surface roughness becomes 0.1 to 101I01R, and the average grain size of Ti and/or Zr is 0.1 to 10u! a step of forming an active metal layer by depositing active metal powder of R or less in an amount of 0.1 to 1086/m; a step of placing a metal brazing layer on the active metal layer; The arc shield is characterized by comprising the steps of arranging the shield so as to be in contact with the metal brazing layer, and melting the metal brazing layer by heating and brazing the arc shield to the inner surface of the ceramic cylindrical body. It is something to do.

(Function) Hereinafter, the present invention will be explained in detail, including explanation of the function necessary for understanding.

First, the bonding method that is the core of the present invention will be explained.

In the present invention, when joining a ceramic cylindrical body and a metal member, T is applied to the joining surface of the ceramic cylindrical body in advance.
Deposit active metals such as i, Zi, etc.

This differs from conventional techniques in that it is simply a deposition process and does not involve any particular metallizing treatment. That is, it is the active metal layer that is preformed and not the metallized layer. Since a metal member is brazed onto the active metal layer, the active metal is diffused into the ceramic cylindrical body by the heating at that time, and therefore brazing is performed simultaneously with metallization. This bonding method can be called a -stage bonding method in that no metallization treatment is performed in advance.

What is more important is that in the one-step bonding method described above, the active metal is deposited in close contact with the ceramic surface, and the amount of deposited metal is limited to 0.1 to 10 η/protection. Therefore, this is different from the conventional example in which an active metal plate is simply placed on the surface of a ceramic member. This feature provides a desirable joint structure as described in FIG. 1(B). This is because the surface of the ceramic member can be satisfactorily metallized by depositing the active metal and keeping the deposition amount within the above range.

For example, after coating the above active metal powder on the surface of an alumina ceramic disk, 72% Ag-Cu and Ag brazing agent were placed and heated in vacuum, and as a result of investigating the spread of the brazing agent, it was found that the active metal Apply amount of powder from 0.1 to 10j29/
d, it was confirmed that the brazing material spread suitably and that good metallization was performed. As a result of such good metallization, it is possible to achieve sufficient bonding strength and a good bond with no gaps even when the bonding area is small, such as in end-face bonding. On the other hand, if the amount of active metal powder deposited is too small or too large, good metallization will not be achieved during subsequent brazing, and the spread of the brazing agent will be poor. Therefore,
A bond with the desired properties cannot be obtained.

By applying the above bonding method, the present invention provides a highly reliable airtight ceramic container with excellent airtightness without increasing the bonding area between the ceramic cylindrical body and the metal lid. Can be done. Moreover, by applying the above-described joining method to joining the arc shield and the inner surface of the ceramic cylindrical body, the arc shield can be fixed in a simple manner without fear of falling off.

In the above bonding method, examples of the method for depositing the active metal powder on the bonding surface of the ceramic cylindrical body include the following method.

The first method is to apply an organic adhesive mixed with a binder and a solvent to the joint surface of the ceramic cylindrical body in advance, and then sprinkle the active metal powder onto the adhesive layer to make it adhere. It is. The binder and solvent used are not particularly limited, but it is desirable that they can be completely decomposed and removed in the subsequent heat treatment step. For example, examples of the binder include polyvinyl alcohol and ethyl cellulose, and examples of the solvent include ethanol and tetralin.

The second method is to prepare a mixture of the active metal powder, an organic binder, and a solvent, and apply the mixture to the joint surface of the ceramic cylindrical body through a screen made of metal mesh or the like. As the binder and solvent, those mentioned above are used.

The third method is to deposit an active metal on the joint surface of the ceramic cylindrical body by vapor deposition, sputtering, or the like.

When using the coating method or the scattering method among the above-mentioned deposition methods, if the particles are too large, the fluidity will decrease.
It is desirable to set it to 0- or less. In addition, T as an active metal
When using a mixture of i and Zr, the mixing ratio is not particularly limited and can be set completely arbitrarily. On the other hand, the surface roughness of the ceramic cylindrical body to which the active metal powder is to be deposited is preferably 0.1 to 10 m. This is because if the surface roughness is too large, the bonding strength may become insufficient.

Note that when joining the arc shield and the ceramic cylindrical body in the vacuum valve, only the spraying method or coating method is particularly used. In addition, in this case, the average particle size of the active metal must be 1 OtuR or less, and the surface roughness of the ceramic cylindrical body must be 0.1 to 10p.

As the metal brazing material used in the above joining method, for example, Ag
-Cu-based, Ag-Cu-Sn-based, Ag-Cu-Zn-based, and other Ag waxes are preferred. During brazing, a brazing material was placed on the joining surface of the ceramic cylindrical body coated with the active metal powder, and the metal member to be joined (metal lid or arc shield) was brought into contact with the brazing material. After that, it is heated to a temperature higher than the melting point of the brazing material. The heat treatment atmosphere at this time is preferably a non-oxidizing atmosphere such as vacuum or argon gas.

Next, a method for manufacturing an airtight ceramic container according to the present invention will be explained. In this case, the material of the ceramic cylindrical body 1 is not particularly limited. For example, oxide ceramics such as A Noko 03, nitride ceramics such as A, fl'N, Si3N, 1, etc. can be suitably used. On the other hand, as the metal lid body 2, it is desirable to use a material whose coefficient of thermal expansion is close to that of the ceramic cylindrical body. As mentioned above, this is to reduce thermal stress during bonding. Preferred materials include Mo, W, Kovar, Imphal, and the like. Further, for joining the ceramic cylindrical body 1 and the metal lid body 2, an end surface joint as shown in FIG. 1 is used in order to reduce the joint area and reduce thermal stress. As described above, in the present invention, sufficient bonding strength and airtightness can be obtained even in end surface bonding.

By the way, in manufacturing the airtight ceramic container according to the present invention, when brazing the ceramic cylindrical body 1 and the metal lid body 2, a thin plate of brazing material as shown in FIG. 2(A) or (B) is used. It is preferable to use As shown,
These brazing thin plates have a rough surface with irregularities only on the upper surface, and a smooth surface on the lower surface. Furthermore, Figure 2 (
In the brazing thin plate B), a hole is formed to penetrate the convex portion. When brazing is performed using this thin plate of brazing material, its smooth lower surface is brought into contact with the joint surface of the ceramic cylindrical body 2, and the uneven work surface is brought into contact with the end surface of the metal lid body 2. By performing brazing in this state, the following effects can be obtained.

During brazing, decomposed gas, adsorbed gas, etc. of impurities are released from the ceramic cylindrical body 2 into the interior of the container as it is heated. Therefore, in order to achieve a desired atmosphere such as a vacuum state within the container, these gases must be exhausted to the outside before brazing is completed. When the thin brazing material plate described above is used, a gap is formed between the thin brazing material plate and the metal lid due to the unevenness. Therefore, the gas is discharged to the outside through this gap, and a desired atmosphere such as vacuum can be obtained inside the container. That is, the unevenness of the upper surface of the brazing material ensures a gas discharge path. This effect is further enhanced by providing through holes as shown in FIG. 2(B). However, as a matter of course, this discharge passage must be completely closed when sealing by brazing is completed, and must be able to achieve sufficient airtightness. From this perspective as well as from the perspective of stability when the brazing material is placed in the joint, the depth or height of the unevenness should be 2.
0- to 511+1 is appropriate.

On the other hand, since the thin brazing material plate described above has a smooth lower surface, it is possible to obtain good bonding even to the ceramic end face, which has poor wettability with the brazing material.

If there is a gap between the brazing material and the surface of the ceramic cylinder, the brazing material will not be able to spread sufficiently over the bonding surface, which has poor wettability, resulting in poor bonding and poor airtightness. cause it to occur.

In this way, the brazing metal thin plates shown in Fig. 2 (A) and (B) form unevenness on the upper surface in contact with the metal to ensure a gas discharge path, and at the same time, the lower surface in contact with the ceramics is smooth to ensure good bonding. This is what we have ensured.

FIG. 3(A) shows another example of a preferable brazing material thin plate. As shown in the figure, this thin plate of brazing material has two layers of brazing material 3.
It has a laminated structure in which a barrier layer made of a metal having a melting point higher than that of the brazing material is interposed between the brazing material and the brazing material. The two brazing metal layers 31 and 32 may be the same or different. The purpose of using such a thin brazing material plate and the effects and effects obtained thereby are as follows.

Unlike diffusion bonding or fusion welding, the technique for joining dissimilar materials using brazing metal does not involve making the materials to be joined react with each other to form an alloy layer. Therefore, it has the advantage of not causing a decrease in strength due to the formation of a brittle alloy layer.

However, depending on the type of members to be joined, the constituent elements of these members may rapidly diffuse into the molten brazing material and react with each other to form a brittle alloy layer. Therefore, the third
By providing the barrier WI32 in the brazing material thin plate shown in FIG. 3A, elements eluted and diffused into the molten brazing material are prevented from coming into contact with each other, thereby preventing the formation of a fragile alloy layer. That is, since the barrier layer 32 has a high melting point, it remains unmelted even when the brazing material layers 31 and 33 melt. Therefore, contact between the elements diffused from the members to be welded on both sides is prevented.

Note that the thickness of the barrier layer 32 is not particularly limited.

However, the range that sufficiently and reliably acts as a barrier and is easy to handle is about 0.01 to 5B.

A brazing material thin plate having a configuration that combines the configuration shown in FIG. 3(A) and the configurations shown in FIGS. 2(A) and (B) may also be used.

Examples of such brazing thin plates are shown in FIGS. 3(B) and 3(C). In this case, the gas discharge described in FIGS. 2(A) and 2(B) can also be performed at the same time.

FIG. 4 shows a state in which an airtight ceramic container is manufactured according to the present invention using the brazing material thin plate shown in FIG. 3(C). From this figure, it is understood that another effect other than the above obtained by using the thin brazing material plates shown in FIGS. 3(A) to 3(C) is obtained. That is, the barrier layer 32 does not melt even when heated during brazing and maintains its mechanical strength. Therefore, even if some misalignment occurs in the alignment of the metal lid 2, the barrier layer 32 functions as a connecting material, and the desired airtight container can be obtained.

In the method for manufacturing a vacuum valve according to the present invention, when manufacturing the vacuum valve illustrated in FIG. 10, an arc shield is directly joined to the inner surface of the ceramic cylindrical body 1 using the above-described joining method. Therefore, in this case as well, a good bond with sufficient strength is obtained between the two, preventing the arc shield from falling off or moving, thereby improving reliability by suppressing fluctuations in withstand voltage characteristics. can be improved. Furthermore, since there is no need to perform metallizing treatment in advance, the process can be simplified.

In addition, in manufacturing this vacuum valve, as shown in Fig. 3 (A),
By using the brazing filler metal shown in , it is possible to obtain the effects described above.

(Example) Hereinafter, the present invention will be explained more specifically based on Examples.

Example 1 (Manufacture of an airtight ceramic container) An airtight ceramic container as shown in FIG. 1 was manufactured in the following manner.

First, outer diameter 60B, inner diameter 50mm, height [iom A)
A ceramic cylindrical body 1 made of 203 was prepared.

In addition, Ti powder and Zr powder with a particle size of 5p or less were mixed in a ratio of 9:1.
An active metal paste was prepared by mixing this with an ethanol solution of ethyl cellulose. Next, apply this paste to the ceramic cylindrical body 1.
It was applied to the open end faces of both ends. At that time, the amount of paste applied was adjusted so that the amount of active metal deposited was 1η/crj.

Next, on the paste application surface of the ceramic cylindrical body 1,
Ag wax (72% Ag-Cu) with a thickness of 5011M was placed. Furthermore, a metal lid body 2.2 made of Kovar (Ni-Co-Fe alloy) was placed on the brazing material as explained in FIG. The thus obtained laminate similar to that shown in FIG. 4 was heated at 850° C. for 5 minutes in a vacuum furnace (2×10″″5 Torr) to form a metallic lid 2.
2 was joined to the open end surface of the ceramic cylindrical body.

After cooling, the airtight ceramic container thus obtained was taken out of the furnace and the state of the joint was examined.

As a result, the brazing material layer 8 that joins the metal lid body 2 and the ceramic cylindrical body expands toward the metallized ceramic surface, as shown in FIG. 1(B).
It was firmly fixed with the good joint structure shown in . Furthermore, when the airtightness of the joint of this airtight ceramic container was evaluated using a He leak test, the amount of He leakage was 10-10 Torr. /see or less, no leakage was observed.

Example 2 (Production of airtight ceramic container) Figure 2 (A
), a doughnut-shaped thin plate (72% Ag-Cu) with an unevenness of 50 g in height on its upper surface, an outer diameter of 5 mm, an inner diameter of 40 mm, and a thickness of 1001 mm was prepared. . Also, A with an outer diameter of 50s, an inner diameter of 40M, and a height of Boa.
A ceramic cylinder body 1 manufactured by Noko 03 was prepared.

LKI/
Ti powder of only CD was applied. The Ag brazing material plate was placed on this Ti-coated surface. Furthermore, in the same manner as in Example 1, a metal lid body 2.2 made of Ni-Fe alloy was placed on a thin plate of brazing material, and heated at 880°C for 6 minutes in a vacuum furnace (2X 10-5 Torr). , the metallic lids 2, 2 were joined to the open end surface of the ceramic cylindrical body.

When the airtight ceramic container thus obtained was taken out from the furnace after cooling and examined, it was found that the internal vacuum degree was high and the bonding state was good.

Example 3 (Production of airtight ceramic container) Figure 2 (B
), the Ag brazing material has a convex portion with a height of 100 x and a through hole provided in the convex portion on the upper surface, and has a donut shape with an outer diameter of 40 mm, an inner diameter of 30 m, and a thickness of 100 u. A wood board (72% Ag-Cu) was prepared. Also, outer diameter 4
0M, inner diameter 30M.

A ceramic cylinder body 1 made of A-saw 03 and having a height of 40M was prepared.

I It
Ti powder with only g/Cd was applied. The Ag brazing material plate was placed on this Ti-coated surface. Furthermore, in the same manner as in Example 1, metal lids 2, 2 made of Ni-Fe alloy were placed on a thin plate of brazing material, and heated in a vacuum furnace (2X 10-5 Torr).
) by heating at 850° C. for 6 minutes, the metal lids 2, 2 were joined to the open end surface of the ceramic cylindrical body.

When the airtight ceramic container thus obtained was taken out from the furnace after cooling and examined, it was found that the internal vacuum degree was high and the bonding state was good.

Reference Example 1 In this Reference Example 1 and the following Reference Example 2, the effect of the barrier layer 32 in the brazing thin plate of FIG. 3(A) was investigated.

As shown in Figure 3(A), 4%Ti-B9%Ag-
A 504-thick Ag brazing material layer 31 made of Cu and 72% A
Made of g-Cu, thickness 50. A barrier layer 32 with a thickness of 50 m made of 13% Cr-Fe is placed between the Ag brazing material layers 33 of
A thin brazing material plate was prepared. In addition, a ceramic cylindrical body 1 made of A, I'203 and having an outer diameter of 40M, an inner diameter of 30u, and a height of 60III was prepared.

The thin plate of brazing material was placed on the open end surface of the ceramic cylindrical body 1. Furthermore, Ni-F with NL plating applied to the surface
The metal lids 2, 2 made of e-alloy were placed on a thin plate of brazing material, and heated at 850° C. in a vacuum furnace (2X10-5 Torr).
By heating at ℃ for 10 minutes, the metal lids 2, 2 were joined to the open end surface of the ceramic cylindrical body. When the airtight ceramic container thus obtained was taken out from the furnace after cooling and examined, it was found that the entire joint surface was well joined.

For comparison, a bonding experiment was conducted using a 100 m thick thin plate of brazing material made of only 1% Ti-71% Ag-Cu, but under the same conditions as above. As a result, there were some parts with poor bonding.

This poor bonding appears to be due to Ni diffused from the Ni plating layer of the metal lid 2 forming an alloy with Ti in the brazing material.

Reference Example 2 As shown in FIG. 3(C), the thickness was 40. 4% Ti-
89%Ag-Cu brazing material layer 31 and 20g IR M
The o-barrier layer 32 and the Ag--Cu brazing material layer 33 having a thickness of 401 m and 72% and having a recessed portion of 204 depth for degassing formed on the lower surface were successively laminated to produce a thin brazing material plate. Also, the outer diameter is 50JIIJI! , inner diameter 40u, height 60M A
, f'203 ceramic cylindrical body 1 and 42% Fe-
A metallic lid body 2 made of Ni was prepared.

Next, as shown in FIG. 4, the ceramic cylindrical body 1 is
, a thin plate of brazing material and a metal lid 2 are placed, and a vacuum furnace (2
The metal lid body 2 was bonded to the open end surface of the ceramic cylindrical body by heating at 850° C. for 10 minutes in a vacuum chamber (X10″″5 Torr).

When the airtight ceramic container thus obtained was taken out of the furnace and examined, it was found that although the position of the metal lid 2 was slightly misaligned, continuous tone was maintained due to the contribution of the barrier layer 32. Airtightness was also well maintained.

Examples 4 to 6 (Manufacture of Q empty valve) In this example, the vacuum valve shown in FIGS. 5 and 6 was manufactured. In these figures, Figures 10 and 1
The same parts as in Figure 1 are given the same reference numbers.

First, the outer diameter is 123M, the inner diameter is 110M, and the height is 170 rt.
A ceramic cylindrical body 1 made of Ag203 with a diameter of 1.5 mm was prepared, and its inner surface 21 was polished. The degree of polishing was 0.1 u (Example 4) and 0.5 ts (Example 5), respectively.
, lO! It was adjusted to have the surface roughness of ER (Example 6).

Next, Ti powder with an average particle size of 3.5p was prepared, and this T
Ceramic cylindrical body inner surface 21 polished and finished with i powder
The active metal adhesion layer 12 was formed by uniformly coating the required portions (the portions to which the arc shield 6 is to be bonded). The coating amount was 1151/d, and the coating method was brush coating through a metal mesh. However, it is also possible to use a method of masking other than necessary portions and then depositing by sputtering, vacuum evaporation, ion blasting, or the like.

As shown in Fig. 2, the above Ti coated surface 21 and the SUS
There is a thickness of 0 between the protrusions 1o provided on the arc shield 8 made of
．． Brazing was performed with two pieces of silver solder 11 interposed.

This brazing was carried out under the conditions of a vacuum degree of 2 x 10 '' Torr, a temperature of 850° C., and a time of 6 minutes.

As a result, the arc shields were completely connected without play in any of the examples.

Further, the vacuum valves obtained in Examples 4 to 6 above were subjected to an impulse withstand voltage test using a lifting method. the result,
When the impulse withstand voltage value of the conventional vacuum valve shown in FIG. 10 is taken as 100%, a high value of 130% was obtained in each case. This result is due to the synergistic effect of not providing the convex portion 10 on the inner surface of the ceramic cylindrical body and perfecting the shield.

Example 7 (Manufacture of Vacuum Valve) In this example, the joint structure shown in FIG. 7 was formed between the arc shield 6 and the ceramic cylindrical body 1. In this case, the arc shield 6 has a convex portion 10 in FIG.
is not provided. Instead, a spacer 13 made of SUS and a silver solder 14 were interposed between the joint portion of the SUS arc shield 6 and the inner surface 21 of the ceramic cylindrical body.

The surface roughness of the inner surface 21 of the ceramic cylindrical body after polishing was set to 0.5p. Further, as in Examples 4 to 6, Ti powder having an average particle size of 3.5p is applied to the part to be joined by 1η/i as the active metal powder 12 to form an active metal layer 12. was formed.

These were placed at a vacuum level of 2 x 10''5 Torr and a temperature of 850°C.
The silver waxes 11 and 14 were melted and bonded to the inner surface 21 of the ceramic member 1 via the active metal powder 12 under conditions of , 6 minutes.

An impact load of 1500 kg[' was repeatedly applied 100,000 times to the obtained vacuum valve, but no movement or rattling of the arc shield occurred.

Further, when a withstand voltage test was conducted using an impulse withstand voltage test (elevating method), a value of 140% was obtained, taking the impulse withstand voltage value of the conventional vacuum valve shown in FIG. 10 as 100%.

Example 8.9 (Manufacture of Vacuum Valve) In these examples, a stress relaxation mechanism was provided in the bonding between the ceramic cylindrical body 1 and the arc shield 6.

That is, in Example 8, the stress relaxation member 15 was interposed between the ceramic cylindrical body 1 and the arc shield 6. Further, in Example 9, a convex portion 16 was provided in a part of the arc shield 6, and the convex portion 16 was given a stress relaxation effect.

Since the thermal expansion coefficients of the ceramic cylindrical body 1 and the arc shield 6 differ by about one order of magnitude, thermal distortion may occur in the arc shield depending on the heating method and conditions during brazing. Therefore, it was decided to alleviate the thermal stress by using the structure shown in FIG. 8 or 9.

Incidentally, except for the adoption of the stress relaxation mechanism described above, all the arc shields were bonded with the same benign properties as in Examples 4 to P'), and the vacuum bar, S,,'k was manufactured. When the same impulse withstand voltage test as above was carried out on the vacuum valves (1) and 2), a value of 135% in Example 8 and 140% in Example 9 was obtained.

In addition, there was no play in the arc shield of any of the vacuum valves.

Examples 10 and 11 (Manufacture of vacuum valve) In Examples 4 to 9 and Comparative Example 1, activated metal powder having an average particle size of 3.5p is used. Therefore, we investigated the effect of changing the particle size of the active metal.

That is, the average particle size is 1. z (Example 10), 10m (Example 11) active metal powder was used, and everything else was Example 7.
I did the same thing.

As a result, the average particle size is lu! R (Example 10), 10p
In any case of (Example 11), Example 7 (3
In order to investigate the effect of the amount of active metal powder applied, the amount of application was changed to 0.5m. O1η/d (Comparative Example 3), 0.1 #/Cd (Example 12), 1Oti/Crj (Example 13), 5
01E/cd (Comparative Example 4), and everything else was carried out in the same manner as in Example 7.

As a result, in Comparative Example 3 (0, OL4/cri), the arc shield and the ceramic member were not sufficiently bonded, and movement of the shield was observed when an impact was applied. Also,
Variations in withstand voltage values were also observed in impulse withstand voltage tests. Comparative Example 4 (506/d) also had some poor bonding points, and good bonding could not be obtained. As a result, variations were observed in the impulse withstand voltage values.

In contrast, Example 12. 13 (0,1η/d.

106/cd), there was no movement of the arc shield and no fluctuation in the impulse withstand voltage value was observed.

Example 14 In this example, Ti:Zr-1:
Example 7 was carried out in the same manner as in Example 7 except that the mixed powder of No. 1 was used. As a result, no movement of the arc shield was observed, and the impulse withstand voltage characteristics were as good as 130%.

In addition, the results of Examples 4 to 14 and Comparative Examples 1 to 4 are as follows:
They are summarized in Table 1 below.

[Effects of the Invention] As described in detail above, according to the present invention, the opening end surface of the ceramic cylindrical body is not subjected to metallization in advance;
By end face-bonding the peripheral edge of the metal lid to the opening end face, an airtight ceramic container having sufficient bonding strength and high ability to maintain airtightness can be manufactured. In addition, when manufacturing a vacuum valve with an arc shield fixed inside this airtight ceramic container, the arc shield can be bonded with sufficient strength in a simple manner to manufacture a vacuum valve with stabilized withstand voltage characteristics. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the method of manufacturing an airtight ceramic container according to the present invention, and FIGS. 2 and 3 are diagrams showing a thin plate of brazing material that can be suitably used in the present invention. FIG. 4 is a diagram showing how to use the thin brazing material plate of FIG. 3(C), and FIGS. 7 to 9 show vacuum 2 obtained by other embodiments of the present invention, respectively.
, A , j (1) Oh ya 8 Oyuu 01, enemy. Oyo. The respective figures are cross-sectional views of conventional vacuum valves. 1... Ceramic cylindrical body, 2... Metallic lid, 3
a... Fixed contact, 3b... Movable contact, 4a... Fixed terminal, 4b... Movable terminal, 5a... Fixed conductive shaft,
5b...Movable conductive shaft, 6...Arc shield, 7.
... Bellows, 8... Metal solder, 10... Convex portion of arc shield, 11.14... Metal solder layer, 12...
・Active metal powder layer, 13... Spacer member, 21...
Inner surface of ceramic cylindrical body, 15.1.6... Stress relaxation member, 31.33... Metal brazing layer, 32... Barrier layer Applicant's representative Patent attorney Takehiko Suzue Figure 1 (A) ( B) Figure 2 (A) Figure 4 (C) Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 b Figure 10

Claims (12)

[Claims] (1) 0.1 to 10 mg/cm^2 of active metal consisting of Ti and/or Zr is applied to the open end surface of the ceramic cylindrical body.
forming an active metal layer by depositing an amount of; placing a metal brazing layer on the active metal layer;
a step of arranging a metal lid for sealing the opening of the ceramic cylindrical body so that its peripheral edge end surface contacts the metal solder layer; and melting the metal solder layer by heating; A method for manufacturing an airtight ceramic container, comprising the step of brazing a metal lid to the open end surface of the ceramic cylindrical body. (2) The method for manufacturing an airtight ceramic container according to claim 1, characterized in that in order to deposit the active metal, a method of applying a paste containing powder of the active metal is used. (3) In order to adhere the active metal, a method is used in which powder of the active metal is spread and adhered to the open end surface of the ceramic cylindrical body coated with an adhesive material. A method for manufacturing an airtight ceramic container according to item 1. (4) As the metal brazing layer, a convex portion is provided on the upper surface along the width direction of the opening end surface of the ceramic container, and the lower surface is a thin plate of metal brazing material that is smooth. The method for manufacturing an airtight ceramic container according to any one of Items 1 to 3. (5) The airtight ceramic container according to claim 4, characterized in that the solder metal layer is a thin plate of brazing metal having through holes provided along the width direction of the open end surface of the ceramic container. Production method. (6) The metal solder layer is characterized by using a metal solder thin plate having a laminated structure in which a barrier layer made of a metal having a higher melting point than these metal solder layers is interposed between two metal solder layers. The method for manufacturing an airtight ceramic container according to any one of claims 1 to 5. (7) An airtight ceramic container manufactured by the method according to any one of claims 1 to 6. (8) The airtight ceramic container according to claim 7, which penetrates from the outside to the inside of the container and is disposed opposite to the container, and is made openable and closable by making at least one movable in the axial direction. a pair of contact shafts, a metal contact member provided at the tip of each of the pair of contact shafts, and a bellows for enabling axial movement of the contact shafts while maintaining a vacuum in the vacuum container. and a metal arc shield disposed surrounding the contact member to prevent metal evaporated from the contact member from adhering to the inner surface of the ceramic cylinder. A step of polishing the inner surface of the shaped body in advance so that the surface roughness becomes 0.1 to 10 μm, and
a step of forming an active metal layer by depositing active metal powder having an average particle size of 0.1 to 10 μm or less in an amount of 0.1 to 10 mg/cm^2, and on the active metal layer; a step of placing a metal solder layer on the metal solder layer, and a step of arranging the arc shield so as to be in contact with the metal solder layer,
A method for manufacturing a vacuum valve, comprising the steps of melting the metal brazing layer by heating and brazing the arc shield to the inner surface of the ceramic cylindrical body. (9) The method for manufacturing a vacuum valve according to claim 8, wherein a method of applying a paste containing powder of the active metal is used to deposit the active metal. (10) In order to adhere the active metal, a method is used in which powder of the active metal is spread and adhered to the inner surface of the ceramic cylindrical body coated with an adhesive. A method for manufacturing an airtight vacuum valve as described in . (11) The arc shield is provided with a stress relaxation member, and the stress relaxation member and the inner surface of the ceramic cylindrical body are bonded to each other. A method of manufacturing a vacuum valve. (12) A vacuum valve manufactured by the method according to any one of claims 8 to 11.