JP2001220254A - Metal-ceramic bonded material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-ceramic bonded material having sufficiently high bonding strength and high function to keep the airtightness. SOLUTION: A metallic tube 3 and a ceramic tube 2 are bonded with each other at their butt ends through a soldering material fillet 5. The cross section of the soldering material fillet 5 has a form expanding from the metallic tube side toward the ceramic tube side. The angle α between the ceramic side bonding end face 6 and the tangential line L1 passing the outer edge point 8 of the ceramic side bonding end face 6 and tangent to the contour line 11 of the cross section of the soldering material fillet 5 is <=40 deg.. The distance d1 between the outer edge point 8 of the ceramic side bonding end face and the outer edge point 9 of the metal side bonding end face is ι0.6 mm measured in the direction perpendicular to the axial line of the metallic tube 3 or the ceramic tube 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a metal-ceramic joint.

[0002]

2. Description of the Related Art Ceramic members have excellent heat resistance, impact resistance and insulation properties, and are being utilized in various fields by utilizing their properties. For example, in a vacuum switch outer tube using a ceramic tube, an opening end of a cylindrical ceramic member is welded and sealed with a cylindrical metal member provided with a lid. In joining such a ceramic member and a metal member, a brazing method of joining the ceramic member and the metal member via a brazing material has been conventionally used.

However, in the conventional joining of a ceramic member and a metal member by brazing, since the ceramic member and the metal member have different coefficients of thermal expansion, residual stress is generated at the joint when brazing. There is. If this residual stress is large, cracks occur in the ceramic member,
For example, when this connection is used for a vacuum switch outer tube or the like, the airtightness may be impaired.

Therefore, in order to reduce the residual stress and prevent the occurrence of cracks, the following brazing techniques have been developed. For example, by providing a buffer layer made of a metal or the like that relieves residual stress between a ceramic member and a metal member having substantially the same bonding surface, or by using an end surface of the ceramic member and an end surface of the metal member as a bonding surface. Also, the joint area between the two is reduced to reduce the magnitude of the residual stress. Also, if the brazing material is left in a place other than the joining surface, for example, around the joining portion, residual stress is applied to the ceramic member due to a difference in coefficient of thermal expansion, so that the ceramic member is easily cracked. A technique has been proposed in which a brazing material pool is provided on the outer peripheral portion of the portion, or a technique for shaving the outer peripheral portion.

[0005]

However, even with the above technique, the amount of brazing material is excessive, the displacement of the joining position, the area of the brazing portion is too small, and the types of the brazing material and the member to be welded.
In some cases, excessive residual stress cannot be eliminated. In addition, for example, there is a problem that the brazing material easily overflows from the joint surface due to uneven filling of the brazing material or the like. When removing the overflowing brazing material to prevent cracking, the removal polishing is performed. The work was also difficult. Alternatively, if the amount of the brazing material used is reduced to prevent overflow of the brazing material, the amount of the brazing material may be too small due to uneven filling, thereby causing a gap in the joint portion and reducing the joining force. There is also a problem of lowering.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the unevenness in the filling of the brazing material by optimizing the filling amount of the brazing material, the joining position, the area of the brazing part, the shape of the brazing part, and the like, and the ceramic member becomes sharp. It is an object of the present invention to provide a metal-ceramic joined body having a sufficient joint strength and a high airtightness maintaining function without causing problems such as the above.

[0007]

Means for Solving the Problems and Functions / Effects To solve the above problems, a metal-ceramic joined body of the present invention comprises a metal tubular body and a ceramic tubular body each having at least one open end face. It has a structure in which the open end face side is coaxially butted, and the butted part is joined via an annular brazing filler metal, and at the butted part, the joint end face between the metal tubular body and the ceramic tubular body is planar. In any cross-section including the axis of the metal tubular body and the ceramic tubular body,
The width of the joining end face (the joining end face on the metal side) of the metal tubular body is made smaller than the width of the joining end face (the joining end face on the ceramic side) of the ceramic tubular body. The metal tubular body covers both sides in the thickness direction so as to be buried, and the cross-sectional shape of the metal tubular body at both the inner surface side and the outer surface side expands from the metal tubular body side toward the ceramic tubular body side. An angle (hereinafter, referred to as a fillet angle) formed between a tangent line passing through the outer edge point of the ceramic-side joint end face and a cross-sectional outline of the brazing filleret and the ceramic-side joint end face is 40 ° or less. And the distance between the outer edge point of the ceramic-side joint end face and the outer edge point of the metal-side joint end face measured in a direction perpendicular to the axis in the cross section (hereinafter, referred to as an end face outer edge distance). , Characterized in that it is secured over 0.6mm in both end inner surface and the outer surface of the metal cylinder body.

The inventors of the present invention have made intensive studies in view of the above-mentioned problems. As a result, when the end faces of the metal cylindrical body and the ceramic cylindrical body are brazed to each other, cracks in the ceramic cylindrical body are caused. The present inventors have found that the main cause of the occurrence is the shape of the brazing filler material, and have completed the present invention. That is, as described above, the brazing filler fillet covers both sides in the thickness direction of the metal tubular body in such a manner as to bury the end of the metal tubular body, and has a cross section on both the inner surface side and the outer surface side of the end portion of the metal tubular body. The outer shape has a shape that expands from the metal tubular body side toward the ceramic tubular body side, and further has a fillet angle of 40 ° or less, and a distance between the end faces of the metal tubular body at any of the inner side and the outer side at the end of the metal tubular body. In this case, cracks in the ceramic cylindrical body are extremely unlikely to occur due to residual stress at the time of brazing, thereby providing a bonded body having sufficient bonding strength and high airtightness. It became possible to do.

If the fillet angle exceeds 40 ° or the distance between the outer edges of the end faces is less than 0.6 mm, cracks are likely to occur in the ceramic cylindrical body after brazing. Factors that cause the fillet angle and the distance between the outer edges of the end faces to be in the above numerical ranges include excessive filling volume of the brazing material, eccentricity due to displacement of the joining position between the metal cylindrical body and the ceramic cylindrical body, and the area of the brazing portion. Is too small. It is also conceivable that sufficient bonding strength and airtightness cannot be ensured due to the influence of uneven filling of the brazing material. On the other hand, if the fillet angle is less than 3 °, the filling volume of the brazing filler metal becomes too small, and it may not be possible to secure sufficient brazing joint strength. In order to increase the distance between the outer edges of the end faces, it is necessary to increase the thickness of the ceramic cylindrical body or to reduce the thickness of the metal cylindrical body. For example, when considering the application of the present invention to a generally used vacuum switch, an increase in the distance between the outer edges of the end face exceeding 2.50 mm means an increase in product dimensions (particularly, an increase in wall thickness of the ceramic cylindrical body). ), Or insufficient strength of the member (especially due to insufficient thickness of the metal member). Therefore, it is preferable to set the value in a range smaller than the above numerical value.

[0010] By forming the joint structure using the brazing filler material as described above, the airtightness of the joint between the metal tubular body and the ceramic tubular body, specifically, when a helium leak test is performed. Helium leak rate of ^10-9
Pa · m ³ / sec or less can be secured.

Both the metal tubular body and the ceramic tubular body can be formed in a cylindrical shape. In this case, the metal-side joint end face is positioned substantially at the center of the ceramic-side joint end face in the radial direction. By positioning and joining the two cylindrical members in this manner, the effect of preventing the occurrence of cracks and the effect of ensuring airtightness due to the above-described mode of the brazing filler material are further remarkable.

The ceramic cylindrical body can be made of an alumina-based ceramic containing alumina as a main component. In addition, the metal cylindrical body contains Fe as a main component, and the secondary component with the highest content is one of Ni and Co, and the secondary component with the second highest content is the other of Ni and Co.
It can be composed of any of a Ni-Co-based alloy, an Fe-Ni-based alloy whose main component is Fe, and a sub-component having the highest content is Ni, and a Cu-based metal whose main component is Cu. . As described above, when the alumina-based ceramic is used, or when the metal cylindrical body containing Fe or Cu as a main component is used, the brazing material fillet of the above-described embodiment is employed, so that the ceramic cylindrical body is formed. Cracking is more effectively prevented, and a metal-ceramic joined body having sufficient joint strength and high airtightness maintaining function is obtained. Note that Fe-N
As the i-Co alloy, for example, Fe: 54%, N
i: 29%, Co: 17%, etc.
As an e-Ni alloy, for example, Fe: 58%, N
Further, as a Cu-based metal, for example, Cu: about 100% oxygen-free copper or Cu: 95.5%, Sn: 4%, P: 0.5% Phosphor bronze or the like can be used.

On the other hand, the brazing filler material is made of an Ag-Cu brazing material containing Ag as a main component and Cu as a subcomponent, for example, BAg-8 (silver solder) containing 72% of Ag and 28% of Cu. It is good to configure. In the case where such a brazing filler material is used, the effect of preventing the occurrence of cracks in the ceramic cylindrical body becomes remarkable by adopting the brazing filler fillet as described above, and has a sufficient joining strength and airtightness. A joined body can be formed. In this specification, the terms “main component”, “mainly” or “main component” refer to a component having the highest weight content in a substance of interest unless otherwise specified. Subsequently, a component having a high content is referred to as a “subcomponent”.

When a metal cylinder containing Ni is used, the metal cylinder and the ceramic cylinder are formed of one or more active materials selected from Ti, Zr and Hf. An active metal component, which is joined via a brazing filler material composed of a reaction layer containing a metal component and at least a brazing material layer in contact with the metal tubular body, and between the brazing material layer and the metal tubular body. The amount of the intermetallic compound containing Ni and Ni should be as small as possible. When an intermetallic compound containing an active metal component and Ni is formed between the metal cylinder and the brazing material layer, the intermetallic compound is very brittle, and the joining strength of the two cylinders decreases. This may be a factor and the fluidity of the brazing material may be impaired, so that the above-mentioned brazing material fillet shape may not be formed.

In order to prevent the formation of an intermetallic compound containing an active metal component and Ni as much as possible when such a metal cylinder containing Ni is used, for example,
The primary brazing metal containing the active metal component is subjected to primary brazing metallization on the end face of the ceramic tubular body, and then has a lower melting point than the primary brazing material and a lower content of the active metal component (desirably). The secondary brazing material can be manufactured by a method of secondary brazing a metal tubular body to a primary brazed portion of an end face of a ceramic tubular body.

According to the above-described process, the primary brazing material is subjected to the metallizing treatment on the joining surface on the ceramic tubular body side with the primary brazing material containing the active metal, so that the joining surface of the ceramic tubular material is provided with the active metal and the active metal. A reaction layer with the ceramic component is formed. The reaction layer has excellent affinity for both the ceramic and the brazing metal components other than the active metal in the brazing filler metal, and forms a strong joint structure between the brazing filler material and the ceramic cylindrical body. Play a central role for. And at the time of secondary brazing,
With the secondary brazing material having a lower melting point than the primary brazing material and having a low content of the active metal component (preferably not containing), brazing is performed at a lower temperature than at the time of the primary brazing,
The diffusion of the active metal component from the reaction layer to the brazing material layer side is suppressed, and the Ni component in the metal cylindrical body joined via the brazing material fillet (consisting of the reaction layer and the brazing material layer); Reaction with the active metal component from the reaction layer (that is, the primary brazing material) is extremely unlikely to occur. As a result, an intermetallic compound containing an active metal component and Ni is hardly formed, and as a result, a metal-ceramic bonded body having a high bonding strength with a stable bonding state at a bonding interface can be obtained.

In the above manufacturing method, the primary brazing temperature T1 depends on the type of the brazing material to be used, but it is 840-8.
The temperature is preferably set to 80 ° C. Similarly, the secondary brazing temperature T2
Is preferably 800 to 820 ° C. The difference ΔT≡T1−T2 preferably satisfies 20 to 80 ° C. That is, by setting the secondary brazing temperature T2 to be lower than the primary brazing temperature T1 by about ΔT, the active metal component in the reaction layer formed by the primary brazing is changed to the brazing material layer during the secondary brazing. , The reaction with the Ni component contained in the metal cylinder can be effectively suppressed, and as a result, an active metal-Ni-based intermetallic compound is less likely to be formed between the brazing filler material and the metal cylinder. . When T1 and T2 are set in the above range, ΔT
Is less than 20 ° C., the above effect is insufficient. On the other hand, when the temperature exceeds 80 ° C., the secondary brazing temperature becomes too low, so that the formation of the brazing material layer becomes incomplete and the bonding strength is rather lowered. ΔT is preferably 3
The temperature is preferably 0 to 70 ° C, more preferably about 40 to 60 ° C.

As the active metal component, Ti can be used particularly preferably because it can exhibit excellent bonding performance to many ceramics and is relatively inexpensive. In this case, in order to enhance the reaction activity of the Ti component, the Ti component in the primary brazing material is titanium hydride (the general composition formula is Ti
Is a H _2, it is desirable that contained in the form of the present invention is not limited to stoichiometric compounds). Also, Ti
H ₂ As By including in the primary brazing material can be such as oxidation or nitridation of Ti also effectively prevented. The primary braze Specifically, it is preferable to use those TiH ₂ is contained 1 to 20% by weight. When the content of TiH ₂ is less than 1% by weight, the formation of the reaction layer becomes insufficient, and the bonding failure may easily occur. On the other hand, when TiH ₂ is 2
If it exceeds 0% by weight, poor wetting may occur between the primary brazing material and the secondary brazing material during secondary brazing, and
In some cases, the reaction layer becomes excessively thick, so that the bonding strength is rather lowered or the airtightness of the bonded portion is lowered. The content of TiH ₂ in the primary brazing material is preferably 5
The content is preferably set to 10 to 10% by weight.

In the above manufacturing method, the primary brazing is preferably performed in a vacuum, and the degree of vacuum is 1.0 × 10
^-3 Torr or less is preferable. Primary brazing 1.
If performed under conditions exceeding 0 × 10 ⁻³ Torr, poor wetting of the primary brazing material may occur, or the active metal component may be oxidized or nitrided, making it difficult to form a stable reaction layer. The atmosphere of the primary brazing is not limited to a vacuum atmosphere, and a stable reaction layer can be formed even if the primary brazing is performed in an inert gas atmosphere such as an Ar gas atmosphere.

For example, in the metallizing treatment by primary brazing, the active metal component in the primary brazing material reacts with the ceramic cylindrical body to form a reaction layer, while the remaining metal component forms the reaction layer in an intimate form. A covering primary metallization layer may be formed. For example, as the primary brazing material, components other than the active metal (hereinafter, referred to as base components), in other words, components to constitute the primary metallization layer, are Ag, Cu,
Au, Sn, etc. can be used, but the secondary brazing material used for the secondary brazing is excellent in wettability or affinity with the primary metallization layer based on the base component,
For example, it may be desirable to use a brazing material having a similar composition to the primary metallized layer. As such a secondary brazing material, specifically, an Ag-Cu alloy can be used. Since the Ag-Cu alloy rarely reacts with an active metal component such as Ti to form an intermetallic compound, has a low melting point, and has good bondability with a metal cylindrical body, the secondary brazing material of the present invention is used. Suitable as. The content ratio of Ag to Cu in the Ag-Cu alloy is preferably 30 to 50 parts by weight of Cu with respect to 100 parts by weight of Ag. If Cu is less than 30 parts by weight, the melting point of the brazing material becomes too high, and for example, the bonding strength may decrease due to the formation of the above-mentioned intermetallic compound due to the diffusion of the active metal component from the reaction layer. On the other hand, if it exceeds 50 parts by weight, in addition to the same problem caused by the high melting point of the brazing material, the oxidation resistance of the brazing material layer may be impaired, and the high-temperature bonding strength and the like may be impaired. In addition, as the above Ag-Cu alloy, for example, JIS-
Silver wax described in Z3261: BAg-8 or the like can be used.

In the metal-ceramic joint, the thickness of the reaction layer in the joining direction between the metal cylinder and the ceramic cylinder is preferably 50 μm to 300 μm. When the thickness of the reaction layer is less than 50 μm, the bondability may decrease due to the lack of the reaction layer, and when it exceeds 300 μm, the reaction layer may become too thick and the bonding strength may decrease. By setting the range of the thickness of the reaction layer to desirably 150 μm to 200 μm, the bonding state of the metal-ceramic bonded body is further stabilized, and the bonding strength is further improved.

In the above metal-ceramic joint, the thickness between the end face of the brazing material layer on the reaction layer side and the joining end face of the metal tubular body (hereinafter referred to as the brazing material joining thickness) is 3 mm.
The thickness is preferably set to 0 μm to 100 μm. The thickness is
When the thickness is less than 30 μm, an intermetallic compound is easily formed between the active metal component and the metal cylindrical body, which may cause a decrease in bonding strength. On the other hand, when the thickness exceeds 100 μm, the brazing material layer becomes too thick, and the bonding strength may be reduced. The above range is desirably 50 μm to 80 μm.
In this case, the bonding state of the metal-ceramic bonded body is further stabilized, and the bonding strength is further improved.

Next, the flatness of the joining surface of the ceramic cylindrical body is preferably set to 0.1 mm or less. 0.1 mm flatness
Exceeding the above may cause incomplete formation of the reaction layer or cause poor brazing at the time of secondary brazing, resulting in a decrease in the bonding strength of the manufactured joined body.

As a use of the metal-ceramic joint as described above, application to a vacuum switch is particularly effective.
In this case, for example, a ceramic cylindrical body is preferably used as an outer tube for a vacuum switch. ADVANTAGE OF THE INVENTION According to the metal-ceramic joined body of this invention, since it has favorable joining strength and a highly airtight joining state can be obtained, it is used for a circuit breaker of a power distribution facility, various vacuum switches, etc. If a ceramic tubular body is used as an outer tube for a vacuum switch and used as a joined body between the ceramic tubular body and a metal tubular body provided with a lid member, the airtight effect can be greatly exhibited. . In this case, if a flange-like portion that bulges outward is provided on the end face side that is not joined to the ceramic tubular body of the metal tubular body, for example, in contact with the lid, the airtightness and strength between the outer tube and the lid are improved. It will be even better.

[0025]

Embodiments of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a schematic sectional view showing a part of an outer tube of a vacuum switch in which a metal-ceramic joint according to an embodiment of the present invention is used. The vacuum switch outer tube 1 has a form in which a cylindrical ceramic tubular body 2 forming a ceramic tube and a cover member 4 are hermetically joined to a cylindrical metal tubular body 3. . FIG. 1 is a cross section including the axis O of the metal tubular body 3 and the ceramic tubular body 2 of the joined body 10. The ceramic tubular body 2 and the metal tubular body 3 are cylindrical bodies each having an open end face, and are coaxially butted on the open end face side. 1 according to the present invention, which is joined through
0 is formed. In addition, on the side of the lid member 4 of the metal tubular body 3, a flange-shaped portion 3 a that bulges outward is formed, and the airtightness and the bonding strength with the lid member 4 are maintained.

FIG. 2 is a sectional view showing one side of the axis O of FIG. 1 in a further enlarged manner. At the abutting portion between the metal tubular body 3 and the ceramic tubular body 2, each of the joining end faces, that is, the metal-side joining end face 7 and the ceramic-side joining end face 6 are formed in a planar shape, and the width of the metal-side joining end face 7 is made of ceramic. The width is smaller than the width of the side joint end face 6. On the other hand, the brazing material fillet 5 covers the entire peripheral edge of the metal cylindrical body 3 so as to bury the joining-side end of the metal cylindrical body 3, and has a cross-sectional outer shape inside and outside the metal cylindrical body 3. 3
It has a shape that expands from the side toward the ceramic tubular body 2 side.

Further, the outer edge point 8 of the ceramic side joining end face 6
The angle (fillet angle) α between the tangent line L1 passing through the soldering material fillet 5 and contacting the cross-sectional outline 11 and the ceramic-side joining end face 6 is 40 ° or less (3 ° or more). Further, between the outer edge point 8 of the ceramic-side joint end face 6 and the outer edge point 9 of the metal-side joint end face 7, the distance between the outer edge of the end face measured in a direction orthogonal to the axis of the metal tubular body 3 or the ceramic tubular body 2. The distance (end face distance) d1 is set to 0.6 mm or more.

The ceramic cylindrical body 2 is made of, for example, an alumina-based ceramic containing alumina as a main component, and the metal cylindrical body 3 is made of, for example, Fe: 54% and Ni: 29.
%, Co: Fe-Ni-Co-based alloy containing 17%. The brazing filler material 5 is made of, for example, an Ag-Cu alloy containing 72% of Ag and 28% of Cu. In addition, as shown in FIG. 3, when the chamfer 32 is performed on the joining surface of the metal cylindrical body,
Surface 7 excluding the chamfered portion of the joining end surface of the metal cylindrical body 30
a and the distance d1 from the outer edge point 7b of the joint surface 7a.
Shall be stipulated.

As shown in FIG. 4, the joining layer (brazing filler material) 5 between the ceramic tubular body 2 and the metallic tubular body 3 is actually divided into two layers. That is, the two layers of the reaction layer 15 containing Ti as an active metal and joined to the ceramic tubular body 2 and the brazing material layer 25 in contact with at least the metallic tubular body 3 and containing almost no active metal are used. Thus, the brazing filler material 5 having the fillet angle α and the end face distance d1 is formed. In this embodiment, for example, a Ti—Ni-based intermetallic compound is not formed as much as possible between the metal cylindrical body 3 and the brazing material layer 25, so that the brazing material fillet shape is achieved. The joint has high joining strength.

Thus, the metal cylindrical body 3 and the brazing material layer 25
In order not to form an intermetallic compound as much as possible between
It is desirable to braze by the following methods.
No. First, as shown in FIG.
Paste of the primary brazing material 104 containing Ti
At the end of the cylindrical body 2 (joining surface), the atmosphere heating furnace
Heating at a given atmosphere and temperature within
Rise processing to form a reaction layer 15 as shown in FIG.
Form. In addition, brazing material components other than the active metal component
Forming a primary metallization layer 5b covering the reaction layer 15 in a contact form
May be. The primary brazing condition is the brazing temperature
T1 is 840-880 ° C. (860 ° C.), and the degree of vacuum is 1.
0x10^-3Torr or less (in this embodiment, for example, 1.
0x10 ^-4Torr) in vacuum
You. The composition of the primary brazing material, for example,
Ag and Cu can be used as active metal components.
For example, Ti, TiH₂1 to 20% by weight in the form of
5% by weight) can be used.

Next, as shown in FIG. 5C, the melting point of the active metal component is lower than that of the primary brazing material and the content of the active metal component is smaller. The secondary brazing material foil 105 that is not contained in the reaction layer 1
5 (or the primary metallization layer 5b), and the end surfaces (joining surfaces) of the metal cylindrical bodies 3 are further abutted to each other and heated in a predetermined atmosphere and temperature in an atmosphere heating furnace to perform secondary brazing. . Thereby, the secondary brazing material foil 10
5 is melted to form a brazing material layer 25 shown in FIG. When the primary metallization layer 5b is formed,
In some cases, a part or the whole thereof is melted and integrated with the secondary brazing material foil 105 and is taken into the brazing material layer 25. The condition of the secondary brazing is that the brazing temperature T2 is 800 to 820 ° C.
(800 ° C. in this embodiment), and the difference ΔT≡T1−T2 from the primary brazing temperature T1 is set to 20 to 80 ° C. (60 ° C. in this embodiment). In addition, as a secondary brazing material, silver brazing BAg- described in JIS-Z3261 is used.
8 (Ag: Cu = 18: 7).

FIGS. 5 (e) and 5 (f) are perspective views schematically showing the above-mentioned brazing process. In the primary brazing, the end surfaces are formed as shown in FIG. 5 (e). When using the corresponding annular primary brazing material foil 104 and performing secondary brazing, as shown in FIG. 5 (f), between the end faces of the ceramic tubular body 2 and the metallic tubular body 3, Brazing is performed so as to sandwich the annular secondary brazing material foil 105.

Next, the ceramic cylindrical body and the reaction layer 1
5, the boundary between the reaction layer 15 and the brazing material layer 25, and the boundary between the brazing material layer 25 and the metal cylindrical body 2 are, for example, electron probe microanalyzer (EPMA), energy dispersive X-ray spectroscopy (ED
S), and can be measured by a known method such as wavelength dispersive X-ray spectroscopy (WDS). In the present invention, it is defined as follows. As shown in FIG. 6, a cation component having the highest content of the ceramic cylindrical body (ceramic member) (for example, an element component having a positive valence when analyzed by X-ray photoelectron spectroscopy (XPS) or the like, A for alumina
l, Si is silicon nitride), Q is the metal component having the highest content of the metal cylinder (metal member), and A is the active metal component. Then, the cross section of the joint is observed with a scanning electron microscope (SEM), and in the joining direction of each part, the cation component Q, the metal component M, and the active metal component A are attached to the EPM attached to the SEM.
Assume that line analysis is performed by A. In this case, the content of each of the component Q, the component M, and the component A is determined by the corresponding characteristic X
It is considered to be proportional to the detected intensity of the line. At this time, the maximum value of the characteristic X-ray intensity based on the component Q is IQmax (measured at the height from the background with the lowest value on the side of the metal cylinder as the background). The maximum value of the line intensity is IMmax (measured at the height from the background with the lowest value on the side of the ceramic cylinder as the background), and the maximum value of the characteristic X-ray intensity based on the component A is IAmax (ceramic The lowest value on the cylindrical body side or metal cylindrical body side as the background,
(Measured at the height from the background), the position at 0.8 IQmax is defined as the boundary BC-R between the ceramic cylinder and the reaction layer, and the position at 0.8IAmax is defined as the reaction layer. As the boundary BR-W with the brazing material layer,
The position at which 0.8IMmax is reached is defined as the boundary BW-M between the brazing material layer and the metal cylinder.

An intermetallic compound containing an active metal component and Ni is provided between the brazing material layer 25 and the metal cylinder 3.
For example, a Ti-Ni-based compound is hardly formed, which is, in other words, the Ni component in the metal cylindrical body,
This means that the reaction with the Ti component forming the reaction layer hardly occurred. As means for specifically confirming this, for example, a crystal structure analysis is performed on the cross section of the joint by micro X-ray diffraction or the like, and for example, Ti ₂ Ni,
If a diffraction peak of a Ti—Ni-based compound such as TiNi or Ni ₃ Ti is not confirmed, it can be considered that a Ti—Ni-based compound is not formed. Further, in FIG. 6, when a line analysis of the active metal component A is performed, the peak value I′Amax of the characteristic X-ray intensity of the active metal component A observed at the interface between the brazing filler metal layer and the metal cylindrical body is shown. ,
Ratio I'Amax / I to peak value IAmax in the reaction layer
Amax is desirably 0.01 or less (preferably substantially zero within the range of measurement variation).

The metal-ceramic joint 10 as described above
Is used for a switch portion between a metal tubular body and a ceramic tubular body of a vacuum valve as shown in FIG.
It is possible to provide a joint having excellent airtightness and strength. The vacuum valve 50 is formed in a container shape by hermetically sealing metal end plates 57, 57 (metal cylinder) with lids at both ends of an insulating container 55 (ceramic cylinder). In this vacuum container, the contacts 60, 6
1 is provided so that the contact 61 is fixed and the contact 60 is movable so that the contact 60 is movable. The fixed electrode rod 52 of the fixed contact 61 is airtightly attached to the end plate 57. The movable electrode rod 56 of the movable contact 60 is a bellows 58. Through the end plate 5
7 is movably and air-tightly attached to the base 7. An arc shield 54 is provided around the fixed contact 61 and the movable contact 60.
The bellows cover 59 of the bellows 58 is attached to the movable electrode rod 56.

When the movable electrode bar 56 is operated in the pulling-out direction by an operating mechanism (not shown) and the contacts 60 and 61 are separated from each other, the contact points 60 and 61 of the vacuum valve 50 are turned off.
When the arc generated during 61 reaches the zero current point, it is diffused into vacuum and cut off. Here, the end plate (metal cylinder) 57 and the insulating container (ceramic cylinder) 55 can be brazed and joined as the metal-ceramic joint of the present invention. Thereby, the joint has high airtightness and joint strength, and can exhibit excellent performance as a vacuum valve.

EXAMPLE The following experiment was conducted to confirm the effects of the present invention. As the ceramic cylindrical body 2 shown in FIG. 1, an alumina-based ceramic (alumina content 92
Weight%, density 3.6 g / cm ³ ), inner diameter 51 mm,
One having an outer diameter of 61 mm and a length of 91 mm was prepared. On the other hand,
As the metal tubular body 3 shown in FIG. 1, Fe: 54% by weight-N
i: 29% by weight-Co: 17% by weight alloy (Kovar)
And an inner diameter of 55 mm, a joint surface side outer diameter of 57.5 mm, a brim part side outer diameter of 62 mm, and a length of 10 mm.

As the primary brazing filler metal, an alloy powder containing 72 parts by weight of Ag and 28 parts by weight of Cu (an alloy powder constituting the balance other than the active metal component) is compared with a TiH ₂ powder as an active metal component. Was mixed at a ratio of 5 parts by weight, and a solvent and a dispersant were added to prepare a primary brazing material paste. In addition, as a secondary brazing material, an inner diameter of 51 mm, an outer diameter of 60 mm,
An annular BAg-8 brazing filler metal foil having a thickness of 0.13 mm was prepared. Further, the end face on the joining side of the ceramic cylindrical body was polished by a grinder and lap polishing so that the flatness became 0.1 mm. In addition, the end face of the joining side of the metal tubular body is
During lace processing (cutting), cutting was performed so that the flatness became 0.1 mm.

Then, the above-mentioned primary brazing material paste is applied at a thickness of 200 μm to the end face on the joining side of the ceramic cylindrical body, and the temperature T1 = 860 ° C., the degree of vacuum = 1 × 10 ⁻³ in an atmosphere heating furnace. Primary brazing was performed by Torr to form a reaction layer (primary metallized layer). Next, in the form of sandwiching the above-mentioned secondary brazing material foil, the joining side end face of the ceramic tubular body on which the reaction layer (primary metallized layer) is formed and the joining side end face of the metal tubular body are abutted. Temperature T2 = 800 ° C.
The secondary brazing was performed at a degree of vacuum = 1 × 10 ⁻⁴ Torr, and the metal-ceramic joined bodies No. having different fillet angles α and end face distances d1 as shown in Table 1 were used. Nos. 1 to 12 were produced.

The fillet angle α can be changed by changing the inner and outer diameters and thickness of the secondary brazing material.
The end face distance d1 was in the range as shown in Table 1 by changing the thickness of the ceramic cylindrical body. Further, the fillet angle α and the end face distance d1 are determined based on the produced metal-
After embedding the resin in the ceramic joint, cut it with a projector.
It was measured at a magnification of two times. For the fillet angle α,
The end face distance d is determined by the angle between the ceramic-side joint end face and the inner tangent of the brazing filler material passing through the outer edge point of the joint end face.
For No. 1, the measurement was made based on the distance between the outer edge point of the ceramic-side joining end face and the outer edge point of the metal-side joining end face.

With respect to each of the metal-ceramic joints having such various fillet angles α and end face distances d1, flaw detection tests and cross-sectional observations with a metallographic microscope were performed to evaluate whether or not cracks occurred in the ceramic cylindrical body. The airtightness of each joined body was also evaluated by a He leak test using a He leak detector.

[0042]

[Table 1]

As described above, with respect to the metal-ceramic joint having a fillet angle of 40 ° or less and an end face distance of 0.6 mm or more, no crack is generated in the ceramic cylindrical body, and good jointability is obtained. It was found to have. In addition, the He leak amount measured by the He leak test is the No. ^10-9 for 1-4 and 7-10
At Pa · m ³ / sec or less, sufficient airtightness was obtained.
On the other hand, No. 10 ^{-9 for} 5, 6, 11, and 12
The value exceeded Pa · m ³ / sec, indicating that the airtightness of the joint was low.

As the metal tubular body, an Fe—Ni alloy (containing 58% of Fe and 42% of Ni) or C
u-based metal (Cu: about 100% oxygen-free copper or C
u: 95.5%, Sn: 4%, P: 0.5%, phosphor bronze), and the same test as in the above example was performed. As a result, the fillet angle was 40 ° or less and the end face was not changed. When the distance was 0.6 mm or more, no cracks occurred in the ceramic cylindrical body, and the ceramic cylindrical body had good jointability.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a metal-ceramic joined body of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the metal-ceramic joined body of FIG.

FIG. 3 is a diagram illustrating a modification of the joining surface of the metal tubular body.

FIG. 4 is a partially enlarged cross-sectional view showing a different configuration of a bonding layer between a metal tubular body and a ceramic tubular body.

FIG. 5 is a diagram illustrating a method for manufacturing a metal-ceramic joint according to the present invention.

FIG. 6 is an explanatory view for determining the thicknesses of a reaction layer and a brazing material layer in the metal-ceramic joined body of the present invention.

FIG. 7 is a sectional view showing an embodiment using the metal-ceramic joined body of the present invention as a vacuum switch outer tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum switch outer tube 2 Ceramic cylindrical body 3 Metal cylindrical body 4 Lid member 5 Brazing filler material 6 Ceramic-side joining end face 7 Metal-side joining end face 8 Ceramic-side joining end face outer edge 9 Metal-side joining end face outer edge 10 Metal-ceramic joint body 15 Reaction layer 25 Brazing material layer 50 Vacuum valve

Claims (9)

[Claims] 1. A structure in which a metal tubular body and a ceramic tubular body each having at least one open end face are coaxially butted on the open end face side, and the butted portions are joined via an annular brazing filler filet. In the abutting portion, the joining end surfaces of the metal tubular body and the ceramic tubular body are each formed in a planar shape, and include any axis including the axis of the metal tubular body and the ceramic tubular body. In the cross-section, the width of the joining end face of the metal tubular body (hereinafter, referred to as a metal-side joining end face) is smaller than the width of the joining end face of the ceramic tubular body (hereinafter, referred to as a ceramic-side joining end face). The material fillet covers both sides in the thickness direction of the metal tubular body so as to bury the end of the metal tubular body, and is formed on both the inner surface side and the outer surface side of the end portion of the metal tubular body. The tangent to the cross-sectional outline of the brazing filler material passes through an outer edge point of the ceramic-side joining end face, and has a cross-sectional profile of the flared portion extending from the metal cylindrical body side toward the ceramic cylindrical body side. And an angle between the ceramic-side joining end face is 40 ° or less, and an outer edge point of the ceramic-side joining end face and an outer edge point of the metal-side joining end face measured in a direction perpendicular to the axis in the cross section. Characterized in that a distance of 0.6 mm or more is secured on both the inner surface side and the outer surface side of the end portion of the metal tubular body. 2. An airtightness of a joining portion between the metal tubular body and the ceramic tubular body by the brazing material fillet,
Helium leakage amount at 10 -9 ^{Pa ·} m 3 ^/ s is ensured in the following claim 1, wherein the metal - ceramic joined article. 3. The metal cylindrical body and the ceramic cylindrical body are both formed in a cylindrical shape, and the metal-side joint end face is positioned substantially at the center of the ceramic-side joint end face in the radial direction. 3. The metal-ceramic joint according to 1 or 2. 4. The metal-ceramic joint according to claim 1, wherein the ceramic tubular body is made of an alumina-based ceramic containing alumina as a main component. 5. The metal cylindrical body contains Fe as a main component, and the sub-component having the highest content is one of Ni and Co, and the sub-component having the second highest content is Ni.
Fe-Ni-Co-based alloy which is the other of Co and Co, Fe-Ni-based alloy containing Fe as a main component, and a sub-component having the highest content of Ni, and Cu-based metal containing Cu as a main component. The metal-ceramic joined body according to any one of claims 1 to 4, wherein 6. The metal according to claim 1, wherein the brazing filler metal is made of an Ag—Cu-based brazing material containing Ag as a main component and Cu as a subcomponent.
Ceramic joint. 7. The metal cylindrical body is configured to contain Ni, and the metal cylindrical body and the ceramic cylindrical body are made of Ti,
A reaction layer containing one or more active metal components selected from Zr and Hf and a brazing material fillet composed of at least a brazing material layer in contact with the metal tubular body; The formation amount of the intermetallic compound containing the active metal component and Ni between the brazing material layer and the metal cylindrical body is made as small as possible.
The metal-ceramic joined body according to any one of the above. 8. The metal-ceramic joint according to claim 1, wherein the ceramic tubular body is an outer tube for a vacuum switch. 9. The metal according to claim 1, wherein the metal tubular body has a flange-like portion bulging outward on an end face side not joined to the ceramic tubular body. -Ceramic joints.