JPH01239070A - Metal ceramic bonded material - Google Patents

Abstract

PURPOSE:To obtain a metal ceramic bonded material having high bond strength and high reliability at room temperature and high temperature, wherein strong chemical bond between a protruded part of a ceramic member and a solder material is avoided at a bond end part of bonded parts between the outer surface of the protruded part of a ceramic member and an inner surface of a dented part of a metallic member. CONSTITUTION:A protruded part 2 of a ceramic member 1 is bonded to a dented part 4 of a metallic member 3 by soldering by using a solder 5. In the bonding, the solder 5 is not strongly bonded to the dented part 2 of the member 1 by chemical bond at a given distance l from the bond end 6. In order to make this constitution, for example, the dented part 2 of part not to be firmly stuck by chemical bond is coated with a substance such as graphite not to bonded to a solder and ordinary soldering operation is carried out. Namely, the whole inner surface of the dented part 4 of the member 3 at a position to be bonded is electroplated with Ni and part of the distance l not to be chemically bonded from the bond end 6 of a position of the protruded part 2 of the member 1 to be bonded is coated with a graphite, a substance not to be bonded to a solder. Then bonding is carried out by using the active metallic solder to give the aimed metallic ceramic bonded material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a metal-ceramic bonded body formed by integrally bonding a ceramic member and a metal member via a brazing material.

(Conventional technology) Ceramics such as zirconia, silicon nitride, and silicon carbide are
Because it has excellent mechanical strength, heat resistance, and wear resistance, it is being put into practical use as a high-temperature structural material or wear-resistant material for gas turbine engine parts, engine parts, etc. However, since ceramics are generally hard and brittle, their moldability is inferior to that of metal materials. In addition, since it has poor toughness, it has low resistance to impact forces. For this reason, it is difficult to form mechanical parts such as engine parts only from ceramic materials, and they are generally used in the form of a composite structure in which a metal member and a ceramic member are bonded together.

During joining, at the joint where the outer surface of the convex part of the ceramic member is joined to the inner surface of the concave part of the metal member by brazing, the brazing material existing between the outer surface of the convex part of the ceramic member and the inner surface of the concave part of the metal member is A metal-ceramic bonded body is known that has a structure in which the entire surface in contact with the convex portion is firmly fixed by chemical bonding.

(Problem to be Solved by the Invention) Generally, when joining a convex part of a ceramic member and a concave part of a metal member by brazing, when the temperature is lowered from the freezing point of the brazing material to room temperature, thermal expansion of the metal member or the brazing material occurs. Since the coefficient of thermal expansion of the ceramic member is large and the coefficient of thermal expansion of the ceramic member is small, the amount of shrinkage of the metal member and the brazing material is greater due to the difference in the coefficient of thermal expansion. However, in a structure in which the convex portion of the ceramic member and the brazing material are firmly fixed by chemical bonding on the entire surface of the contact surface as described above, when the metal member or the brazing material contracts when the temperature drops, the brazing material and the ceramic material is firmly fixed and cannot slip at the bonding interface between the brazing material and the ceramic component, so the shrinkage force of the metal component or brazing material is applied to the ceramic component, causing unreasonable tensile stress in the ceramic component. was there. Further, sufficient consideration has not been given to the relationship between the tip surface of the convex portion and the bottom surface of the concave portion, and furthermore, the relationship between the diameter and the joining length.

Therefore, tensile stress concentration increases particularly at the joint ends of the ceramic member, and this stress concentration reduces the strength of the joined body against bending and torsion, resulting in a decrease in reliability.

An object of the present invention is to solve the above-mentioned problems and provide a metal-ceramic bonded body with high bonding strength and reliability both at room temperature and high temperature.

(Means for Solving the Problems) A first aspect of the metal-ceramic joined body of the present invention is that the convex portion provided on the ceramic member is inserted into the recessed portion provided on the metal member, and is integrally joined by brazing. In the metal-ceramic bonded body having a structure, the protrusion and the brazing material are chemically bonded at least at the joint end of the joint between the outer surface of the protrusion of the ceramic member and the inner surface of the recess of the metal member. It is characterized by the fact that it is not firmly fixed by joints.

Further, in a second aspect of the metal-ceramic bonded body of the present invention, the convex portion provided on the ceramic member is inserted into the recessed portion provided on the metal member, and the outer circumferential surface of the convex portion and the inner circumferential surface of the recessed portion In a metal-ceramic bonded body having a structure in which two parts are integrally joined by brazing, there is a space between the tip surface of the convex part of the ceramic member and the bottom face of the concave part of the metal part, or a low elasticity material made of a substance that does not bond with the solder. This is characterized by the interposition of an intermediate body, and a structure in which the thickness G of this space or the intermediate body satisfies the following formula.
-TR) Here, Ll: distance from the bottom of the recess of the metal member to the joint end get α: coefficient of thermal expansion of the metal member α': coefficient of thermal expansion of the ceramic member TS; solidification temperature of the solder TS: room temperature.

Furthermore, the third aspect of the metal/ceramic bonded body of the present invention is a metal/ceramic bonded body having a structure in which a protrusion provided on a ceramic member is inserted into a recess provided in a metal member and is integrally joined by brazing. In the ceramic bonded body, when the axial joining length between the concave portion of the metal member and the convex portion of the ceramic member is L2, and the diameter of the convex portion is D, 0.2≦L2/D≦0 It is characterized by being joined so as to satisfy the following relationship: .39.

(Function) In the configuration of the first invention described above, at least at the joint end of the joint part, the brazing material and the convex part of the ceramic member are not firmly fixed by chemical bonding, so that the joint in the ceramic member is not firmly fixed. The tensile stress concentration due to the difference in thermal expansion between the metal member or brazing material and the ceramic member at the end portion is reduced, and the strength of the joined body against bending and torsion is increased, resulting in higher reliability. Furthermore, since a soft metal such as a brazing material is interposed between the convex portion of the ceramic member and the concave portion of the metal member, the effect of a cushioning material can also be obtained. Furthermore, since the brazing material is present outside the bonding interface where the chemical bonding between the ceramic component and the metal component is occurring, it is possible to prevent corrosive gases from entering the bonding interface where the chemical bonding is occurring. It can be prevented.

Furthermore, a bonded body in which the brazing material of the bonded part is not firmly fixed to the entire outer circumferential surface of the convex part of the ceramic member through chemical bonding has the highest bending strength as shown in the examples below, and therefore the turbocharger rotor It can be suitably applied to parts that are subjected to bending loads such as.

However, in a bonded body in which the brazing material is not firmly fixed to the entire outer circumferential surface of the convex portion through chemical bonding, when the temperature of the entire bonded portion becomes higher than that of the bonded portion of the turbocharger rotor, for example, 600°C, the ceramic Since the shrink fit effect due to the difference in thermal expansion between the member and the metal member is reduced, there is a concern that the bonding strength will be reduced.

Here, the fact that the brazing material and the ceramic member are not firmly fixed by chemical bonding means that the brazing material and the ceramic material are in contact with each other; This refers to a state in which the brazing material mechanically tightens the ceramic member without making a strong chemical bond at the contact interface. Also, the joint end is
It means the end of the joint where the ceramic member and the brazing material are joined near the opening of the recess.

In order to prevent the solder metal and the ceramic member from firmly adhering due to chemical bonding at the joint end of the joint described above, when brazing is performed using the active metal solder described below, it is necessary to By forming a thin layer of a material that does not have any active metal on the outer surface of the ceramic component at a position corresponding to the joining edge, or when brazing with a solder that does not contain active metals, the ceramic This is achieved by forming a metallized layer on the outer surface of the convex part of the member at positions other than those corresponding to the joint ends, and not forming metallized layers at positions corresponding to the joint ends. be able to.

Further, it is more preferable to apply Ni plating to the recessed portion of the metal member, since this improves the wettability between the recessed portion and the solder.

Note that the bonding between the metal member and the ceramic member is limited between the outer peripheral surface of the protrusion of the ceramic member and the inner peripheral surface of the recess of the metal member, and a space is created between the tip of the protrusion of the ceramic member and the bottom of the recess of the metal member. Alternatively, if a low-elasticity intermediate made of wax and a non-bonding substance or a film made of the substance is interposed to prevent bonding or contact between the top surface of the convex part of the ceramic member and the bottom surface of the concave part of the metal member, the tip of the convex part of the ceramic member Furthermore, it is possible to obtain a highly reliable metal-ceramic bonded body that is less likely to break due to bending or twisting and is more preferable because the stress concentration due to residual stress at the bonded end is alleviated.

Furthermore, by brazing only the contact area between the outer circumferential surface of the convex portion and the inner circumferential surface of the concave portion of the metal member, the residual stress generated at the joint end can be alleviated, and furthermore, at the joint portion other than the joint end, the solder and the ceramic member and the metal member is firmly fixed by chemical bonding, and a strong bond is formed between both parts, which not only increases the bonding strength from room temperature to high temperature, but also adds a firing effect when cooling from the bonding temperature. This is preferable because high strength can be stably obtained.

The bonding portion can be limited to the above position by forming a thin film made of a substance that does not have bonding properties with wax on the tip surface of the convex part provided on the ceramic member, or by providing an intermediate body or space made of the substance on the metal member. The ceramic member may be disposed between the bottom surface of the concave portion and the tip surface of the convex portion provided on the ceramic member, or a combination thereof may be performed.

Here, the outer circumferential surface of the convex portion refers to the outer side surface of the convex portion,
Although it does not include the tip surface of the convex portion, the outer surface of the convex portion refers to the entire outer surface of the convex portion and includes the tip surface of the convex portion. Similarly,
The inner peripheral surface of the recess refers to the inner side surface of the recess and does not include the bottom surface of the recess, but the inner surface of the recess refers to the entire inner surface of the recess and includes the bottom surface of the recess.

In the configuration of the second invention described above, the ceramic member and the metal member can be bonded by providing a space having a thickness G determined by each material of the metal, ceramic, and solder used, or by providing a low-elasticity intermediate made of a substance that does not bond with the solder. This prevents mutual interference between the top surface of the protrusion of the ceramic member and the bottom surface of the recess of the metal member due to the difference in thermal expansion between them, and also prevents stress concentration due to residual stress at the joint end at the joint interface between the ceramic member and the metal member. As a result, a joined body having sufficient strength against bending and torsion and high reliability can be obtained. Thickness G is (α−α′)X (TS −T
ll) XLI or above is sufficient for brazing, as long as a space or an intermediate body larger than the difference in shrinkage due to the thermal expansion difference between the metal member and the ceramic member during the cooling period is provided. This is because the bottom surface of the concave portion of the member and the tip surface of the convex portion of the ceramic member are in direct contact and do not interfere with each other.

Note that the thickness G of the space and the intermediate body may be a thickness provided at the freezing point temperature of the solder during brazing. Moreover, since it is difficult to control the thickness, it is more preferable that the thickness G is a thickness provided after brazing and cooling. Furthermore, the thickness G of the intermediate may be the thickness at room temperature before bonding. In this case, by controlling the thickness during mass production, a bonded body with high bonding strength and high reliability can be easily obtained.

As a joint, brazing is performed between the outer circumferential surface of a convex portion provided on a ceramic member and the inner circumferential surface of a concave portion provided on a metal member, and a space or Methods for interposing an intermediate made of a substance that does not bond to the wax include forming a thin film made of a substance that does not bond to the wax on the tip surface of the convex portion, or interposing an intermediate made of the substance between the bottom surface of the concave portion and the surface of the convex portion. and the tip surface of the convex portion, and a combination thereof.

In the configuration of the third invention described above, by selecting the optimal bonding length 2 based on the diameter D of the convex portion of the metal member, the bonding end of the bonding portion due to the difference in thermal expansion between the ceramic member and the metal member can be reduced. As a result, the strength of the joined body against bending and torsion is improved, and reliability is also improved. Here, the value of L2/D is 0.
The reason why it is limited to 2 or more and 0.39 or less is because, as is clear from the examples described later, if the value of L2/D is larger than 0.39, the breaking bending load decreases and the desired strength cannot be achieved. It is. In addition, if the value of L2/D is less than 0.2, the brazing area will decrease and the bonding strength will decrease, resulting in a decrease in tensile strength and the possibility that the convex part of the ceramic member will not meet the concave part of the metal member. The reason for this is that it can be easily removed from the part.

However, the bonding length L2 is the length of the bond between the inner circumferential surface of the recess of the metal member and the outer circumferential surface of the convex portion of the ceramic member by the brazing material.

Note that the bonding between the metal member and the ceramic member is limited between the outer peripheral surface of the protrusion of the ceramic member and the inner peripheral surface of the recess of the metal member, and a space is created between the tip of the protrusion of the ceramic member and the bottom of the recess of the metal member. Alternatively, if a low-elasticity intermediate made of wax and a non-bonding substance or a film made of the substance is interposed to prevent bonding or contact between the top surface of the convex part of the ceramic member and the bottom surface of the concave part of the metal member, the tip of the convex part of the ceramic member Furthermore, it is possible to obtain a highly reliable metal-ceramic bonded body that is less likely to break due to bending or twisting and is more preferable because the stress concentration due to residual stress at the bonded end is alleviated.

Furthermore, by brazing only the contact area between the outer circumferential surface of the convex portion and the inner circumferential surface of the concave portion of the metal member, the residual stress generated at the joint end can be alleviated, and furthermore, the solder reacts with the ceramic member and the metal member, causing the bonding of both members. Since a strong joint is formed between the two, not only does the joint strength from room temperature to high temperature become stronger, but also a firing effect is added when cooling from the joining temperature, so high strength can be stably obtained, which is preferable. .

The bonding portion can be limited to the above position by forming a thin film made of a substance that does not have bonding properties with wax on the tip surface of the convex part provided on the ceramic member, or by providing an intermediate body or space made of the substance on the metal member. The ceramic member may be disposed between the bottom surface of the concave portion and the tip surface of the convex portion provided on the ceramic member, or a combination thereof may be performed.

Graphite is an example of a material that does not bond with solders. The graphite film can be easily formed on the tip surface of the convex portion by applying a graphite particle suspension with a brush or spray, or by dipping. Further, as the intermediate body, it is preferable to use a low elastic body such as a sliver made of graphite fiber, felt, web, web sintered body, or woven fabric alone or in combination.

Furthermore, when the intermediate body is interposed between the tip surface of the convex portion and the bottom surface of the recessed portion, the joining area can be easily and reliably limited, thereby reducing residual stress generated at the joining end of the ceramic member after joining. This makes it possible to increase bond strength and reduce variation.

The interposition of the intermediate body made of a low elastic material not only has the effect of preventing the solder from joining with the bottom surface of the concave portion, but also prevents the tip of the convex portion caused by the difference in the amount of shrinkage between the ceramic member and the metal member upon cooling from the bonding temperature. The effect of preventing mutual interference between the bottom surfaces of the recess and the generation of excessive residual stress in the joint, and the effect of efficiently penetrating the molten solder into the gap between the outer peripheral surface of the convex part and the inner peripheral surface of the recess. It also has

The brazing material used to join the ceramic member and the metal member by brazing is preferably an active metal brazing material containing an active metal element capable of chemically bonding to the ceramic member.

The solder may be an alloy solder containing an active metal element, or a brazing material having a structure in which a metal base material is coated with an active metal element. Considering adjustment of the amount of active metal added to the brazing filler metal, ease of handling, and ease of manufacturing, it is preferable to use a brazing filler metal with a structure in which the active metal element is coated on the metal base. It is more preferable to use a brazing material having a structure in which an active metal element is vapor-deposited. Examples of such active metal elements include Zr, Ti, Ta, Hf, and V when the ceramic member to be joined is a ceramic containing at least a nitride and/or a carbide.

At least one metal element selected from the group consisting of Cr, La, Sc, Y and Mo is preferable, and when the ceramic member to be joined is an oxide ceramic, B
At least one metal element selected from the group consisting of e, Zr and T1 is preferred.

Since the active metal solder has good wettability with ceramics, there is no need to perform special pretreatment such as metallization treatment on the ceramic member. Furthermore, if the metal member is plated with Ni, it will be better wetted by the wax.

Therefore, if this solder is used, it is possible to infiltrate the molten solder into a predetermined joining position using capillary action.
Even without placing a brazing material at the planned joining position, brazing can be performed with fewer defects such as bubbles and sink marks by simply managing the gap formed in the parts to be joined.

For example, when brazing the joined body of the first invention described above with a solder that does not contain an active metal, a metallized layer is placed at a position other than the joint end of the planned joint position on the outer surface of the convex part of the ceramic member. By applying N1 plating to the metallized layer, and more preferably applying N1 plating to at least the intended bonding position on the inner surface of the recess of the metal member, the same effect as in the case of the above-mentioned active metal-containing solder can be obtained. . In this case, the existing brazing material and the protrusion are not firmly fixed by chemical bonding at the corresponding position of the joining end of the protrusion where the metallized layer is not provided. Similarly, if a metallized layer is not provided on the tip surface of the convex portion, the solder and ceramic will not react and will not be bonded, and a space will be formed between the tip surface of the convex portion and the bottom surface of the concave portion.

Furthermore, it is more preferable to apply N1 plating to the intended joining position on the inner surface of the recess of the metal member, since this improves the wettability between the inner surface of the recess and the solder.

Furthermore, active metal foil is placed at a position other than the joint end of the planned joining position between the outer surface of the convex part of the ceramic member and the inner surface of the recess of the metal member, and By forming a thin layer of a non-bonding substance such as graphite at the corresponding position, and placing a brazing filler metal that does not contain active metal on the bottom of the recess of the metal member and performing brazing, active metal solder can be applied. You can also get the same effect as using it.

The ceramic material forming the metal-ceramic bonded body of the present invention may be any material, but in consideration of practicality, it is made of silicon nitride, silicon carbide, sialon, zirconia, alumina, mullite, aluminum titanate, and cordierite. Preferably, it is at least one ceramic material selected from the group consisting of: Which of these ceramic materials to use may be determined depending on the purpose of use of the metal-ceramic bonded body of the present invention and the type of metal material and solder to be bonded.

Furthermore, by combining any one of the first, second, and third inventions, it is possible to further reduce stress concentration occurring at the joint end of the convex portion of the ceramic member, further increasing the strength of the joint. A strong and reliable metal-ceramic bonded body can be obtained.

(Example) FIGS. 1A to 1C are partial cross-sectional views showing an example of a metal-ceramic bonded body according to the first aspect of the present invention. In each example, the convex portion 2 of the ceramic member 1 and the concave B4 of the metal member 3 are joined by brazing using the solder 5, and the solder 5 is connected to the convex portion of the ceramic member 1 by a predetermined distance β from the joint end 6. The structure is such that it is not firmly fixed to the portion 2 by chemical bonding. From now on, this predetermined distance β
is called the chemical non-bonding distance. Convex portion 2 of ceramic member 1
In order to prevent the solder 5 from being firmly fixed by chemical bonding, for example, the convex portion 2 of the ceramic member 1 that is not to be firmly fixed by chemical bonding is usually coated with a non-bonding substance such as graphite. Brazing can be achieved by performing an operation.

In the embodiment shown in FIG. 1(a), N1 plating is applied to the entire inner surface of the recess 4 of the metal member 3 at the planned joining position, and from the joining end 6 of the convex part 2 of the ceramic member 1 at the planned joining position. After applying wax and graphite, which is a non-bonding substance, to the part of the chemical non-bonding distance β, the inner surface of the recess 4 and the outer surface of the convex part 2 of the ceramic member 1 are bonded using activated gold fume wax 5. The entire surface of the contact surface at the planned joining position with the surface is brazed, and the convex portion 4 and the active metal solder 5 at the part of the chemically non-bonding distance β from the joining end 6 are not firmly fixed due to chemical joining. The structure shows a metal-ceramic bonded body. In addition, when using a normal Ag solder that does not contain active metal elements, after Ni plating the entire inner surface of the recess 4 described above, the convex part 2 at the planned joining position excluding the part of the chemical non-bonding distance β is Similar bonding can be achieved by providing a metallized layer over the entire outer surface and plating the metallized layer with Ni.

In the embodiment shown in FIG. 1(b), the recess 4 at the planned joining position is
N1 plating is applied to at least the inner circumferential surface of the convex portion 2, and graphite is applied to the portion of the chemical non-bonding distance β and the tip surface of the convex portion 2, and then the outer circumferential surface of the convex portion 2 and the concave portion are bonded using active metal solder 5. It is joined by brazing to the inner circumferential surface of 4, and
Convex portion 4 at a chemically non-bonding distance from the bonding end 6
The active metal solder 5 is not firmly fixed by chemical bonding, and a space 7 is provided between the bottom surface of the concave portion 4 and the tip surface of the convex portion 2.

In the embodiment shown in FIG. 1(C), the recess 4 at the planned joining position is
N1 plating is applied to at least the inner circumferential surface of , and graphite is applied to the part of the chemical non-bonding distance β and the tip surface of the convex portion 2 , and the bottom surface of the concave portion 4 is in contact with the tip surface of the convex portion 2 . Graphite felt 8, which is a low-elasticity intermediate made of wax and a non-bonding substance, is provided with an active metal solder on the graphite felt, and the convex portion 2 is inserted into the concave portion 4 to form a bonding assembly, and then the bonding is performed. The solder assembly is heated in a vacuum to melt the solder, and the molten solder is penetrated into the intended joining position using capillary action to form a bond between the outer circumferential surface of the convex portion 2 and the inner circumferential surface of the recessed portion 4. At the same time, the convex part 4 and the active metal solder 5 at a chemically non-bonded distance β from the joint end 6 are not firmly fixed due to chemical bonding, and the bottom surface of the concave part 4 and the convex part 2 are This shows a structure in which an intermediate body exists between the bottom surface of the concave portion 4 and the tip surface of the convex portion 2, and the bottom surface of the concave portion 4 and the tip surface of the convex portion 2 are not joined or in direct contact with each other.

As shown in FIGS. 1(b) and 1(c) above, the recess 4
In an embodiment in which the bottom surface of the concave portion 4 and the tip surface of the convex portion 2 are not in direct contact with each other by the space T or the graphite felt 8 or are not joined, the bottom surface of the concave portion 4 and the tip surface of the convex portion 2 are in contact with each other. This is preferable because stress concentration in the vicinity of the tip of the convex portion 2 or the joint end 6, which occurs when the convex portion 2 is bonded or bonded, can be prevented.

FIGS. 2(a) and 2(a) are partial cross-sectional views showing an example of a metal-ceramic bonded body according to the second aspect of the present invention. In each embodiment, the convex portion 1 of the ceramic member 11
2 and the recess 14 of the metal member 13 is a space or an intermediate body at the bottom between the outer peripheral surface of the projection 12 and the inner peripheral surface of the recess 14 at a distance from the bottom of the recess 14 to the joint end 18. An example is shown in which the parts are joined by brazing to have a thickness of G.

In the embodiment shown in FIG. 2(a), the recess 1 at the planned joining position is
After applying N+ plating to at least the inner circumferential surface of the convex portion 12 and applying graphite to the tip surface of the convex portion 12, active metal solder 15 is used to connect the outer circumferential surface of the convex portion 12 and the inner circumferential surface of the concave portion 14. The structure is shown in which they are joined so that the distance from the bottom of the recess 14 to the joining end 18 is Ll, and a space 16 with a thickness G is provided between the bottom of the recess 14 and the tip surface of the protrusion 12. . Note that when using an ordinary Ag solder that does not contain active metal elements, after Ni plating is applied to at least the inner circumferential surface of the recess 14 described above, a metallized layer is provided on the outer circumferential surface of the protrusion 12 at the planned joining position. A similar bond can be achieved by applying N1 plating to the metallized layer.

In the embodiment shown in FIG. 2(b), the recess 1 at the planned joining position is
Ni plating is applied to at least the inner circumferential surface of the recess 14, and a graphite felt 17 having a thickness G, which is a low elastic intermediate made of a wax and a non-bonding material, is placed on the bottom surface of the recess 14, and an active metal solder is placed on the graphite felt. After applying graphite to the tip surface of the convex portion 12, the convex portion 12 is inserted into the concave portion 14 to form a bonding assembly, and the bonding assembly is heated in a vacuum. The solder is melted, and the molten solder permeates into the planned joining position using capillary phenomenon, and the area from the bottom of the recess 14 between the outer circumferential surface of the protrusion 12 and the inner circumferential surface of the recess 14 to the joining end 18 is melted. They are joined by brazing so that the distance is Ll, and an intermediate body exists between the bottom surface of the recess 14 and the front end surface of the projection 12, and the bottom surface of the recess 14 and the front end surface of the projection 12 are joined or in direct contact. It shows a structure that is not.

In the present invention, in the embodiment shown in FIGS. 2(a) and 2(b), the coefficient of thermal expansion of the ceramic member and the metal member is α'
and α, and when the solidification temperature of the active metal solder or solder 5 is T5 and the room temperature is TR, the thickness G of the space or intermediate body is G/Ll > (α−α′)
A good bonded body can be obtained by designing to a value that satisfies (TS - TR).

FIGS. 3(a) to 3(C) are partial cross-sectional views showing an example of a metal-ceramic bonded body according to the third aspect of the present invention. In each embodiment, the convex part 22 of the ceramic member 21 and the concave part B24 of the metal member 23 are joined by brazing using the solder 25, and the convex part 22 and the concave part 24
An example is shown in which the length of the joint in the axial direction between the two is L2, and the diameter of the convex portion is D, and the condition of 0.2≦L2/D≦0.39 is satisfied.

In the embodiment shown in FIG. 3(a), after N+ plating is applied to the entire inner surface of the recess 24 of the metal member 23 at the planned joining position, the active metal solder 25 is used to join.
This shows a structure in which substantially the entire surface of the contact surface between the inner surface of the recess 24 and the outer surface of the protrusion 22 of the ceramic member 21 is brazed. In addition, when using a normal Namoho gauze containing an active metal element, after Ni plating the entire inner surface of the recess 24 described above, a metallized layer is applied to the entire outer surface of the protrusion 22 at the planned bonding position. Similar bonding can be achieved by providing a metallized layer and plating the metallized layer with Ni.

In the embodiment shown in FIG. 3(b), the recess 2 at the planned joining position is
After applying N1 plating to at least the inner peripheral surface of the projection 2 and applying graphite to the tip surface of the projection 22, an active metal solder 25 is used to connect the outer peripheral surface of the projection 2 and the inner peripheral surface of the recess 4. At the same time, the bottom of the recess 24 and the protrusion 22 are joined by brazing.
A structure is shown in which a space 26 is provided between the tip surface and the tip surface.

In the embodiment shown in FIG. 3(C), the recess 2 at the planned joining position is
Ni plating is applied to at least the inner peripheral surface of the convex portion 22, graphite is applied to the tip surface of the convex portion 22, and a low material made of a non-bonding substance is placed on the bottom of the concave portion 24 at a position that contacts the tip surface of the convex portion 22. Graphite felt 27 is an elastic intermediate, and an active metal solder is provided on the graphite felt, and the convex portion 22 is connected to the concave portion 24.
After inserting the solder into the solder to form a joining assembly, the joining assembly is heated in a vacuum to melt the solder, and further, using capillary action, the molten solder penetrates into the intended joining position,
The outer circumferential surface of the convex portion 22 and the inner circumferential surface of the concave portion 24 are joined by brazing, and an intermediate body exists between the bottom surface of the concave portion 24 and the tip surface of the convex portion 22, and the bottom surface of the concave portion 24 and This shows a structure in which the tip surface of the convex portion 22 is not joined or in direct contact.

As shown in FIGS. 3(b) and 3(C) above, there is an embodiment in which the bottom surface of the concave portion 24 and the tip surface of the convex portion 22 are not in direct contact with each other due to the space 26 or the graphite felt 27, or are not joined to each other. This is preferable because it can prevent stress concentration near the tip of the protrusion 22 or the joint end 28, which occurs when the bottom surface of the recess 24 and the tip surface of the protrusion 22 are in contact with or are joined.

An actual example will be explained below.

Example 1 (First invention) A metal member 3 is provided with a recess 4 having an inner diameter of 11.05 a + m and a depth of 8 mm and a thin shaft portion having a diameter of 12 mm at one end of a solution-treated Incoloy 903 round bar with a diameter of 18 mm. , diameter: 11. A ceramic member 1 having a convex portion 2 with a length of 10 mm and a length of 10 mm was produced.

Note that the bottom corner of the recess 4 has a C0,2 chamfer,
Additionally, the open end corners are each tapered. Similarly, the tip edge of the convex portion 2 has a C015 taper, and the base has an R2 curved surface.

For these metal members and ceramic members, an active metal solder in which T1 with a thickness of 2 μm was deposited on the surface of a silver solder plate with a thickness of 0.1 mm was applied using the method shown in FIGS. 1(a) to (C) described above. the distance between the joint end 6 and the bottom of the recess by 5 m.
Metal-ceramic bonded bodies of the present invention and comparative examples were obtained by varying the chemical non-bonding distance l while fixing it to m.

At this time, the thickness of the Ni plating in Fig. 1 is 10 μm.
In the example shown in FIG. 1(C), the thickness is 0.4 mm.
graphite felt was used as a low modulus intermediate consisting of wax and non-bonding material.

The protrusions 2 of the ceramic member 1 were bonded by fixing the gold R member 3 and applying a load to the ceramic member 1 using the bending test apparatus shown in FIG. The bending load at the time of failure was measured from near the end and was defined as the failure bending load. In addition, in FIG. 4, β is -40 mm, and β2 = 5 mm. Results first
It is shown in the table and FIG.

From Table 1 and Figure 5, it can be seen that in the case of the structure shown in Figure 1 (a) where the entire surface is brazed, the chemical non-bonding distance β of the comparative example is 0, that is, the entire side surface is brazed, and the joint ends are also brazed. Compared to the product in which the entire outer surface of the convex portion 2 including the entire surface is firmly fixed by chemical bonding, the product of the present invention in which at least the bonded end is not firmly fixed by chemical bonding, that is, the product of the present invention has β other than 0. was found to exhibit a high fracture bending load. In addition, the chemical non-bonding distance β is Q when the bonding distance at the contact surface between the outer circumferential surface of the convex part and the inner circumferential surface of the concave part is approximately 5 m+n, preferably 1 when it is 5 m+n or more, and a higher fracture bending load when it is 9 mm or more. The specimen whose entire side surface was not chemically bonded showed the highest fracture bending load.

In addition, in full-surface brazing as shown in FIG. 1(a), the joined body with a space provided between the bottom surface of the concave part and the tip surface of the convex part shown in FIG. 1(b) is better than the joined body of the structure shown in FIG. 1(a). Furthermore, Figure 1 (C)
It was found that the bonded body with graphite felt as an intermediate shown in Figure 1 shows a higher fracture bending load.

Example 2 (Second Invention) A metal member 13 having a recess 14 with an inner diameter of 11.05 +++ m, a depth of 8, and a thin shaft portion with a diameter of 12 at one end of a solution-treated Incoloy 903 round bar with a diameter of 18+no+. And, diameter: 11.0 at one end of the silicon nitride sintered body by pressureless sintering method.
mm, length: A ceramic member 11 having 10 convex portions 12 was produced.

The bottom corner of the recess 14 has a C092 chamfer, and the open end corner is tapered. Similarly, the tip edge portion of the convex portion 12 is tapered at C0, 5, and the base portion is curved at R2.

For these metal members and ceramic members, an active metal solder with a 2 μm thick Ti deposited on the surface of a 0.1 mm thick silver solder plate was applied using the method shown in FIGS. 2(a) and 2(b). The metal-ceramic bonded bodies of the present invention were obtained by varying the space and the thickness G of the intermediate such as graphite felt. At this time, FIG. 2(a).

The thickness of N17 ink in (b) is 10/! Jm, 2nd
The thickness of graphite felt 17 in figure (b) is 0.4 mm
Met.

In addition, the thermal expansion coefficient α of the metal member: 13. OXl0-6
1/l, coefficient of thermal expansion α' of ceramic member: 3.5X
10-1/l, wax solidification temperature 'r, : 780℃,
Room temperature Ti: 20℃, in this case (α−α′
) What is the value of X (TS - TR)? , 2X10-3.

On the other hand, with a similar shape, the contact surface between the inner surface of the recess 14 and the outer surface of the projection 12 is substantially A joined body of a comparative example, whose partial cross section is shown in FIG. 6, was prepared by brazing the entire surface.

By fixing the metal member 13 and applying a load to the ceramic member 11 using the bending test apparatus shown in FIG. The bending load at which the joint broke from the joint end was measured and defined as the breaking bending load. In addition, in FIG. 4, f! ,, =40mm, L-5+nn+
It was seven years ago. The results are shown in Table 2 and Figure 7. Note that the space G shown in Figure 2 (a) is the value measured by cutting it open after the test and observing it with a stereomicroscope, and the thickness G of the intermediate body shown in Figure 2 (a) is the value measured from the thickness of the intermediate body before bonding. It was measured.

From Table 2 and Figure 7, it is clear that the joined body of the present invention in which a predetermined space or intermediate body is provided exhibits a higher fracture bending load compared to the joined body of the comparative example in which such space or intermediate body is not provided. Ta. In addition, G/L is the value of (α-α') x (TS TR), which is 7. It is found that the fracture bending load becomes sufficiently high when it exceeds 2X10-3, and G/Ll > l0XIO-
3 is more preferred, and G/Ll>20XlO-3 is even more preferred.

Example 3 (Second Invention) In order to investigate the bonding strength at high temperatures, a normal tensile test was conducted on the same bonded body as in Example 2 at a test temperature of 450°C. The results are shown in Table 3.

Table 3 From the results in Table 3, it can be seen that as the value of G/L + increases, the bonding strength at high temperatures decreases;
/ L l ≦0.4 is preferable, and furthermore, G / L +
≦0°3 is preferable. This is because the joint area by brazing becomes smaller.

From the results of Examples 2 and 3, it can be seen that the thickness G of the space or the intermediate such as graphite felt is sufficient as long as the tip surface of the convex portion and the bottom surface of the concave portion do not interfere with each other due to the difference in thermal expansion.

Embodiment 4 (Second invention) A turbine rotor with a diameter of 12.0 mm at the tip of the shaft of a turbine rotor in which the turbine wheel and shaft are integrally formed of silicon nitride by pressureless sintering.
A ceramic member was prepared by providing a convex portion with a length of 7.5 mm and a length of 7.5 mm. In addition, a 12 mm diameter alloy steel (e.g. JIS-3NC
A bar material was prepared by friction welding a round bar of M439).

Next, the rod material is machined to the outer diameter necessary for the construction of the turbocharger rotor, and a recessed portion of 1.2.05 mm in diameter and 7.0 mm in depth is provided at the end on the Incoloy 903 side to form a metal member. did. After applying N1 plating to the inner circumferential surface of the recess, it was joined by the same method as described in Example 2, and the joined part had a space as shown in FIG. 2(a). A turbocharger rotor assembly of the present invention having graphite felt as shown in (b) was produced.

In addition, the thickness G of the space and graphite felt is G/L+-2
It was set to 0X10-3.

Further, these joined bodies were subjected to finishing processing according to a predetermined process to produce a turbine rotor for a turbocharger.

On the other hand, a turbine rotor for a turbocharger with a similar shape has the contact surface between the inner surface of the recess and the outer surface of the projection completely brazed without providing a space or an intermediate body between the bottom surface of the recess and the tip surface of the projection. was prepared and used as a comparative example.

The turbine rotors for turbochargers of the present invention and the comparative example were installed in a high-temperature rotation test device, and a rotation test was conducted.

As a result, both turbine rotors of the present invention have a diameter of 200.
Although the turbine rotor of the comparative example rotated without any abnormality at 800° C. and 000 rpm and did not break, the turbine rotor of the comparative example broke while increasing the rotation to 200,000 rpm.

Example 5 (Third invention) A recess 24 with an inner diameter of 11.05 mm and a depth of 3 mm is formed at one end of a solution-treated Incoloy 903 round bar with a diameter of 18 mm.
and a metal member 23 having a thin shaft portion with a diameter of 12 mm, and a silicon nitride sintered body with a diameter of 11.0 mm at one end by the pressureless sintering method.
, Length: Ceramic member 21 provided with convex portions 22 of 10 cities.
was created.

The bottom corner of the recess 24 has a C092 chamfer, and the open end corner is tapered. Similarly, the tip end edge of the convex portion 22 is tapered with CD and 5, and the base is curved with R2.

For these metal members and ceramic members, an active metal solder in which a 2 μm thick Ti layer was deposited on the surface of a 0.1 mm thick silver solder plate was applied using the method shown in FIGS. 3(a) to (C) described above. Using these materials, L2/D was varied to obtain gold-ceramic bonded bodies of the present invention and comparative examples. At this time, the thickness of N1 plating in Fig. 3 is 1
In the example shown in FIG. 3(C), the thickness is 0 μm.
A 4 mm graphite felt 27 was used as a low modulus intermediate consisting of wax and non-bonding material.

By fixing the metal member 23 and applying a load to the ceramic member 21 using the bending test apparatus shown in FIG. The bending load at the time of failure was measured and defined as the failure bending load. In addition, in FIG. 4, βl −=4 omms β2=5 mm. The results are shown in Table 4 and Figure 8.

From Table 4 and FIG. 8, it was found that if the value of L2/D was 0.2 or more and 0.39 or less, a breaking bending load of 70 kg or more could be obtained. In addition, the value of L2/D is 0.25
More preferably, it is 0.35 or less.

In addition, the full-surface brazing shown in Fig. 3(a) is better for a joined body with a space provided between the bottom surface of the concave part and the tip surface of the convex part, as shown in Figure 3, etc., than for the joined body of the structure. It was found that the bonded body shown in FIG. 3(C) in which graphite felt was provided as a low-elasticity intermediate made of a non-bondable material exhibited a higher fracture bending load.

The present invention is not limited only to the embodiments described above;
Many variations and changes are possible. For example, in the above-mentioned embodiments, when a space or an intermediate body is provided between the bottom of the recess and the tip surface of the convex part, the space or the intermediate body is used. It is clear that the same effect can be obtained by forming it at the tip of the convex part of the ceramic member, and that the same effect can also be obtained by mixing some of thin films, spaces, and intermediates.

(Effects of the Invention) As is clear from the detailed explanation above, according to the metal-ceramic bonded bodies of the first to third aspects of the present invention, the bonding state of the bonded portion, the tip surface of the convex portion of the ceramic member, The difference in thermal expansion between the shellac member and the metal member or the ceramic member and the brazing filler metal can be reduced by limiting the space between the bottom surface of the concave part of the metal member or the state of the intermediate body, the diameter of the convex part, and the joint length. By reducing the stress concentration caused by residual stress acting on the joint ends due to the above, it is possible to obtain a metal-ceramic joint that is resistant to bending or torsion and has high reliability.

Further, in the metal-ceramic bonded body of the present invention, a part of the turbine impeller and the turbine shaft are made of silicon nitride ceramics,
If the other parts of the turbocharger rotor are made of high-strength metal, it can reduce residual stress, provide a buffering effect for the brazing filler metal, prevent corrosive gases such as high-temperature exhaust gas from entering the joint interface, and increase durability. A highly efficient turbocharger rotor with excellent performance and responsiveness can be obtained.

[Brief explanation of the drawing]

FIGS. 1(a) to (C), FIGS. 2(a) and (b), and FIGS. 3(a) to (C) are partial cross-sectional views showing an example of the metal-ceramic joined body of the present invention, respectively, Fig. 4 is a diagram showing the bending test device used in the test, Fig. 5 is a graph showing the results of the bending load test in the first invention of the present invention, and Fig. 6 is a section showing a metal-ceramic bonded body of a comparative example. The cross-sectional view, FIG. 7, and FIG. 8 are graphs showing the results of bending load tests in the second and third aspects of the present invention, respectively. 1, 11.21...Ceramic member 2, 12.22
... Convex portions 3, 13.23... Metal members 4, 14.24... Concave portions 5, 15.25... Braze or active metal solder 6, 1
8.28...joint end? , 16.26... Space 8, 17.27... Graphite felt Figure 1 H--→ L2 Figure 4 Figure 7 G/L1

Claims (1)

[Scope of Claims] 1. A metal-ceramic bonded body having a structure in which a protrusion provided on a ceramic member is inserted into a recess provided in a metal member and is integrally joined by brazing, comprising: A metal characterized in that, at least at the joint end of the joint between the outer surface of the projection and the inner surface of the recess of the metal member, the projection and the brazing material are not firmly fixed by chemical bonding.・Ceramic bonded body. 2. A metal having a structure in which a protrusion provided on a ceramic member is inserted into a recess provided in a metal member, and the outer circumferential surface of the protrusion and the inner circumferential surface of the recess are integrally joined by brazing. - In the ceramic bonded body, a space or a low-elasticity intermediate made of a substance that does not bond to wax is interposed between the tip surface of the convex portion of the ceramic member and the bottom surface of the concave portion of the metal member, and the thickness of this space or the intermediate body is A metal-ceramic bonded body characterized in that G satisfies the following formula: G/L_1>(α-α')×(T_S-T_R), where L_1: Joining from the bottom of the recess of the metal member Distance to end α: Coefficient of thermal expansion α′ of metal member: Coefficient of thermal expansion T_S of ceramic member: Solidification temperature of solder T_R: Room temperature. 3. In a metal-ceramic bonded body having a structure in which a protrusion provided on a ceramic member is inserted into a recess provided in a metal member and is integrally joined by brazing, the recess of the metal member and the ceramic member It is characterized by joining so that the relationship 0.2≦L_2/D≦0.39 is satisfied, where L_2 is the axial joining length with the convex part and D is the diameter of the convex part. metal
Ceramic bonded body.