JPH1045481A - Ceramics metal joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the joined body in which a metallic joining layer for joining a ceramic body to be joined and a metallic body to be joined to each other, consists of a material that has appropriate deformability and is hardly subjected to hardening due to eutectic formation and the like in it and accordingly, which has an excellent stress relaxing effect. SOLUTION: This joined body 1 is formed by joining a ceramic body to be joined 2 and a metallic body to be joined 6 to each other through a metallic joining layer 7. At this time, the metallic joining layer 7 comprises an Ag based layer 3 that is formed on the side of the ceramic body to be joined 2 and contains >=80wt.% Ag, and an Ni based layer 4 that is formed on the opposite side to the ceramic body 2 through the Ag based layer 3 and consists essentially of Ni. Since the Ag based layer 3 contg. >=80wt.% Ag has sufficient deformability and yet, any eutectic and the like is hardly formed in the layer 3 at the time of solidifying it, the Ag based layer 3 also functions as a stress relaxing layer, together with the Ni based layer 4. That is, since both of the layers 3 and 4 show their respective stress relaxing effects, stress fracture of the ceramic body 2 can be prevented from occurring even when the deference in linear expansion coefficient between the ceramic body to be joined 2 and the metallic body to be joined 6 is considerably large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a joined body of ceramic and metal.

[0002]

2. Description of the Related Art Ceramics are applied to various industrial fields such as automobile parts by making use of their excellent properties such as high-temperature strength, wear resistance and electric insulation. However, ceramics have conventionally been often used in combination with metal materials from the viewpoints of reliability problems due to the brittleness of the material and high processing costs due to the difficulty in processing the material. Here, as such a joining technique of ceramics and metal, shrink fit, press fitting, brazing, solid phase diffusion bonding, etc. are used, but brazing is performed due to simplicity of pre-processing such as machining of the joint. Is particularly useful.
As the brazing material, for example, a brazing material based on Ag, for example, an Ag-Cu-Ti-based brazing material is widely used.

[0003]

When a ceramic and a metal are joined by brazing, a difference in the coefficient of linear expansion between the two often becomes a problem. If the difference is large, a large tensile force is applied during cooling after joining. The ceramic part may be destroyed due to stress. Therefore, if the brazing material layer is made of a relatively soft material, the stress can be reduced to some extent by plastically deforming the brazing material layer. Here, in the above-mentioned Ag-based brazing material, Ag is relatively soft, but a relatively large amount of Cu is added in order to enhance the fluidity of the liquid phase generated during the heating / joining treatment. It is limited to at most about 70% by weight. In this case, the Ag content is low and the Ag content is low.
Since the Cu-based solid solution or eutectic is formed and the brazing material layer is hardened, the above-mentioned stress relaxation effect cannot be expected so much. Therefore, it is conceivable to interpose an intermediate layer mainly composed of a soft metal such as Cu separately from the brazing material layer to relieve the stress by plastic deformation of the intermediate layer. Is too large, there is a problem that a sufficient buffer effect cannot be obtained.

[0004] An object of the present invention is to provide a metal-based bonding layer for bonding a ceramic-based bonded body and a metal-based bonded body to each other,
An object of the present invention is to provide a bonded body of ceramics and metal which is made of a material having an appropriate deformability and hardly causing hardening due to eutectic formation and the like, and which is excellent in stress relaxation effect.

[0005]

Means for Solving the Problems and Actions / Effects In order to solve the above-mentioned problems, a bonded body of the present invention is formed by bonding a ceramic-based bonded body and a metal-based bonded body to each other via a metal-based bonding layer. In addition, the metal-based bonding layer is formed on the ceramic-based bonded body side and includes an Ag-based layer containing 80% by weight or more of Ag and a ceramic-based coating that is mainly composed of Ni and sandwiches the Ag-based layer. And a Ni-based layer formed on the side opposite to the joined body.

In the above structure, for example, when the Ag-based layer functions as a brazing filler metal layer, it contains 80% by weight or more of Ag and has a high deformability, and since a eutectic or the like is hardly generated at the time of solidification, it can be used as a stress relaxation layer. It will work. Further, the Ni-based layer functions as a stress buffer layer as in the case of the conventional bonded body. As described above, since both layers exhibit a stress relaxation effect, the synergistic action of the two layers enables, for example, even when the difference in the coefficient of linear expansion between the ceramic-based article and the metal-based article is considerably large. It is possible to prevent stress fracture of the ceramics, and to obtain a high-strength and sound bonded body. The Ag content in the Ag-based layer was 80%.
When the content is less than 10% by weight, a sufficient stress relaxation effect cannot be obtained. Therefore, the content of Ag is adjusted within a range of 80% by weight or more, preferably 90% by weight or more.

FIG. 1A conceptually shows an example of such a joined body. That is, in the bonded body (1), the metal-based bonding layer (7) is composed of the Ag-based layer (3) and Ni.
And a ceramic-based article (2),
The Ag-based layer (3), the Ni-based layer (4), and the metal-based article (6) are joined and integrated so as to be adjacent to each other in this order. Note that the metal-based bonding layer may include another Ag-based layer formed between the Ni-based layer and the metal-based bonded object. With this configuration, the bonding strength between the ceramic-based workpiece and the metal-based workpiece can be further increased. This other Ag-based layer is also adjusted to have an Ag content of 80% by weight or more, preferably 90% by weight or more. An example is conceptually shown in FIG. That is, in the bonded body (1), the metal-based bonding layer (7) includes the Ag-based layer (3), the Ni-based layer (4), and another A-based layer (4).
g-based layer (5), and the ceramic-based article (2), the Ag-based layer (3), the Ni-based layer (4), the Ag-based layer (5), and the metal-based article (6) They are joined and integrated so as to be adjacent to each other in order.

Next, the Ag-based layer is substantially entirely formed of A
g, but components other than Ag can be included as appropriate. For example, Ti, Zr,
One or more kinds of Hf can be contained in a range of 10% by weight or less in total. These active metal components serve to enhance the bondability by forming a chemical bonding layer with the ceramic. If the content of the active metal exceeds 10% by weight, the amount of the interface reaction product with the ceramic joined body increases and the bonding strength decreases. Therefore, the content of the active metal is 10% by weight or less, desirably. It is preferable to adjust the amount within a range of 5% by weight or less.

In the Ag-based layer, in addition to the active metal component,
Metal components such as Ni and Pd can be contained. For example, the effect of improving the heat resistance of the brazing material layer can be achieved by adding Ni. Further, Pd improves the heat resistance of the brazing filler metal layer and, when the Ag-based layer is also formed on the metal-based bonded body side, suppresses the penetration of the Ag component into the metal-based bonded body grain boundary. Even this has the effect of preventing or suppressing the embrittlement. When the above metal components are contained, the total content of those metal components excluding the active metal component is set to 5% by weight or less. In the Ag-based layer, A
g to form a solid solution or eutectic and harden it
It is desirable not to add u as much as possible, for example, the addition amount is preferably 1% by weight or less.

Next, the Ni-based layer has a Ni component content of 8%.
It is desirably 0% by weight or more. Ni content is 80
When the content is less than% by weight, the components other than Ni diffuse into the Ag-based layer, and the stress relaxation effect of the Ag-based layer may be impaired. In this case, the Ni content is more desirably 90% by weight. Also in the Ni-based layer, it is desirable that Cu that reacts with Ag in the Ag-based layer to form a solid solution or a eutectic is not added as much as possible. For example, the addition amount is preferably 1% by weight or less.

[0011] The ceramic-based article is, for example, Si ₃
N ₄ , SiC, TiC, Al ₂ O ₃ , MgO, ZrO ₂ , T
It can be mainly composed of iO ₂ or the like. Further, the metal-based bonded object is made of Ni, Fe, Nb, Ti, Zr, Mo, M
It can be composed of n, W, Pt, Pd, Ta and an alloy containing them as main components. Here, the joined body of the present invention, in which the metal-based joining layer is configured as described above, is configured such that the ceramic-based joined body and the metal-based joined body are separated from the room temperature by 50%.
5 × 10 difference in linear expansion coefficient in the temperature range up to 0 ° C.
^When a material having a temperature of ⁻⁶ / ° C. or more, particularly 7 × 10 ⁻⁶ / ° C. or more, is selected, the effect of relaxing the stress can be more effectively obtained. In other words, even in the above-described combination of the objects to be welded, in which the stress based on the difference in linear expansion coefficient cannot be alleviated in the conventional configuration, the configuration of the present invention can secure a sufficient bonding strength. . As a specific example, Al
Combination of ₂ O ₃ with iron-based materials such as chromium molybdenum steel, stainless steel, or Si ₃ N ₄ and chromium molybdenum steel,
Examples include combinations with iron-based materials such as stainless steel.

As shown in FIG. 2, for example, the joined body of the present invention is formed between a ceramic member (12) to be a ceramic-based joined body and a metal member (16) also to be a metal-based joined body. Ag that constitutes the Ag-based layer
A bonding process such as sandwiching a Ni-based metal plate (or foil: 13 or 15) and a Ni-based metal plate (or foil: 14) that constitutes a Ni-based layer and bringing them into contact with each other and heating them in a predetermined atmosphere. And can be manufactured by integrating them. Specifically, in addition to the so-called brazing process in which the Ag-based metal plate is once melted during the joining process and joining is performed through the liquid phase generated at that time, a solid phase diffusion process that does not generate a liquid phase, or hot pressing Or a method such as friction welding.

When the Ag-based layer contains an active metal component or another alloy component, the Ag-based metal plate is
It can be configured as a single plate made of an alloy having a composition corresponding to the Ag-based layer. On the other hand, in place of such a single plate material, for example, a method of using a laminate of an Ag plate and a single metal plate of an alloy component and fusing and homogenizing them by heating or melting to form an Ag-based layer upon heating. Is also possible.
Further, a metallizing layer of an active metal component or another alloy component is formed on the surface of a ceramic member (or a metal member) by a refractory metal method or a vapor deposition method, and an Ag plate is laminated thereon and heated. Alternatively, the composition of the metallizing layer may be diffused to form an Ag-based layer. On the other hand, on the surface of the metal member, in order to improve the wettability with the liquid phase based on the melting of the Ag-based metal plate (brazing material),
If necessary, nickel plating or the like can be applied.

[0014] Here, as a necessary result of performing a bonding process such as heating, a ceramic-based bonded body, an Ag-based layer, a Ni-based layer, (another Ag-based layer), and a metal-based bonded body are required. A diffusion layer or a reaction layer may be formed in the vicinity of each adjacent boundary (or bonding interface) due to diffusion or reaction of components. Correspondingly, the Ag concentration in the Ag-based layer and the Ni concentration in the Ni-based layer may change under the influence of the diffusion or reaction as approaching the adjacent boundary. Therefore, the Ag concentration in the Ag-based layer and the Ni concentration in the Ni-based layer defining the range in the joined body of the present invention are as follows:
In any case, it means the average concentration of a portion (so-called bulk portion) which is not affected by the above-mentioned diffusion or reaction in each layer. The concentrations of these components can be determined by known methods such as an electron probe microanalyzer (EPMA) and an X-ray microanalyzer (XM
A), energy dispersive X-ray analysis (EDX), wavelength dispersion spectroscopy (WDS), Auger electron spectroscopy (AES), and the like.

[0015]

Embodiments of the present invention will be described below. That is,
In the positional relationship shown in FIG.
(Diameter 10mm, length 50mm), A as Ag-based metal plate
g-based brazing plates 13 and 15 (diameter 10 mm, thickness 0.05
mm), Ni-based metal plate 14 (diameter 10 mm, thickness 0.5 m)
m) and various metal members 16 (diameter 10 mm, length 50 m)
m) were overlaid, and they were fixed using a jig (not shown). In addition, the joining surface side of each metal member 16 has Ag
In order to improve the wettability with the solder, electrolytic nickel plating having a thickness of 3 μm was applied. Then, the sample fixed to the jig is heated to a predetermined temperature and brazed, and FIG.
The joined body 1 shown in FIG.

It should be noted that in FIG.
Is made of Si ₃ N ₄ (linear expansion coefficient: α = 2.4 ×
_{^{10 -6 / ℃), A1 2}} 0 3 (α = 7.1 × 10 -6 / ℃),
Three types of ZrO ₂ (α = 10.6 × 10 ⁻⁶ / ° C.) were used. The material of the metal member 16 is stainless steel (SUS316, α = 14.5 × 10 ⁻⁶ / ° C.), chromium molybdenum steel (SCM430, α = 13.7 × 10 ⁻⁶ / ° C).
° C]. On the other hand, Ag-based brazing material plates 13 and 1
As the material of No. 5, Ag-4 wt% Ti alloy (other contained elements: total 0.5 wt% or less), Ag-4 wt% P
Two kinds of d-3% by weight Ti alloy (other contained elements: 0.5% by weight or less in total) were used. Further, a Ni-based metal plate 14
Of pure Ni (purity of 99.9% or more), Ni
-4 wt% Mo alloy (other content elements: 0.5% or less in total) and Ni-2 wt% Mo-2 wt% A1 alloy (other content elements: 0.8% or less in total) were used.

Table 1 shows the combinations of the ceramic member 12 and the metal member 16 employed to form the joined body 1 (FIG. 1), together with the difference in their linear expansion coefficients α. The joined body 1 includes the ceramic member 12 and the metal member 16.
Of all combinations shown in Table 2 (a to
b, w to z) Ag-based brazing plates 13, 15 and Ni
It was manufactured using the base metal plate 14. In Table 2,
The ones marked with * indicate that they are outside the scope of the present invention (comparative examples). For the combination d, a Cu plate was used instead of the Ni-based metal plate 14. For the combination e, Ni
The system metal plate 14 was omitted (all were comparative examples).

From the joint obtained in this way, a width of 4 mm and a thickness of 4 mm
A 3 mm prismatic bending test specimen was cut out and subjected to JISR160.
Based on the method described in 1 (Test Method for Bending Strength of Ceramics), the four-point bending strength of each test piece was measured at room temperature. Table 1 shows the results. In each sample, the number of test pieces was n = 4. After the completion of the bending test, the fracture surface of the test piece was observed with a scanning electron microscope. Further, the test piece was cut perpendicular to the bonding surface, and the Ag concentration in the Ag-based layers 3 and 5 and the Ni concentration in the Ni-based layer 4 were analyzed using an X-ray microanalyzer (XMA). Table 2 shows the results. In addition, the measurement was performed at five locations for one sample, and the average value was adopted.

[0019]

[Table 1]

[0020]

[Table 2]

As is clear from Table 1, the test pieces (ac, w, fh, xz) according to the examples of the present invention all have high strength of 170 MPa or more. In particular, in a combination of the ceramic member 12 and the metal member 16 in which the difference in linear expansion coefficient α is 5 × 10 ⁻⁶ / ° C. or more,
It can be seen that the test piece of the example shows higher strength than the test pieces (d, e, i to k) of the comparative example. And A
The test pieces a to c and f to h using the Ag-based brazing plate 13 containing 90% by weight or more of g show particularly good strength,
In particular, it can be seen that the strength is increased in combinations where the difference in α is 7 × 10 ⁻⁶ / ° C. or more. 3 and 4
Are Ag-based brazing plates 13 and 15 and Ni-based metal plates 14
FIG. 4 is a graph showing the bending strength of the joined body 1 produced using each of the combinations shown in FIG. 2 in relation to the difference in α.

From the observation of the fracture surface, it was found that the test piece of the comparative example had cracks, chips, etc. due to stress rupture at the portion of the ceramic-based article in a combination where the difference of α was 5 × 10 ⁻⁶ / ° C. or more. Was confirmed, and it was found that the rupture was expanding and proceeding from the starting point. On the other hand, with respect to the test pieces of the examples, such sharpness and chipping were not observed. From these, the difference of α is 5 × 10 ⁻⁶ / ° C.
As described above, in the bonded body of the comparative example, the stress relaxation in the metal-based bonding layer is insufficient and the ceramic-based bonded body 2
Defects such as nicks and chips, which are the starting points of destruction, occur, and as a result, the strength is reduced. On the other hand, in the joined body of the embodiment, both the Ag-based layer and the Ni-based layer act as stress buffer layers. Even if the difference of α becomes large, the stress is sufficiently relaxed,
It is believed that high bonding strength is achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a joined body of a ceramic and a metal according to the present invention.

FIG. 2 is a diagram showing an arrangement of a ceramic member, an Ag-based brazing material plate, a Ni-based metal plate, and a metal member for producing the joined body of FIG.

FIG. 3 is a graph showing test results of an example.

FIG. 4 is another graph showing test results of the example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bonded body 2 ceramic-based bonded body 3 Ag-based layer 5 another Ag-based layer 4 Ni-based layer 6 metal-based bonded body 7 metal-based bonded layer

Continued on the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location B23K 20/12 B23K 20/12 G

Claims (5)

[Claims] 1. A ceramic joint body and a metal joint body are joined to each other via a metal joint layer, and the metal joint layer is formed on the ceramic joint body side. An Ag-based layer containing 80% by weight or more of Ag and a Ni-based layer containing Ni as a main component and formed on the opposite side of the ceramic-based joined body with the Ag-based layer interposed therebetween. Ceramic-metal joint. 2. A ceramic jointed body and a metal jointed body are joined to each other via a metal jointed layer, and the metal jointed layer is formed on the ceramic jointed body side. An Ag-based layer containing 90% by weight or more of Ag and a Ni-based layer containing Ni as a main component and formed on the opposite side of the ceramic-based joined body with the Ag-based layer interposed therebetween. Ceramic-metal joint. 3. The metal-based bonding layer is formed between the Ni-based layer and the metal-based workpiece, and contains 80% by weight of Ag.
The joined body according to claim 1, further comprising another Ag-based layer contained above. 4. The ceramic-based article and the metal-based article are each made of a material having a difference in linear expansion coefficient in a temperature range from room temperature to 500 ° C. of 5 × 10 ⁻⁶ / ° C. or more. The joined body according to any one of claims 1 to 3, which is constituted. 5. The ceramic-based joined body and the metal-based joined body are each made of a material having a difference in linear expansion coefficient in a temperature range from room temperature to 500 ° C. of 7 × 10 ⁻⁶ / ° C. or more. The joined body according to any one of claims 1 to 3, which is constituted.