JPH09249464A - Complex gold material for brazing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of cracks caused by difference in thermal expansion and to improve brazing properties, by supporting granules on gold. SOLUTION: A metal or a nonmetal granule having >=50 deg.C melting point and 0.1-100μm particle diameter in an amount of 0.01-8.0vol.% is supported on gold or a gold alloy to give a complex gold material for brazing a metal to a ceramic, having >=4.0×10<-6> />= (20-500 deg.C) difference in coefficient of thermal expansion. The surface of a ceramic to be bonded is coated with a coated film of Ti having 0.1-1.0μm thickness, which is coated with a coated film of Ni having 0.5-5μm thickness. The complex gold material for brazing is bonded to the coated ceramic to carry out brazing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite gold material suitable for joining materials exposed to high temperatures such as a metal heating device, and more particularly, to a composite gold material used for joining materials having different thermal expansion coefficients. The present invention relates to a brazing composite gold material capable of preventing cracks caused by a difference.

[0002]

2. Description of the Related Art Structural materials and parts such as a metal heating device are made of heat-resistant metal only, and are subjected to a predetermined stress of 500.
When used by being exposed to a high temperature of ℃ or higher, the life of the refractory metal against deformation is limited. Moreover, even if a ceramic material that can withstand deformation at high temperatures is used instead of a heat-resistant metal, it is easily cracked by impact with other members and it does not have excellent workability like metal. There is a limit to the use. For this reason, it has been required to braze the heat resistant metal material and the ceramics for use. Here, as a brazing material that can withstand a high temperature of 500 ° C. or higher,
Gold or gold alloys are commonly used.

However, when a heat resistant metal material and ceramics are brazed using gold or a gold alloy as a brazing material and exposed to a high temperature, cracks easily occur in the ceramics without impact by other members. It has the drawback of In particular, when a force is applied to this after brazing, cracks generated in the ceramic become remarkable. This is because the coefficient of thermal expansion of heat-resistant metals and metal materials such as gold or gold alloys is 13 to 16 × 10 ⁻⁶ / ° C. (20 to
However, the thermal expansion coefficient of ceramics such as SiC and Al ₂ O ₃ is 4.0 to 8.6 × 10 ^−6.
/ C (20 to 500 ° C), it is considered that the above-mentioned crack is caused by the stress due to thermal expansion applied to the ceramics.

On the other hand, the difference in coefficient of thermal expansion is 4.0 ×
Metals and ceramics with a temperature of 10 ^-6 / ° C (20 to 500 ° C) or more are brazed with a brazing material that can withstand a high temperature of 500 ° C or more, and even if stress is applied to them, brazing that does not cause cracks I haven't found any materials yet.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to braze a heat resistant metal material and ceramics at a high temperature of 500 ° C. or higher. It is an object of the present invention to provide a brazing gold material which is excellent in brazability even when exposed to and is less likely to cause cracks in ceramics even when stress is applied after brazing.

[0006]

As a result of intensive studies by the present inventors, gold or a gold alloy was used as a base material as a brazing material, and a predetermined amount of metal and / or non-metal particles was retained on the base material. It was found that the above-mentioned object can be achieved by using the composite gold material as described above, and the present invention has been completed.

That is, the first invention of the present application is a brazing composite gold material characterized in that gold is used as a base material, and the granular material is held in this material in an amount of 0.01 to 8.0% by volume.

In the second invention of the present application, the brazing in the first invention has a difference in coefficient of thermal expansion of 4.0 × 10 ^-6 / ° C.
It is a composite gold material for brazing, characterized in that it is used for joining a metal having a temperature of (20 to 500 ° C.) or higher to a ceramic.

A third invention of the present application is the brazing composite gold material according to the second invention, wherein the ceramic bonding surface is coated with Ni having an underlying Ti layer.

A fourth invention of the present application is the composite gold material for brazing according to the second invention, wherein the metal bonding surface is Ni-coated, and the ceramic bonding surface is Ni-coated with an underlying Ti layer. Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention is a composite gold material in which a base material is gold or a gold alloy as a brazing material, and a predetermined amount of metal and / or nonmetal particles is held in the base material. It is configured to use. The detailed configuration of the present invention and its operation will be described below.

In the present invention, it is necessary to use gold or a gold alloy as the base material. Among the brazing filler metals that can be used by being exposed to a high temperature of 500 ° C. or higher, gold or a gold alloy has excellent fluidity and wettability, and the melting point can be widely selected by using a gold alloy. Au has a melting point of 1063 ° C., and if a gold alloy with Sn, Sb, Si and Ge is used, the content can be selected up to 500 ° C. or less. Therefore, it is necessary to use gold or a gold alloy corresponding to the purpose.

In the present invention, it is necessary that the above-mentioned base material holds the particulate matter. As the material of the granular material used in the present invention, either metal or non-metal may be used, or these may be mixed and used. As the metal particles,
A metal such as Ni, Ti, Ag, or Cu having a melting point of 500 ° C. or higher and an alloy thereof are preferably used. Examples of non-metallic particles include SiC, SiO ₂ , Al ₂ O _{3 and the} like. Among these, in order to achieve the object of the present invention, Ni
It is preferable to use a granular material. The shape of the particulate matter may be spherical, square, or amorphous. The dimension is preferably such that the maximum diameter or the side is 0.1 to 100 μm.

The retention amount of the granular material used in the present invention is 0.0
It is necessary to be 1 to 8.0% by volume. When the amount of retained particulate matter is less than 0.01% by volume, high temperature after brazing,
The ceramic cracks under pressure. Also 8.
If it exceeds 0% by volume, the bonding strength becomes weak. It is considered that this is because the fluidity and wettability, which are excellent properties as a brazing filler metal, possessed by gold or a gold alloy as a base material are deteriorated.

In the present invention, holding the particulate matter means that the particulate matter adheres to the surface of the base material, is mixed nonuniformly in the base material, and is sandwiched in the base material to form a band shape. Any of the existing states may be used.

The joining metal used in the present invention is preferably heat resistant steel that can withstand a high temperature of 500 ° C. or higher. Stainless steel is particularly preferably used.

Examples of the bonding ceramics used in the present invention include SiC, SiO ₂ , Al ₂ O _{3 and the} like. Of these, Al ₂ O ₃ has a thermal expansion coefficient of 8.6 × 1.
0 ^-6 , SiC 4.0 x 10 ^-6 , SiO ₂ 0.5 x 1
Since it is 0 ^-6 , the thermal expansion coefficient of the metal system (13 to 16 x 1
It is preferable to use Al ₂ O ₃ or SiC close to 0 ⁻⁶ / ° C.).

In the present invention, in order to braze the ceramic and the brazing material, it is preferable to coat the ceramic bonding surface with Ni. When the ceramics and the brazing filler metal are directly brazed, the brazing filler metal penetrates into the area because the ceramic surface is porous, and the brazing performance of the brazing filler metal deteriorates due to the oxide film and foreign matter on the ceramics surface. It is preferable to correspond to. When Ni coating is applied in advance, it is possible to perform a sealing treatment of ceramics having a porous bonding surface and the bonding property between Ni and the brazing material is good.

Further, in order to strengthen the Ni coating, it is preferable to apply a Ti coating as a base treatment for the Ni coating. It is preferable that the ceramic is coated with a Ti coating having a thickness of 0.1 to 1.0 μm, and the Ni coating having a thickness of 0.5 to 5 μm is provided thereon. Considering that the surface of the ceramic is porous, it is preferable to use a dry method such as sputtering as a coating method rather than a wet method such as electroless plating. As a result, the ceramic and Ti are strongly bonded together, and Ti and Ni are also firmly bonded together, so that the ceramic bonding surface is firmly coated with Ni.

In order to braze the metal and the brazing material, it is preferable to coat the metal joint surface with Ni having a thickness of 0.5 to 5 μm. If the metal and the brazing material are directly brazed, the brazing property of the brazing material will deteriorate due to the oxide film on the metal surface and foreign matter.
It is preferable to deal with this. If Ni coating is applied in advance, the bondability between Ni and the brazing material will be good, so it is preferably used as the above-mentioned method.

It is not clear why the above object can be achieved by using gold or a gold alloy as a base material as the brazing composite gold material and holding a predetermined amount of the granular material on the base material. However, the fact that it has a structure in which the granular material is held on the base material, when joining members having different thermal expansion coefficients,
It is thought that it became possible to absorb the difference in thermal expansion.

The production of the brazing composite gold material of the present invention will be described below. The following three production methods can be exemplified. Granules are sown on the surface of a gold or gold alloy base material and rolled. According to this method, particles are present near the surface of the substrate. The base material on which the granular material is sown is stacked and rolled. Alternatively, when the two base materials are clad-rolled, a granular material is put between them to roll. According to this method, the particles are present in layers inside the substrate. When melting gold or a gold alloy, granular materials having a higher melting point are mixed and rapidly cooled as a composite metal for casting.
According to this method, the particles are dispersed inside the substrate.

[0023]

EXAMPLES Examples and comparative examples shown in Tables 1 to 3 will be described below. Example 1 As a base material for a composite brazing material, 1 wt% Si-
Thickness of Au alloy composition 0.1mm, length 10mm x width 10m
m pellets were used, and the average particle size was 20μ on the pellet surface.
A composite brazing material was prepared by sowing Ni particles of m. At this time, the amount of Ni particles retained was 0.01% by volume. As a metal material, SUS307 has a height of 30 mm and a length of 15 mm ×
A 15 mm wide stainless steel was prepared, and one surface of the 15 mm square was surface-coated with Ni having a thickness of 2 μm by electroplating. Ceramic material, thickness 3mm, length 15mm ×
A 15 mm wide SiC is prepared, and one side of the 15 mm square is coated with Ti having a thickness of 0.5 μm by the sputtering method.
The surface of Ni was coated to a thickness of μm.

Then, as shown in FIG. 1, the ceramic material 1, the composite brazing material 2, the metal material 3, and the load material 4 were stacked in this order from the bottom. The load material 4 was adjusted in its load so that the stress applied to the ceramic material 1 was 3 g / mm ² . At this time, the surface-coated surface of the ceramic material 1, that is, the Ni-coated surface 1a having the underlying Ti layer, and the surface-coated surface of the metal material 3, that is, the Ni-coated surface 3a were respectively the contact surfaces with the composite brazing material 2.

The test material 5 laminated as shown in FIG. 1 as described above was subjected to a thermal cycle test in which it was held at a high temperature for 30 minutes and then air-cooled for 1 hour, for 5 cycles. As high temperature conditions, two kinds of tests, 500 ° C. and 650 ° C., were performed, and 10 sets of test materials were used for each test. After the heat cycle test, the crack generation rate and the brazing material peeling rate were measured. Table 3 shows the test results.

The measuring method was as follows. [Crack Occurrence Rate] Non-bonded portions of ceramic materials (positions lateral to the bonded portions) were observed with a magnifying glass, and those having cracks were regarded as defective. The rate of occurrence of defective products was defined as the rate of occurrence of cracks

[Release rate of brazing material] The brazing portion was visually inspected and the joining state was manually inspected, and those not joined were determined to be defective. The occurrence rate of defective products was defined as the brazing material peeling rate.

[Examples 2-9, 11 / Comparative Examples 1-2] Except that the base material composition of the composite brazing material, the material of the granules, the amount of the granules retained, and the material of the ceramics were as described in the table. Was tested in the same manner as in Example 1. Table 3 shows the test results.

[Embodiment 10] In producing a composite brazing material, Ni was placed between each of three tapes having a thickness of 0.1 mm.
The test was conducted in the same manner as in Example 1 except that the granules were sown and rolled to 0.1 mm, and pellets prepared from a tape having the granules distributed therein were used. Table 3 shows the test results.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

From the above measurement results, in Examples 1 to 11 of the present invention in which gold is used as the base material and the granular material is held in the amount of 0.01 to 8.0% by volume, the crack generation rate and the brazing material peeling are observed. It is found that both of them are excellent in the rate and are extremely useful for joining metal and ceramics.

On the other hand, Comparative Example 1, which has a structure in which gold is used as the base material and does not contain particulate matter, has the same effect as the present invention in the brazing material peeling rate, but in terms of the crack generation rate, It turns out that the task cannot be satisfied. Further, even if the composition is made of gold as the base material and contains the granular material, in Comparative Example 2 in which the retained amount of the granular material exceeds the specified range of the present invention, although the crack generation rate is equivalent to that of the present invention, the brazing material is obtained. It is understood that the object of the present invention cannot be satisfied in terms of peeling rate.

[0035]

As described above, according to the present invention, a brazing composite material having a novel structure in which gold is used as a base material, and 0.01 to 8.0% by volume of particles are held in the base material is used. Even when the heat-resistant metal material and the ceramic are brazed and used after being exposed to a high temperature of 500 ° C. or more, the brazing property is excellent, and even if stress is applied after the brazing, the ceramic hardly cracks. . Therefore, in a structure that is suitably used for joining a metal and a ceramic having a difference in coefficient of thermal expansion of 4.0 × 10 ⁻⁶ / ° C. (20 to 500 ° C.) or more, and is exposed to a high temperature such as a metal heating device. ,
The place where workability is required is made of metal material, and the temperature is 500 ℃.
The above-mentioned location exposed to a high temperature can be used very effectively in the case of being composed of a ceramic material bonded to the metal material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a test material for brazing a metal material and a ceramic material using the composite material according to the present invention and subjecting the metal material and the ceramic material to a heat cycle test under stress.

[Explanation of symbols]

 1: Ceramics Material 1a: Ni-Coated Surface Having Underlying Ti Layer 2: Composite Brazing Material 3: Metal Material 3a: Ni-Coated Surface 4: Load Material 5: Test Material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C22C 5/02 C22C 5/02 C23C 14/14 C23C 14/14 G D 14/16 14/16 A 14/18 14/18

Claims (4)

[Claims] 1. A gold base material, on which particles of 0.01 are added.
A composite gold material for brazing, wherein the composite gold material is retained at ˜8.0% by volume. 2. The difference in the coefficient of thermal expansion of brazing is 4.0 ×
The composite gold material for brazing according to claim 1, which is for joining a metal having a temperature of 10 ^-6 / ° C. (20 to 500 ° C.) or more to a ceramic, and is for brazing. 3. The brazing composite gold material according to claim 2, wherein a Ni coating having an underlying Ti layer is applied to the ceramic bonding surface. 4. The composite gold material for brazing according to claim 2, wherein the metal bonding surface is coated with Ni and the ceramic bonding surface is coated with Ni having an underlying Ti layer.