JPS59141393A - Brazing filler material - Google Patents

Abstract

PURPOSE:To provide a brazing filler material which improves the resistance in the joint part of members having different coeffts. of thermal expansion to thermal impact by superposing plural sheets of sheet-like brazing filler materials on each other by interposing powder of a metallic hydride. CONSTITUTION:Powder of hydride of >=1 kind selected from Li, Ca, Sr, Ba, Y, Ti and Zr is spread by coating, spraying, etc. on a sheet-like brazing filler material composed of silver-copper, etc. and >=1 sheet of such sheet-like brazing filler materials are superposed on each other. The laminated brazing filler material is placed on a member to be brazed and the other member to be brazed is superposed thereon, then both members are brazed. The brazing material is suitable for brazing of ceramics to each other or ceramics to a metallic member and minimizes the thermal stress to be generated between the joined members.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brazing material, and particularly to a brazing material suitable for brazing ceramics together or ceramics and metal members.1 In recent years, silicon carbide, silicon oxide, aluminum oxide, So-called new ceramics such as zirconium oxide are attracting a lot of attention and research due to their excellent properties such as high strength and high heat resistance. However, in order to improve the properties of these ceramics, attention has been paid to composite materials made by bonding ceramics together or ceramics and metals.

Conventionally, brazing methods using various brazing materials have been used as a method of joining ceramics together or ceramics and metals. However, in the conventional brazing method (・), there is a problem in that the narrowing of the gap between the parts to be joined causes thermal stress to be applied to both parts during use due to the difference in the coefficient of thermal expansion of the parts to be joined. In addition, some brazing filler metals have a composition near their eutectic point in order to lower their melting point, resulting in poor ductility and the above-mentioned problems may become apparent.

On the other hand, conventional methods for bonding ceramics and metals include the Telefunken method, active metal method, hydride compound method, sulfurization method, metal oxide method, powder compression method, hot press method,
Various methods such as solder and glass methods have been developed. In these various conventionally known methods, heating must be carried out in a specific atmosphere. This requires extra and complicated steps and operations to adjust the heating atmosphere.Moreover, the resulting adhesive has the problem of thermal stress due to the difference in thermal expansion coefficients as described above. be.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and even if members with different coefficients of thermal expansion are joined, the thermal stress generated between the two members will be extremely small, and the resistance to thermal shock will be significantly improved. The aim is to provide materials.

The brazing material of the present invention is characterized in that a plurality of sheets of brazing material are stacked one on top of the other, and metal hydride powder is interposed between at least two sheets of the brazing material. .

The present invention will be explained in detail below. The brazing material of the present invention has a metal hydride powder interposed between sheets of brazing material. In other words, by containing such a metal hydride, during brazing, when the wax is melting, the metal hydride decomposes and hydrogen is released, which causes the brazing filler metal to foam and the brazing metal to melt. The difference in thermal stress that occurs between the two parts when the multilayer brazing metal is porous and joins members with different coefficients of thermal expansion, such as metal and ceramics or different types of ceramics. It alleviates the Therefore, in the brazing material of the present invention, a metal hydride whose decomposition temperature is higher than the solidification completion temperature of the mother alloy and lower than the brazing temperature is used.

In the present invention, various kinds of sheet brazing materials can be used, such as silver soldering, copper soldering, nickel soldering,
Palladium wax or brass wax can be used.

The metal hydride to be sandwiched between these sheet brazing materials is preferably one that decomposes and releases hydrogen at a temperature of 600 to 900°C. Examples of such metal hydrides include hydrides of one or more elements selected from the group consisting of Ll, Ca, Sr, Ba, Y, Ti, and Zr. The amount of these metal hydrides sandwiched between the sheet brazing filler metals is preferably 0.01 to 3% by weight, more preferably 0.05 to 1% by weight. If the metal hydride content is less than 0.01%, the amount of hydrogen generated will decrease, and if it exceeds 3%, complex intermetallic compounds will occur in the lul with the mother alloy that constitutes the sheet brazing filler metal, resulting in a decrease in ductility. Problems such as a decrease in toughness or a decrease in toughness occur.

Also, the thickness of one sheet of brazing material is 10 to 300 μm.
1, particularly preferably 20 to 200 μm.

The brazing filler metal of the present invention has a plurality of sheets of brazing filler metal that are stacked one on top of the other, and the number of stacked sheets is arbitrary, such as two or more. For example, in the case of two sheets, the metal hydride powder is sandwiched between them (preferably, three or more sheet-shaped brazing materials are also sandwiched together), and the metal hydride powder is sandwiched between each note. In addition, when three or more sheets of brazing filler metal are stacked together, it is not necessary to sandwich the metal hydride powder in the fields of all the sheets.
In the end, metal hydride powder is sandwiched between at least two sheets of brazing filler metal.

In addition, the composition of each sheet-shaped brazing filler metal may be the same or different from each other. I'll try to do that (・.

The brazing filler metal of the present invention can be developed by, for example, applying, spraying, or sprinkling metal hydride powder on the surface of one sheet-shaped brazing filler metal, and then overlapping the other sheet-shaped brazing filler metal. After this overlapping, the sheet brazing filler metal may be pressed together.

The brazing material of the present invention can be prepared in advance and used for brazing work.It is also possible to use it in the following way. First, one or more sheets of brazing filler metal are placed on the surfaces to be joined of the parts to be soldered, and metal hydride powder is applied to each of the placed sheet-shaped brazing fillers. The powder is spread by means such as spraying, and then one or more sheets of brazing material are superimposed on the spread surface, and then the other side is In this method, the brazing material of the present invention is used in the soldering process.

Note that the sheet-shaped brazing material used in the brazing material of the present invention is manufactured by various manufacturing methods. For example, there is a method in which a molten master alloy is poured onto a rotating row 2 and rapidly cooled to form a sheet. Alternatively, the melted alloy may be rolled into a sheet shape.

Although the brazing filler metal of the present invention is suitable for joining members having different coefficients of thermal expansion, it goes without saying that it may also be used for joining members having the same coefficient of thermal expansion. Further, even when the members to be joined are ceramics or metals, the type thereof is not particularly limited, and various materials can be adopted depending on the use of the joined members.

Examples (2) will be described below, but the present invention is not limited to the following examples unless the gist of the invention is exceeded.

Example Silver solder having a composition of 70% silver and 30% silver was melted at 900° C. in an argon atmosphere. This molten metal was poured onto a rotating roll and rapidly cooled to produce a sheet-like brazing filler metal with a thickness of 40 μm. The surface E of this sheet-shaped brazing filler metal is mixed with methanol @? The powdered calcium hydride powder was applied, and methanol was evaporated to spread the metal hydride powder on the surface of the sheet-like brazing material. The particle size of metal hydride powder is 30
0 mesh anchorage, and the applied amount was 0.05% by weight of the sheet brazing filler metal. Next, a sheet Iζ material prepared in the same manner was superimposed on the sheet-like brazing material coated with the calcium hydride powder to obtain a brazing material of the present invention. Then, a sintered body of aluminum oxide whose surface is nickel plated and carbon #t(o,z%c)
, 'c', the brazing filler metal of the present invention thus produced was sandwiched, heated in air to 830°C, and bonded.

On the other hand, as a comparative example, ordinary silver solder (composition: silver 70% by weight, copper 30% by weight) was sandwiched between an aluminum oxide sintered body whose surface was nickel-plated and carbon steel (0.2% C). ,
It was heated to 830°C and brazed.

The parts brazed in this way were heated to 10"C.
[After heating, when the members were placed in water at 0° C., no peeling occurred between the members in both the example and the comparative example. However, when the brazed members were heated to 300°C and then placed in water at 0°C, the brazed members according to the example did not peel off, but the members according to the comparative example did. It was confirmed that the brazing filler metal according to the example had excellent thermal shock resistance.

Further, when the brazing material according to Example #1 of the present invention was observed under a microscope after brazing, it was found that it was a porous body containing a large number of pores.

When brazing using the brazing material of the present invention, the brazing metal becomes porous, so even when brazing members with different coefficients of thermal expansion, the resistance to thermal stress after joining is significantly increased. Thermal shock resistance is improved. Moreover, this brazing can also be performed in air, and the brazing work is easy.

Therefore, it is particularly suitable for use in brazing ceramics and metals or ceramics together. .

Claims (2)

[Claims] (1) Multiple sheets of brazing filler metal are stacked on top of each other,
A brazing material characterized in that metal hydride powder is interposed between at least two sheets of the brazing material. (2) Metal hydrides include Ll, CaXSr, Ba
, Y, T1, and Zr, or a hydride of two or more elements selected from the group consisting of Y, T1, and Zr.