JPS5895673A - Method of bonding ceramic and metal with oxide solder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining ceramics and metal.

In recent years, ceramics have been used in various fields due to their excellent heat resistance, and the development of composites by bonding them with metals is progressing. For example, when adhering alumina porcelain and F.-Ni-00 alloy (commonly known as 1 Copal), an organic binder is added to fine powders of molybdenum and manganese and then kneaded.

Coated on the alumina surface, alloyed with molybdenum and manganese by heat treatment at 1300 to 1700'C in heated hydrogen gas, then nickel plated, then brazed with copal using a low melting point base metal. It is carried out.

Although this method allows for a highly airtight bond, there are considerable differences in thermal properties, specifically thermal expansion coefficient and thermal conductivity, between ceramics and metals, making it difficult to use at high temperatures. Further, when used under conditions of rapid heating and rapid cooling, the thermal shock resistance is not sufficient, and the joining operation is complicated and difficult.

An object of the present invention is to provide a method for joining ceramics and metal to obtain a joined product that exhibits excellent heat shock resistance against thermal changes.

The bonding method of the present invention uses glass powder containing preferably about 2% of bismuth oxide, 5 to 40% of lithium aluminate, and 0 to 101 of the metal oxide to be bonded, preferably about 2%. Apply it to the surface of the metal, pressure bond it, melt it, and then cool it.
400 to 120σG, preferably 700 to 95
It is characterized in that a glass phase containing crystals is generated in the bonding layer at a temperature of 0°C.

That is, it is characterized in that a glass layer having thermal properties intermediate between those of ceramics and metals is formed to alleviate the difference in thermal properties between the ceramic phase and the metal phase.

The glass powder used in the method of the present invention has a silicon oxide content of 3% compared to 40 to 60% in ordinary flint glass.
〇- or below (d), which has a high ratio of bismuth oxide and lithium oxide.

Bismuth and lithium generate crystalline regions in the glass phase 3J'8
In particular, bismuth precipitates fibrous microcrystals, lowering the coefficient of thermal expansion of the glass phase and increasing thermal shock resistance. Metallic compounds are effective in increasing compatibility with the metals being joined, but if they exceed about 1096, bismuth,
This will damage the properties of lithium.

Generally, the softening point of glass is between 400° and 1600°0, and in the method of the present invention, after melting the glass powder, it is kept in a certain temperature range for a certain period of time during the cooling process to form crystals. There is a need to encourage growth. Although the range varies depending on the composition, it is between 400 and 1200°C, and particularly 700 to 950°C is preferable for the growth of the above-mentioned fibrous microcrystals.

FIG. 1 schematically shows a cross section of the ceramic-metal bonding layer obtained in this manner. In the 1st, l is alumina porcelain, 2 contains crystals of petalite (lithium aluminum silicate, LtAJsiO40,.), and the alumina-rich glass intermediate m%3 is a fully crystallized glass phase with a fibrous 81□ Contains B, O, crystals. 4 is a glass interlayer rich in cobalt and nickel.

5 is copal. In other words, the crystallization has a thin intermediate layer between the lath phase and the material to be joined, which alleviates the mismatch in thermal properties, and the presence of fibrous microcrystals in the glass phase in the center improves thermal shock resistance. This seems to be helping to strengthen the

Example Bismuth oxide 48% by weight, lithium aluminate 27i1
! [Amount] 20 parts of carbinol acetate was added to 100 parts of a finely powdered glass having a composition of 21% by weight of silicon thioxide, 2,2% of cobalt oxide, and 2% of acid, and the mixture was kneaded to make a paste. And so. Next, high purity alumina sintered body (50
Apply the above paste to a thickness of about 70μ on the surface of a Kovar plate (mx5ogmx6m, lfi roughness 0.1μ).
After crimping 50m x 5(m+x-), 12(m
Carpitol acetate was volatilized by heat treatment for 20 minutes. Subsequently, the glass powder was sufficiently melted at 1300℃ for 10 minutes in a nitrogen atmosphere, and the alumina porcelain and copal (=
After being blended, the mixture was cooled to 900° C. at a cooling rate of 20°C, maintained for 40 minutes, and then cooled to room temperature.

Comparative Example High-purity molybdenum and manganese powders were mixed in a ratio of 40 and 60 parts by weight, respectively, and 30 parts of carpitol acetate was added to 100 parts of this mixture, and the paste was obtained by thoroughly stirring and mixing. It was applied to a high purity alumina sintered body in the same manner as in the example. After drying at 120°C, heat treatment was performed at 15000°C for 2 hours in a hydrogen atmosphere containing 296°C moisture,
M.

-A film of Mn alloy was formed. Next, electrolytic nickel plating was applied to this film, and then it was brazed to copal using an ordinary brazing filler metal.

FIG. 2 shows the results of an adhesive strength test performed on the bonded products obtained in the above Examples and Comparative Examples.

Figure 3 shows the relationship between the temperature difference and adhesive strength after heating and air cooling according to the Yatsuselman test (white dots: Example, black dots: Comparative example). The relationship between the number of repeated rapid cooling tests and adhesive strength is shown. It is clear from FIGS. 2 and 3 that the difference in superiority between the example and the comparative example widens as the temperature difference and the number of tests increase.

[Brief explanation of drawings]

jllGill is a schematic W of the joint obtained by the present invention.
FIG. 2 is a graph showing the adhesive strength according to the Yatsuselman test, and FIG. 3 is a graph showing the adhesive strength according to the repeated rapid cooling test. In the figure. l... Alumina porcelain 2 - Alumina-rich glass intermediate layer 3 - Crystallized glass layer 4 - Co, Mi-rich glass intermediate layer 5... Kovar patent applicant Toyota Motor Corporation Co., Ltd. Figure 1

Claims (1)

[Claims] 8 to 60% by weight of bismuth oxide, 5 to 40% by weight of lithium aluminate and 0% of the oxide of the metal to be joined.
Apply glass powder containing 1 to 10 I to the surface of the ceramic, press the metal, melt the crease bonding material, cool it, and form the glass phase containing crystals in the bonding layer between 400 and 120 directions. A method for joining ceramics and metal using an oxide solder, which is characterized by the formation of an oxide solder.