JPH0426570A - Method for joining ceramics and metal - Google Patents

Abstract

PURPOSE:To improve the heat resistance of a joined part and the stability of strength by disposing stress relieving materials consisting of a plate, which is formed by coating W particles with Ni particles and sintering the particles, and Ni plates on both sides thereof between ceramics and a metal and disposing a brazing material between the ceramics and the Ni plate. CONSTITUTION:The sintered W plate 3 plated with the Ni is inserted between, for example, an Si3N4 ceramics molding 1 and a stainless steel 2 and the Ni plates 4, 5 are disposed on both sides thereof. Cu foil 6 applied with a Ti film 7 is disposed between the molding 1 and the Ni plate 5 in such a manner that the Ti film 7 comes into contact with the molding 1. The sintered W plate is produced by coating the surfaces of the W particles of 1 to 10mu average grain size with the Ni particles of 0.1 to 1 to 10mu average grain size by utilizing a surface reforming system and sintering the particles under specific conditions in a vacuum. The above-mentioned plates are superposed on each other and are heated in a vacuum of 5X10<-5>Torr. The deterioration by the oxidation of the stress relieving materials is prevented and the stable joint strength is maintained by this method. The degradation in the strength in the joined part is obviated in spite of heating and cooling at about 800 deg.C.

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a method for joining ceramics and metal.7 (Prior Art) Conventionally, a method for joining a powder compact such as ceramics and metal is described. One method is the active metal method.

This material is a material that easily reacts with ceramics.

That is, this is a method in which titanium or silconium, which easily combines with oxygen, etc., is used as a brazing material. The brazing material used in this active metal method is an alloy based on titanium or silconium, and a Ti-Cu-Ag alloy is often used.

JP-A-59-232693 discloses Ti-Cu-
A crat-type brazing material has been proposed for use in joining metals and ceramics made of Ag-based alloys.

In the conventional method of joining ceramics and metal using the active metal method, the bondability of the brazing filler metal using a Ti-Cu-Ag alloy is good, or because the brazing filler metal contains silver and the melting point of silver is low, If the temperature exceeds that value, the bonding strength will decrease rapidly.

In order to improve this point, the applicant changed the silver of the brazing material to nickel to improve high temperature strength.
A patent application (Japanese Patent Application No. 1-313222) has been previously filed.

[Invention or problem to be solved]

In all of the above-mentioned methods for joining ceramics and metal, a tungsten plate is used as the thermal stress III material, and this tungsten plate is heated to around 800°C and cooled.
It turns out that it oxidizes and deteriorates.

Therefore, the heat resistance in the atmosphere can only be expected to be about 400° C., which poses a problem when used in the high temperature environment around the engine combustion chamber.

The present invention solves the above problems and provides heating at around 800°C.
The object of the present invention is to provide a method for joining ceramics and metal, which does not cause a decrease in joint strength even when cooled and can maintain stable joint strength.

(Steps and effects for solving the problem) The present invention uses a sintered plate in which tungsten particles are coated with nickel particles and sintered between the ceramic and the metal, and a stress relaxation material with nickel plates on both sides of the sintered plate. This is a ceramic/metal bonding method in which a brazing material is interposed between the ceramic and the nickel plate and heated in a predetermined vacuum state.

By heating in K air, the brazing material between the ceramic and nickel plate acts to join the ceramic and metal. The tanksten sintered plate, which is a stress relaxation material, is coated with each tungsten particle or nickel particle, so oxidation is sufficiently prevented, and the bond strength remains stable even with MJ heat and cooling at around 800°C, with no decrease in bond strength. hold.

(Example) Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing heating conditions during bonding.

As shown in Figure 1, silicon nitride (
Si, N4) Ceramic...lux molded body 1 and stainless steel (SUS304) 2 were selected as the materials to be joined, and between both grooves was a 1.0 mm thick tank stainless steel manufactured by the method described below. A thickness of 1.0- is placed on both sides of the connecting plate 3.
A nickel plate 4.5 with a thickness of 1.5 mm is placed between the ceramic molded body l and the nickel plate 5 with a thickness of 1.5 mm.
A #4 foil 6 with a thickness of 20 mm and coated with a titanium film 7 of 5 u, 2 is placed so as to be in contact with either the titanium film 7 or the ceramic molded body l.

The tank stainless steel sintered plate 3 is manufactured by the following method.

The surface of tungsten particles with an average particle diameter of 1 to 10 μLm is coated with a layer of Ni-Sogal particles with an average particle diameter of 0.1 to 1 μL using a surface modification system of the Hyturitization System. These particles are heated and sintered in a vacuum of 3 x 10-'rurr under the following conditions. 0.9K each at 150℃, 400℃, and 700℃ to spread to No. 71A
After holding it for 1.44Ks at 1200℃, in order to join the metal, overlap them,
5 X l+)−'□. , heated in vacuum.

Figure 2 shows time on the horizontal axis and applied temperature on the vertical axis, and heating rate t.
=0. ff4℃/sec, heat to t = 12QQ''C and hold T + = 11.06Ks, then lower the temperature to 1. = 1150℃ and hold Tz = 0.6Ks, and further 1° = lowered to 1100℃ T□ = 3.6Ks
Hold. When bonded under these heating conditions, the four-point bending strength was 200['.

or obtained.

The reason why the tank stainless sintered plate 3 and the nickel plate 4.5 are arranged between the ceramic 1 and the stainless steel 2 to form the N1-W-Ni layer in the bonding method described in 1-1 is because of the bonding between the ceramic and the metal. This is intended to alleviate thermal stress caused by differences in linear expansion coefficients, and the nickel plate 5. copper? eJ6. The titanium film 7 acts as a brazing material for the N1-Cu-TiJ system.

Under the above bonding conditions, the heating temperature t□(1tOo゛(:
) and held for a time T (16Ks) to allow the diffusion of copper in the filler metal to proceed. The copper concentration was lowered to improve heat resistance. Also, the setting of the thickness of the copper foil 6 and the nickel plate 5 of the tungsten plate IM is important, and the bonding strength changes depending on the thickness. FIG. 3 shows the relationship between the thickness of the nickel plate 5 and the bonding strength. In the figure, the horizontal axis shows the thickness of the nickel plate 5, and the vertical axis shows the four-point bending strength.

As is clear from the figure, the thickness of the nickel plate 5 is 1.5 m.
It is optimal to set it to m, and even in the range of 1.0 to 1.7, a four-point bending strength of 2 (1 (llII Pa) can be obtained.

rNi using nickel instead of silver as a brazing material
-Cu-Ti J-based brazing material improves the heat resistance of the joint. Figure 84 shows the conventional “Ti-Cu
-Ag J-based alloy and rNi -C
The relationship between bonding strength and temperature when using a u-Ti J brazing filler metal is shown.

In case 1 (solid line ■) using rNi -Cu -Ti J-based brazing filler metal, the 4-point bending number and strength are 20011Pa'Jt#l from room temperature to 600℃, or the conventional rTi -
When a Cu-AgJ brazing filler metal is used (broken line ■), ζ has a four-point bending strength of 20,011 Pa or less at 400°C, and the bonding strength rapidly decreases as the temperature rises below.

On the other hand, when a tungsten plate is used as a thermal stress relaxation material, it deteriorates due to oxidation. Figure 5 shows that a silicon nitride ceramic molded body and stainless steel are bonded to a thickness of 1.
Using 0-1 tungsten plate as a thermal geological force mitigation material,
The relationship between oxidation time and four-point bending strength when the oxidation temperature is 800°C is shown.

The tungsten plate has deteriorated due to oxidation, and its four-point bending strength is rapidly decreasing.

FIG. 6 is a diagram showing the influence of oxidation on the tungsten sintered plate of the present invention, and shows the relationship between oxidation time and four-point bending strength when the oxidation temperature is the same at 800°C. As is clear from the figure, no decrease in the four-point bending strength was observed even after 160 Ks had passed.

In the present invention, oxidation of tungsten is sufficiently prevented by using a tungsten plate as a thermal stress relaxation material as a tungsten sintered plate in which tungsten particles are coated with nickel particles and sintered. In particular, when additional processing is performed on the joined body, since all of the tungsten particles are coated with nickel particles, there is no risk of deterioration due to oxidation.

Therefore, even when heated or cooled to around 80°C (1°C), the bonding strength does not decrease, and stable bonding strength can be maintained.
It can be used in high-temperature environments such as around engine combustion chambers.

In the embodiment described in E, stainless steel is used as the metal to be joined, but the present invention can also be applied to joining metals other than stainless steel and ceramics.

(Effects of the Invention) The present invention can sufficiently prevent deterioration due to oxidation of the thermal stress relaxation material used in the joint between ceramic and metal, maintain stable joint strength, and maintain the joint even by heating and cooling at around 800'C. This has the advantage that the ceramic-metal bonded body can be used in a high-temperature environment without causing a decrease in the strength of the parts.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is a diagram showing the heating conditions during bonding, Fig. 3 is a diagram showing the relationship between the thickness of the nickel plate and the bonding strength, and Fig. 4 is a diagram showing the relationship between the thickness of the nickel plate and the bonding strength. Figure 5 is a diagram showing the relationship between bonding strength and temperature. Figure 5 is a diagram showing the decrease in bending strength due to oxidation of products by the conventional method. Figure @6 is a diagram showing the influence of oxidation on products by the joining method of the present invention. Figure M47. FIG. 2 is a diagram showing sintering conditions for a tungsten sintered plate.

Claims (1)

[Claims] A sintered plate made of tungsten particles coated with nickel particles and sintered, and a stress relaxation material with nickel plates on both sides are interposed between the ceramic and the metal, and a brazing filler metal is placed between the ceramic and the nickel plate. A method for joining ceramics and metal, which is characterized by heating in a predetermined vacuum state.