JPS62148381A - Manufacture of ceramic-metal joined body - 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 Field of Industrial Application The present invention relates to a method for manufacturing a bonded body of ceramics and metal, and more specifically, it involves heating a ceramic raw material powder placed on the surface of a metal body to a high temperature under pressure. By heating for a short time, the ceramic raw material powder is sintered and the surface of the metal body is coated with cotton. This is extremely difficult because both materials are different. The main reasons are as follows. (1) Metals and ceramics are difficult to "wet" with each other. (2) Since metals and ceramics have different coefficients of thermal expansion, thermal stress occurs in the joint, and this stress causes the joint to break or reduce the joint strength.

Regarding (1), the conventional method for solving these problems is generally to find a brazing material that is easy to "wet" the ceramic and the metal, and to interpose the brazing material between the two to join them. An example of this is
No. Ml-containing wax.

Japanese Patent Publication No. 58-36'? There are No. 85 oxide waxes, etc.

Regarding (2), a metal with a coefficient of thermal expansion between the ceramics and the metal is interposed, or
There are known methods such as interposing a foamed metal with a low elastic modulus.

In addition, metallization of the ceramic surface by electroless plating, coating with molybdenum paste, and other methods has also been adopted for the purpose of making it possible to solder electronic components. ing. Conversely, a method of coating the surface of a metal body with ceramics by a method such as plasma spraying, CVD, or PVD is also widely used.

Problems to be Solved by the Invention (1) The method of coating ceramics on the surface of a metal body using C■ or PVD provides a coating with good adhesion, but unfortunately the growth rate is slow and it is difficult to use it industrially. is limited to a ceramic layer thickness of about 10 μm. For this reason, it is not suitable for parts that require sufficient wear allowance for the ceramic layer or parts that take advantage of the heat insulating properties of the ceramic layer.

(2) The method of forming a ceramic layer on the surface of a metal body by plasma spraying makes it easier to obtain a thicker coating layer than CVD or PVD, but the ceramic layer is porous and has the disadvantage that its strength is significantly lower than that of sintered ceramics. be.

In addition, even if a thermal stress relieving layer called a band coat is interposed between the ceramic layer and the metal body, the thicker the ceramic layer, the greater the thermal stress (and the more likely it is that peeling will occur).
There's a problem.

Therefore, even if it is allowed that the ceramic layer itself is porous and has low strength, the thickness of the ceramic layer that can be practically used is about one layer.

(3) A method of metallizing the surface of ceramics using electroless plating, vapor deposition, molybdenum paste, etc. This method is effective for soldering conductor wires and forming electrical conductor layers, and is widely used in electronic components. However, its adhesion strength is low and it is difficult to use it as a mechanical part.

(4) The method of joining sintered ceramics to a metal body with a brazing material or a thermal stress relaxation material interposed is the method described in (2) above.
Compared to (3), the bonding strength is greater (and there is no limit to the thickness of the ceramic and metal bodies), which is effective when using ceramics as mechanical parts.

However, the bonding strength is still low compared to the strength of the ceramic itself, and it is desired to improve its performance.

For example, if a method can be found to firmly bond a ceramic sintered body layer, which has excellent heat resistance, corrosion resistance, abrasion resistance, and radiation damage resistance, to the surface of a metal body several times thick, it would be possible to Said properties of the body can be significantly improved.

Furthermore, if a material in which a plate-shaped metal body is firmly bonded to a ceramic sintered body layer with a certain thickness can be obtained, the reliability of ceramics that are poor in toughness can be greatly improved. It is also possible to bond to other metallization via this plate-shaped metal body using a known metal/metal bonding method.

Purpose of the Invention The present invention has been made in view of the above circumstances, and its purpose is to provide a bonding method in which ceramics with excellent heat resistance, corrosion resistance, abrasion resistance, and radiation damage resistance are firmly joined to a metal body. It can be used as parts in various industrial fields that require the above characteristics, and unlike the conventional method of joining ceramics with a sintering agent to a metal body, ceramic raw material powder can be sintered in a short time. It is an object of the present invention to provide a method for manufacturing a ceramic-metal bonded body that can be bonded to a metal body.

Means and Action for Solving the Problems In order to achieve the above object, the present invention forms a ceramic raw powder layer on the surface of a metal body, and also forms a thermite composition layer on the surface of the ceramic raw powder layer. This assembly A is maintained under pressure, and the layer of thermite composition in the assembly A is ignited to sinter the ceramic raw material powder and bond it to the surface of the metal body. This is what I did.

Example The present invention will be explained below.

The present invention is a method in which a metal body and unsintered ceramic raw material powder are brought into contact with each other, and the ceramic is bonded to gold while being welded under pressure. More specifically, (1) forming a ceramic raw material powder layer on the surface of the metal body and arranging a layer of thermite composition on the surface of the ceramic raw material powder layer to constitute the assembly A; (2) forming the assembly A; (3) The thermite composition layer of the assembly A is ignited to sinter the ceramic raw material powder and join it to the surface of the metal body.

This is a method for manufacturing a joined body of ceramics and metal, which consists of various steps.

Note that a reaction prevention layer may be interposed between the thermite composition and the ceramic raw material powder layer.

Thermite compositions instantaneously generate a large amount of reaction heat upon ignition, making them suitable for short-term, high-temperature heating. Its composition is described in Japanese Patent Application No. 60-053252, and a method of sintering ceramics using the heat generated by the thermite reaction is described in Japanese Patent Application No. 60-026424.

When thermite is ignited under pressure in the arrangement (1) above,
Heat flows in from the thermite composition/ceramic raw material powder layer interface, rapidly heating and sintering the ceramic raw material powder layer. On the other hand, at least the outermost layer of the metal body melts,
The molten metal infiltrates into the voids of the ceramic raw material powder, forming a composite layer of the ceramic and the metal body at the interface between the two.

If heat generated by thermite reaction is applied to the ceramic raw material powder layer while the metal body and the ceramic raw material powder layer are pressed together, sintering of the ceramic and the formation of a composite layer at the metal-ceramic interface can be achieved in a short time. , a metal body and a ceramic can be firmly pressure bonded via the composite layer. Note that the formation of the composite layer has intermediate characteristics between ceramics and metals, and plays the role of mediating between the dissimilar ceramics and metals.

Next, one embodiment of the present invention will be described based on FIGS. 1 to 3.

Figure 1 shows assembly A, in which 1 is a nickel plate with a diameter of 22 mm and a thickness of 0.5 rm, and 2 is a β-type silicon carbide powder with 0.5 weight percent of graphite as a sintering aid. 700"!9 ceramic raw powder powder layer mixed with powder, 3 is aluminum powder and Fe2O3 powder in a molar ratio of 2:1
4 is a reaction prevention layer provided for the purpose of preventing contamination of the ceramic raw material powder when the thermite composition is ignited, and 2t of hexagonal boron nitride is It is made uniform in thickness by cold forming to a height of 3 cm.

These assemblies A were arranged as shown in FIG. 1, and filled into a holder 5 which was actually manufactured by cold-opening hexagonal boron nitride powder.

Next, the holder 5 was filled with a known piston/cylinder type pressurizing device, and while pressurized to 1 GPa, the molybdenum wire led to the thermite composition 4 was energized to ignite the thermite. After ignition, hold for 2 minutes, remove pressure, and collect assembly A.

From the recovered assembly A, a bonded body in which a sintered layer of silicon carbide was bonded to a nickel plate 1 could be easily taken out, and the surface of the silicon carbide was protected by a reaction prevention layer and was not contaminated by thermite at all. It was smooth.

Figure 2 is a microscopic photograph of the joined body after cutting and polishing the cut surface.
It is shown enlarged twice. In FIG. 2, the area marked with ■ is the sintered silicon carbide portion, and the area marked with ■ is the nickel plate 1. It can be seen that the silicon carbide part (■) has no pores and is densely sintered. Furthermore, an intermediate phase (■) is formed between the areas (■) and (2). It is thought that particles were present in the intermediate phase (2), and at least the outermost surface of the nickel plate 1 was melted and infiltrated into the ceramic raw material powder layer (2) to form a composite.

The calorific value of the thermite composition in this example is 20Kc
However, by selecting the ceramic raw material powder in consideration of the type, thickness, melting point, thickness of the metal body, specific heat, thermal conductivity, and melting point, the conditions as in this example can be achieved. It is easy to find out.

Next, in order to evaluate the bonding strength, the bonded body was bent so that the ceramic side was convex, and the condition of the bonded surface was examined.

Figure 3 is a 200x magnification (micrograph) of the bonded surface after the bending test. The upper part of the silicon carbide layer (2) fell off due to the fracture, and cracks starting from the stress-concentrated areas penetrated through the remaining silicon carbide layer (2) and the composite layer. However, this crack stopped when it reached the nickel plate 1, and no cracks were observed on the bonded surface, confirming that the strength of the bonded surface was high.

Effects of the Invention As detailed above, the method for manufacturing a ceramic-metal bonded body according to the present invention includes forming a ceramic raw material powder layer on the surface of a metal body and forming a thermite composition layer on the surface of the ceramic raw material powder layer. This assembly A is maintained under pressure, and the layer of thermite composition in assembly A is ignited to sinter the ceramic raw material powder and bond it to the surface of the metal body. This is a method for manufacturing a joined body of ceramics and metal, characterized in that:

Therefore, a bonded body in which ceramics with excellent heat resistance, corrosion resistance, abrasion resistance, and radiation damage resistance are firmly bonded to a metal body can be obtained, and can be used as parts in various industrial fields that require the above characteristics.

In addition, if a thin plate is used as the metal body, it is possible to form a strong metal layer on the surface of the ceramic.The metal layer can strengthen the fragile ceramic, provide conductivity, and improve bondability to other metal bodies. It is possible to improve the

Furthermore, unlike the conventional method of joining ceramics as a sintering agent to a metal body, the ceramic raw material powder can be sintered and joined to the metal body in a short time.

In carrying out the present invention, the ceramics used are not limited to the examples (for example, SiC, Ti
Carbides such as C, WC, ZrC, HfC, B, C, nitrides such as 8i3N4, TiBz.

ZrBs, borides such as HfB2, AL203,
It may also be an oxide such as ZrO2. However, for materials with poor thermal conductivity such as oxides, the thickness of the ceramic layer must be thinner than for materials with good thermal conductivity.

Furthermore, the type of metal body is not limited to the examples, and any steel material, nickel-based alloy, cobalt-based alloy, or copper alloy can be used.

Furthermore, the melting area of the metal body varies depending on the composition and amount of thermite, the type of ceramic, the particle size and thickness, and the thickness of the metal body, but the optimum conditions can be easily achieved by increasing or decreasing the calorific value of thermite. is found. Furthermore, if the metal body is a thin plate, it is also possible to arrange a heat sink in contact with it.

The pressure is also not limited to this example, and may be appropriately selected in consideration of the sintering properties of the ceramics; for example, hot pressing may be sufficient in some cases.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the structure of the assembly used in the method of the present invention;
The figure is a cross-sectional view of a joined body manufactured by the method of the present invention, and a photograph is attached as a reference figure. FIG. 3 is a cross-sectional view of the joint surface of the joined body after the bending test, and a photograph is attached for reference. A is an assembly.

Claims (1)

[Claims] A ceramic raw material powder layer is formed on the surface of the metal body, and a layer of thermite composition is formed on the surface of the ceramic raw material powder layer to constitute an assembly A, and this assembly A is maintained under pressure. A method for producing a joined body of ceramic and metal, characterized in that the layer of the thermite composition in A is ignited to sinter the ceramic raw material powder and join it to the surface of the metal body.