JPH03228877A - Method for bonding ceramics - Google Patents

Abstract

PURPOSE:To bond ceramics at relatively low pressure and temp. and to obtain a bonded body having high strength and characteristic by depositing a slurry having a specified composition on the surfaces to be bonded, abutting the surfaces on each other, pressing and heating the assembly. CONSTITUTION:(A) A formulation (e.g. a mixture of lanthanum octylate, calcium octylate and acetylacetone chromium) having the same composition as the ceramic to be bonded and (B) the powder of ceramics to be bonded (e.g. La-Ca- Cr-O-based ceramic powder) are dissolved or dispersed in (C) a solvent (e.g. toluene) to produce a slurry. The slurry is then deposited on the surface of at least one ceramic to be bonded. The surfaces to be bonded are then abutted on each other, and the assembly is pressed and heated to bond both ceramics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for joining ceramics, and particularly to a method for joining ceramics that can join ceramics together at relatively low pressure and temperature.

[Prior Art] Among the methods that have been put to practical use in the past as a method for joining ceramics together, there is a solid phase pressing method in which objects to be joined are heated while applying pressure while being brought into close contact with each other.

[Problems to be Solved by the Invention] In the conventional solid phase pressing method, high temperatures, that is, temperatures between the melting point Tm and 0.5 Tm of the materials of the objects to be joined, and high pressures, for example 0.
．． Since heating and pressurization of 1 to 15 MPa are required, there is a drawback that the effects on the members to be joined are large, such as deterioration or destruction of the members to be joined.

The purpose of the present invention is to solve the problems of the conventional solid-phase pressing method described above, and to provide a method for joining ceramics that can industrially advantageously join ceramics under relatively low temperature and low pressure conditions. do.

[Means for Solving the Problems] In the method for joining ceramics of the present invention, when joining ceramics of the same type or different types, an organic compound blended to have the same composition as that of the ceramic is applied to the surface of at least one of the ceramics to be joined. The method is characterized in that after a slurry obtained by dissolving or dispersing a metal compound and the ceramic powder in a solvent is applied, the surfaces to be joined are brought into contact with each other and pressurized and heated.

The present invention will be explained in detail below. In the method of the present invention, the slurry deposited on the surfaces of the ceramics to be joined consists of: (1) an organometallic compound prepared to have the same composition as the ceramics (2) powder of the ceramics (2) a solvent.

As the organometallic compound (2), metal acetates, alkoxides, octylates, naphthenates, carbonates, acetylacetone metal salts, etc. can be used. These organometallic compounds may be single metal salts or alkoxides, or complex metal salts or alkoxides. Therefore, in the case of joining ceramics containing two or more types of metals, two or more types of organometallic compounds can be used, but one type of composite metal compound can also be used.

The metals in the organometallic compound include, for example, zinc, aluminum, antimony, yttrium, cadmium, gadolinium, gallium, calcium, chromium, silicon, germanium, cobalt, samarium, zirconium, tin, strontium, cesium, cerium, and selenium. , tungsten, tantalum, titanium, iron, copper, niobium, nickel, vanadium, barium, bismuth, boron, magnesium, manganese, molybdenum, lanthanum, and the like.

(2) As the ceramic powder, it is possible to use a powder of ceramics made of the same material as the members to be joined and having an average particle size of several tens of micrometers or less.

(2) The solvent is not particularly limited as long as it can dissolve the organometallic compound (2). For example, alcohol:
Ketones; Esters; Aromatic solvents such as benzene and toluene; Dimethylformamide, dimethylacetamide,
1 of nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone
Examples include a species or a mixed solvent of two or more species.

In the present invention, other additives such as thickeners, stabilizers, etc. may be added to the slurry prepared from the above-mentioned organometallic compound, ceramic powder, and solvent within a range that does not interfere with the purpose of the present invention. It's okay.

The amount of solvent in such a slurry affects the viscosity of the slurry, and this viscosity affects the thickness of the joint formed between the members to be joined. That is, if other bonding conditions are the same, the thickness of the bonded portion increases as the viscosity of the slurry increases. An increase in the thickness of the joint portion effectively contributes to joining members to be joined that have uneven surfaces.

On the other hand, the mixing ratio of the organometallic compound and the ceramic powder is an important factor that affects the density of the joint, and by decreasing the ratio of ceramic powder, the density of the joint can be lowered, depending on the purpose of use. It is also possible to create a porous structure.

In the present invention, in the usual case, (1) 83 parts by weight of an organometallic compound (10 parts by weight) and (1) solvent = 17 to 40 parts by weight are mixed to obtain a viscosity of 103 to 105 c. p. It is preferable to form a slurry of approximately

As a method for adhering such a slurry to the surfaces to be joined of the members to be joined, ordinary coating methods such as a brush coating method, a screen printing method, a spray method, a dipping method, a spin coater method, etc. can be employed. Although it is preferable that the slurry be applied to both surfaces of the members to be joined, it is possible to join the members by applying the slurry only to one of the surfaces to be joined.

Note that the amount of slurry attached is 0 or 1 relative to the area of the surface to be joined.
It is preferable to set it to about ˜Ig/crn''.

In the present invention, after such a slurry is applied to the surfaces of the members to be joined, the surfaces to be joined are brought into contact with each other and pressurized and heated. 100g
/ crd~several tens of kilograms/crn', several hundred~
At several thousand degrees Celsius, it is possible to use significantly lower pressure and lower temperature conditions than in conventional solid phase pressurization.

[Operation] A slurry obtained by dissolving or dispersing an organometallic compound prepared to have the same composition as the ceramics constituting the members to be joined and powder of the ceramic in a solvent is applied to the surfaces to be joined of the members to be joined. By pressurizing and heating, it is possible to bond under lower pressure and lower temperature pressurizing and heating conditions than in conventional solid-phase pressing methods. Furthermore, due to this pressurization and heat treatment, a joint portion having almost the same composition and crystal structure as the ceramics constituting the members to be joined is formed between the surfaces of the members to be joined. Since this bonded portion has high-temperature strength and density comparable to those of the members to be bonded, and other functions unique to the ceramic, a bonded body with extremely high strength and high properties can be obtained. Moreover, the joint formed by applying the slurry absorbs the irregularities of the surfaces to be joined of the members to be joined, and is almost unaffected by the surface roughness of the surfaces to be joined. Good bonding can be achieved even if the material is

[Example] EXAMPLES The present invention will be described in more detail with reference to Examples below.

Example 1 Lao9Ca (ICry2) ceramic members were joined together according to the method of the present invention.

That is, first, La (1, g Ca
o, CrC1+ceramics powder (average particle size 2 μm
) to prepare a slurry, add 22.35 g of L a 6. g Ca o, 1
Approximately 0.1 g/err? by brush coating on the surface of the Cr O3 ceramic member to be joined. After applying, touch the surface to be joined and apply 1 kg/crr? Approximately 1
It was fired at 000°C.

As a result, a high-performance bonded body with significantly high strength at the bonded portion was obtained.

From the results of this example, it was found that according to the method of the present invention, it is possible to significantly lower the joining processing temperature, which was conventionally performed at a ceramic sintering temperature of 1400 to 1500 °C, by 400 to 500 °C. Moreover, it is clear that the pressing force at that time can also be significantly lowered.

[Effects of the Invention] As detailed above, according to the method for joining ceramics of the present invention, it is possible to join ceramics at a significantly lower temperature and pressure than in the conventional solid phase pressing method.
A joined body with high strength and high properties can be obtained. Moreover,
Even ceramic members with high surface roughness on the surfaces to be joined can be joined well without any pretreatment such as surface polishing, and its industrial usefulness is extremely high.

Claims (1)

[Claims] (1) When joining ceramics, a slurry obtained by dissolving or dispersing an organometallic compound prepared to have the same composition as the ceramic and powder of the ceramic in a solvent is applied to the surface of at least one of the ceramics to be joined. A method for joining ceramics, which is characterized by applying pressure and heating by pressing and heating the surfaces to be joined after adhering the materials.