DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is based upon a finding that, if the surface of a ceramic member is surface-treated with a bonding agent or is bonded after a bonding agent is added thereto, the ceramic and metal members may be securely bonded to each other in such a way that they will not separate over a long period of time.
The ceramic member to be used herein may consist of a nonoxide-type ceramic such as a nitride, e.
g.
, silicon nitride, aluminum nitride, or titanium nitride; a carbide, e.
g.
, silicon carbide or titanium carbide; a boride, e.
g.
, lanthanum boride; or, an oxide-type ceramic such as silica, alumina and zirconia.
A ceramic selected may contain, as a sintering auxiliary, an oxide of yttrium, aluminum, calcium, strontium or beryllium; a carbonate; or other salts.
The method of the present invention is particularly effective in bonding a nonoxide-type ceramic member to a metal member.
A bonding agent to be used herein produces a eutectic in combination with a metal and may include oxygen, sulfur, phosphorus, silicon or the like.
The bonding agent may be selected in accordance with the types and combinations of the ceramic and metal members.
For example, when the metal member comprises copper, iron, chromium or the like, the most desirable bonding agent is oxygen or sulfur.
If the metal member comprises aluminum, silicon is suitable for use as a bonding agent.
The amount of bonding agent needed to achieve satisfactory bonding is somewhere between the maximum amount at which the bonding agent is in the form of a solid solution and the eutectic-forming amount.
Addition of a bonding agent to the surface layer of the ceramic member may be performed by a conventional method.
For example, when a ceramic member consists of a nitride and the bonding agent is oxygen, the ceramic member is heated to 1,000.
degree.
to 1,400.
degree.
C.
in air or is heated to 1,250.
degree.
to 1,500.
degree.
C.
in a wet-forming gas (H.
sub.
2 +N.
sub.
2), to achieve oxidation
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