Method for surface treatment

摘要

A method for forming a layer of a carbide or nitride of a metallic element or boron nitride on the surface of a ceramics article. A molten salt bath is prepared by heating and melting a bath agent composed of boron oxide and/or borate, and at least one metallic element selected from Group IVa, Va, VIa elements, etc. An article to be treated which is made of silicon nitride, silicon carbide or sialon is immersed in the salt bath. This method provides a ceramics product with a uniform surface layer having superior frictional and electrical properties.