Carbo-nitriding process using nitriles

Claim 1

A process for producing on a metallic or metalloid substrate, which consists at least partially of one or more of the elements selected from the group consisting of iron, boron, silicon and the transition metals of sub-groups 4 to 6 of the periodic table, a diffusion layer of material selected from the group consisting of said metal carbide, nitride, and carbonitride which comprises heating said substrate to a temperature of 500° C to 1800° C, and contacting said substrate with a gaseous or vaporous reactant stream comprising a carrier gas selected from argon and hydrogen and at least one carbon- and nitrogen- releasing compound which readily decomposes at substrate temperature, said compound selected from the group consisting of acetonitrile, adipodinitrile, 3-chloropropionitrile, tetracyanoethylene, acrylonitrile, tolunitrile, butyronitrile, succinodinitrile, 3-dimethylaminopropionitrile and cyclohexanecarboxylic acid nitrile, permitting reaction thereof to form said diffusion layer on said substrate.