Treatment of chromium-containing iron alloys
AssigneeThe International Nickel Company, Inc.
InventorWilliam H. Sutton
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Abstract
A method of providing a hard film on stainless steel comprising treating the stainless steel in an aqueous solution of chromic and sulfuric acids to provide a film and then treating the metal containing the film in an aqueous solution of a water-soluble silicate for a period of time sufficient to harden the film.
Claims6
A method of providing a hard film on the surface of a stainless steel comprising treating the stainless steel in an aqueous solution of chromic and sulphuric acids, with or without other constituents to provide a film on the surface thereof, without heat treating the film subjecting the stainless steel bearing the film to electrolysis as the cathode in a hardening electrolyte and thereafter treating the stainless steel bearing the hardened film in an aqueous solution of a water soluble silicate for a period of time of at least about 5 minutes sufficient to harden the film.
Dependencies are inferred from the claim text.