HARD COATING FILM EXCELLENT IN CORROSION RESISTANCE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To reduce pinholes in the film, to increase the corrosion resistance of a substrate and to produce the hard coating film excellent in wear resistance with high efficiency by coating the surface of a metallic substrate with a metallic layer of the group IVa, Va or VIa and furthermore coating the surface with a hard layer of the nitrides, carbides and carbonitrides of metals. ;SOLUTION: The surface of a metallic substrate is coated with a layer of metals belonging to the group IVa, Va or VIa by a vapor phase synthesis method. As the metals belonging to the group IVa, Va and VIa, Ti, Cr, V or Zr is given, and Cr is preferable. The surface of this metallic layer is, if required, coated with a hard layer of the nitrides, carbides or carbonitrides of these metals to improve its wear resistance as well as corrosion resistance. Furthermore, the surface of this hard layer is coated with a metallic layer belonging to the group IVa, Va or VIa and a hard layer composed of the nitrides, carbides or carbonitrides of these metals as well to improve its wear resistance. Preferably, the surface roughness of the metallic substrate is controlled to ≤0.20 μm by Ra, and the thickness of the metallic layer to be formed is controlled to ≥0.2 μm.;COPYRIGHT: (C)2000,JPO