초록 ▼

Duplex coated steel composite products comprising a first layer of a nitrided layer formed by applying glow discharge at a current density from 0.001 to 2.0 mA/cm.sup.2 to the surface of metal parts by using gaseous ammonia and gaseous hydrogen while maintaining the temperature of the metal parts at

Duplex coated steel composite products comprising a first layer of a nitrided layer formed by applying glow discharge at a current density from 0.001 to 2.0 mA/cm.sup.2 to the surface of metal parts by using gaseous ammonia and gaseous hydrogen while maintaining the temperature of the metal parts at 300 to 650.degree. C., thereby applying plasma nitriding and a second layer comprising a hard film comprising a nitride, carbide and/or carbonitride of one or more of elements selected from Ti, Zr, Hf, V, Nb, Ta and Cr coated on the first layer by the PVD method of a laminate film or a gradient laminate film of such hard film. The treated products are excellent in adhesion with the substrate and durability and have both oxidation resistance and wear resistance.

대표청구항 ▼

[ What is claimed is:] [1.] A duplex coated steel composite product which comprises a steel substrate having a first diffusion layer formed of steel alloy with nitrogen atoms diffused therein, and a second layer located on said first diffusion layer, said second layer including at least one hard fil

[ What is claimed is:] [1.] A duplex coated steel composite product which comprises a steel substrate having a first diffusion layer formed of steel alloy with nitrogen atoms diffused therein, and a second layer located on said first diffusion layer, said second layer including at least one hard film selected from the group consisting of a hard film which contains at least one of a nitride, carbide or carbonitride of a metal selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta and Cr, a laminate film and a gradient laminate film of said hard film.