MICROHARDNESS DISTRIBUTION AT INTERFACE OF(N~++IP)-TiN COMPOSITE COATINGS ON STEEL

The composite coating of(N~++IP)-TiN was prepared by ion-plated TiN film ontoion-nitrided case on the low carbon steel substrate.The microhardness measurement along in-terface between IP-TiN coating and substrate was detected as a moderate decrease in magni-tude with increase of distance from the coating surface.This seems due to the occurrence ofion nitride case,ε-Fe_3N-Fe_2N and Fe_4N phases,along the interface.