Fabrication of WC-Ni Composite Hard Coatings by Wet Plating and Gas Carburizing Complex Method and Evaluation of Its Mechanical Properties

Abstract

WC-Ni composite hard coatings were prepared by the complex method consist of wet plating and gas carburizing. The coatings conducted only gas carburizing after wet plating indicated that the microstructure composed of random-oriented fine needle like WC crystal surrounded by Ni matrix. Whereas the coatings conducted both reduction heat treatment and gas carburizing after wet plating showed that the microstructure composed of specific-oriented columnar WC crystal surrounded by Ni matrix. This fact suggested that the changing of fabrication procedure of the coatings, which occurred difference of WC crystal formation process, was able to control microstructure of the coatings. The coatings conducted both reduction heat treatment and gas carburizing after wet plating also demonstrated that the significant improvement of its mechanical properties compared to the coatings conducted only gas carburizing after wet plating.