Influences of intermediate Si-Ni thin film conditions on adhesion of Ni-TiN gradient thick films

Abstract

The influences of the intermediate thin film properties, that is internal stress and preferred orientation, on the adhesion of thick film were studied. The intermediate layers were designed Si and Ni multilayer structures, which were formed by the ion beam and vapor deposition method. Si films were prepared by evaporation of Si and simultaneous irradiation with Ar ions on to WC-Co substrates after surface cleaning by Ar ion beam irradiation. After the preparation of Si films, Ni films were also prepared by evaporation of Ni and Ar ion irradiation simultaneously. The internal stresses and preferred orientations of both films were controlled by changing the ion beam energy. Ni-TiN gradient thick films were formed on to these Si-Ni multilayer films by the cathodic arc ion plating method. It was found that the improvements of the internal stress and the preferred orientation conformities at the interface between the intermediate films and the thick films were important factors for high adhesion of thick film. The Ni-TiN gradient thick film reached a thickness of 600 μm with an adhesion high enough for practical use.