Wear-resistive and electrically conductive nitrogen-containing DLC film consisting of ultra-thin multilayers prepared by using filtered arc deposition

Abstract

Nitrogen-containing diamond-like carbon (N-DLC) multilayer films approximately 500 nm thick were fabricated on tungsten carbide substrates as surface protective films with high wear-resistive and conductive properties. Each layer thickness of the N-DLC multilayer films was approximately 10 nm, and the films were a periodic bilayer structure consisting of hard and soft N-DLC layers. Owing to the high abrasion resistance of the hard layer and the low aggressiveness and high adhesion of the soft layer, the multilayer films showed good polishing and wear resistances compared with the hard N-DLC monolayer film, and the electrical resistivity was about half. In the case of DLC multilayer films consisting of hard N-free DLC and N-DLC films, the decrease of each layer thickness leads to the reduction of the polishing resistance. From X-ray reflectivity analysis of ultra-thin N-free DLC films, it was indicated that the film density of an ultra-thin N-free DLC film is lower than that of a thick N-free DLC film. In the DLC multilayer film with thin N-free DLC layers, it is possible that the polishing resistance of the whole DLC film reduced because the hardness the N-free DLC layer was decreased due to the low film density of each N-free DLC layer.