Reactive Sputter Deposition of WC_x Films for Replacing Hexavalent Chromium

Abstract

This paper investigates the reactive sputter deposition of tungsten carbide (WCx) films for replacing hexavalent chromium which was found to cause cancer in human body. The deposition rate of the films was proportional to rf-power and inversely proportional to the CH4 content in the sputtering gas. The hardness of the WCx coatings increased as the rf-power increased. The highest hardness was obtained at the CH4 concentration of 10 vol.% in the sputtering gas. The hardness of the WCx film deposited under optimal conditions was far higher than that of the electroplated chromium film although the corrosion-resistance of the former was slightly inferior to that of the latter. Considering all these experimental results, it may be concluded that the reactive sputterdeposition of WCx coatings can be effectively applied to the parts with complex geometries as an alternative to chromium electroplating.