Effect of the Incorporation of SiC Fine Particle on the Tribological Behaviors of Chromium Coating Deposited from Trivalent Chromium Bath (Investigation on Dry Sliding Characteristics against Alumina)

In terms of safety and environmental impact, trivalent chromium plating is a potential surface treatment which alternates conventional hexavalent chromium plating. In order to improve the tribological properties, including friction characteristics, of the coating from trivalent baths, the authors attempted to incorporate silicon carbide (SiC) fine particles in the coating. Composite coating incorporating SiC particle deposited on a mild steel rod substrate successfully reduced the friction coefficient against alumina rod even while no significant increase in film hardness was achieved by particle incorporation. The effect of the coating hardness on the reduction in friction coefficient was limited. It was supposed that a possible reason for friction reduction was attributed to the reduction in the contact area by the incorporated particles. Coating surface texture modified by incorporating SiC particle should have contributed to the reduced friction because the texture allowed to bury wear debris and SiC particles detached from the film. Such a feature was supposed to promote reduced shear resistance as well as eliminate three-body abrasive wear.