Tribological Behavior of HVOF Cermet Coatings as Alternative to Cr-Plating in Artificial Salt-Fog Atmosphere

Two kinds of cermet coatings (WC-10Co4Cr and Cr3C2-NiCr) were prepared by high velocity oxygen fuel (HVOF) to enhance the wear- and corrosion-resistance of key components in aviation and marine fields. Their tribology behavior in salt-fog condition were studied by a reconstructive friction testing machine equipped with artificial salt-fog spraying apparatus. Traditional chrome plating (Cr-plating) was also researched for comparison. The results show that different coating display different wear-mechanisms. Cr-plating exhibits mainly adhesive-wear mechanism, however, the WC-10Co4Cr coatings displays mainly abrasive-wear mechanism, while the Cr3C2-NiCr coating shows both mechanisms of adhesive-wear and abrasive-wear. Salt-fog atmosphere has important effects on tribological behavior of the coatings, which reduces the friction coefficient and corrosion loss of the coatings, resulting in the wear-mechanism of WC-10Co4Cr coating change to oxidation/corrosion wear.