Influence of Cr addition on tribocorrosion behavior of high velocity oxygen-fuel thermal sprayed WC-based cermet coatings

This research investigates the tribocorrosion behavior and the effect of Cr addition on the wear mechanism of the WC-10Co4Cr and WC-10Co coatings prepared with high velocity oxygen-fuel (HVOF) technology, compared with 3Cr13 substrate. The WC-based cermet coatings exhibited significantly higher microhardness, with average microhardness values of 1488 HV_0.3 and 1429 HV_0.3, respectively. The coatings exhibited minor decarburization during fabrication, and average porosities are 1.2 % and 1.8 %, respectively. In 3.5 wt% NaCl solution, WC-10Co4Cr, and WC-10Co coatings show tribocorrosion resistance 12.5 and 7.6 times greater than that of 3Cr13, respectively. The addition of Cr in the WC-10Co4Cr coating imparted superior corrosion resistance, with the corrosion-wear synergistic interaction affecting only 19.3 % of the coating's performance. In contrast, the WC-10Co coating showed relatively poorer corrosion resistance, with corrosion-wear interaction accounting for 51.8 % of its volume loss. The main mechanism of corrosion-wear interaction is corrosion-promoted wear. The primary wear mechanisms for the WC-10Co4Cr coating include abrasive wear and electrochemical corrosion wear while the WC-10Co coating also suffers from more severe fatigue wear.