The Tribocorrosion Resistance of Posttreated Supersonic Plasma-Sprayed MoSi2 Coating

MoSi2 coatings were prepared on a 45CrNi substrate by supersonic plasma spraying (SAPS). The tribocorrosion resistance of MoSi2 coating and posttreated MoSi2 coating (P-MoSi2) in the seawater environment was analyzed. After posttreatment, some new phases such as MoO3, SiO2, and Mo9O26 are generated in the P-MoSi2 coating. The electrochemical test results indicated that the P-MoSi2 coating has lower current density and larger −βc and Rp values than MoSi2 coating in both static corrosion and tribocorrosion tests. The wear test results indicated that the posttreatment reduces the wear-rate and friction coefficient of the coating. The wear mechanisms of both coatings were described to explain the differences. Also, the mechanism of the improved tribocorrosion resistance after posttreatment was explained.