Abstract:A NiCrBSi coating was fabricated on 304 stainless steel substrate using high-velocity oxygen-fuel (HVOF) spraying. The friction and wear behaviors of the coating were systematically investigated at room temperature (RT), 200 °C, 400 °C, and 600 °C to reveal the influence of elevated temperatures on its wear mechanisms. The effects of temperature on the microstructure and mechanical properties of the coating were analyzed by scanning electron microscopy (SEM) and high-temperature microhardness testing, respectively. The morphology and chemical composition of the wear tracks were characterized using white light interferometry and Raman spectroscopy. The results indicate that the NiCrBSi coating exhibits a distinct crystallization exothermic peak at approximately 505 °C. Above this temperature, the crystallinity and microstructure of the coating were significantly improved. As the temperature increased, both the porosity and microhardness of the coating generally decreased, with a relatively gradual decline below 505 °C and a sharp drop beyond it. The combined effect of mechanical action between the coating and the counterpart ball and the high-temperature environment induced oxidation during friction, generating oxides such as NiO, Cr?O?, and NiCr?O?. At temperatures below 505 °C, the high-temperature environment led to a certain reduction in the friction coefficient. With a further increase in temperature, the lubricating effect of the oxides further contributed to the decrease in the friction coefficient. Meanwhile, the wear rate of the coating continuously increased with temperature, rising from 2×10?? mm3/(N·m) at RT to 11.3×10?? mm3/(N·m) at 600 °C. At room temperature, the dominant wear mechanism was fatigue wear. As the temperature increased to 600 °C, the marked decrease in coating hardness led to the generation of substantial debris, making abrasive wear the predominant mechanism.