SURFACE–INTERFACE MICROSTRUCTURES AND FRICTION-WEAR PERFORMANCES OF THERMAL SPRAYED FeCrBSi COATINGS OBTAINED BY HIGH-VELOCITY OXYGEN FUEL PROCESS

Abstract

A layer of FeCrBSi coating was prepared on H13 hot work steel using a high-velocity oxygen fuel spraying (HVOF). The morphologies and distribution of chemical elements and phases in the obtained coatings were analyzed using a field emission scanning electron microscopy (FMSEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The friction-wear performance of FeCrBSi coating was examined using a wear test, and the wear mechanism was also discussed. The results show that the coating is primarily composed of Fe, Cr, B, and Si elements, which are uniformly distributed in the coating, enriched in the coating, and poor in the substrate at the coating interface. Among them, the Fe content decreases gradually in the substrate–coating direction, the Fe content of the coating is 40% lower than that of the substrate. The Cr, B, and Si contents in the coating are higher than those in the substrate, which form compounds and diffusion at the interface; as a result, the coating is combined with the substrate in the form of metallurgical bonding. The coating has a good friction reduction and wear resistance, the average COF (coefficient of friction) is 0.2126, the wear rate is 1.5 • 10^–6 mm³/sec • N, and the wear mechanism consists abrasive wear and spalling.