SURFACE-INTERFACE MICROSTRUCTURES AND HIGH-TEMPERATURE WEAR PERFORMANCE OF HVOF-SPRAYED AND LASER-REMELTED NiCrBSi ALLOY COATINGS

Abstract

A high-velocity oxygen fuel (HVOF)-sprayed NiCrBSi coating on H13 hot work die steel was processed with laser remelting; and the surface-interface morphologies, concentrations of chemical elements, and phases of the coating were analyzed with scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. The friction-wear behaviors of the coating at high temperatures were investigated by the means of ball/plane contact. The effects of high temperature on the coefficient of friction (COF) and wear performance are discussed. The results show that the coating is dense and tightly bonded to the substrate at the interface. The average COFs at 500[Formula: see text]C, 600[Formula: see text]C, and 700[Formula: see text]C are 0.3749, 0.3609, and 0.4556, respectively. The wear mechanism is slight adhesive wear at 500[Formula: see text]C, and primarily oxidative wear and fatigue wear at 600[Formula: see text]C. The wear mechanism at 700[Formula: see text]C is oxidized wear and fatigue wear in the early stage, and mainly adhesive wear in the later stage. During high-temperature wear, an oxide film is formed on the coating surface, decreasing the wear resistance of the coating, which is primarily dependent on the compounds of Ni, Cr, B, Si, and C and the oxides of Si.