LAUSR

Abstract A novel Cr 3 C 2 -WC-NiCoCrMo and commercial Cr 3 C 2 -NiCr thermal spray-grade powders with particle size of −45 + 15 μm were prepared by an agglomeration and sintering process. Cr 3 C 2 -WC-NiCoCrMo and Cr 3 C 2 -NiCr coatings were deposited by high velocity oxygen fuel (HVOF) spraying. The fundamental properties of both coatings were evaluated and friction wear test against Al 2 O 3 counterbodies of both coatings at high temperatures (450 °C, 550 °C, 650 °C) were carried out ball-on-disk high temperature tribometer. All specimens were characterized by optical microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and 3D non-contact surface mapping profiler. The results have shown that the Cr 3 C 2 -WC-NiCoCrMo coating exhibited lower porosity, higher micro-hardness compared to the Cr 3 C 2 -NiCr coating. The Cr 3 C 2 -WC-NiCoCrMo coating also exhibited better wear resistance and higher friction coefficient compared to the Cr 3 C 2 -NiCr coating when sliding against the Al 2 O 3 counterpart. Wear rates of both coatings increased with raising temperature. Both coatings experienced abrasive wear; hard phase particles (WC and Cr 3 C 2 ) with different sizes, distributed in the matrix phase, will effectively improve the resistance against wear at high temperatures.