Wear behavior of NiCrBSi coatings produced by HVOF

A NiCrBSi coating was produced on the surface of cast iron by high-velocity-oxygen-fuel spraying to investigate the wear behavior at different temperatures. The wear behavior was evaluated by pin-on-disc tester at room temperature and 300 ℃. The effect of temperature on friction coefficient and wear rate was analyzed. The phase and microstructure of the coating were analyzed by XRD and SEM. The worn surface and cross section of NiCrBSi coating were observed by SEM. The results showed that NiCrBSi coating was dense and exhibited typical lamellar structure. The coating was composed of γ-Ni, Cr₇C₃, Ni₃B and CrB. The porosity was 1.11% and the hardness was 742 HV0.1±24 HV0.1. At room temperature, stick-slip phenomenon was observed. With the increase of temperature, the friction coefficient of NiCrBSi coating decreases, but the wear rate increases and the wear resistance decreases. The wear was mainly caused by abrasive wear and fatigue wear at both temperatures. With the increase of temperature, abrasive wear becomes more and more serious.