Tribological performance of c-BN/TiC-enhanced NiCrBSi coatings prepared by high-velocity oxy-fuel spraying tested from room temperature to 1000 °C

Abstract

The c-BN/TiC-enhanced NiCrBSi composite powder and coatings were prepared by spray-drying and high-velocity oxygen-fuel (HVOF) spraying, respectively. The phases, microstructures and tribological performance were studied from room temperature to 1000 °C, and the wear mechanisms of coatings were analyzed and discussed. The results showed that TiC and c-BN distributed evenly in NiCrBSi phase, but with the increase of temperature, c-BN showed a certain degree of aggregation, while TiC particles grew significantly. Therefore, the coating shows good wear resistance at room temperature. As the temperature increased, the wear rate of the coating increased, and the wear resistance decreased, so the maximum wear rate was obtained at 800 °C. However, when the temperature was increased to 1000 °C, a composite enamel layer of oxide and hard phase was generated on the surface of the abrasion marks, which improved the wear resistance of the coating, significantly reducing the wear rate.