Characterization of microstructure and rolling contact fatigue performance of NiCrBSi/WC–Ni composite coatings prepared by plasma spraying

• NiCrBSi/WC–Ni coating consisted mainly of γ-Ni, Cr7C3, Cr23C6, and WC/W2C phases.
• Evenly distributed W2C/WC phases were well wetted by other phases.
• NiCrBSi/WC–Ni coating had higher hardness than NiCrBSi by addition of hard WC–Ni.
• RCF performance of NiCrBSi/WC–Ni coating was superior to NiCrBSi under 0.881 GPa.

In this paper, the properties of NiCrBSi/WC–Ni composite coatings deposited by plasma spraying were analyzed, including their microstructure, element distribution, phase composition, porosity, and microhardness. The rolling contact fatigue (RCF) life and failure modes were also investigated. The results showed that the NiCrBSi/WC–Ni composite coating exhibited a typical lamellar structure. Furthermore, evenly distributed W2C/WC phases were well wetted by other phases. In addition to WC and W2C phases, the NiCrBSi/WC–Ni composite coating consisted mainly of γ-Ni, Cr7C3, Cr23C6, FeNi3, Ni3Si, CrB, and NiC. The study also found that the NiCrBSi/WC–Ni composite coating (porosity of 1.84%) had a slightly lower density than the NiCrBSi coating (porosity of 1.62%). The microhardness of the NiCrBSi/WC–Ni composite coating was significantly enhanced by the addition of hard WC–Ni. Furthermore, the results indicated that the NiCrBSi/WC–Ni composite coating had a higher dispersion degree of the RCF life and a longer life than the NiCrBSi coating under 0.881 GPa. Therefore, under this stress level, the RCF performance of the NiCrBSi/WC–Ni composite coating was superior to that of the NiCrBSi coating.