Effects of modification of hBN by nickel plating on coating structure and properties of supersonic plasma spraying NiCr-Cr3C2-hBN@Ni coatings

Hexagonal boron nitride (hBN) with excellent self-lubrication performance is expected to relieve the friction resistance and wear of NiCr-Cr3C2 coatings. However, the poor wettability of hBN with most materials makes it difficult to fabricate NiCr-Cr3C2-hBN composite coating with good cohesion strength. In this study, hBN was firstly pretreated through magnetron-sputtering aided Ni plating to form hBN@Ni particles. Then, NiCr-Cr3C2- hBN@Ni powder was prepared by spray granulation. Next, corresponding coatings were prepared through su-personic atmosphere plasma spraying. It was found that in comparison with NiCr-Cr3C2-hBN coating, the NiCr-Cr3C2-hBN@Ni coating exhibited a decreased porosity (from 3.6% to 0.3%), elevated cohesion (from 52.78 N to 62.11 N), and the wear rate decreased by an order of magnitude. It was concluded that hBN@Ni can effectively improve the component interface inside powder, enhance the cohesion of molten in-flight particles, and make the internal structure of the coating denser.