Wear behavior and corrosion resistance of laser-clad Ni60-1 % carbon nanotubes coating

Abstract

Carbon nanotubes (CNTs) can improve the performance of composite coatings as reinforcing powders due to their three-dimensional (3D) tubular structure and good self-lubricating properties. Unfortunately, CNTs are difficult to mix uniformly with other powders due to their extremely light mass and fragile microstructure. Therefore, in this study, the alcohol-stirring mixing method was used for powder mixing. The results showed that Ni60 powder and 1 wt% CNTs were mixed homogeneously by this method, and large-area CNTs deposition was achieved on the surface of Ni60 powder. The properties of the Ni60/CNTs coatings fabricated by laser cladding (LC) were examined. The microstructure of the Ni60/CNTs coating was refined, and M23C6 carbides were generated. Compared with the Ni60 coating, the microhardness of the Ni60/CNTs coating increased by 41.6 %, and the wear rate decreased by 76.76 %. The improvement is mainly due to the excellent self-lubricating properties of CNTs and their tubular structure, which improves the friction behavior of the coating. In addition, the refinement of microstructure and the generation of C23C6 carbides also play an enhanced role. The bridging of the tubular structure of CNTs and the filling effect of carbides resulted in improved corrosion resistance of the Ni60/CNTs coatings.