Analysis of the wear behavior and corrosion resistance of CoCrFeNiMn-2% CNTs laser cladding composite coating

Abstract

Carbon nanotubes (CNTs), as a kind of nanopowder, can be used as reinforcing powder to improve various properties of coatings because of their good self-lubricating properties and three-dimensional structure. However, CNTs are difficult to mix uniformly with other powders due to their easily disrupted microstructure and extremely low density. Therefore, CoCrFeNiMn HEA and 2 wt% CNTs were mixed by a new mixing method—alcohol stirring and ball-less ball mill mixing methods. CoCrFeNiMn/2 wt% CNTs coatings prepared by laser cladding (LC). The phase composition, microstructure, wear resistance, and corrosion resistance of the HEA/CNTs coating were analyzed by various characterization techniques. The results showed that grain refinement occurred in the coatings after adding CNTs, generating fine carbides. It was calculated that the densification percentage of the HEA/CNTs coating increased and the porosity decreased. Compared with the HEA coating, the microhardness of the HEA/CNTs coating increased by 101.66%, and the friction coefficient and wear rate of the HEA/CNTs coating were only 63.30% and 6.22% of the HEA coating. The more positive Ecorr and smaller Icorr indicated that the HEA/CNTs coating has better corrosion resistance.