A novel self-lubricating Ni-P-AlN-WS₂ nanocomposite coating

In this study, a novel Ni-P-AlN-WS₂ nanocomposite coating has been successfully prepared on AZ31 alloy substrate by electroless co-deposition process. The effect of nanoWS₂ concentration in the plating bath on the surface morphology, microhardness, friction coefficient and wear behavior of the composite coatings have been investigated. The results showed that the Ni-P-AlN-WS₂ nanocomposite coatings had a fine nodular structure and AlN and WS₂ nanoparticles were uniformly dispersed in the composite coatings. The Ni-P-AlN nanocomposite exhibited the highest hardness of 810 HV₂₀₀, which is 291 higher than that of conventional Ni-P coating. The incorporation of WS₂ nanoparticles in the Ni-P-AlN nanocomposite coatings reduced the hardness of Ni-P-AlN-WS₂ nanocomposite coatings, which is 702 HV₂₀₀ at 1.5 g l⁻¹ nanoWS₂ concentrations in the bath and the hardness decreased with the increase of nanoWS₂ concentration in the bath. However, the incorporation of WS₂ nanoparticles in the Ni-P-AlN nanocomposite coatings significantly decreased the friction coefficient and improved wear resistance of Ni-P-AlN-WS₂ nanocomposite coatings. It indicated that Ni-P-AlN-WS₂ nanocomposite coatings exhibited both lower friction coefficient and higher wear resistance at the same time. (paper)