Tribological performance optimization and synergistic lubrication evolution of Pb-free FeS/Cu-Bi composites

The tribological properties of Pb-free FeS/Cu-Bi (FCB) self-lubricating composites were optimised with the Taguchi method. The effects of lubricant content and ball milling time on the anti-friction and wear resistance of FCB composites were investigated. Then the evolution of the friction interface was observed through interrupted microscopy measurement to reveal its synergistic lubrication mechanism. The results showed that the primary and secondary factors that affected the anti-friction and wear resistance of the FCB composites were FeS content, Bi content and ball milling time. The synergistic lubrication mechanism of FCB composites was that FeS could prevent the crack from extending with the continuous Bi mesh and could prevent the matrix with Bi debris from peeling off, which was conducive to the formation of a lubricant-rich tribofilm at the friction interface to improve the tribological properties of the composites.