Tribological properties of Cu-(CF)n composites under different electric currents

Abstract

Metal matrix self-lubricating composites have emerged as key materials in sliding electrical contact applications due to their integrated lubrication and electrical conductivity. In this study, Cu-(CF)n composite and pure Cu were prepared by the powder metallurgy. The effects of electric currents on the tribological properties of the Cu-(CF)n composite and pure Cu were investigated. The results show that the (CF)n particles are uniformly distributed and show no significant decomposition in the Cu-(CF)n composite. As the electric current increases from 1 A to 15 A, both pure Cu and the Cu-(CF)n composite show a declining friction coefficient alongside increased wear. Nevertheless, the composite maintains a lower and more stable friction coefficient and exhibits less wear on both itself and its counter ball compared to pure Cu. With increasing current, pure Cu shows rising contact resistance and electrical noise, whereas the Cu-(CF)n composite exhibits the opposite trend. The worn surface of the Cu-(CF)n composite is smooth and flat, showing no evidence of arcing. The wear debris primarily consists of thin flakes, characteristic of delamination wear. The improved sliding electrical contact performance stems from the (CF)n-induced lubrication, which enhances real contact area, effectively suppressing arc erosion and oxidation. The incorporation of (CF)n substantially improves the tribological properties of the Cu-(CF)n composite under electric currents.