Abstract:Cu/graphite composite coating was prepared on TC4 alloy by cyanide free electroplating. The wear behavior and wear mechanisms of the coating were investigated. The results show that Cu/graphite composite coatings with compact structure and relatively strong coating/substrate combination can be obtained by cyanide free electroplating on TC4 alloy. However, increasing the graphite content in the coating would reduce the bonding strength between the coating and the substrate, and lead to a small decrease in coating hardness.The wear tests show that Cu/graphite composite coating can protect the TC4 substrate from wear effectively, demonstrated by its much lower friction coefficients and wear rates than both TC4 substrate and the pure copper coating. Based on a comprehensive analysis of the wear morphologies, wear products and friction coefficients of the coatings, the main wear mechanisms of the pure copper coating can be deduced as ploughing wear, adhesion wear and peeling wear, while those of the Cu/graphite composite coating are concluded as slight layer cutting wear and fatigue wear.