Microstructure and properties of plasma sprayed copper-matrix composite coatings with Ti3SiC2 addition

Obtaining excellent mechanical properties and high electrical conductivity for ceramic/metal composites is of great significance. In this study, the Ti3SiC2/Cu composite coatings (20 wt% and 50 wt% Ti3SiC2) were prepared by plasma spraying with the agglomerated Ti3SiC2/Cu powders. The effects of Ti3SiC2 content on the micro-structure, mechanical properties, electrical conductivity and tribological properties of the coatings were analyzed. The results showed that besides the primary compound region, the diffusion and decomposition zones also coexisted within the coatings. The 20 wt% Ti3SiC2/Cu composite coating showed a denser microstructure with the highest microhardness of 224 HV0.1, whereas higher fracture toughness was obtained for the 50 wt% Ti3SiC2/Cu coating (1.26 MPa center dot m1/2). Moreover, the 20 wt% and 50 wt% Ti3SiC2/Cu composite coatings had considerably high electrical conductivity, with the values of 7.9 x 106 S/m and 4.3 x 106 S/m, respectively. Compared to dry friction, the friction coefficient of the coating increased under current-carrying condition, and the wear of the tribo-pairs was accelerated. Generally, the main wear mechanisms of the 50 wt% Ti3SiC2/Cu composite coating under dry friction and current-carrying conditions are the adhesion wear, abrasive wear and fatigue wear.