Microstructure and Tribological Behavior of Plasma Sprayed (Ti,Cr)C-Ni Composite Coatings

Thermally sprayed cermet coatings are widely used in many engineering applications to protect against wear and corrosion. In this study, three kinds of (Ti,Cr)C-based powders with 18, 25, 33 wt.% content of Ni binder were deposited onto stainless steel substrates by plasma spraying technique. The microstructure and dry sliding wear resistance of the (Ti,Cr)C-Ni coatings were investigated. The (Ti,Cr)C-Ni coatings have a heterogeneous structure composed of (Ti,Cr)C particles and Ni binder. Fracture and partial dissolution of the (Ti,Cr)C particles were found to occur during the plasma spray process. Among all the tested coatings, (Ti,Cr)C-33wt.%Ni coating exhibits lower wear rates and friction coefficients under all conditions. Worn surfaces of the coatings were analyzed using SEM to investigate the wear mechanism. With the increase in Ni content from 18 up to 33wt.%Ni wear mechanism of the (Ti,Cr)C-Ni coatings changes from abrasive to tribo-oxidation.