Significantly enhanced mechanical and tribological properties of Co-based alloy coatings by annealing treatment

In the present work, the wear resistance of plasma sprayed CoMoCrSi alloy coatings was dramatically enhanced more than 45 times by annealing treatment. The microstructure, element distribution, phase transformation, mechanical and tribological properties of the coatings annealed at 200 degrees C, 600 degrees C and 1000 degrees C were systematically investigated. Results show that the mechanical properties and wear resistance were significantly improved with the increment of annealing temperature. Especially the coating annealed at 1000 degrees C (S1000) exhibits lower friction coefficient and ultrahigh wear resistance without obvious wear scar. Worn surface analyses suggested that the extraordinary tribological properties were mainly attributed to the elimination of defects and the dense Cr2O3-riched lubricating film on the worn surface.