Effects of laser powers on the microstructure and wear resistance of molybdenum coatings prepared by supersonic laser deposition

The molybdenum coatings were deposited by the supersonic laser deposition process. The microstructure, phase composition, microhardness and tribological properties of the coatings were characterized by a combination of X-ray diffractometer (XRD), scanning electron microscope (SEM), microhardness tester and tribometer. The results show that the coatings are all single Mo phase. As the laser power increases, the microstructure in the bottom and middle of the coatings changed from large deformed grains to equiaxed grains, and the micro-hardness of the coatings decreased. The fracture mode of the coatings changed from dissociation fracture to intergranular fracture with the increase of laser power. As the laser power increases, the wear resistance of the coatings gradually decreases. Moreover, the wear mechanism of the coatings gradually changed from abrasive wear to adhesive wear.