Microstructure, thermal behavior and mechanical properties of Mo coatings deposited by plasma spraying and dry-ice blasting

Abstract: Mo coatings were usually deposited using atmospheric plasma spraying (APS) for the application of diesel engine motor. In this work, a combination process of plasma spraying and dry-ice blasting was employed to deposit Mo coatings on different substrates in order to decrease the oxidation of Molybdenum. The microstructure of the deposited Mo coatings was investigated in terms of the oxide content and porosity. The results show that the Mo coating deposited by the combination process has less porosity and oxide content compared with the coating deposited by the conventional APS process. Thermal behavior of these coatings was tested through a thermal cycling machine in order to evaluate heating cyclic ability. A delimination between the coating and substrate can be observed after thermal cycling. In addition, the microhardness, adhesion strength and wear behavior of the dry-ice blasted Mo coating were evaluated and compared with those of the conventional coating.