Effect of spraying power on the microstructure and mechanical properties of supersonic plasma-sprayed Ni-based alloy coatings

The aim of this paper was to investigate the microstructure and mechanical properties of the supersonic plasma-sprayed Ni–Cr–B–Si–C coatings prepared at different spraying powers. The microstructure, phase composition, porosity, Youngʹs modulus, micro-hardness, and residual stresses of the coatings were investigated and determined. The variations of the porosity, Youngʹs modulus and micro-hardness of the coatings were evaluated by using statistical method. Results showed that the variations of porosity, Youngʹs modulus and micro-hardness of the coatings followed the Weibull distributions. With increasing the porosity, the micro-hardness and Youngʹs modulus of the coating decreased. The mean value of the Youngʹs modulus of the coating calculated from Weibull plot was almost proportional to the square root of the micro-hardness of the coating. With increasing the power, Youngʹs modulus of the coating increased, which, in turn, resulted in the increment of the residual stress at the coating surface.