Influence of molybdenum on the microstructure and wear resistance of nickel-based alloy coating obtained by plasma transferred arc process

The influence of 6 wt% Mo on the microstructures and wear resistance properties of nickel-based alloy coating obtained by plasma transferred arc process were investigated using optical microscopy, scanning electron microscopy (SEM) with X-ray energy dispersive spectroscopy (EDS) and X-ray diffraction. More detailed information about the crystallographic structure and phase compositions of the coatings was obtained with the application of Rietveld refinement method to analyze X-ray diffraction spectra. The results show that the morphology of Cr-rich carbides observed in the interdendritic region of the nickel-based alloy coating changed from plate-like to net-like, as well as the refinement of Ni-rich dendrites because of the addition of 6 wt% Mo. The weight fraction of Cr-rich carbides increased from 36 wt% to 45 wt%. The wear resistance for 6 wt% Mo-modified nickel-based alloy coating increased by 47.2%. The microstructural change and phase contents variation were responsible for the improvement of the wear resistance of the 6 wt% Mo-modified nickel-based alloy coatings.