Impact abrasive wear of tungsten carbide reinforced NiBSi coating fabricated by plasma transferred arc welding

The development of spherical cast eutectic WC/W2C (WCSC) reinforced Ni alloy coatings is limited by insufficient understanding of the microstructure evolution and its impact on abrasive wear behavior, which makes it challenging to enhance wear performance through microstructure control. In this study, NiBSi alloy coating reinforced by WCSC particles was prepared using plasma transferred arc welding (PTAW) technology. The microstructure of the coating was characterized using XRD, SEM, LCM, and TEM analysis. The results show that a large number of secondary carbides identified as W2C, M6C, and M4C were generated due to the partial dissolution of WCSC in the Ni-based molten pool. Two kinds of eutectics formed in the matrix were determined to be gamma-Ni + M6C and gamma-Ni + Ni3B. The microstructure evolution mechanism was revealed with the aid of EPMA analysis and CALPHAD-type calculations. The microhardness of the matrix was increased by dispersion strengthening and solid solution strengthening. The impact abrasive wear performances were analyzed using the MLD-10 wear tester, and the maximum impact wear mass loss of coating was observed at an impact energy of 3 J. At an impact energy of 1 J, furrow-type wear and fatigue wear are the main wear mechanisms of the coating. WCSC particles can effectively prevent the cutting of the matrix by abrasive particles. With the increase of impact energy to 3 J, the wear mechanism of the coating is mainly dominated by the fatigue wear and spalling pits of the matrix, as well as the fatigue and spalling of the WCSC particles and secondary carbides. At a high impact energy of 5 J, the fragmentation and spalling of the WCSC particles were generated, and massive spalling pits existed in the matrix. It is suggested that the control of the degradation of the WCSC particles should be focused on in future research.