Microstructure and mechanical properties of supersonic plasma sprayed coating

NiCrBSi coating was sprayed by supersonic plasma spraying technology, and microstructure and mechanical properties of NiCrBSi coating were analyzed. Microstructure of coating was investigated by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS), hardness and elastic modulus were measured by nano-indention method. Bonding strength between coating and substrate was investigated by tensile test. The distribution of residual stress alongside the coating thickness was measured by X-ray diffraction method. The results showed that the coating structures were uniform and had a low porosity and oxide. Nano-hardness was near to 15 GPa, nano elastic modulus was 200 GPa and boding strength was close to 50 MPa. It is concluded that the coating has good wear-resistance and excellent mechanical properties. Residual stress in the coating is tensile, and decreases with the incrense of the distance from the coating surface.