Investigation of corrosion resistance of electrodeposited Ni-W/SiC composite coatings

In this research, Ni-W/SiC composite coatings were electrodeposited from a plating bath containing suspension of SiC particles. The influences of SiC particle concentration in the plating bath on the composition of composite coatings were investigated. The surface morphology and composition of the composite coatings were characterised by scanning electron microscopy, energy dispersive X-ray measurements and X-ray diffraction analysis. The corrosion characteristics of Ni-W/SiC composite coatings were investigated by mass loss and electrochemical measurements, including open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarisation in a 3.5 wt-% NaCl solution. The results showed that the addition of SiC particle to the deposition bath of Ni-W significantly increased the corrosion resistance. The significant improvement in corrosion resistance observed for Ni-W/SiC composite coatings (17100 Omega cm(2)) compared to Ni-W (5619 Omega cm(2)) could have resulted from the microstructural differences.