Preparation and Corrosion Resistance of Ni-W/SiC Nano-composite Coatings

Ni-W/SiC nano-composite coatings were prepared by electrodeposition method. The effects of SiC content on the microstructure and properties of Ni-W/SiC composite coatings were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The corrosion resistance of the composite coating in 3.5 wt.% NaCl solution was studied by electrochemical method. The results show that the addition of SiC nanoparticles could promote the nucleation and growth of crystals in the coatings, and could change the crystal structure, which would improve the microhardness, wear resistance and corrosion resistance. Ni-W/SiC nano-composite coating prepared in SiC concentration of 6 to 9 g/L had the best properties. Because higher concentration of SiC would lead to agglomeration of nanoparticles and thus impair their dispersibility. And the improvement of wear resistance was not ideal, if concentration of SiC was too low.