Influence of SiC particle size on wear and corrosion resistance of electrodeposited Ni- SiC composite coatings

Ni-SiC composite coatings were prepared by the co-electrodeposion of Ni matrix with micron and nano-sized SiC particles (1.5 μm and 20 nm), respectively. The microstructure, hardness, tribological properties and corrosion behaviours of the composite coating on medium carbon steels were investigated. The results indicate that the incorporation of SiC particles in metallic matrix significantly improves the hardness and wear resistance of deposited layer. Moreover, the hardness of the composite coatings is much more improved by the micron-particles than by the nano-sized ones, while there is almost no difference for wear and abrasion resistance between these two sized particles reinforced composite coatings. The corrosion behavior of the composite coatings was evaluated by the electrochemical impedance spectroscopy in 3.5% NaCl solution at room temperature. It is observed that the composite coatings incorporated with SiC particles provide higher corrosion resistance than the pure Ni coating, moreover, the incorporation of the nano SiC particles significantly improves the corrosion resistance than that of the micron-sized ones. The mechanism of improvement of wear resistance and corrosion resistance for the composite coatings was also discussed.