中文摘要：

在正交实验基础上，对比研究微米SiC（平均粒径1．5um）和纳米SiC（平均粒径20nm）增强复合镍基镀层的摩擦磨损行为和耐腐蚀性能。通过TEM、SEM、EDX和XRD等手段研究颗粒分散状态以及复合镀层的表面和截面形貌、成分及相结构。采用球-盘滑动摩擦磨损试验机研究复合镀层的耐磨性。电化学阻抗谱测量在3．5％的NaCl水溶液中进行。结果表明：微米级颗粒增强复合镀层可以获得更高的表面硬度，两种增强复合镀层具有相似的摩擦磨损行为。电化学阻抗谱分析表明：SiC颗粒的加入可以提高镀层的耐腐蚀性，且纳米颗粒复合镀层具有更好的耐蚀性。

英文摘要：

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, whiie 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.