Ni coating was deposited on carbon steel by a mechanical attrition enhanced electroplating （MAEE） process. During the electroplating, the mechanical attrition（MA） was introduced by impact of glass balls on the sample surface with a special vibrating frequency. The surface and cross-sectional images of Ni coating were observed with SEM. The microstructure and crystallinity of coating were examined with TEM and XRD. The electrochemical performance of coating was measured with polarization curves and electrochemical impedance spectroscopy （EIS） and its mechanical behaviours, such as tensile strength and hardness, were studied. The results show that the MA has significant effects on the microstructure and property of the electroplated Ni coating. By MA, the coating becomes smooth, compact, thin and has refined grains and is free of cracks and pores. Consequently, the adhesion, tensile strength, hardness and corrosion resistance of coating are improved significantly.
Aluminum capacitor foils with a tunnel etch structure were reacted with boiling water and then anodized at 530 V in boric acid solution or boric acid＋citric acid mixed solution.The microstructure and crystallinity of the resulting anodized film were examined by TEM and XRD.The special capacitance,resistance and withstanding voltage of the film were explored with electrochemical impedance spectroscopy（EIS）,LCR meter and small-current charging.The results show that the high voltage anodized oxide film consists of an inner layer with high crystallinity and an outer layer with low crystallinity.However,the crystallinity of the film formed in boric acid＋citric acid mixed solution is higher than that of the film formed in only boric acid solution,leading to an increase in film＇s field strength and special capacitance.Meanwhile,there are more defects from phase transformation in the out layer of the film formed in boric acid＋citric acid mixed solution than in that of film formed in only boric acid solution,leading to a decrease in film＇s resistance and withstanding voltage.
