换向比对脉冲电沉积镍-铁合金镀层耐蚀性的影响

Effects of Reverse Ratio on Corrosion Resistance of Ni-Fe Alloy Coatings Prepared by Pulse Electroplating

采用脉冲电沉积方法，在不同换向比下制备镍铁合金。使用SEM及EDS对镀层的表面形貌及名义成分进行表征；使用电化学工作站对镀层在质量分数为3．5％的NaCl溶液中的极化曲线和交流阻抗谱进行测量。结果表明：当换向比为2．5-10时，获得致密均匀的合金镀层，其中铁的质量分数基本一致，平均值约为（14．95±0．45）％；当换向比为3．3时，镀层的耐蚀性最佳，沉积镀层电阻约为35810Ω／cm^2，自腐蚀电流密度约为0．79μA／cm^2。换向比引起镀层表面形貌的差别可能是由于镀层的耐蚀性不同造成的。

The Ni-Fe alloy coatings were prepared by using pulse electrodepositing method at different reverse ratios （r）. SEM and EDS were used to characterize the surface morphology and nominal composition of the as-deposited coatings. The electrochemical station was used to measure the anodic polarization curves and electrochemical impedance spectroscopy （EIS） of the coatings in 3. ,9% NaCI solution. As r is 2.5-10, compact and uniform coatings are obtained, of which Fe mass fractions are basically in agreement, with an average value of about （14.95-0.45）%. The coating deposited when r=3.3 exhibits the best corrosion resistance, with an electric resistance of about 35 810 Ωcm2 and a self-corrosion current density of about 0.79 μA/cm^2. The difference in surface morphology of the coatings resulting from might be caused by different corrosion resislances of the coatings.