纳米晶镍脉冲电沉积层在NaCl和NaOH溶液中的腐蚀性能

Corrosion Resistance of Pulse Electrodeposited Nanocrystalline Ni Coatings in NaCl Solution and NaOH Solution

目前,对纳米材料耐腐蚀性研究的结论不尽相同,对其腐蚀机制的见解也不统一。通过脉冲电沉积方法制备了纳米晶Ni沉积层。采用浸泡法和电化学方法研究了纳米晶Ni沉积层在3.5%NaCl(质量分数)以及10.0%NaOH(质量分数)溶液中的腐蚀行为。结果表明:在3.5%NaCl溶液中,纳米晶Ni沉积层具有较低的自腐蚀电位和较宽的钝化区,其耐腐蚀性能随着晶粒尺寸的减小而降低;在10.0%NaOH溶液中,纳米晶Ni沉积层的阳极极化曲线有较宽的钝化区,其耐腐蚀性能随着晶粒尺寸的减小而提高。

Nanocrystalline Ni coatings were prepared by using pulse electrodeposition. The corrosion behavior of the nanocrystalline Ni coatings in 3.5wt% NaCl solution and 10.0wt% NaOH solution was evaluated by using soaking and electrochemical polarization methods respectively. Results indicate that the nanocrystalline Ni coatings have a low corrosion current and a wide passivation zone in 3.5wt% NaCl solution,and their corrosion resistance decreases gradually with the reduction of grain sizes. In 10.0wt% NaOH solution,the corrosion resistance of the coatings increased with the reduction of grain sizes,and wide passive zones also emerged in the Tafel curves of the coatings.