碘化钾对铝合金表面化学镀镍耐蚀性的影响

通过扫描电子显微镜考察了碘化钾(KI)对2024铝合金表面化学镀Ni-P层表面形貌的影响,采用浸泡法和动电位极化以及交流阻抗等电化学方法,研究了KI对Ni-P镀层在质量分数为3.5%的NaCl溶液中腐蚀行为的影响。实验结果表明,KI减少了Ni-P镀层中表面缺陷的数量,细化了晶粒,镀层更加平整致密,表面质量得到改善。同时,KI也增加了镀层中磷的质量分数。这两个原因使Ni-P镀层的耐蚀性进一步提高。

Effects of KI on the Corrosion Resistance of Electroless Ni-P Plating Coating on Aluminum Alloy

The effect of KI on the surface micrograph of electroless Ni-P coating for 2024 aluminum alloy was observed using scanning electron microscopy(SEM),and corrosion resistance of Ni-P coating in 3.5%NaCl solution was investigated by immersion,potendynamic polarization curves and electrochemical impedance spectroscopy(EIS).The experimental results show that KI reduces the amount of defect such pole in Ni-P coating,and the crystal grain becomes finer.The surface morphology of Ni-P coating gets more homogenous and smoother.Moreover,the phosphorus content of Ni-P coating is increased by KI.Both factors contribute to a better corrosion resistance for Ni-P coating in 3.5% NaCl solution.