化学镀非晶态Ni-P镀层盐雾腐蚀行为

Behaviors of salt spray corrosion foramorphous Ni-P coatings by chemical plating

为了改善铝合金的耐腐蚀能力,利用化学镀在5052铝合金表面制备了非晶态Ni-P镀层,通过SEM、EDS和XRD等手段对Ni-P镀层盐雾腐蚀前后表面-界面形貌、化学元素和物相组成进行了表征,分析了非晶态Ni-P镀层盐雾腐蚀失效机理.研究表明:化学镀Ni-P镀层为非晶态,由直径10～50!m的颗粒组成,颗粒分布比较均匀,界面结合状态良好;Ni-P镀层为高P镀层,其物相以单质Ni和Ni-P相为主;盐雾腐蚀后镀层表面整体耐蚀性强,表面原始缺陷是导致界面局部出现腐蚀坑和镀层脱落的主要原因.

To improve the corrosion resistance of aluminum alloy,amorphous Ni-P coating was prepared on the surface of 5052 aluminum alloy by chemical plating,and the coating surface and interface morphologies,chemical elements and phase compositions before and after salt spray corrosion were characterized by SEM,EDS and XRD,respectively.The failure mechanism of Ni-P coating in salt spray corrosion was researched.The results show that the Ni-P coating by chemical plating is an amorphous state,forming by the particles of diameter 10-50 μm,which are evenly distributed,and the interface combines well.The Ni-P coating is the high-P,and its phases are mainly simple substance Ni and Ni-P alloy.After salt spray corrosion,the whole corrosion-resistance of Ni-P coating surface is better,the local phenomenon of corrosion pits and coating peeling are caused by the original defects of chemical plating.