Zr-8Al合金酸性化学镀Ni-P镀层

Ni-P coating by acidic electroless plating on Zr-8Al alloy

采用酸洗粗化、磷化处理等预处理,然后再采用酸性化学镀在Zr-8Al合金表面成功制备了厚度为15μm左右的Ni-P镀层,并对镀层的物相、结构、显微硬度以及在3.5%NaCl溶液中的极化行为进行了分析。结果表明,酸洗及磷化处理有效地促进了化学镀Ni-P镀层的沉积。化学镀Ni-P镀层成典型的胞状结构、非晶结构。与未化学镀合金相比,化学镀Ni-P镀层显微硬度提高了58%,在3.5%溶液中的自腐蚀电位发生了正移。腐蚀极化后仍然保留了胞状特征,避免了Zr-8Al合金的选择性腐蚀,说明化学镀Ni-P镀层提高了Zr-8Al合金的抗腐蚀性能。

Acid pickling, phosphating and acidic electroless plating were applied to Zr-SAI alloy and Ni-P plating coating about 15 μm thickness was prepared. The phases, microstructure, micro-hardness and polarization behavior in 3.5% NaCI solution of the plating coating were investigated. The results show that the pickling and phosphating promote the deposition of eleetroless Ni-P plating. The electroless Ni-P plating coating consists of amorphous and typical cellular structure. Compared with that of un-plated alloy, the micro- hardness of Ni-P plating coating is improved by 58% and the corrosion potential of Ni-P plating coating in 3.5% NaC1 solution shifts positively. The plating coating still has cellular structure after corrosion polarization. Selective corrosion of Zr-8A1 alloy is prevented, which indicates that the corrosion resistance of Zr-8A1 alloy is improved after acidic electroless Ni-P plating.