前处理工艺对镁合金化学镀Ni-P质量的影响

采用扫描电镜和性能检测的方法,分析了表调、活化和浸锌等前处理工艺对镁合金化学镀Ni-P质量的影响.结果表明,表调可使晶界凸出于α-Mg基体,降低镁合金的表面粗糙度,提高化学镀层的结合强度.活化及浸锌后,促进了化学镀的进行.按表调、活化、一次浸锌、退镀、二次浸锌的工艺进行前处理后实施化学镀,得到的Ni-P镀层致密、平整,与基体结合力强,有效提高了镁合金表面耐蚀性及显微硬度.

Effect of Pretreatment on Electroless Ni-P Plating Quality of Magnesium Alloy

The effects of pretreatment including surface conditioning and activation and zinc dipping on the electroless Ni-P plating quality of AZ31 magnesium alloy were investigated by microstructure analysis and property test.The surface conditioning could improve the bond strength between electroless Ni-P plating and magnesium matrix,resulted from the projection of grain boundaries and the decrease of surface roughness of magnesium matrix.The electroless Ni-P plating of AZ31 magnesium alloy was promoted owing to the formation of crystal nucleus of elemental zinc through zinc dipping for Ni-P coating.The Ni-P coating was even,dense and had good bond strength when the pretreatment including surface conditioning,activation,zinc dipping,deplating and twi-zinc dipping was adopted before electroless Ni-P plainting.The corrosion resistance and micro hardness of AZ31 magnesium alloy were improved by electroless Ni-P plating.