Abstract:The quality of electro-less Ni-P plating is dependent on the process of pretreatment. In this paper, phosphating pretreatment was preformed for electro-less Ni-P plating on Zr-8.8Al alloy. The effect of phosphating process on the microstructure, microhardness and corrosion resistance in 3.5 wt% NaCl solution of electro-less Ni-P plating was investigated. The results show that the phosphating film obtained at 45℃ for 2min was uniform and even. The electro-less Ni-P plating has amorphous cellular structure and was about 25μm thickness. Compared with that of nonplated alloy, the microhardness of electroless Ni-P plating after phosphating pretreatment was improved by 60 percent. The corrosion potential of electro-less Ni-P plating after phosphating pretreatment in 3.5 wt% NaCl solution shift positively. The plating after corrosion is still complete, which shows that the corrosion resistance of electroless Ni-P plating after phosphating pretreatment is excellent.