Effect of Heat-treatment on Corrosion Resistance of High-phosphorus Chemical Plating Thick Coating

The high-phosphorus electroless Ni-P plating coating with 11.64wt% was prepared by electroless technology.The morphologies and phase structures of the coating after heat treatment were analyzed by means of XRD and SEM.Furthermore, the corrosion resistance of the coating was studied by PARM273 A electrochemical detection system. The results show that, with the increase of heat-treatment temperatures, the corrosion resistance of the coating increases at first then decreases. Treated at 400 ℃ for 1 h, the corrosion resistance is the best. The thermal shock test suggests that a perfect cohesion exists between coating and matrix.