Primary Study on Electroless Plating Ni-Co-P Process on Al Alloy Substrate and the Performances of the Coating

The influence of electroless plating process parameters on the performances of Ni-Co-P coating on a hyper-eutectic Al-Si casting alloy is studied by orthogonal experiment.The effects of process parameters,such as pH and the component in electroless plating bath on the performance of Ni-Co-P layer,such as the thickness and hardness,have been obtained.It is indicated that the thickness of Ni-Co-P electroless plated layer increases with the increase of pH and the NiSO4·6H2O concentration,the moderate NaH2PO2·H2O concentration,and the decreasing of the CoSO4·7H2O concentration.The hardness of coating can be increased by increasing pH,using the moderate NiSO4·6H2O concentration and NaH2PO2·H2O concentration,and decreasing the CoSO4·7H2O concentration.