Technology of Electroless Ni-P Deposition on Magnesium Alloy

AZ91D magnesium alloy samples were pretreated in zinc phosphating bath,and then plated with Ni-P deposits from the bath containing nickel sulphate．The morphology and microstructure of the electroless Ni-P coating was studied using SEM and XRD．The electroless Ni-P coating was compact and no obvious defects．The hardness values of the Ni-P coatings were about 350 HV and the phosphorus content of this coating was about 7.9％ (mass)．