Investigation of Electroless Plating on AZ31 Magnesium Alloys

Direct electroless Ni-P plating on the AZ31 magnesium alloys in a plating bath containing nickel carbonate was investigated.The morphology and microstructure of the electroless Ni-P coating were studied by SEM and XRD.The electroless Ni-P coating was compact and no obvious defects.The hardness value of the Ni-P coatings was 566 HV and the phosphorus content of this coating was about 9.77 wt%.The deposition rate of the electroless Ni-P alloys was about 0.32μm/ h.The acid pickle pretreatment on the AZ31 magnesium alloy substrate provides surface pits to act as sites for mechanical interlocking to improve adhesion between the coating and the substrate.The adherence of them is 22N.