Study Of Electroless Ni-P Alloys Plating On AZ91D Magnesium Alloys

Magnesium alloys have a number of desirable features,including low density,high strength-to-weight ratio,excellent castability,good machinability and damping characteristics,and its use in a variety of applications,particularly in aerospace, automobile,mechanical and electronics components,is now growing rapidly.However, poor corrosion resistance has often prevented it from further exploitation. Electroless-nickel-plating(EN),being one of the surface treatments of magnesium alloys, has attracted much attention due to the possession of a combination of properties,such as good corrosion and wear resistance,deposit uniformity,electrical and thermal conductivity,and solder-ability etc.However,this process is now far from completeness, particularly in corrosion resistance aspects.Therefore,this dissertation is aimed at optimization procedure by orthogonal design ways.In this paper,temperature,pH value, and 2NiCO₃·3Ni(OH)₂·4H₂O,NaH₂PO₂·H₂O,H₈C₆O₇·H₂O was researched to understand that the factors influencing direct-electroless-plating on magnesium alloys,and the optimization parameters were obtained.Using the scan electronic microscope equipped with energy dispersive,and X-ray diffraction,micro-hard tester,salt spray tester etc,the surface morphology and microstructure,micro-hardness,adherence between the plating and matrix,and the corrosion resistance of the plating were observed.The result showed that the optimization parameters were fit to direct electroless plating on magnesium alloys.The morphology of the plating was very nice and the adherence between the plating and matrix was choiceness,and the corrosion resistance of the plating was outstanding.