Electroless nickel-plating on die cast magnesium alloy AZ91D

摘要

Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated.Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy.Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5% (mass fraction) NaCl solution.The results show that plating deposition is initiated on the crevices and then spread onto primary α phase.The corrosion potentials for die cast magnesium alloy AZ91D and nickel-plating coating are about .1.45 V and .0.36 V (vs.SCE),respectively.No discoloration,cracks,blisters,or peeling appear by heat-quench test.The results show that the corrosion potential of Ni-P coating is increased by 1 000 mV and corrosion resistance for die cast magnesium alloy AZ91D is improved.The adhesion between the coating and the substrate is excellent.Electroless nickel plating is a promising method to enhance magnesium alloys resistance for attacking.