Electrochemical behavior of the super high strength aluminum alloy as a cathode in zinc electrodeposition

The characteristics of commercial pure aluminum and a super high strength aluminum alloy as cathodes in zinc electrodeposition were studied in this paper.In a ZnSO₄-H₂SO₄ system,the electrochemical behavior of the two cathodes was investigated by electrochemical test,the initial nucleation was observed by scanning electron microscopy,and the crystalline orientations of zinc sheets were observed by X-ray energy dispersive spectrometry.The results show that under a current density of 500 A·m^-2,the deposition potential and exchange current density of the commercial pure aluminum and super high strength aluminum alloy are -1.541 V,7.74×10^-11 A·cm^-2 and -1.496 V,6.07×10^-3 A·cm^-2,respectively.The addition of alloying elements can increase the initial nucleation sites and promote the rate of nucleation,but the increase of nucleation rate can inhibit cathode corrosion by halogen elements.There is no change in the crystalline orientations of zinc sheets after deposition for 3 h.The super high strength aluminum alloy is prone to burn the plate and blister,with a lower current efficiency of only 84.54%.The current efficiency of the pure aluminum is 88.04%,the morphology of deposited zinc is flat and smooth,but the cathode plate is easy to be corroded by halogen elements.