The analysis of the deposition mechanism of Zn/Ni alloy plating using an EQCM

The formation of the double hydroxide and its electrolytic reduction at the cathode in zinc-nickel alloy deposition were investigated. By using an EQCM method combined with the electrochemical measurement, it was clarified that the hydrogen generation occurs prior to the alloy deposition and the double hydroxide adheres to the electrode surface. It was confirmed that the electrolytic reduction product of the adhered material on the quartz surface was the zinc/nickel alloy with a Zn: Ni ratio of about 9: 1, from the analysis by using SEM/EDX. The double hydroxide adsorbed on the cathode surface probably acts as a precursor of the alloy deposition reaction.