Abstract:The electroplating behavior of Zn-P alloy on copper from light acid chloride solutions (LACS) was investigated using cyclic voltammetry and linear potential sweep method. It is found that, under the experimental conditions, the concentrations of H₃PO₃ and ascorbic acid in LACS change the codeposition mechanism of Zn-P alloy, the addition of H₃PO₃ into LACS promotes the three-dimentional (3-D) instantaneous nucleation/growth, while the addition of ascorbic acid promotes the two-dimentional (2-D) instantaneous nucleation and layer-by-layer growth. H₃PO₃ and zinc ions inhibit the deposition each other. The experimental results also show that H₃PO₃ in the LACS can be reduced on the cathode individually, and low pH value of the LACS promotes the reduction of H₃PO₃.

Key words: Zn-P alloy; codeposition; electrochemical behavior