Journal of Applied Electrochemistry, Vol.39, No.10, 1975-1982, 2009
Electrochemical studies of Zn-Ni alloy coatings from acid chloride bath
The electrodeposition of Zn-Ni alloy from chloride bath was carried out in presence of condensation product (CP) formed between vanillin and hexamine. The investigation of electrodeposition and nucleation process was carried out on glassy carbon electrode using cyclic voltammetric and chronoamperometric techniques. During the anodic scan of cyclic voltammetry, three anodic peaks were observed corresponding to the dissolution of zinc and nickel from different phases of Zn-Ni alloy. The model of Scharifker and Hills was used to analyze the current transients and it revealed that Zn-Ni electrocrystallization process in the presence of CP, under the studied conditions, is governed by three-dimensional nucleation process controlled by diffusion. In presence of CP, the results indicated that nucleation process changes from progressive to instantaneous when the deposition potential becomes more negative. The phase structure and surface morphology of the deposits were characterized by means of X-ray diffraction analysis and Scanning electron microscopy, respectively.