Electrodeposition of Zn-Ni alloys. Part I. ALSV Determination of the phase composition of deposits

摘要

Deposits of Zn-Ni alloy obtained from three different electrolytes typical of those used in plating practice were investigated for phase composition. Results of the classical X-ray method were contrasted with those recorded by anodic linear sweep yoltammetry (ALSV). It was found that deposits obtained from electrolytes containing tetraethylene pentamine (TEPA) at different cathodic potentials/current densities all consisted of a single phase, likely to be the γ-phase. Those obtained from citrate-borate and ammonia containing electrolytes were found to consist of three phases, i.e., that of pure Zn, the δ-phase and the γ-phase. The deposit from the ammonia electrolyte had a significantly smaller content of pure zinc than that fromthe former. Although a single phase alloy is favored for corrosion protection, the current efficiency of deposition from TEPA is rather low.