Physico-Chemical Properties of Zn-Ni Alloy from an Alkaline Sulphate Bath Containing Triethanolamine and Mercaptopyridine

Abstract

The composition, properties and morphology of electrodeposited Zn-Ni alloy from an alkaline sulphate bath containing triethanolamine (TEA) and mercaptopyridine (MPY) have been investigated. A bath solution containing 3.5% wt. Ni content produced an alloy deposit with 12.5% wt. Ni (more noble metal) indicating preferential deposition of nickel (i.e. Regular co-deposition process). With increase in current density and the concentration of TEA, the percentage of nickel in the alloy deposit decreased. An increase in temperature, thickness and the concentration of MPY increases the percentage of nickel (more noble) in the Zn-Ni alloy deposit. CCE was decreased with current density, increased with temperature and stirring of the bath solution. Static potentials of Zn-Ni alloy were less noble to nickel and more noble to zinc. Hardness of the alloy increased with an increase in %Ni in an alloy. Fine grained deposits were observed morphologically.