Stripping of Zn-Ni alloys deposited in acetate-chloride electrolyte under potentiodynamic and galvanostatic conditions

Variations in the phase composition of Zn-Ni alloy electrodeposited in acetate-chloride electrolyte have been studied as a function of ZnCl2 concentration in electrolyte and deposition conditions: the cathodic current density (i(c)), the cathodic potential (E-c) and deposition temperature (t, degreesC), by using the potentiodynamic stripping method. It has been determined that the quantity of Ni in galvanostatically deposited coatings decreases more significantly at 20 degreesC as compared with that at 50 degreesC with an increase in ZnCl2, whereas the cathodic current efficiency (CE) passes through a minimum in both cases. It has been determined that the quantity of eta-phase in the Zn-Ni alloy decreases with an increase either in i(c) or E-c. The data obtained by using the partial cycling method suggest that, in the potential range of i(a) peak D, not only does Ni dissolve, but the dissolution of Zn-Ni alloy also takes place. (C) 2004 Elsevier B.V. All rights reserved.