Studies of phase composition of Zn–Ni alloy obtained in acetate-chloride electrolyte by using XRD and potentiodynamic stripping

• Published in: Electrochimica acta 2005-01, Vol.50 (5), p.1189-1196
• Main Authors: Petrauskas, A., Grincevičienė, L., Češūnienė, A., Juškėnas, R.
• Format: Article
• Language: English
• Subjects: Acetate-chloride electrolyte; Cross-disciplinary physics: materials science; rheology; Electrodeposition; Electrodeposition, electroplating; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Stripping; Zn–Ni coatings
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.07.044

The phase composition of Zn–Ni alloy electrodeposited in acetate-chloride electrolyte has been studied as a function of ZnCl 2 concentration and cathodic current density ( i c) by the potentiodynamic stripping and XRD methods. It appeared to be dependent only on the Zn/Ni ratio in the alloy, irrespective of whether the result was attained by varying the cathodic current density or by changing the [Zn 2+]/[Ni 2+] ratio in electrolyte. A Zn–Ni alloy dissolving in the potential range of i a peak D can be obtained by the method of cyclic voltammetry. This phase is a compact black coating. It has been determined by potentiodynamic stripping that pure Ni oxidizes only in the range of positive potentials, while Zn–Ni alloy containing some quantity of Zn oxidizes in the range of negative potentials. It was determined that the preciser data of potentiodynamic stripping were obtained in electrolyte containing Cl − ions. Zn–Ni alloy can be chromated only in the case when the η-phase makes up a sufficiently large portion of Zn–Ni alloy.