Zinc electrodeposition from alkaline solution containing trisodium nitrilotriacetic added
By de Carvalho, Marcos F. & Carlos, Ivani A.
Published in Electrochimica Acta
2013
Abstract
An alkaline solution for the electrodeposition of Zn was developed, with trisodium nitrilotriacetic (NTA) as the complexing agent for Zn(II). The voltammetric studies showed that the NTA has a beneficial effect, displacing the initial reduction potential of Zn(II) species to more positive values than in its absence. Cyclic voltammetry of 1010 steel in alkaline Zn electrodeposition solution with 0.20 M NTA indicated the occurrence of the Zn underpotential electrodeposition, UPD, (regions wave c' and c″) and followed by Zn overpotential electrodeposition, OPD (region peak c‴). The Zn electrodeposit produced voltammetrically at limiting potential (Ef) -0.81 V (region wave c') was characterized by XRF and showed Zn presence. Zn electrodeposits produced potentiostatically at a potential -1.26 V were characterized by means of SEM, EDS and XRD. SEM results showed that fine-grain and compact Zn electrodeposits were obtained in the presence of 0.20 M NTA, at an electrodeposition charge density (qd) of 10.0 C cm-2. AFM analysis showed that the roughness of the Zn electrodeposits is greater in the presence than absence of 0.20 M NTA to both qd 2.0 and 10.0 C cm-2. The adhesion test showed that the Zn electrodeposits, in general, had no area detached. The XRD pattern revealed that the Zn electrodeposits had a crystal structure with preferential orientation [0 0 2]. It was showed that NTA was a suitable complexing agent for the electrodeposition of Zn without dendrites and cracks.