Electrodeposition of copper-tin-zinc ternary alloys from disodium ethylenediaminetetraacetate bath

• Cu-Sn-Zn alloy deposition from various composition of EDTA bath was studied.
• Voltammetric curves show reduction of [CuY]2 −; [SnY]2 −and [ZnY]2 −.
• EDS results show Cu-Sn-Zn co-deposition at − 1.50 V, − 1.60 V and − 1.70 V.
• SEM results show Cu-Sn-Zn electrodeposits formed by globular crystallites.
• XRD results show the formation of Cu-Sn-Zn ternary alloy.

The voltammetric profile of Cu-Sn-Zn ternary alloys electrodeposition onto AISI 1010 steel from an acid bath containing disodium ethylenediaminetetraacetate (EDTA) showed four different cathodic regions, depending on bath composition, which were associated with the reduction of [CuY]2 −, [SnY]2 − and [ZnY]2 − complexes through of the analysis of the voltammetric curves together with the energy-dispersive X-ray spectroscopy results. However, Cu-Sn-Zn co-deposition occurred only at electrodeposition potentials (Ed) more negative than − 1.26 V, depending on bath composition, indicating that a transition Ed exists wherein a transition from Cu-Sn binary alloy to Cu-Sn-Zn ternary alloy occurred. Analysis of the photomicrographs showed that Cu-Sn-Zn electrodeposits showed dense and uniform morphologies depending on Ed and bath composition. Also, adhesion tests showed that the Cu-Sn-Zn electrodeposits obtained at Ed − 1.70 V, with qd of 3.0 C cm− 2, from baths containing 0.20 M CuSO4 + 0.050 M SnCl2 + 0.050 M ZnSO4 and 0.10 M CuSO4 + 0.10 M SnCl2 + 0.10 M ZnSO4 presented good adherence. X-ray diffraction of Cu-Sn-Zn electrodeposits obtained at Ed − 1.70 V, with qd of 3.0 C cm− 2, showed a mixture of Zn, Sn, CuO, ZnO, SnO, η-Cu6Sn5, Cu20Sn6 and CuZn phases, depending on bath composition, indicating the formation of Cu-Sn-Zn ternary alloy.