A Study on the Electrodeposited Cu-Zn Alloy Thin Films

In this article, electrochemical deposition of the nanocrystalline Cu_1−x Zn _x alloys on to aluminum substrates from a non-cyanide citrate electrolyte at 52.5, 105, 157.5, and 210 A m⁻² current densities were described. The bath solution of the Cu_1−x Zn _x alloys consisted of 0.08 mol L⁻¹ CuSO₄·5H₂O, 0.2 mol L⁻¹ ZnSO₄·7H₂O, and 0.5 mol L⁻¹ Na₃C₆H₅O₇. The effect of the current density on the microstrain, grainsize, phase structure, and DC electrical resistivity behavior was investigated. The electrolyte was investigated electrochemically by cyclic voltammetry (CV) studies. A scanning electron microscope (SEM) was used to study the morphologies of the deposits. Deposited alloys were investigated by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and four-point probe electrical resistivity techniques. With an increase in applied current density values from 52.5 to 210 A m⁻², the amount of deposited copper in the alloy was decreased significantly from 65.5 to 16.6 pct and zinc increased from 34.4 to 83.4 pct. An increase in the current density was accompanied by an increase in grain size values from 65 to 95 nm. SEM observations indicated that the morphology of the film surface was modified to bigger grained nanostructures by increasing the current density. The XRD analysis showed alloys have a body-centered cubic (bcc) crystal structure with preferential planes of (110) and (211). Furthermore, four-point measurements of the films revealed that the resistivity of the deposited films was tailored by varying current densities in the electrolyte.