Effects of ZnO and NaOH in Zn–Ni bath

Abstract

This study investigated the influence of a Zn–Ni solution on the phase composition and surface morphology of Zn–Ni (zinc–nickel) alloy coatings, which were deposited in a non-cyanide alkaline bath that contained ethylenediamine (ED) and triethanolamine (TEA) as complexing agents. The structural investigations and surface morphology of the coatings were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. A full 22 factorial design methodology was used to study the effects of the ZnO and NaOH concentrations on the Ni % and Zn–Ni thickness of the deposited coatings. The results indicated that NaOH reduced the change in Ni % content in the deposited Zn–Ni alloys. The XRD and SEM results revealed that an increase in the NaOH concentration decreased the particle size and the smallest average grain size of the Zn–Ni coating was obtained when the NaOH and ZnO concentrations were 125 and 10 g L−1 respectively.