Effects of ZnO and NaOH in Zn-Ni bath

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 2(2) 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.