Electrodeposition of Zn-Mn Alloys at Low Current Densities

The electrodeposition of zinc-manganese alloys was studied at low current densities to design a process suitable for the automotive industry. Hull cell experiments were used to select the plating bath. The best results were obtained when both metals were in complexed forms Zn(II) with ethylenediaminetetraacetic acid and Mn(II) with citrate or malate. With these electrolytes the codeposition was achieved at low current densities, but current efficiencies were low. The characterization of the alloys obtained galvanostatically showed that most deposits were compact and showed different morphologies, mainly depending on the composition of the alloys and on the complexing agent for Mn(II). On the other hand, various phases of Zn-Mn alloys were identified in the coatings obtained under different experimental conditions.