Effect of Temperature and Co2+ Concentration of Bath on Composition of Zn-Co Alloy Coatings

Zn-Co electrodeposits have attracted interest because of their significantly higher corrosion resistance in comparison with pure zinc. In this research the influence of bath temperature and electrolyte’s Co2+ concentration on the morphology and composition of the Zn-Co coatings, electrodeposited on an AISI1018 steel substrate from a weakly alkaline glycine solutions, has been studied. SEM and EDS analysis were used to study surface morphology and composition of Zn-Co alloy coatings. It was shown that by increasing the bath temperature and Co2+ concentration in electrolyte, the cobalt concentration in the coating was increased. By increasing the cobalt concentration in the bath favoring the formation of smaller grains; however further increase of cobalt in the bath resulted in coarsens the morphology of the coating.