Kei Higashi

Relationship between Composition of Electrodeposited Fe-Zn Alloys and Plating Factors

The electrodeposition of Fe-Zn alloys was interested in the properties of deposits and the mechanism of their deposition. Although many works have been contributed to the studies on this deposition, its mechanism has not yet been clarified.Standard single electrode potential of Zn in single salt solution is less noble than that of Fe. However, it was noted that Zn preferentially deposits under a certain plating condition. It suggests that the type of these alloys is formed by anomalous codeposition.In this paper, the effects of plating factors upon the composition of the deposits from chloride solutions are investigated in order to clarify the mechanism of anomalous codeposition.The composition of these alloys was a function of many factors. The main factors included bath composition, total ion concentration of metals, current density, temperature, and pH of the bath. Transition current density for anomalous codeposition was determined by these results.On the other hand, it was found that there is a transition point of bath composition, at which the type of deposition changes from anomalous to regular. The point depended on temperature, but not on current density.