Influence of Current Density on the Mechanism of Electrodeposition and Dissolution of Zn-Fe-Co Alloys

The electrodeposition of zinc-iron-cobalt alloys from sulfate bath was carried out galvanostatically on steel. A complementary approach based on of a combination of different electrochemical techniques was used to clarify the deposition mechanism. The electrodeposition of the alloys was of an anomalous type. The corrosion behavior of the coatings was evaluated from polarization measurements in hydrochloric acid. The deposition at different current densities exhibited varied influence on the corrosion potential of alloys obtained from sulfate baths. It was shown that increased corrosion protection of steel can be achieved by electrochemical deposition of ternary alloys with higher amounts of the Co and Fe. The composition of the ternary alloy can be optimized by proper choice of the current density.