Electrochemical behavior of Zn–Co–Fe alloy electrodeposited from a sulfate bath on various substrate materials

Abstract

Electrodeposition of ternary Zn–Co–Fe alloy, on copper (high purity 99.9%), AISI 4340 steel, 9021I steel rod (iron 99.98%) and 304-stainless steel substrates, from a sulfate bath was studied. The electrodeposition of Zn–Co–Fe alloy on the various substrate materials was investigated by using cyclic voltammetric (CV) technique, to understand the reduction and oxidation processes occurring at the different electrodes surfaces, and galvanostatic technique to detect the formation of the initial deposits. Also potentiodynamic polarization method was used to assess the corrosion performance of the coating on each substrate material. The results were confirmed using EDXF and SEM analysis which show that the substrate material type influences the electrodeposition process and morphology of the deposits. The obtained results using galvanostatic technique showed that the substrate type affects the deposition potential. The cyclic voltammograms for steel substrate have different behavior than the other used substrate materials; also a clear reduction was shown in the associated charge for copper substrate. The corrosion resistance for Zn–Co–Fe alloy deposited on stainless steel substrate was better corrosion resistant than for a steel rod, steel and copper substrates.