Physico-Chemical Properties of Zn-Fe Alloy Deposits from an Acid Sulphate Bath Containing Triethanolamine

Abstract

The composition, properties, structure and morphology of electrodeposited Zn-Fe alloy deposits obtained from an acid sulphate bath containing triethanolamine have been investigated. A bath containing less zinc (20%) produced an alloy deposit with higher zinc content (80%), i.e. anomalous co-deposition process. The composition of alloy remained constant with pH of the plating bath and thickness of the alloy deposit. The cathodic current efficiency depends on plating variables. The shift in deposition potentials of Zn-Fe alloy is a chief cause in the co-deposition process to produce alloy of varying composition. Phase structure determination by X-ray diffraction studies showed a wide variety of inter metallic phases. Zn-Fe alloy showed a superior corrosion resistance than zinc coatings. An alloy containing greater than 40% Fe showed a good paintability. Hardness of the alloy deposits increased with increase in iron content in the alloy. Smooth, uniform and fine grained deposits were obtained for the Zn-Fe alloy containing 20% Fe.