Studies on electrodeposited Zn-Fe alloy coating on mild steel and its characterization

Ramesh Bhat,Ampar Chitharanjan Hegde

doi:10.5599/jese.565

Abstract

Chloride bath containing ZnCl2 ∙7H2O, FeCl2 ∙H2O and a combination of sulphamic acid and citric acid (SA+CA) were optimized for electrodeposition of bright Zn-Fe alloy coating on the mild steel. Bath constituents and operating parameters were optimized by the Hull cell method for highest performance of the coating against corrosion. The effect of current density and temperature on deposit characteristics such as corrosion resistance, hardness, thickness, cathode current efficiency and glossiness, were studied. Potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) methods were used to assess corrosion behaviour. Surface morphology of coatings was examined using scanning electron microscopy (SEM). The Zn-Fe alloy with intense peaks corresponding to Zn (100) and Zn (101) phases, evidenced by X-ray diffraction (XRD) study, showed the highest corrosion resistance. A new and economical chloride bath for electrodeposition of bright Zn-Fe alloy coating on mild steel was proposed and discussed.

Highlights

Electrodeposition of metals and alloys has become extensively used in many industries, showing distinctive advantages compared to most of other finishing technologies [1]
Effect of each bath constituent on Hull cell panels were examined in terms of their appearance and surface morphology
Increase in Fe content with current density is attributed to the rapid depletion of more readily depositable Zn2+ ions at the cathode coating [2]

Summary

Introduction

Electrodeposition of metals and alloys has become extensively used in many industries, showing distinctive advantages compared to most of other finishing technologies [1]. Keywords Zn-Fe alloy; chloride bath; sulphamic/citric acid; corrosion; XRD study Hegde et al [12] showed that transition of metal alloys shows anomalous co-deposition, occurring as a result of changes in the applied current density during electrodeposition of zinc–nickel, zinc-iron and zinc-nickel alloys in the acidic medium.

Results

Conclusion