Investigation on the Functionally Graded Properties of Zn–6MgO–12MnO2 Composite Coating Fabricated by Dual Anode Electrolytic Deposition Technique

Abstract

The effect of MnO2 particulates on Zn–MgO composite prepared via electrocodeposition route on low carbon steel was investigated. The experiment was conducted at constant current density of 11.2 A cm−2. The microstructural properties of the coated surfaces were characterized using high-resolution Nikon Optical Microscope (OPM) and scanning electron microscopy attached with energy-dispersive spectrometer (SEM/EDX). The corrosion behaviour was examined using linear polarization method in 3.5% NaCl-simulated seawater environment. The micro-hardness features of the electrodeposits were analyzed by dura scan hardness tester. The homogenizing and thermal stability of the fabricated composite was determined at 200 °C for 4 h. The results show that the structural performance and corrosion resistance property of the coating is dependent on the dispersion strengthening of the particle incorporation. The micro-hardness of the deposited samples increased with the increased addition of MnO2 with over 90%. The improvement in the micro-hardness of the deposited samples suggests that MnO2 has a strengthening effect on the mild steel.