Characterization and corrosion behaviour of plasma sprayed Zn-Sn alloy coating on mild steel

Extensive effort to enhance the mechanical and electrochemical surface properties of mild steel has been reported by various engineers worldwide. This investigation presents a comparative test of corrosion behaviour, residual stresses and coating characterization for different Zn-Sn alloy composition on mild steel substrate, with aim of enhancing surface properties and extending the application of mild steel in industries. Coating of about 200 μm was successfully deposited by plasma spray on mild steel substrate. The residual stresses were measured by X-ray diffraction sin2ψ technique using Cu-Kα radiation. Characterization and mechanical properties of the surface were investigated using Optical, Scanning electron microscopy, XRD and Emco Dura Scan tester to observe the microstructure, grain size, porosity, phase changes and hardness determination. The corrosion behaviour was examined in NaCl and H2SO4 solution. Direct current (DC) polarization tests were conducted and electrochemical corrosion behaviour of the surfaces was studied using scanning electron microscope (SEM/EDX). The results show an improvement as evidenced by the increased in corrosion resistance in NaCl and H2SO4 solutions, as well as increased in microhardness values on the coating.