Effects of mechanical forming on the corrosion of electrogalvanised steel

This paper presents a morphological and electrochemical characterisation of electrogalvanised steel (EG) and phosphated electrogalvanised steel (PEG) after plastic deformation. Previous investigations focused on the deformation of a coil-coating with the same substrates. The effect of forming on the complete system is known but not its influence on the individual layers. The study now reported used SEM to analyse the surface changes of EG and PEG after uniaxial and biaxial deformation and EIS and SVET to characterise the corrosion of the samples when immersed in 0.1 M NaCl.

► Effect of mechanical forming on EG and PEG was characterised by SEM, EIS and SVET.
► Corrosion of intact PEG is markedly slower compared to the bare EG.
► Mechanical forming cracks the phosphate layer decreasing the corrosion resistance.