Corrosive properties of different surfaces to understand the degradation mechanism of paint film

Abstract

Inadequate surface preparation of mild steel panels prior to painting could be the leading cause of the paint film failure. This work evaluated the surface preparation treatments in order to improve the paint integrity and thereby increasing the corrosion resistance of the steel panel in artificial sea water. The AISI 1020 steel ground and grit blasted samples were prepared followed by applying zinc based epoxy primer and top coat. The degradation mechanism was devised by immersing the samples in 3.5% NaCl solution. The degradation due to blistering within the paint was analyzed by following ASTM D-610 and ASTM D-714. Energy Dispersive Spectroscopy of corrosion product revealed a correlation with the degradation mode of painted sample. It was deduced that degradation of paint depends on surface morphology of substrate.