Impact and corrosion resistances of duplex epoxy/enamel coated plates

The microstructure, impact resistance, pull-off adhesion strength, and corrosion resistances of duplex epoxy/enamel coating applied on steel plates are investigated experimentally. In comparison with those of individual epoxy and enamel coatings, the duplex coating has lower adhesion strength, higher impact resistance, higher short-term and long-term corrosion resistances both in 3.5 wt% NaCl solution and saturated Ca(OH)2 solution with various chloride concentrations. This is because the outer epoxy fills the micro pores in the inner enamel. Impact induced damage significantly reduces the corrosion resistances of epoxy and duplex coatings but has little effect on the corrosion resistance of enamel coating.