Structure and Corrosion Protection of Rust Layer Formed on Pre-rusted Carbon Steel Covered with the Reactive Paint Coating

Abstract

Effect of Al ion on the structure and corrosion protection of rust layer on a carbon steel has been examined. It was found that coexistence of Al ion in atmospheric corrosion environment leads to preferential formation of α-FeOOH structure in the rust layer. Addition of Al ion into heavy-duty coating brings the structural change effect to the rust layer; that is, residual rust consisting mainly of β-FeOOH and Fe₃O₄ on salinity-pre-corroded carbon steel can change its structure to α-FeOOH considerably after applying the heavy-duty reactive paint coating. This change in the structure of rust layer results in higher corrosion protection properties of the reactive paint.