Corrosion Mechanism of Organic-composite-coated Steel Sheets in Iron Rust Containing Environments

Abstract

Corrosion mechanism of organic-composite-coated steel sheets (OCS) in iron rust containing environments was investigated. Cathodic current density of OCS increased and its corrosion potential changed to noble when iron rust was added to NaCl solution. Magnetite changed the corrosion potential of OCS to noble and accelerated its corrosion. It has been speculated that the degradation of corrosion resistance in iron rust containing environments is caused by the high cathodic current density on the surface of magnetite that has the higher electro-conductivity.