Inhibition of Localized Corrosion of Hot Dip Galvanized Steel by Phenylphosphonic Acid

Abstract

Phenylphosphonic acid (H2PP) is investigated as a corrosion inhibitor of hot dip galvanized steel (HDG) fully immersed in a 5% (w/v) sodium chloride electrolyte. An in-situ Scanning Vibrating Electrode Technique (SVET) is used where concentrations of H2PP are systematically added to the electrolyte in neutral conditions. H2PP, at a concentration of 5 × 10−2 mol dm−3, is shown to effectively inhibit localized corrosion over a 24 h period with 96% efficiency. H2PP is compared with a sodium phosphate (Na3PO4) inhibitor at the same concentration over a wide pH range