Influence of Bath Composition on the Corrosion Resistance of Autodeposited Organic Coatings

摘要

Autodeposition of organic coatings on metal surfaces is used for corrosion prevention in many branches of industry. The main advantages are its simplicity, ease of operation, low energy costs, and no volatile organic compounds. Furthermore the thickness of the coating is uniform regardless of the sample's shape. The autodeposition process consists of cleaning the metal surface, water rinsing, coating in the autodeposition bath, water rinsing, and curing. The coating process is due to multivalent metal ions produced by the oxidation of the metal surface, which destabilize the dispersion polymer particles. Typically an autodeposition bath consists of an acidic water emulsion of a polymer, to which an oxidant, a complexing agent, and an emulsifier are added. The oxidant is usually hydrogen peroxide.