Polypyrrole film on 55% Al-Zn-coated steel for corrosion prevention

For corrosion protection of 55% Al-Zn-coated steel, a dense polypyrrole (PPy) film is electrochemically formed on 55% Al-Zn-coated steel in an acidic tartrate solution under constant current control. The film potentially consists of an inner layer of aluminium and/or zinc oxide and an outer PPy layer doped with tartrate anions. The PPy layer can maintain passivation of 55% Al-Zn-coated steel in a 3.5 wt.% NaCl aqueous solution and protected the steel for several hours. The doping of molybdate anions into the PPy-tartrate film greatly improved the film's protective properties. (C) 2011 Elsevier Ltd. All rights reserved.