Inhibition of Filiform Corrosion on Polymer Coated AA2024-T3 by Hydrotalcite-Like Pigments Incorporating Organic Anions

Abstract

Benzotriazolate, ethyl xanthate, and oxalate anion-exchanged hydrotalcite (HT) pigments are evaluated with respect to their ability to inhibit filiform corrosion (FFC) on organic coated AA2024-T3 aluminum alloy. Following FFC initiation by application of aqueous HCl to a penetrative coating defect, the time-dependent extent of coating delamination was determined both optically and by repeated in situ measurements performed using a scanning Kelvin probe (SKP). Inhibitor efficiency is shown to increase in the order ethyl Benzotriazolate is also shown to interact specifically with the alloy surface, depressing Volta potential values by up to 0.4 V. © 2004 The Electrochemical Society. All rights reserved.