A corrosion protection coating for AA2024-T3 composed of a blend of camphorsulfonate-doped poly(aniline) (PANI) and poly(methylmethacrylate) (PMMA) is described. The open-circuit potential (OCP) for the bare and coated alloy in H2SO4 solutions is presented vs. time. Raman spectroscopy revealed the oxidation state of the PANI component of the blend, both on undamaged films and as a function of distance away from a scratch on purposefully damaged films. The open-circuit and Raman data show galvanic coupling between the coating and the alloy, causing reduction of the PANI component. Scanning electrochemical microscopy was used to monitor H-2 evolution over a scratch on the surface of either PANI blend or PMMA films coated on AA2024. These experiments show that the scratched surface is highly active toward H-2 evolution when coated with only a PMMA film. In contrast, the blend coating drastically suppresses the amount of H-2 evolution in a scratch. This suppression of H-2 evolution was mimicked by poising the OCP of the PMMA-coated alloy at the same value at which it is poised by the PANI-containing film. It is shown that camphorsulfonate anion has no inhibitory effect on H-2 evolution in scratches on PMMA-coated AA2024. (C) 2004 The Electrochemical Society. All rights reserved.