A study on pitting corrosion of aluminum alloy 2024-T3 by scanning microreference electrode technique

Micropitting corrosion of aluminum alloy 2024-T3 was investigated by using scanning microreference electrode technique combined with scanning electron microscopy and X-ray energy dispersive spectroscopy. It was found that the micropitting initiated immediately after the exposure of Al 2024–T3 to NaCl solution at open-circuit potential. Some corrosion active nuclei developed with time while others disappeared. Most of the micropits were found to be associated with the second phase particles, specially the S phase particles (Al2CuMg). Three types of corrosion behavior of Al2CuMg were discussed.