FILIFORM INVESTIGATIONS ON ALUMINUM ALLOY 2024-T3

摘要

The advancement of filiform corrosion (FFC) on aluminum alloys is not yet fully understood. To increase our understanding of the various roles of conversion coatings, pigmented coatings and intermetallic particles in the alloy matrix, we have investigated filiform filaments as well as corroded surfaces. Alloy surfaces free of coatings (either prior to coating or removed following FFC) were examined through optical microscopy, SEM and TOF-SIMS. The Sanchem pre-treatment, in combination with surface chromating, was found to be most effective in reducing FFC. Chromate-containing pigments in coatings proved to be the most successful for preventing wide spread corrosion although the resulting corrosion morphology on these samples is quite unlike that of FFC. The role of intermetallic particles in filiform propagation was further investigated with Al-Cu model samples which indicated that FFC could be generated with such samples.