Effect of Precipitates on Filiform Corrosion Growth of Al-Mg-Si-Cu Alloy

Abstract

The effect of precipitates on filiform corrosion （FFC） growth of coated Al-Mg-Si-Cu alloys with different coolings and chemical components was investigated using a cyclic corrosion test and dynamic polarization in an acid solution. Total FFC growth was accelerated by air cooling, while being suppressed by water quenching for high Cu contained Al alloy. Comparing water quenching with air cooling, cathodic current densities and the number of precipitates including Cu were lower after water quenching at high Cu contained Al alloy. These results suggest that suppression of precipitates including Cu improves FFC growth resistance of Al-Mg-Si-Cu alloys.