Corrosion of packaged galvanised steel analysed by capillary electrophoresis

Abstract

While many failure analyses have been successfully performed using conventional analytical tools, there are cases in which the corrosive agent responsible cannot be unambiguously identified. In some cases this is due to the lack of a technique that allows the speciation of the solution very close to the metal surface during the corrosive attack. The results of the application of capillary electrophoresis, an advanced solution analysis technique, to the corrosion failure of outdoor electrical enclosures is presented. It is shown that the corrosion was due to vapour phase attack by organic acids (mainly acetic acid). It is most likely that these acids originated from the seasoning of the oak pallets used to transport the manufactured products. The acid vapours accumulated inside the packages owing to the shrinkwrap used to bind the packages to the oak pallet. This work demonstrates the utility of a simple ‘trinse and analyse’ approach in assisting in the determination of both the identity of the corrosive species and their likely origin.