CONICET | Buscador de Institutos y Recursos Humanos

Based on extensive scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDAX) on aeronautical aluminum alloys a new microbial influenced corrosion (MIC) mechanism was demonstrated. The first evidence of the fungus Hormoconis resinae chemosensing capacity as the MIC driving force was published in 1990. Electrochemical results obtained since the seventies in aqueous cultures as well as in water drained from contaminated aircraft fuel tanks were interpreted as the addition of various corrosion processes. The supposed stochastic microbial colonization of alloy surfaces, as suggested by certain authors during these studies, was clarified when microscopic observation coupled to EDAX demonstrated a direct correlation between colonization sites with determined phases or inclusions on different alloy samples. However, the revealing main factor, associated to the always localized attack on secondary phases of the alloys was demonstrated well afterwards, when the drop test was added to these corrosion studies. Updated information has since provided a different approach to the problem through SEM and EDAX. The apparent MIC random attack distribution was found to be caused by the secondary phase localization through the alloys during their solidification and not by the microbial attack on the corresponding site.