Filiform corrosion of aluminium sheet. II. Electrochemical and corrosion behaviour of bare substrates

摘要: Abstract Colled rolled aluminium substrates of the AA1000, 3000 and 8000 series in various tempers were characterized by corrosion potential (Ecorr) potentiostatic measurements an acidic chloride solution. The time dependence these data indicated presence active surface layer on annealed that susceptible to filiform (FFC) after painting. This was electrochemically more than bulk material whose Ecorr stable at well known critical pitting (Ec) alloy. substrate negative Ec metal immediately exposure test solution, rising with immersion time, as dissolved Analogously, high anodic current transients, decaying lower steady-state values equivalent amount (of order 1 μm thickness) removed from surface. reactivity layers, quantified this manner, depended chemical composition same way susceptibility layers FFC.