Confocal microscopy study and corrosion process: The Al-(HF,HNO3,HCl) system

Classical electro-chemical measurements do not give quantitative information on the morphology of corrosion process. In this paper, a complementary way to study the corrosion process using a confocal microscope and image analysis is proposed. By this way, the corrosion of aluminium by a mixture of acids was studied. To perform this analysis, morphological tools dedicated to grey tone images were used. The corrosion process was studied by several roughness and topological parameters. Their evolutions during corrosion process show that two opposite phenomena must be taken into account in this corrosion process: the minimisation of the energy and the dependence of the corrosion rate with the heterogeneities of the material (grains boundaries, dislocations networks, ...).