Study of the Corrosion Mechanism and Corrosion Inhibition of 2024 Aluminum Alloy by SKPFM Technique
Aluminum alloys have found many applications in different branches of industry. In spite of the valuable properties, there is a significant drawback because of the strong corrosion susceptibility, especially in chloride-containing medium. The present work is focused on study of the 2024 aluminum alloy corrosion mechanism on early stages using Scanning Kelvin Probe Force Microscopy (SKPFM). The corrosion impact was studied measuring the Volta potential (VP) and topography of alloy matrix and S-phase intermetallics after immersion in different electrolytes and pH. It is shown that presence of the chloride anions in the electrolyte leads to increase of aluminum matrix potential for about 100 mV. This can be resulted from the adsorption of chloride ions and their incorporation into the native oxide layer changing semiconductive properties of the oxide. The zones surrounding the S-phase intermetallics are changed more significantly demonstrating higher increase of VP close to the inclusion. These regions are correlated with the increased oxygen content suggesting formation of thicker oxide layer due to local polarization. Addition of an inhibitor to electrolyte also leads to change in Volta potential that is reflected on lower corrosion impact of aggressive environment.
António Torres Marques, António Fernando Silva, António Paulo Monteiro Baptista, Carlos Sá, Fernando Jorge Lino Alves, Luís Filipe Malheiros and Manuel Vieira
K.A. Yasakau et al., "Study of the Corrosion Mechanism and Corrosion Inhibition of 2024 Aluminum Alloy by SKPFM Technique", Materials Science Forum, Vols. 587-588, pp. 405-409, 2008