Morphology Characterization and Kinetics Evaluation of Pitting Corrosion of Commercially Pure Aluminium by Digital Image Analysis

Marinalda C. Pereira, José W. J. Silva, Heloisa A. Acciari, Eduardo N. Codaro, Luis R. O. Hein

Department of Materials and Technology, S?o Paulo State University, S?o Paulo, Brazil.
Department of Physics and Chemistry, S?o Paulo State University, S?o Paulo, Brazil.

DOI: 10.4236/msa.2012.35042                

Abstract

The pit morphology and growth kinetics of commercially pure aluminium in naturally aerated NaCl solutions were studied using an image processing method based on reflected light microscopy. In order to distinguish between pits and pre-existing cavities, metallographic examination and statistical analysis were carried out before and after corrosion testing. The results show that the pit shapes and sizes are more dependent on the immersion time than the chloride concentration. Pits are predominantly hemispherical, but they undergo reasonable geometric transitions associated with increased immersion time and occur without significant depth variation. The role of chloride ions is more closely associated with the pit nucleation phenomenon.

Keywords

Aluminium; Alloys; Pitting Corrosion; Morphology Characterization; NaCl Solution; Image Processing

Conflicts of Interest

The authors declare no conflicts of interest.

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