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Pitting Corrosion Mechanisms and Characteristics of Aluminum in Solar Heating Systems
Author(s) -
Liang ChengHao,
Zhang Wei
Publication year - 2006
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200600039
Subject(s) - corrosion , pitting corrosion , fractal dimension , chemistry , aluminium , immersion (mathematics) , tap water , fractal , metallurgy , ion , analytical chemistry (journal) , materials science , environmental chemistry , environmental engineering , mathematical analysis , mathematics , organic chemistry , engineering , pure mathematics
Abstract The complex characteristics and mechanisms of aluminum pitting corrosion in a solar heating system were studied by the chemical immersion method and electrochemical techniques as well as fractal theory. The results showed that pitting corrosion of Al occurred in a tap water environment due to the local enrichment of Cl − ions. The higher the Cl − ions concentration, the more negative the critical pitting potential ( E b ) of Al. A linear relationship between E b and the logarithm of Cl − ions concentration was observed. The pitting corrosion mechanism of Al in neutral water was explained in terms of complexation corrosion theory. The corrosion surface images of aluminum immersed in tap water were captured and analyzed by image processing technique and box‐dimension method. The fractal characteristics of pit distribution, described by fractal dimension, have been identified. The fractal dimension of the pit distribution increased with the increase of immersion time and had the same trend as that of the weight loss. Fractal dimension can, thus, be used as an important parameter for quantitative evaluation of pitting corrosion of aluminum.