Electrochemical Noise Generation During Stress Corrosion Cracking of the High-Strength Aluminum AA 7075-T6 Alloy Available to Purchase

Electrochemical noise generation during stress corrosion cracking (SCC) of high-strength aluminum AA⁽¹⁾ 7075-T6 alloy has been investigated in 3.5% NaCl solution under free corrosion potential. The electrochemical noise was observed as spontaneous potential fluctuations. The readings obtained were analyzed using the maximum entropy method. In the results, the power spectra densities were found to decrease with an increase in frequency. A low frequency (LF) noise was obtained with all the specimens tested and it characteristically indicated LF or “flicker" noise. The noise generated from the corroding specimen/bulk solution interface was found, generally, to increase with the degree of corrosion. The cracking of the specimen gave the highest noise amplitudes in most cases; the cracking is also indicated by the highest standard deviation peaks. The results obtained for this aluminum alloy further show the corrosion cracking behavior to be consistent with the film rupture/anodic dissolution mechanism.