Influence of chloride ions concentration on the development of severe localised corrosion and its effects on the electrochemical response of the 2198-T8 alloy

Abstract

The development of severe localised corrosion (SLC) on the 2198-T8 alloy was investigated in solutions of various NaCl concentrations (0.001, 0.005 and 0.01 mol L −1 ). Immersion tests, optical profilometry, conventional and local electrochemical analyses were performed to evaluate the corrosion behaviour of the alloy. Immersion tests showed that the alloy is susceptible to SLC in all conditions, although the pits sizes were dependent on the solution concentration. The largest anodic areas, corresponding to SLC sites, were observed for the sample immersed in 0.001 mol L −1 NaCl, whereas pits with similar sizes were observed for the samples immersed in solutions with 0.005 and 0.01 mol L −1 of NaCl. Moreover, the maximum depth of attack was observed for the sample immersed in 0.001 mol L −1 NaCl. These results were in agreement with the scanning ionselective electrode technique (SIET) maps which showed stronger acidification on the sample exposed to 0.001 mol L −1 NaCl solution.

Comparative study on mechanism of DC and AC current on corrosion of copper–aluminium composites

“…As is reported in the literature, the corrosion of the aluminium matrix is a cyclic process: pitting → passive film folding and cracking → corrosion product accumulation → corrosion product shedding → new pitting. 24,25 The mechanism of salt spray accelerated corrosion is the formation of a liquid film containing aggressive Cl − ions on the surface of the sample. The Cl − ions will improve the overall corrosion rate of the material by accelerating the pitting corrosion of the aluminium matrix and the shedding of corrosion products.…”

Correlating corrosion modes with the microstructure of the 2XXX series alloys: A comparative approach

“…According to the literature, the T1 phase (Al‐Cu‐Li) is initially anodic relative to the matrix, 8,13,21 because of its high reactivity, Li is preferentially dissolved resulting in copper enrichment, leading to reversal polarity, and, ultimately, to dissolution of the Al matrix 8,13,22,23 . The literature indicates development of severe localized corrosion in Al‐Cu‐Li alloys when exposed a corrosive solutions 17,24,25 . Machado et al 24 displayed the development of severe localized corrosion on AA2198‐T851 even in low concentration sodium chloride solution (0.001 M).…”

“…8,13,22,23 The literature indicates development of severe localized corrosion in Al-Cu-Li alloys when exposed a corrosive solutions. 17,24,25 Machado et al 24 displayed the development of severe localized corrosion on AA2198-T851 even in low concentration sodium chloride solution (0.001 M). Milagre et al showed severe types of corrosion, pitting, trenching, and intergranular attack, on the AA2098-T351 after exposition in 0.005 Mxl À1 NaCl.…”