Mechanism of corrosion inhibition of AA2024 by rare-earth compounds
authors Yasakau, KA; Zheludkevich, ML; Lamaka, SV; Ferreira, MGS
nationality International
journal JOURNAL OF PHYSICAL CHEMISTRY B
keywords ALUMINUM-ALLOY 2024-T3; SOL-GEL COATINGS; PROBE FORCE MICROSCOPY; PITTING CORROSION; NACL SOLUTION; ATOMIC-FORCE; AL2CUMG; BEHAVIOR; 2024-ALUMINUM-ALLOY; PERFORMANCE
abstract The mechanism of corrosion protection of the widely used 2024-T3 aluminum alloy by cerium and lanthanum inhibitors in chloride media is described in detail in the present work. The corrosion process was investigated by means of scanning Kelvin probe force microscopy (SKPFM), in situ atomic force microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy. Employment of the high-resolution and in situ techniques results in a deep understanding of the details of the physical chemistry and mechanisms of the corrosion processes. The applicability of the SKPFM for mechanistic analysis of the effect of different corrosion inhibitors is demonstrated for the first time. The inhibitors under study show sufficient hindering of the localized corrosion processes especially in the case of pitting formation located around the intermetallic S-phase particles. The main role of Ce3+ and La3+ in the corrosion protection is formation of hydroxide deposits on S-phase inclusions buffering the local increase of pH, which is responsible for the acceleration of the intermetallics dealloying. The formed hydroxide precipitates can also act as a diffusion barrier hindering the corrosion processes in active zones. Cerium nitrate exhibits higher inhibition efficiency in comparison with lanthanum nitrate. The higher effect in the case of cerium is obtained due to lower solubility of the respective hydroxide. A detailed mechanism of the corrosion process and its inhibition is proposed based on thermodynamic analysis.
publisher AMER CHEMICAL SOC
issn 1520-6106
year published 2006
volume 110
issue 11
beginning page 5515
ending page 5528
digital object identifier (doi) 10.1021/jp0560664
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000236294300052
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journal analysis (jcr 2019):
journal impact factor 2.857
5 year journal impact factor 2.88
category normalized journal impact factor percentile 50.629
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