Hierarchically organized Li-Al-LDH nano-flakes: a low-temperature approach to seal porous anodic oxide on aluminum alloys
authors Mata, D; Serdechnova, M; Mohedano, M; Mendis, CL; Lamaka, SV; Tedim, J; Hack, T; Nixon, S; Zheludkevich, ML
nationality International
journal RSC ADVANCES
keywords LAYERED DOUBLE HYDROXIDE; ANION-EXCHANGE INTERCALATION; X-RAY-DIFFRACTION; CORROSION PROTECTION; TARTARIC ACID; FILMS; COATINGS; AA2024-T3; BEHAVIOR; ELECTROLYTES
abstract This work suggests a low-temperature sealing approach for tartaric-sulfuric acid (TSA) anodized AA2024 based on hierarchically organized Li-Al-layered double hydroxide (LDH) structures. The new proposed sealing is expected to be directly competitive to the standard hot water sealing (HWS) approaches because of its reduced treatment temperature and high protection efficiency. A hierarchical organization of in situ formed LDH nano-flakes across the depth length of the TSA pores, from the macrodown to the nano-size range, was observed with transmission electron microscopy (TEM). Electrochemical impedance spectroscopy (EIS) studies showed that the densely packed LDH arrangement at the porous oxide layer is directly related to the drastically improved barrier properties of TSA. Moreover, LDH flake-like structures worked as "smart" reservoirs for corrosion inhibiting vanadium species (VOx) that are released on demand upon the onset of corrosion. This was confirmed using a scanning vibrating electrode technique (SVET), giving relevant insights into the time-resolved release activity of VOx and the formation of the passivation layer on cathodic intermetallics, corroborated with EDX and analytical Raman spectroscopy. Passive and active corrosion protection was imparted to the anodic layer via new Li-Al-LDH structures with long-term protection exceeding that of standard HWS procedures.
publisher ROYAL SOC CHEMISTRY
issn 2046-2069
year published 2017
volume 7
issue 56
beginning page 35357
ending page 35367
digital object identifier (doi) 10.1039/c7ra05593e
web of science category Chemistry, Multidisciplinary
subject category Chemistry
unique article identifier WOS:000405811400050
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  impact metrics
journal impact factor (jcr 2016): 3.108
5 year journal impact factor (jcr 2016): 3.257
category normalized journal impact factor percentile (jcr 2016): 64.759
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