LDH Post-Treatment of Flash PEO Coatings

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Olmo, Rubén del and Mohedano Sánchez, Marta and Mingo, Beatriz and Arrabal Durán, Raúl and Matykina, Endzhe (2019) LDH Post-Treatment of Flash PEO Coatings. Coatings, 9 (6). p. 354. ISSN 2079-6412

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Official URL: https://doi.org/10.3390/coatings9060354




Abstract

This work investigates environmentally friendly alternatives to toxic and carcinogenic Cr (VI)-based surface treatments for aluminium alloys. It is focused on multifunctional thin or flash plasma electrolytic oxidation (PEO)-layered double hydroxides (LDH) coatings. Three PEO coatings developed under a current-controlled mode based on aluminate, silicate and phosphate were selected from 31 processes (with different combinations of electrolytes, electrical conditions and time) according to corrosive behavior and energy consumption. In situ Zn-Al LDH was optimized in terms of chemical composition and exposure time on the bulk material, then applied to the selected PEO coatings. The structure, morphology and composition of PEO coatings with and without Zn-Al-LDH were characterized using XRD, SEM and EDS. Thicker and more porous PEO coatings revealed higher amounts of LDH flakes on their surfaces. The corrosive behavior of the coatings was studied by electrochemical impedance spectroscopy (EIS). The corrosion resistance was enhanced considerably after the PEO coatings formation in comparison with bulk material. Corrosion resistance was not affected after the LDH treatment, which can be considered as a first step in achieving active protection systems by posterior incorporation of green corrosion inhibitors.


Item Type:Article
Uncontrolled Keywords:PEO; LDH; active protection; corrosion; aluminium
Subjects:Sciences > Chemistry > Materials
ID Code:66157
Deposited On:14 Jun 2021 15:09
Last Modified:15 Jun 2021 08:07

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