Hybrid sol–gel coatings doped with cerium nanocontainers for active corrosion protection of AA2024

• Published in: Progress in organic coatings Vol. 138; p. 105428
• Main Authors: Thai, Thu Thuy, Trinh, Anh Truc, Olivier, Marie-Georges
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-01-2020; Elsevier BV
• Subjects: AA2024; Aluminum; Aluminum base alloys; Cation exchanging; Cerium; Cerium salts; Chromates; Corrosion; Corrosion effects; Corrosion inhibitors; Corrosion prevention; EIS; Montmorillonite; Platelets; Polarization; Pretreatment; Salt spray tests; Sodium chloride; Sol-gel processes; Sol–gel coating; Substrates; Cerium salts; Corrosion; Montmorillonite; AA2024; EIS; Sol–gel coating
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2019.105428

•Cerium modified montmorillonite (CeMMT) is an efficient corrosion inhibitor for AA2024.•60 wt.% of cerium ions are released in 0.1 M NaCl from modified nanoclays.•CeMMT improves the barrier properties of the doped sol–gel film applied on AA2024.•Cerium ions provide an active corrosion protection to the doped sol–gel film.
This work presents a new approach to develop protective pre-treatment for AA2024 based on the inhibitor efficiency of cerium ions which are considered as a promising alternative to replace chromate compounds. The inhibition properties of cerium salts for improving the anti-corrosion performance of AA2024 have been characterized by polarization curves and EIS measurements. Cerium ions were inserted into nanoclays platelets by cationic-exchange reactions (CeMMT). XRD analysis proved the presence of cerium ions intercalated into clay structure. EIS measurements and polarization curves highlighted a high corrosion inhibition effect of cerium-modified nanoclays. This effectiveness can be related to the release of 60% of cerium ions from CeMMT structure in sodium chloride as determined by UV–vis measurements. Salt spray test made on scratched sol–gel samples indicated a self-healing effect of cerium ions which provide an active corrosion protection to aluminum substrate. EIS measurements revealed that hybrid sol–gel films doped with CeMMT improve barrier properties and anticorrosion protection of aluminum 2024 substrate.