2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 9: Physics, Advanced Materials, Multifunctional Materials
| Editors: | Kongoli F, Dubois JM, Gaudry E, Fournee V, Marquis F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 275 pages |
| ISBN: | 978-1-987820-32-4 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Smart Functional Coatings for Corrosion Protection of AA2024 Alloys
Fatima Montemor1; Rodrigo Della Noce1;1INSTITUTO SUPERIOR TECNICO, Lisbon, Portugal;
Type of Paper: Regular
Id Paper: 238
Topic: 22
Abstract:
Light alloys such as AA2024 alloy has found various applications in the transportation industry due to the relatively high strength-to-weight ratio. The precipitation nucleation of intermetallic particles during the manufacturing of the alloy results in the high strength as well as susceptibility towards localized corrosion. One of the most effective strategies to protect the AA2024 alloy consists on the application of chromate-based conversion coatings or on the application of organic coatings modified with chromate-based anti-corrosion pigments. However, chromates are being slowly discarded due to the growing environmental concerns and their carcinogenic effects. Thus, there is a need to find alternative systems that can replace the use of hexavalent chromium pigments.<br />Presently, the design and development of self-healing coatings are considered powerful alternatives for corrosion protection of metallic structures. To guarantee effective corrosion protection, the coating matrices can be modified with smart particles, or smart containers, loaded with corrosion inhibitors that can be triggered by external stimulus, releasing the inhibitor to the active sites. <br />In this work, two different pH sensitive additives were explored as potential smart systems to design self-healing coatings for corrosion protection of AA2024 alloys. The pH sensitive particles were added to commercial water based epoxy primer, individually, or by combining the two types of containers loaded with different corrosion inhibitors, to study the active corrosion protection properties in coatings of industrial relevance.<br />The anticorrosion activity of these additives was investigated by electrochemical impedance spectroscopy and localized electrochemical impedance spectroscopy. The results reveal that an enhancement of the active protection effect can be reached when additives loaded with different inhibitors are combined in the same protective system.