Print Email Facebook Twitter Corrosion Inhibition at Scribed Locations in Coated AA2024-T3 by Cerium- and DMTD-Loaded Natural Silica Microparticles under Continuous Immersion and Wet/Dry Cyclic Exposure Title Corrosion Inhibition at Scribed Locations in Coated AA2024-T3 by Cerium- and DMTD-Loaded Natural Silica Microparticles under Continuous Immersion and Wet/Dry Cyclic Exposure Author Denissen, P.J. (TU Delft Novel Aerospace Materials) Shkirskiy, Viacheslav (Institut de Recherche de Chimie Paris) Volovitch, Polina (Institut de Recherche de Chimie Paris) Garcia, Santiago J. (TU Delft Novel Aerospace Materials) Date 2020-05-20 Abstract Earlier studies on cerium-loaded naturally occurring silica microparticles (i.e., diatomaceous earth) demonstrated the potential to efficiently protect small scratches in epoxy-coated AA2024-T3 panels during relatively short immersion times. The current work investigates the potential of such inhibitor-loaded microparticles to protect wide and deep scribes (up to 1 mm wide) in long-time immersion testing and during cyclic (wet/dry) conditions. For this, cerium nitrate and 2,5-dimercaptothiadiazole (DMTD) were used as inorganic and organic corrosion inhibitors. The corrosion protection was evaluated using a hyphenated real-time optics/electrochemistry method and two individual local techniques measuring oxygen concentration and electrochemical impedance (LEIM) inside the scribe. SEM/EDS was used to analyze the samples after exposure. The results show significant levels of corrosion protection at damaged locations at low cerium concentrations (3.7 wt % Ce3+ relative to the total coating mass) during 30 days of immersion in salt solution. However, for a given scribe geometry, the protection was found to be dependent on the electrolyte volume with larger electrolyte/exposed metal ratios leading to short protection time. A partial replacement of the Ce3+ by DMTD in the microcarriers resulted in a higher degree of passivation than when DMTD was used alone. Wet/dry cyclic exposure tests showed that cyclic conditions can increase the buildup of stable inhibitor-containing layers in the case of cerium-loaded silica microparticles. This underlines the need for more research using wet/dry exposure conditions. Subject ceriumDMTDinhibitorlocal electrochemistryself-healing To reference this document use: http://resolver.tudelft.nl/uuid:44a04136-82a3-45bf-9cf1-29144404f91b DOI https://doi.org/10.1021/acsami.0c03368 ISSN 1944-8244 Source ACS applied materials & interfaces, 12 (20), 23417-23431 Part of collection Institutional Repository Document type journal article Rights © 2020 P.J. Denissen, Viacheslav Shkirskiy, Polina Volovitch, Santiago J. Garcia Files PDF acsami.0c03368.pdf 3.7 MB Close viewer /islandora/object/uuid:44a04136-82a3-45bf-9cf1-29144404f91b/datastream/OBJ/view