Print Email Facebook Twitter Surface engineering of aerospace aluminium alloys Title Surface engineering of aerospace aluminium alloys: Understanding alloying effects on chemical pre-treatment and sol-gel coating adhesion Author van Dam, J.P.B. (TU Delft Team Yaiza Gonzalez Garcia) Tiringer, U. (TU Delft Team Peyman Taheri; Jozef Stefan Institute) Abrahami, S.T. (TU Delft Team Shoshan Abrahami) Milošev, I. (Jozef Stefan Institute) Terryn, H.A. (Vrije Universiteit Brussel) Kovač, J. (Jozef Stefan Institute) Mol, J.M.C. (TU Delft Team Arjan Mol) Date 2024 Abstract The sol–gel process is a chemical surface preparation method based on hydrolysis and polycondensation reactions for enhanced adhesion for metallic substrates in adhesive bonding and coating applications. This paper describes an investigation into the effect of the microstructural complexity of two commonly used aerospace aluminium alloys (AAs) 2024-T3 and 7075-T6, on the response to different surface pre-treatments before deposition of the sol-gel coating and subsequent adhesive bonding. Different surface pre-treatments, including two abrasive treatments and three chemical surface pre-treatments were used, and their effect on surface chemistry, wettability and roughness was assessed. Surfaces were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, profilometry and static contact angles. A hybrid silane sol-gel film was deposited on the differently pre-treated aluminium alloys, an epoxy adhesive was applied and the adhesion properties were evaluated using pull-off testing. The role of the altered physicochemical properties of the pre-treated surfaces was related to the adhesion strength of the sol–gel reinforced epoxy/aluminium interfaces. The microstructural complexity of the aerospace alloys caused non-uniform responses to the pre-treatments, proving the importance of compatibility between material and treatment conditions. Statistical analysis revealed that, despite that overall higher adhesion values were obtained on rougher surfaces, only a strong correlation exists between the surface hydroxyl fraction and adhesion strength. The relation of roughness and water contact angle to interfacial adhesion was found to be non-significant. The findings of this study underscore the critical role of surface pre-treatments and their impact on adhesion strength in aerospace aluminium alloys, providing valuable insights for the effective utilization of sol-gel coatings in adhesive bonding and coating processes. Subject AdhesionAdhesiveAluminiumAluminium alloysSol-gelSurface chemistrySurface morphologySurface pre-treatmentWettability To reference this document use: http://resolver.tudelft.nl/uuid:a7b51c0e-73c8-4166-906d-8982cb8b6f3e DOI https://doi.org/10.1016/j.surfcoat.2024.130901 ISSN 0257-8972 Source Surface and Coatings Technology, 485 Part of collection Institutional Repository Document type journal article Rights © 2024 J.P.B. van Dam, U. Tiringer, S.T. Abrahami, I. Milošev, H.A. Terryn, J. Kovač, J.M.C. Mol Files PDF 1-s2.0-S0257897224005322-main.pdf 7.23 MB Close viewer /islandora/object/uuid:a7b51c0e-73c8-4166-906d-8982cb8b6f3e/datastream/OBJ/view