Examinando por Autor "Montemor, M.F."

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Functionalized graphene – Modified sol-gel coatings: Controlling the degradation of bioresorbable AZ31 magnesium alloy for biomedical applications
(Elsevier, 2025-05-21) Fernández-Hernán, J.P.; Alves, M.M.; Taryba, M.G.; Montemor, M.F.; Torres, B.; Rams, J.
The fast degradation of Mg alloys requires strategies tailored for the controlled delay of corrosion. Pristine hybrid silica sol-gel coatings (SG) and sol-gel coatings doped with 0.05 wt% COOH-functionalized graphene nanoplatelets (SG + GNP) were successfully generated on AZ31 magnesium alloy substrates by dip-coating. The physicochemical properties and the anticorrosion behaviour of the coatings were evaluated by Field Emission Gun – Scanning Electron Microscope (FEG-SEM), Energy Dispersive Spectroscopy (EDS), ASTM D3359 standard adhesion tests, scanning vibrating electrode technique (SVET), scanning ion-selective electrode technique (SIET), and electrochemical impedance spectroscopy (EIS). Both coatings improved the behaviour in terms of localized and general corrosion, with the SG + GNP coating offering better protection. The presence of the COOHfunctionalized graphene nanoplatelets enhanced the mechanical properties of the sol-gel coating, improving their adhesion resistance and making them less brittle, and therefore offering a better barrier effect and anticorrosion protection. Also, high Ca–P accumulations were found after corrosion tests on both sol-gel coatings, indicative of in-vitro biocompatibility. Thus, SG + GNP coatings can enhance corrosion resistance and biocompatibility of magnesium alloys for biomedical applications.