Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study

This study reports the development of novel, sustainable bionanocomposite coatings for AA2024-T3 aluminium alloy, achieved by integrating eco-friendly carbon–sepiolite nanofillers within chitosan and zein biopolymer matrices. The carbon–clay filler was prepared by impregnating a suspension containin...

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Autores: Barra, Ana, García-Galván, Federico, Galván Sierra, Juan Carlos, Nunes, Cláudia, Ferreira, Paula, Ruiz-Hitzky, Eduardo
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/400745
Acceso en línea:http://hdl.handle.net/10261/400745
https://api.elsevier.com/content/abstract/scopus_id/105012413095
Access Level:acceso abierto
Palabra clave:Carbon-clay
Bionanocomposite coatings
Sepiolite
Hybrid sol-gel coatings
AA2024-T3 aluminium alloy
Corrosion protection
Electrochemical impedance spectroscopy
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spelling Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical studyBarra, AnaGarcía-Galván, FedericoGalván Sierra, Juan CarlosNunes, CláudiaFerreira, PaulaRuiz-Hitzky, EduardoCarbon-clayBionanocomposite coatingsSepioliteHybrid sol-gel coatingsAA2024-T3 aluminium alloyCorrosion protectionElectrochemical impedance spectroscopyThis study reports the development of novel, sustainable bionanocomposite coatings for AA2024-T3 aluminium alloy, achieved by integrating eco-friendly carbon–sepiolite nanofillers within chitosan and zein biopolymer matrices. The carbon–clay filler was prepared by impregnating a suspension containing multiwalled carbon nanotubes and liquid caramel into sepiolite clay, being the graphitization of caramel performed by hydrothermal treatment (180 °C for 18 h) followed by pyrolysis (550 °C for 1 h). The resultant carbon-sepiolite filler was blended with chitosan or zein matrices to obtain bionanocomposite suspensions. Thin bionanocomposite layers were deposited by dip-coating on the metal aluminium alloy surfaces, and selected samples were sealed with a hybrid organic–inorganic sol–gel topcoat to eliminate inherent porosity and boost passive corrosion resistance. The hybrid coating was prepared from a mixture of tetramethyl orthosilicate (TMOS) and γ-methacryloxypropyltrimethoxysilane (MAPTMS), used as alkoxysilane precursors. Electrochemical impedance spectroscopy (EIS) as a rigorous, non-destructive methodology for assessing the coatings' protective performance against corrosion. EIS analysis revealed a clear two-stage degradation and protection mechanism: initially, the sol–gel layer provides a robust passive barrier, and upon its gradual deterioration, the underlying bionanocomposite film activates active corrosion inhibition via physical obstruction and controlled release of functional additives. Field-emission scanning electron microscopy confirmed the integrity, uniformity, and adherence of both monolayer and bilayer systems before and after immersion tests. Electrochemical studies revealed that the degradation process of these coatings occurs in two distinct stages. In the initial stage, the top sol-gel coating primarily provides a barrier effect. Once this layer deteriorates, an active corrosion protection mechanism from the bionanocomposite film is activated. These results demonstrate that the synergy between advanced material design and electrochemical characterization can yield high-performance, environmentally responsible coatings. The innovative carbon–sepiolite bionanocomposite approach, validated by EIS, offers superior corrosion resistance and represents a promising alternative to conventional chromate-based inhibitors in demanding engineering applications.NoElsevierGalván Sierra, Juan Carlos [0000-0002-8841-9716]Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202520252025info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Preprintinfo:eu-repo/semantics/submittedVersionapplication/pdfhttp://hdl.handle.net/10261/400745https://api.elsevier.com/content/abstract/scopus_id/105012413095reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1016/j.clay.2025.107955Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/4007452026-05-22T06:33:51Z
dc.title.none.fl_str_mv Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
title Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
spellingShingle Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
Barra, Ana
Carbon-clay
Bionanocomposite coatings
Sepiolite
Hybrid sol-gel coatings
AA2024-T3 aluminium alloy
Corrosion protection
Electrochemical impedance spectroscopy
title_short Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
title_full Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
title_fullStr Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
title_full_unstemmed Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
title_sort Bionanocomposite coatings incorporating carbon-sepiolite within biopolymer matrices for corrosion protection of aluminium alloys: an electrochemical study
dc.creator.none.fl_str_mv Barra, Ana
García-Galván, Federico
Galván Sierra, Juan Carlos
Nunes, Cláudia
Ferreira, Paula
Ruiz-Hitzky, Eduardo
author Barra, Ana
author_facet Barra, Ana
García-Galván, Federico
Galván Sierra, Juan Carlos
Nunes, Cláudia
Ferreira, Paula
Ruiz-Hitzky, Eduardo
author_role author
author2 García-Galván, Federico
Galván Sierra, Juan Carlos
Nunes, Cláudia
Ferreira, Paula
Ruiz-Hitzky, Eduardo
author2_role author
author
author
author
author
dc.contributor.none.fl_str_mv Galván Sierra, Juan Carlos [0000-0002-8841-9716]
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Carbon-clay
Bionanocomposite coatings
Sepiolite
Hybrid sol-gel coatings
AA2024-T3 aluminium alloy
Corrosion protection
Electrochemical impedance spectroscopy
topic Carbon-clay
Bionanocomposite coatings
Sepiolite
Hybrid sol-gel coatings
AA2024-T3 aluminium alloy
Corrosion protection
Electrochemical impedance spectroscopy
description This study reports the development of novel, sustainable bionanocomposite coatings for AA2024-T3 aluminium alloy, achieved by integrating eco-friendly carbon–sepiolite nanofillers within chitosan and zein biopolymer matrices. The carbon–clay filler was prepared by impregnating a suspension containing multiwalled carbon nanotubes and liquid caramel into sepiolite clay, being the graphitization of caramel performed by hydrothermal treatment (180 °C for 18 h) followed by pyrolysis (550 °C for 1 h). The resultant carbon-sepiolite filler was blended with chitosan or zein matrices to obtain bionanocomposite suspensions. Thin bionanocomposite layers were deposited by dip-coating on the metal aluminium alloy surfaces, and selected samples were sealed with a hybrid organic–inorganic sol–gel topcoat to eliminate inherent porosity and boost passive corrosion resistance. The hybrid coating was prepared from a mixture of tetramethyl orthosilicate (TMOS) and γ-methacryloxypropyltrimethoxysilane (MAPTMS), used as alkoxysilane precursors. Electrochemical impedance spectroscopy (EIS) as a rigorous, non-destructive methodology for assessing the coatings' protective performance against corrosion. EIS analysis revealed a clear two-stage degradation and protection mechanism: initially, the sol–gel layer provides a robust passive barrier, and upon its gradual deterioration, the underlying bionanocomposite film activates active corrosion inhibition via physical obstruction and controlled release of functional additives. Field-emission scanning electron microscopy confirmed the integrity, uniformity, and adherence of both monolayer and bilayer systems before and after immersion tests. Electrochemical studies revealed that the degradation process of these coatings occurs in two distinct stages. In the initial stage, the top sol-gel coating primarily provides a barrier effect. Once this layer deteriorates, an active corrosion protection mechanism from the bionanocomposite film is activated. These results demonstrate that the synergy between advanced material design and electrochemical characterization can yield high-performance, environmentally responsible coatings. The innovative carbon–sepiolite bionanocomposite approach, validated by EIS, offers superior corrosion resistance and represents a promising alternative to conventional chromate-based inhibitors in demanding engineering applications.
publishDate 2025
dc.date.none.fl_str_mv 2025
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Preprint
info:eu-repo/semantics/submittedVersion
format article
status_str submittedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/400745
https://api.elsevier.com/content/abstract/scopus_id/105012413095
url http://hdl.handle.net/10261/400745
https://api.elsevier.com/content/abstract/scopus_id/105012413095
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1016/j.clay.2025.107955
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,81155

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