The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions

Autores
Tomachuk, C. R.; Culcasi, José Daniel; Elsner, Cecilia Ines; Costa, Isolda; Di Sarli, Alejandro Ramón
Año de publicación
2014
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Electroplated zinc coatings have been largely employed as active galvanic protection for steel substrates. However, as zinc is highly electrochemically active, its corrosion rate may be very high. For this reason, a post treatment to increase the lifetime of the coatings is necessary, which, in industrial practice, consists of immersion in a chemical bath that forms a conversion layer on plated zinc. This layer must be a dielectric passive coating with high corrosion resistance that also offers good adherence to paints. The main problem of conventionally used post treatments is the presence of Cr6+ salts which are carcinogenic substances whose usage was forbidden by European regulations. In this work the effect of trivalent chromium and Co ions in solution of passivation treatments on the corrosion resistance of electrogalvanised steel has been investigated in 0.1 M Na2SO4 solution by electrochemical impedance spectroscopy (EIS) and polarization curves. Prior and after the corrosion tests, the chemical composition and morphology of the electrogalvanised surface was characterized by SEM and XPS. The EIS results showed that impedance values associated to the surface with Cr3+ + Co treatments were inferior to those exhibited by the Cr6+ treated ones. The higher impedances related to the Cr6+ samples could be explained by the self-healing effect of this type of coating. The SEM analyses revealed coating cracks associated to the surface of the Cr6+ treated samples whereas for those treated in the Cr3+ + Co solution, elongated fissures were seen. These last samples presented inferior corrosion resistance to that of the Cr6+ passivated ones. The cobalt addition to the trivalent chromium containing solution was not sufficient to increase the corrosion resistance to acceptable levels in comparison to the Cr6+ conversion coating.
Fil: Tomachuk, C. R.. Universidade de Sao Paulo; Brasil
Fil: Culcasi, José Daniel. Universidad Nacional de La Plata. Facultad de Ingeniería. Departamento de Mecánica. Laboratorio de Investigación de Metalurgia Física; Argentina
Fil: Elsner, Cecilia Ines. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina
Fil: Costa, Isolda. Universidade de Sao Paulo; Brasil
Fil: Di Sarli, Alejandro Ramón. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina
65th Annual Meeting of the International Society of Electrochemistry
Lausanne
Suiza
International Society of Electrochemistry
Materia
GALVANIZED STEEL
COATINGS
PASSIVATION
TRIVALENT CHROMIUM
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/239147

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network_name_str CONICET Digital (CONICET)
spelling The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ionsTomachuk, C. R.Culcasi, José DanielElsner, Cecilia InesCosta, IsoldaDi Sarli, Alejandro RamónGALVANIZED STEELCOATINGSPASSIVATIONTRIVALENT CHROMIUMhttps://purl.org/becyt/ford/2.5https://purl.org/becyt/ford/2Electroplated zinc coatings have been largely employed as active galvanic protection for steel substrates. However, as zinc is highly electrochemically active, its corrosion rate may be very high. For this reason, a post treatment to increase the lifetime of the coatings is necessary, which, in industrial practice, consists of immersion in a chemical bath that forms a conversion layer on plated zinc. This layer must be a dielectric passive coating with high corrosion resistance that also offers good adherence to paints. The main problem of conventionally used post treatments is the presence of Cr6+ salts which are carcinogenic substances whose usage was forbidden by European regulations. In this work the effect of trivalent chromium and Co ions in solution of passivation treatments on the corrosion resistance of electrogalvanised steel has been investigated in 0.1 M Na2SO4 solution by electrochemical impedance spectroscopy (EIS) and polarization curves. Prior and after the corrosion tests, the chemical composition and morphology of the electrogalvanised surface was characterized by SEM and XPS. The EIS results showed that impedance values associated to the surface with Cr3+ + Co treatments were inferior to those exhibited by the Cr6+ treated ones. The higher impedances related to the Cr6+ samples could be explained by the self-healing effect of this type of coating. The SEM analyses revealed coating cracks associated to the surface of the Cr6+ treated samples whereas for those treated in the Cr3+ + Co solution, elongated fissures were seen. These last samples presented inferior corrosion resistance to that of the Cr6+ passivated ones. The cobalt addition to the trivalent chromium containing solution was not sufficient to increase the corrosion resistance to acceptable levels in comparison to the Cr6+ conversion coating.Fil: Tomachuk, C. R.. Universidade de Sao Paulo; BrasilFil: Culcasi, José Daniel. Universidad Nacional de La Plata. Facultad de Ingeniería. Departamento de Mecánica. Laboratorio de Investigación de Metalurgia Física; ArgentinaFil: Elsner, Cecilia Ines. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Costa, Isolda. Universidade de Sao Paulo; BrasilFil: Di Sarli, Alejandro Ramón. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina65th Annual Meeting of the International Society of ElectrochemistryLausanneSuizaInternational Society of ElectrochemistryInternational Society of Electrochemistry2014info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObjectCongresoBookhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/239147The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions; 65th Annual Meeting of the International Society of Electrochemistry; Lausanne; Suiza; 2014; 1-1CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.ise-online.org/ise-conferences/annmeet/folder/2014-LAUSANNE-BoA.pdfInternacionalinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:46:08Zoai:ri.conicet.gov.ar:11336/239147instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:46:08.776CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
title The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
spellingShingle The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
Tomachuk, C. R.
GALVANIZED STEEL
COATINGS
PASSIVATION
TRIVALENT CHROMIUM
title_short The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
title_full The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
title_fullStr The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
title_full_unstemmed The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
title_sort The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions
dc.creator.none.fl_str_mv Tomachuk, C. R.
Culcasi, José Daniel
Elsner, Cecilia Ines
Costa, Isolda
Di Sarli, Alejandro Ramón
author Tomachuk, C. R.
author_facet Tomachuk, C. R.
Culcasi, José Daniel
Elsner, Cecilia Ines
Costa, Isolda
Di Sarli, Alejandro Ramón
author_role author
author2 Culcasi, José Daniel
Elsner, Cecilia Ines
Costa, Isolda
Di Sarli, Alejandro Ramón
author2_role author
author
author
author
dc.subject.none.fl_str_mv GALVANIZED STEEL
COATINGS
PASSIVATION
TRIVALENT CHROMIUM
topic GALVANIZED STEEL
COATINGS
PASSIVATION
TRIVALENT CHROMIUM
purl_subject.fl_str_mv https://purl.org/becyt/ford/2.5
https://purl.org/becyt/ford/2
dc.description.none.fl_txt_mv Electroplated zinc coatings have been largely employed as active galvanic protection for steel substrates. However, as zinc is highly electrochemically active, its corrosion rate may be very high. For this reason, a post treatment to increase the lifetime of the coatings is necessary, which, in industrial practice, consists of immersion in a chemical bath that forms a conversion layer on plated zinc. This layer must be a dielectric passive coating with high corrosion resistance that also offers good adherence to paints. The main problem of conventionally used post treatments is the presence of Cr6+ salts which are carcinogenic substances whose usage was forbidden by European regulations. In this work the effect of trivalent chromium and Co ions in solution of passivation treatments on the corrosion resistance of electrogalvanised steel has been investigated in 0.1 M Na2SO4 solution by electrochemical impedance spectroscopy (EIS) and polarization curves. Prior and after the corrosion tests, the chemical composition and morphology of the electrogalvanised surface was characterized by SEM and XPS. The EIS results showed that impedance values associated to the surface with Cr3+ + Co treatments were inferior to those exhibited by the Cr6+ treated ones. The higher impedances related to the Cr6+ samples could be explained by the self-healing effect of this type of coating. The SEM analyses revealed coating cracks associated to the surface of the Cr6+ treated samples whereas for those treated in the Cr3+ + Co solution, elongated fissures were seen. These last samples presented inferior corrosion resistance to that of the Cr6+ passivated ones. The cobalt addition to the trivalent chromium containing solution was not sufficient to increase the corrosion resistance to acceptable levels in comparison to the Cr6+ conversion coating.
Fil: Tomachuk, C. R.. Universidade de Sao Paulo; Brasil
Fil: Culcasi, José Daniel. Universidad Nacional de La Plata. Facultad de Ingeniería. Departamento de Mecánica. Laboratorio de Investigación de Metalurgia Física; Argentina
Fil: Elsner, Cecilia Ines. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina
Fil: Costa, Isolda. Universidade de Sao Paulo; Brasil
Fil: Di Sarli, Alejandro Ramón. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina
65th Annual Meeting of the International Society of Electrochemistry
Lausanne
Suiza
International Society of Electrochemistry
description Electroplated zinc coatings have been largely employed as active galvanic protection for steel substrates. However, as zinc is highly electrochemically active, its corrosion rate may be very high. For this reason, a post treatment to increase the lifetime of the coatings is necessary, which, in industrial practice, consists of immersion in a chemical bath that forms a conversion layer on plated zinc. This layer must be a dielectric passive coating with high corrosion resistance that also offers good adherence to paints. The main problem of conventionally used post treatments is the presence of Cr6+ salts which are carcinogenic substances whose usage was forbidden by European regulations. In this work the effect of trivalent chromium and Co ions in solution of passivation treatments on the corrosion resistance of electrogalvanised steel has been investigated in 0.1 M Na2SO4 solution by electrochemical impedance spectroscopy (EIS) and polarization curves. Prior and after the corrosion tests, the chemical composition and morphology of the electrogalvanised surface was characterized by SEM and XPS. The EIS results showed that impedance values associated to the surface with Cr3+ + Co treatments were inferior to those exhibited by the Cr6+ treated ones. The higher impedances related to the Cr6+ samples could be explained by the self-healing effect of this type of coating. The SEM analyses revealed coating cracks associated to the surface of the Cr6+ treated samples whereas for those treated in the Cr3+ + Co solution, elongated fissures were seen. These last samples presented inferior corrosion resistance to that of the Cr6+ passivated ones. The cobalt addition to the trivalent chromium containing solution was not sufficient to increase the corrosion resistance to acceptable levels in comparison to the Cr6+ conversion coating.
publishDate 2014
dc.date.none.fl_str_mv 2014
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/conferenceObject
Congreso
Book
http://purl.org/coar/resource_type/c_5794
info:ar-repo/semantics/documentoDeConferencia
status_str publishedVersion
format conferenceObject
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/239147
The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions; 65th Annual Meeting of the International Society of Electrochemistry; Lausanne; Suiza; 2014; 1-1
CONICET Digital
CONICET
url http://hdl.handle.net/11336/239147
identifier_str_mv The protection of electrogalvanised steel by passivation treatment with trivalent chromium and cobalt ions; 65th Annual Meeting of the International Society of Electrochemistry; Lausanne; Suiza; 2014; 1-1
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://www.ise-online.org/ise-conferences/annmeet/folder/2014-LAUSANNE-BoA.pdf
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
dc.coverage.none.fl_str_mv Internacional
dc.publisher.none.fl_str_mv International Society of Electrochemistry
publisher.none.fl_str_mv International Society of Electrochemistry
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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