Self-lubricity of WSe<inf>x</inf> nanocomposite coatings

© 2015 American Chemical Society. Transition metal chalcogenides with lamellar structure are known for their use in tribological applications although limited to vacuum due to their easy degradation in the presence of oxygen and/or moisture. Here we present a tailored WSe<inf>x</inf> coa...

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Autores: Domínguez-Meister, Santiago, Conte, Marco, Igartua, A., Rojas, T. Cristina, Sánchez-López, J.C.
Tipo de recurso: artículo
Fecha de publicación:2015
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/117124
Acceso en línea:http://hdl.handle.net/10261/117124
Access Level:acceso abierto
Palabra clave:Nano-structure, Friction
Raman
Electron microscopy
Tungsten selenide
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spelling Self-lubricity of WSe<inf>x</inf> nanocomposite coatingsDomínguez-Meister, SantiagoConte, MarcoIgartua, A.Rojas, T. CristinaSánchez-López, J.C.Nano-structure, FrictionRamanElectron microscopyTungsten selenide© 2015 American Chemical Society. Transition metal chalcogenides with lamellar structure are known for their use in tribological applications although limited to vacuum due to their easy degradation in the presence of oxygen and/or moisture. Here we present a tailored WSe<inf>x</inf> coating with low friction (0.07) and low wear rates (3 × 10<sup>-7</sup> mm<sup>3</sup> Nm<sup>-1</sup>) even in ambient air. To understand the low friction behavior and lower chemical reactivity a tribological study is carried out in a high-vacuum tribometer under variable pressure (atmospheric pressure to 1 × 10<sup>-8</sup> mbar). A detailed investigation of the film nanostructure and composition by advanced transmission electron microscopy techniques with nanoscale resolution determined that the topmost layer is formed by nanocrystals of WSe<inf>2</inf> embedded in an amorphous matrix richer in W, a-W(Se). After the friction test, an increased crystalline order and orientation of WSe<inf>2</inf> lamellas along the sliding direction were observed in the interfacial region. On the basis of high angle annular dark field, scanning transmission electron microscopy, and energy dispersive X-ray analysis, the release of W atoms from the interstitial basal planes of the a-W(Se) phase is proposed. These W atoms reaching the surface, play a sacrificial role preventing the lubricant WSe<inf>2</inf> phase from oxidation. The increase of the WSe<inf>2</inf> crystalline order and the buffer effect of W capturing oxygen atoms would explain the enhanced chemical and tribological response of this designed nanocomposite material.Peer ReviewedAmerican Chemical Society2015201520152015info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/117124reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglésinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1171242026-05-22T06:33:51Z
dc.title.none.fl_str_mv Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
title Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
spellingShingle Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
Domínguez-Meister, Santiago
Nano-structure, Friction
Raman
Electron microscopy
Tungsten selenide
title_short Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
title_full Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
title_fullStr Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
title_full_unstemmed Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
title_sort Self-lubricity of WSe<inf>x</inf> nanocomposite coatings
dc.creator.none.fl_str_mv Domínguez-Meister, Santiago
Conte, Marco
Igartua, A.
Rojas, T. Cristina
Sánchez-López, J.C.
author Domínguez-Meister, Santiago
author_facet Domínguez-Meister, Santiago
Conte, Marco
Igartua, A.
Rojas, T. Cristina
Sánchez-López, J.C.
author_role author
author2 Conte, Marco
Igartua, A.
Rojas, T. Cristina
Sánchez-López, J.C.
author2_role author
author
author
author
dc.subject.none.fl_str_mv Nano-structure, Friction
Raman
Electron microscopy
Tungsten selenide
topic Nano-structure, Friction
Raman
Electron microscopy
Tungsten selenide
description © 2015 American Chemical Society. Transition metal chalcogenides with lamellar structure are known for their use in tribological applications although limited to vacuum due to their easy degradation in the presence of oxygen and/or moisture. Here we present a tailored WSe<inf>x</inf> coating with low friction (0.07) and low wear rates (3 × 10<sup>-7</sup> mm<sup>3</sup> Nm<sup>-1</sup>) even in ambient air. To understand the low friction behavior and lower chemical reactivity a tribological study is carried out in a high-vacuum tribometer under variable pressure (atmospheric pressure to 1 × 10<sup>-8</sup> mbar). A detailed investigation of the film nanostructure and composition by advanced transmission electron microscopy techniques with nanoscale resolution determined that the topmost layer is formed by nanocrystals of WSe<inf>2</inf> embedded in an amorphous matrix richer in W, a-W(Se). After the friction test, an increased crystalline order and orientation of WSe<inf>2</inf> lamellas along the sliding direction were observed in the interfacial region. On the basis of high angle annular dark field, scanning transmission electron microscopy, and energy dispersive X-ray analysis, the release of W atoms from the interstitial basal planes of the a-W(Se) phase is proposed. These W atoms reaching the surface, play a sacrificial role preventing the lubricant WSe<inf>2</inf> phase from oxidation. The increase of the WSe<inf>2</inf> crystalline order and the buffer effect of W capturing oxygen atoms would explain the enhanced chemical and tribological response of this designed nanocomposite material.
publishDate 2015
dc.date.none.fl_str_mv 2015
2015
2015
2015
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/117124
url http://hdl.handle.net/10261/117124
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
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 15,812429

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