Tribological Properties of 1-Alkenes on Copper Foils: Effect of Low-Coordination Surface Sites
It has been suggested from molecular dynamics simulations that low-coordination-number sites are produced at a sliding metal–metal interface, but, because of their instability, they may rapidly relax to increase their coordination number. The possible presence of such low-coordination sites on the s...
| Autores: | , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2013 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositório: | CONICET Digital (CONICET) |
| Idioma: | inglês |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/5669 |
| Acesso em linha: | http://hdl.handle.net/11336/5669 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Copper Foils 1-Alkenes Friction Auger Analysis https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Resumo: | It has been suggested from molecular dynamics simulations that low-coordination-number sites are produced at a sliding metal–metal interface, but, because of their instability, they may rapidly relax to increase their coordination number. The possible presence of such low-coordination sites on the surface is tested by exploiting the observation that the desorption temperatures of 1-alkenes on copper increase with both the number of carbons atoms in the 1-alkenes and the surface roughness. Thus, 1-alkenes desorb from a Cu(111) single crystal, with relatively few low-coordination sites, at temperatures between 60 and 100 K lower than from a polycrystalline copper foil. The decrease in friction after impinging a flux of various 1-alkenes on a copper foil, while rubbing in an ultrahigh vacuum tribometer, correlates very well with the corresponding 1-alkene coverages on a copper foil, estimated using the desorption kinetics. This suggests either that rubbing does not result in the formation of lower-coordination sites or that they relax sufficiently rapidly that they do not influence the surface chemistry of 1-alkenes. Surface analyses indicate that shear at the interface causes carbon to diffuse into the subsurface region to form a tribofilm. |
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