Antiwear performance of ionic liquid+graphene dispersions with anomalous viscosity-temperature behavior

New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 35...

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Veröffentlicht in:Tribology international 2018-06, Vol.122, p.200-209
Hauptverfasser: Pamies, R., Avilés, M.D., Arias-Pardilla, J., Espinosa, T., Carrión, F.J., Sanes, J., Bermúdez, M.D.
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Sprache:eng
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Zusammenfassung:New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 357K (for IL = [EMIM][DCA]) or from 385K (for IL = [EMIM][TFSI]) to 393K. IL + G dispersions with G > 0.5 wt% show linear viscosity increases with increasing temperature, from 306K (for [EMIM][DCA]+1 wt%G) and from 330K to 393K (for [EMIM][TFSI]+0.75 wt%G and [EMIM][TFSI]+1 wt%G). Addition of graphene improves the poor wear reducing performance of [EMIM][DCA], and prevents surface damage on steel when added to [EMIM][TFSI]. Graphene increases the load-carrying ability of ILs, forms a surface layer on the sliding path and retains wear debris, preventing the formation of large abrasive particles. [Display omitted] •Graphene prevents wear by a surface layer and inhibits large wear debris.•Unprecedented rheology for ionic liquid + graphene nanolubricants is described.•A critical 0.5 wt% graphene concentration for non-Newtonian efficient lubrication.
ISSN:0301-679X
1879-2464
DOI:10.1016/j.triboint.2018.02.020