Hybrid combinations of graphene nanoplatelets and phosphonium ionic liquids as lubricant additives for a polyalphaolefin

Tribological performance of three ionic liquids (ILs), trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (IL1), tributylethylphosphonium diethylphosphate (IL2) and bis(2,4,4-trimethylpentyl)phosphinate (IL3) combined with graphene nanoplatelets (GnP) as hybrid additives for a polyalphaolefin (PAO 32) base oil was studied. For this purpose, several dispersions were prepared by mixing, stirring, then sonicating according to the following combinations: PAO 32 + (a wt%) IL (b GnP, where b represent concentration added oil. In study is 0 or 1 0.05 0.1. Three wt% mixtures also prepared. Thermophysical properties stability against sedimentation studied means rotational viscometer visual observation, respectively. Furthermore, friction wear behaviors analyzed using ball-on-disk configuration tribometer operating in mode both 3D optical profiler scanning electronic microscope, Confocal Raman microscopy used identify compounds tribofilms formed on tracks. The combinations 32/ILs/GnP improved reduction corresponding binary 32/GnP nanolubricants 32/IL mixtures. Interestingly, low concentrations GnP (with GnP) are more effective than those 0.1 GnP. Results show that addition led reductions up 36% 27%, compared capabilities neat 32. IL1 IL3, containing cation, generate lubricants best (stability, viscosity tribological properties) all tested.