Experimental investigation of isobaric heat capacity and viscosity for suspensions of alumina nanoparticles in [C4mim][BF4] ionic liquid.

Ionic liquids are deliberated, lately, as the perfect candidate for new heat transfer fluids. This article aims to debate on several experimental outcomes in terms of viscosity and isobaric heat capacity for [C4mim][BF4] ionic liquid and several suspensions of Al2O3 nanoparticles (up to 2.5 mass%) in [C4mim][BF4]. The methodological approach involved the suspensions preparation, isobaric heat capacity and viscosity tests, as well as discussing the outcomes. Experimental data were acquired at 293.15 K and after several heating–cooling cycles, while the results outlined that the ionic liquid has a Newtonian behavior, while the suspensions with alumina have non-Newtonian behavior at low shear rates, while at upper shear rates the flow is changed into Newtonian. Also, the suspensions viscosity was found discreetly higher if compared with the base ionic liquid. A novelty is the study of a possible hysteresis in terms of viscosity, while the successive heating–cooling tests revealed a good stability. The isobaric heat capacity tests revealed a moderate decrease when nanoparticles are added. Concluding, this experimental may shed some light on both [C4mim][BF4] and its ionanofluids with Al2O3 nanoparticles; however, it is only a step forward so as to gain a full synopsis on these new fluids. [ABSTRACT FROM AUTHOR]