After doing several miscibility essays with eight ionic liquids (ILs) and four base oils, the ILs tri(butyl)ethylphosphonium diethylphosphate [P4,4,4,2][C2C2PO4] trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate [P6,6,6,14][(C2F5)3PF3] were selected to be studied as lubricant additives. The neat IL [P4,4,4,2][C2C2PO4], blends characterized in terms of density, viscosity, thermal stability. tribological performance miscible oil/IL (1 wt %) evaluated for lubrication an...

This work presents the antifriction and antiwear properties of TiO2 nanoparticles coated with oleic acid, TiO2-OA, as additives a low viscosity polyalphaolefin base oil, PAO8. To find optimal concentration nanoadditives that minimize friction wear, four PAO8 based nanodispersions were formulated: + 0.10 wt% 0.25 0.35 TiO2-OA 0.50 TiO2-OA. Tribological experiments performed under pure sliding rolling-sliding conditions at 120 °C, formulated nanolubricants oil. All showed lower coefficients...

This work reviews the results on temporal stability of nanodispersions containing chemically modified nanoadditives: carbon-based nanomaterials, metals, metal oxides, sulfides, nanocomposites, among others. Morphology, size, coating type and concentration NPs as well viscosity base oil are main characteristics that affect stability. Coated spherical with mean diameter lower than 20 nm most common those which led to nanolubricants stabilities longer two months. The tribological higher one...

Antifriction and antiwear performances of Al2O3 nanoparticles (NPs) as additives an automatic transmission fluid, ATF, are presented in this research. For purpose, four nanodispersions were formulated: ATF + 0.05 wt% NPs, 0.10 0.15 NPs 0.20 to identify the optimal concentration additive. Tribological experiments taken at pure sliding conditions, with formulated nanolubricants under a working load 20 N. The tested resulted lower friction coefficients than those obtained using reaching maximum...

Casalini and Roland [Phys. Rev. E 69, 062501 (2004); J. Non-Cryst. Solids 353, 3936 (2007)] other authors have found that both the dielectric relaxation times viscosity, η, of liquids can be expressed solely as functions group (TV (γ)), where T is temperature, V molar volume, γ a state-independent scaling exponent. Here we report exponents γ, for viscosities 46 compounds, including 11 ionic liquids. A generalization this thermodynamic to transport properties, namely, self-diffusion...

Tribological performance of polyalphaolefin 32, PAO, is investigated by adding two nanomaterials (graphene nanoplatelets, GnP, and hexagonal boron nitride nanoparticles, h-BN) an ionic liquid ([P6,6,6,14][DEHP], IL1, [P2,4,4,4][DEP], IL2, or [P6,6,6,14][(iC8)2PO2], IL3). Designed double hybrid nanodispersions are PAO/1 wt% ILX/0.05 GnP/0.1 h-BN (X = 1, 2 3). The best anti-friction behavior corresponds to PAO/IL3/GnP/h-BN (40% reduction compared that achieved with PAO). Anti-wear similar for...

In this work, ZnO nanoparticles (NPs) were successfully synthesized and coated with oleic acid (OA). The mean diameter of these NPs (ZnO-OA) was around 11.5 nm, their core characterized by XRD coating FTIR Raman. Homogeneous dispersions at different concentrations (0.10, 0.25, 0.50, 0.75 1.00 wt%) ZnO-OA in polyalphaolefin 40 (PAO40) oil thermophysically tribologically characterized. Both density viscosity values increased the concentration NPs, reaching relative increments 0.5% 4.0%,...

The main task of this work is to study the tribological performance nanolubricants formed by trimethylolpropane trioleate (TMPTO) base oil with magnetic nanoparticles coated oleic acid: Fe3O4 two sizes 6.3 nm and 10 nm, Nd alloy compound 19 nm. Coated (NPs) were synthesized via chemical co-precipitation or thermal decomposition adsorption acid in same step. Three nanodispersions TMPTO 0.015 wt% each NP prepared, which stable for at least 11 months. Two different types tests carried out: pure...

In this work, antifriction and antiwear capabilities of hexagonal boron nitride nanoparticles (h-BN) or graphene nanoplatelets (GnP) as additives a polyalphaolefin neat oil (PAO 40) were studied at pure sliding conditions. For purpose, eight PAO 40 nanodispersions prepared: four with h-BN others based on GnP. The mass concentrations these dispersions are 0.25, 0.50, 0.75 1.00 wt% 0.05, 0.10. 0.25 0.50 GnP, having all them good stability against sedimentation (at least 96 h). Tribological...

The use of biodegradable lubricants based on vegetable oils is receiving increasing attention, being an important area research, in order to promote products with a reduced environmental impact during their entire life cycle. Compressibility one the key properties that should be taken into account develop efficient hydraulic fluids and gear oils. isothermal compressibility four reference fluids, sunflower base oil up 50 MPa from 298.15 K 373.15 has been determined. For this aim experimental...

In this work, the solubility of carbon dioxide, CO2, in pentaerythritol tetrapentanoate (PEC5) and tetra(2-ethylhexanoate) (PEBE8) has been performed from (283 to 333) K pressures up 7 MPa a new high-pressure gas apparatus. The results show that present analyzed range CO2 is highly soluble these oils expressed as mole fraction practically not dependent on branching acid chain, whereas it increases slightly with length PE chains compositions. data were satisfactorily correlated...

This research is based on the investigation of tribological properties a biodegradable polymeric ester lubricant (BIOE) additivated with two different pristine graphene nanoplatelets (GnPs), named as GnP7 and GnP40. These GnPs have lateral sizes 7 40 μm, thickness 3 10 nm, respectively. Four nanoadditive loadings: 0.015, 0.035, 0.055 0.075 wt% been used. Stability nanolubricants has investigated using visual control refractive index evolution during time, revealing slightly better stability...

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...

This work reports tribological properties of PAO6 containing SiO2 nanoparticles modified with stearic-acid (SiO2-SA) as additives at concentrations (0.05, 0.10, 0.20, 0.30 wt%) and the same concentration SA a dispersant. Tribological experiments were performed 120 °C in pure sliding rolling-sliding conditions (5% slide-to-roll ratio). All nanolubricants have better anti-friction capabilities than PAO6. The optimum for friction reduction was wt% both conditions. best anti-wear results...

Knowledge of proper lubricant selection and its handling can substantially influence the reliability a refrigeration system. In this sense awareness several thermophysical properties refrigerants, lubricants, their mixtures under different conditions pressure temperature is highly important for designing systems. Polyol ester oils have been proposed as candidates work, we studied density two polyol esters, pentaerythritol tetraheptanoate tetranonanoate, in range 278.15 ≤ T/K 353.15 0.1 p/MPa...