Tribological properties of hexagonal boron nitride nanoparticles or graphene nanoplatelets blended with an ionic liquid as additives of an ester base oil

Abstract

Antifriction synergies between an ionic liquid (IL) and nanopowders as additives of an ester base oil were analysed at rolling conditions. For this aim, two nanodispersions based on hybrid combinations of hexagonal boron nitride nanoparticles (h‐BN) or graphene nanoplatelets (GnP) with tri(butyl) ethylphosphonium diethylphosphate ionic liquid as additives in triisotridecyltrimellitate (TTM) base oil and the mixture of TTM and IL were analysed using two tribometer techniques. Film thickness characterisation and tribological tests were performed at rolling conditions [5% slide‐roll‐ratio (SRR)], under 50N and at operating temperatures of 30, 50 and 80°C. Stribeck curves showed that friction coefficients for the prepared lubricants are lower than those found for the TTM, being the best friction behaviour for the hybrid GnP nanolubricant. Furthermore, friction torque loss tests were performed in rolling ball bearings, observing that for the two hybrid nanolubricants lower friction torque values were obtained.

Tribological enhancement of potential electric vehicle lubricants using coated TiO2 nanoparticles as additives

“…To achieve representative values, at least 3 replicates were performed with each nanolubricant. More details about this device can be found in previous articles [21][22][23][24][25]. With the aim of analyzing the worn surface after tribological tests, a 3D Optical Profilometer was utilized to measure the wear produced on the pins.…”

“…Subsequently, coefficient of friction is determined with normal force and friction forces. More information about this tribometer can be observed in previous articles [22,24]. It should be noted that these friction tests were performed for the PAO8 base oil and the TiO 2 -OA nanolubricants under fully flooded lubrication (around 130 mL of lubricant) at the operating temperature of 120 °C, under a constant 50 N load that generates a maximum Hertz pressure of 0.7 GPa, and a 5 % slide-to-roll ratio (SRR):…”