Tribological properties of bis(2-hydroxyethyl)ammonium oleate in glycerol and polyethylene glycol aqueous solutions

The use of eco-friendly water-based lubricants can benefit manufacturing processes and the health of operating personnel while reducing environmental pollution. This study investigates the tribological properties of bis(2-hydroxyethyl)ammonium oleate protic ionic liquid (PIL) as a potential additive to enhance tribological properties in aqueous solutions of glycerol and polyethylene glycol. The studied con-centration of bis(2-hydroxyethyl)ammonium oleate was in the range of 0.1 to 1.5 wt%. The base fluids contained 50 wt% glycerol and 12 wt% polyethylene glycol, respectively. The physicochemical properties, wettability, and corrosion-prevention ability were evaluated. Lubricity was investigated using a ball-on -plate configuration in reciprocation mode and a four-ball tribometre. The wear scars were analysed using optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The intro-duction of PIL into the base fluids enhanced their wettability and ability to prevent corrosion. Furthermore, the PIL improved the wear and reduced the friction coefficient of both fluids. Moreover, their load-carrying ability was enhanced. Based on the observed results, friction and wear reduction mechanisms were suggested. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the impact of bis(2-hydroxyethyl)ammonium oleate protic ionic liquid (PIL) as an additive on the tribological properties of aqueous solutions of glycerol and polyethylene glycol. The introduction of PIL improves the wettability, corrosion-prevention ability, lubricity, and load-carrying ability of the base fluids.