Rheological and Tribological Characterization of Ionic Liquid Water-based Lubricants

Abstract

Research on environmentally friendly replacements for petroleum-based lubricants has become necessary due to the rising awareness of sustainability and limited sources of petroleum-based oils. Water-based lubricants (WBLs) are potentially good alternatives in some industrial applications such as metalworking, metal deformation and machinery. However, water alone is insufficient as a lubricant for these applications, necessitating the addition of additives in various forms to enhance lubrication performance.

This study investigates the rheological and tribological behaviours of WBLs containing amino acid ionic liquids (AAILs) using both molecular dynamics (MD) simulations and experimental methods. With the introduction of AAILs into the water, superior lubrication performances were observed across all tested conditions, encompassing different lubrication regimes. The underlying lubrication mechanism involves a combination of the layered structure of the lubricant and improved viscosity. Additionally, anticorrosion studies reveal that increasing the concentration of AAIL additives reduces the corrosion level, with complete elimination at a certain concentration of AAIL additives.

This comprehensive study of AAIL WBLs’ rheological and tribological behaviours highlights their promise as eco-friendly lubricants, contributing to the advancement of a circular economy in industries reliant on lubrication.