DELVING INTO THE SYNERGISTIC BEHAVIOURS OF TRIBOLOGICAL ADDITIVES IN MINERAL AND VEGETABLE OILS VIA THERMODYNAMIC ANALYSIS

This study presents a comprehensive thermodynamic modelling and analysis to enhance lubrication assessment in tribotests, focusing on ASTM D2783 extreme pressure (EP) and ASTM D4172 anti-wear (AW) tests.The model facilitates the identification of optimal high-performance lubrication and synergistic additive combinations, even for lubricants yielding similar test results.A case study evaluates 36 lubricant samples, including mineral oil, vegetable oil, and blends.Rooted in the entropy balance, the model employs the dissipative coefficient U w to simulate friction-wear interplay, providing insights into wear conditions, lubrication mechanisms, and efficacy.Both mineral-based and vegetable-based lubricants exhibit analogous friction-wear dynamics, but their compatibility with additives differs, resulting in distinct synergistic packages.Blended base oils' compositional complexity significantly influences additive synergies, challenging conventional tribotest evaluations.The U w parameter-based approach empowers the selection of optimal lubricant formulations, aiding in designing effective lubricant solutions by considering wear conditions, lubrication mechanisms, and additive compatibilities.