Low-Viscosity Fatty Alcohol-Based Deep Eutectic Solvent for Ultralow Wear Behavior toward Steel Substrates under High-Load Conditions

Liquid lubricants are crucial for advanced bearing equipment, as they help mitigate key tribological issues including friction and wear, thereby reducing the risk of failure and extending service life. Herein, a low-viscosity, high-affinity deep eutectic solvent (TB-C 12 OH DES) was synthesized by blending tetrabutylammonium chloride with 1-dodecanol using a simple heating-stirring method, and it was used as a high-performance lubricant for steel substrates. The as-synthesized TB-C 12 OH DES showed favorable physicochemical properties. Reciprocating friction tests demonstrated that TB-C 12 OH DES achieved low friction coefficients (0.081–0.090) and ultralow wear rates (3.02–4.75 × 10 –9 mm 3 N –1 m –1 ) under high-load conditions (2.16–3.12 GPa). These results are attributed to the formation of stable adsorption film and tribofilms consisting of carbonaceous compounds and iron oxides at the tribointerface through adsorption and tribochemical reactions. This straightforward preparation strategy not only meets specific lubricant requirements but also paves the way for the development of eco-friendly DES-based lubricants with high lubricating performance to address friction and wear challenges under complex operating conditions.