Superlubricity and Corrosion-Resistant Behavior of Glycerol Aqueous Lubricants Containing Corrosion Inhibitors

Water-based lubricants have shown great potential in friction reduction, thermal management, cost control, and environment sustainability compared to oil-based lubricants. Among them, glycerol aqueous lubricants can achieve superlubricity (coefficient of friction ≤ 0.01) under suitable conditions but are susceptible to corrosion in metallic systems. In this study, three different corrosion inhibitors were incorporated into a glycerol aqueous lubricant with a water/glycerol weight ratio of 0.2 to evaluate their ability to maintain superlubricity. Tribological tests on a mini-traction machine with a ball-on-disk setup revealed that the corrosion-inhibitor-containing formulations maintained ultralow friction under identical loads and sliding speeds comparable to that found with the base glycerol aqueous solution. Complementary corrosion tests following a modified ASTM D1384 procedure showed that lubricants with the corrosion inhibitors provided protection against corrosion in multiple metal species, compared to the base fluid without the inhibitors. These results demonstrate that properly formulated glycerol aqueous lubricants can provide both ultralow friction and corrosion resistance, showing their potential as sustainable, water-based lubricants for engineering systems.