Macroscale superdurable superlubricity achieved in lubricant oil via operando tribochemical formation of fullerene-like carbon
Jingjie Pan, Xinxin Gao, Chang Liu, Kan Zhang, Weitao Zheng, Changfeng Chen
Abstract
Friction and wear are ubiquitous in moving mechanical assemblies, causing energy and equipment loss and producing harmful emissions. Mitigation efforts have long relied on oil-based lubricants, but challenges remain in achieving concurrent ultralow friction and wear without oil additives. Here, we demonstrate that a dual-phase TiB2-MoS2 film lubricated by oil without additives exhibits superdurable superlubricity characterized by a vanishingly small friction coefficient (0.007) and ultralow wear rate (10−9 mm3N−1m−1) maintained in lubricants over an unprecedentedly long sliding distance without performance deterioration. We identify a tribochemical route for the decomposition of oil molecules catalytically activated by the TiB2-MoS2 film, leading to operando formation of fullerene-like carbon that leads to diminished friction. First-principles calculations unveil strong stress responses of a TiB2 structural framework under wear strains, offering insights into the ultralow wear rate. These findings showcase a promising strategy to develop high-performance superlubricating materials that meet stringent conditions for demanding applications.