Enhancing near-zero wear behavior on engineering steel surfaces through graphene-based nanofluids inspired by snail mucus

Bioinspired GO nanofluids achieve near-zero wear under 2.46 GPa. • Hydrodynamic lubrication and tribofilms enable durable performance. • Strategy offers enhanced near-zero wear for engineering steel. Near-zero wear behavior of engineering steel is instrumental to achieving unprecedented performance in longevity, reliability, and precision for advanced mechanical systems. However, achieving near-zero wear is typically accomplished under mild conditions and with specific friction pairs, which makes it difficult to meet the strategic requirements for high loads and general applicability. Herein, inspired by the advanced lubrication of snail mucus, biomimetic graphene-based nanofluids (GO NFs) were synthesized as lubricants by grafting graphene oxide (GO) with organosilane (KH560) and polyethyleneimine (PEI) via covalent linkage. Importantly, the obtained nanofluids demonstrate significant near-zero wear performance on steel substrate under a high contact pressure of 2.46 GPa, achieving an ultralow wear rate of 1.32 × 10 −10  mm 3 ·N −1 ·m −1 and corresponding friction coefficient reduced to 0.068. Further analysis of the worn surfaces and lubrication regimes calculations reveals that the synergistic combination of hydrodynamic lubrication, replenishable adsorption films, and protective tribochemical films collectively contributed to the effective friction reduction and near-zero wear on the steel substrate. This work offers new insights into the lubrication mechanisms of GO NFs and provides guidance for designing high-performance lubricants with enhancing near-zero wear characteristics of engineering steel. Download: Download high-res image (179KB) Download: Download full-size image