Catalytic formation of graphene oxide on diamond surface for achieving superlubric drawing of ultrafine metals

The exceptional hardness of diamond dies renders them indispensable in metal wire drawing; however, they remain prone to severe wear and high friction, leading to wire breakage and surface irregularities. Here, we report the achievement of sustained superlubricity on diamond surfaces, characterized by an ultralow friction coefficient of 0.008 and an extremely short running-in period, achieved within 1.6 × 10 6 cycles (equivalent to a sliding distance of 16 km). This remarkable behavior arises from the in situ formation of a graphene oxide-based tribolayer, synergistically driven by metal-catalyzed tribochemical reactions and oligoethylene glycols. Our experiments with several types of friction pair (Ni, Cu and GCr15 steel) and condition (dry friction, drawing oil, diethylene-, triethylene- and tetraethylene-glycol), together with atomistic simulation reveal the mechanism. We further demonstrate the practical viability of this approach using industrial drawing equipment, achieving a 10-91% reduction in drawing force compared to conventional drawing oils. Download: Download high-res image (288KB) Download: Download full-size image