Edge oleylaminated graphene as ultra-stable lubricant additive for friction and wear reduction

Graphene has caught growing interest in the field of lubricant additives for its lubricating and antifraying effect. However, the critical agglomeration and sedimentation of graphene particles strongly impede its industrial applications. Here, we proposed a facile way to massively prepare edge-oleylaminated graphene (EOG) via ball milling method. The EOG was well dispersed in lubricant and showed longer than 8 months stability for its extremely thin structures and strong affinity with lubricant. The viscosity index (VI) of base lubricant was greatly improved from 81 to 119 by adding an optimized EOG amount of 0.1 wt.%. Besides, the wear scar diameter (WSD) decreased from 0.88 to 0.46 mm, while the maximum nonseizure load (P_B) and the sintering load (P_D) increased 64.86% and 56.18%, respectively. The enhanced VI indicates EOG additive could upgrade the base oil from normal grade to special grade. The obvious improvement of wear resistance and load-carrying capacity demonstrates EOG is an ultra-stable and effective additive for specific lubricants.