▎ 摘　　要

Graphene has attracted tremendous research interest in recent years owing to its exceptional properties. We report the remarkable ability to transform an insulating material, such as Al2O3, into a highly conductive material by filling the matrix with alumina nanofibers encapsulated by multi-layered graphene. The fibers of 7 nm in diameter were covered by graphene by catalyst-free one-step CVD process for the first time. Coupling between graphene layers and Al2O3 nanofibers results in the development of a novel type of fillers for ceramics, which modify the intrinsic electrical properties of the insulating materials by addition of less than 1 wt.% of graphene into the ceramic matrix. We believe that the general strategy described in this study will open new avenues in developing of graphene-ceramic composites with enhanced electrical properties that can be then suitable for high-precision electrical discharge machining. (C) 2015 Elsevier Ltd. All rights reserved.