Directional conductivity in layered alumina

Abstract

Here we report a novel strategy to consolidate layered alumina demonstrating the directional electrical and thermal conductivity. The material was produced via incorporation of alumina nanofibers (20 ± 2 nm in diameter) decorated by several layers of graphene wrapped around longitudinal axes of the fibers. The graphenated fibers, obtained with the help of one-step catalyst-free CVD process, offered inhibition of grain growth combined with electrical conductivity to the sandwiched composites, which were consolidated by spark plasma sintering. Impact of the concentration of the fillers together with thickness of the conductive graphene-containing layer on thermal properties was studied. A graphene-containing interlayer with 50 μm thickness, sandwiched between two monolithic 10 mm layers of alumina shows ~30% enhancement in isotropic thermal conductivity of monolithic alumina.