▎ 摘　　要

Within the present work, reduced-graphene oxide (rGO)/silicon nitride (Si3N4) nanocomposites were prepared upon pyrolysis of a graphene oxide (GO)-filled polysilazane. The novel preparative approach consists in the synthesis of the polysilazane in the presence of different concentrations of GO, yielding a homogeneous GO/polysilazane composite which was subsequently thermally converted in Ar atmosphere into rGO/Si3N4 nanocomposites. Hot-pressing of the obtained nanocomposite powders delivered monolithic rGO/Si3N4. All prepared samples exhibited the presence of homogeneously dispersed rGO phase within an amorphous or crystalline silicon nitride matrix, as for the as-prepared and hot-pressed samples, respectively. An increasing amount of rGO in the nanocomposites was found to gradually suppress the crystallization of the silicon nitride matrix into alpha-Si3N4. Moreover, depending on the volume fraction of the graphene phase in the ceramic nanocomposites, different dielectric properties were observed, indicating a facile preparative method to produce materials with tunable electromagnetic waves (EMW) behavior. (C) 2016 The Ceramic Society of Japan. All rights reserved.