Dielectric properties and electromagnetic wave absorbing performance of single-source-precursor synthesized Mo4.8Si3C0.6/SiC/Cfree nanocomposites with an in-situ formed Nowotny phase.

For the first time, dielectric properties and electromagnetic wave (EMW) absorbing performance of single-source-precursor derived Mo4.8Si3C0.6/SiC/Cfree ceramic nanocomposites with a highly electrically conductive intermetallic Nowotny phase (NP, i.e., Mo4.8Si3C0.6) are reported. High-temperature phase evolution of the nanocomposites reveals that free carbon (Cfree) plays a crucial role in the in-situ formation of the NP, indicating that the microstructure of the nanocomposites can be tailored via molecular design of the single-source precursors. Compared with SiC/Cfree and MoSi2/SiC/Cfree nanocomposites obtained under the same conditions, the Mo4.8Si3C0.6/SiC/Cfree nanocomposites exhibit significantly enhanced EMW absorbing performance. A minimum reflection loss (RL) of -59 dB was achieved at 8 GHz for the thickness of 2.46 mm, proving the superiority of the Mo4.8Si3C0.6/SiC/Cfree nanocomposite as an outstanding EMW absorbing material. Based on our previous discovery that the Mo4.8Si3C0.6 embedded in a SiC-based matrix with high specific surface area exhibits excellent electrocatalytic properties suitable for the electrochemical hydrogen evolution reaction, the present results prove that Mo4.8Si3C0.6/SiC/Cfree nanocomposites have to be considered as novel multifunctional materials with tailorable microstructure and excellent performance in two different fields including electrochemical water splitting and EMW absorption.