Dielectric Properties and Electromagnetic Wave Absorbing Performance of Single-Source-Precursor Synthesized...

For the first time, dielectric properties and electromagnetic wave (EMW) absorbing performance of single-source-precursor derived Mo_4.8Si₃C_0.6/SiC/C_free ceramic nanocomposites with a highly electrically conductive intermetallic Nowotny phase (NP, i.e., Mo_4.8Si₃C_0.6) are reported. High-temperature phase evolution of the nanocomposites reveals that free carbon (C_free) 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/C_free and MoSi₂/SiC/C_free nanocomposites obtained under the same conditions, the Mo_4.8Si₃C_0.6/SiC/C_free 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 Mo_4.8Si₃C_0.6/SiC/C_free nanocomposite as an outstanding EMW absorbing material. On the basis of our previous discovery that the Mo_4.8Si₃C_0.6 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 Mo_4.8Si₃C_0.6/SiC/C_free 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.