Molten salt synthesis of highly crystalized (TaNbTiV)C flake and its electromagnetic wave absorption property

M site high-entropy transition metal carbide powder, (TaNbTiV)C, is synthesized via a molten salt synthesis method. Corresponding metal oxides and graphite are used as starting materials, with CaCl2 serving as the reaction medium. XRD and SEM techniques are employed to observe the phase transition and morphology of the reaction product at elevated temperatures. Pure (TaNbTiV)C powder is obtained at 1500 °C, exhibiting highly crystallized flake-like morphology and even distribution of micro-scale elements. The electromagnetic wave (EMW) absorption performance of (TaNbTiV)C in the frequency range of 1–18 GHz is studied by fabricating (TaNbTiV)C/paraffin wax with 10–50 vol % absorbent contents. Paraffin-based sample with 50 vol% content of (TaNbTiV)C exhibits the lowest reflection loss (−37.1 dB) and an effective absorption bandwidth (EAB) of 4.6 GHz. Conductive and dielectric losses are identified as its main mechanisms for EM wave absorption, while magnetic loss does not significantly affect its EM wave absorption ability. The significance of this work lies in the detailed elucidation of the fabrication and purification process involved in molten salt synthesis of flake-like (TaNbTiV)C, as well as the clarification of its electromagnetic wave absorbing mechanism.