Electromagnetic wave absorbing properties of high-entropy transition metal carbides powders

The electromagnetic wave absorption performance of high-entropy transition metal carbides, including (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C, (Ti0.2Zr0.2Mo0.2Nb0.2Ta0.2)C and (Ti0.2Zr0.2Cr0.2Nb0.2Ta0.2)C, was investigated in the frequency from 2 GHz to 18 GHz. The electromagnetic parameter measurement and subsequent electromagnetic wave absorption evaluation showed that the high-entropy transition metal carbides possessed good electromagnetic wave absorbing properties, which had a great relation to the solid-solution elements. The (Ti0.2Zr0.2Mo0.2Nb0.2Ta0.2)C with a 1.50 mm thickness displayed a minimal reflection loss of -32.1 dB, and the effective absorption bandwidth (<-10 dB) was in the frequency range of 13–18 GHz. Intriguingly, the minimum reflection loss reached -36.6 dB at the thickness of 2.50 mm. The electromagnetic wave absorption performance was mainly associated with conductivity loss and dipole polarization, which originated from intrinsic conductivity of the high-entropy carbides and lattice distortion resulting from solid solution of multiple elements, respectively. The experimental results show that the high-entropy transition metal carbides may be promising structural-functional integrated ceramics in wide applications.