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• High-entropy carbides powders were synthesized by carbothermal reduction method. • The solid-solution elements have a great influence on EMW absorption capability. • The intrinsic characteristics make the high-entropy carbides promising EMW absorbing materials. The electromagnetic wave absorption performance of high-entropy transition metal carbides, including (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)C, (Ti 0.2 Zr 0.2 Mo 0.2 Nb 0.2 Ta 0.2)C and (Ti 0.2 Zr 0.2 Cr 0.2 Nb 0.2 Ta 0.2)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 (Ti 0.2 Zr 0.2 Mo 0.2 Nb 0.2 Ta 0.2)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. The single-phase high-entropy transition metal carbide powders without complex structure and multi phases design present excellent EMW absorption properties, including minute reflection loss and broad absorption bandwidth. [Display omitted] [ABSTRACT FROM AUTHOR]

With the continuous development of microwave technology, the electromagnetic (EM) environment we face is becoming increasingly complex. EM wave absorbing materials, which convert EM wave energy into other forms of energy such as thermal energy, have attracted much attention in EM shielding technology for reducing and isolating EM interference. Finding absorbing materials with both strong and wideband absorption performance in 2–18 GHz is particularly important. In this paper, (Zr 0.2 Ti 0.2 Hf 0.2 Ta 0.2 Cr 0.2)C, (Zr 0.2 Ti 0.2 Hf 0.2 Ta 0.2 Ni 0.2)C, (Zr 0.2 Ti 0.2 Hf 0.2 Nb 0.2 Cr 0.2)C and (Zr 0.2 Ti 0.2 Hf 0.2 Nb 0.2 Ni 0.2)C high-entropy carbide powders were prepared through calculation and design, and their properties were compared with TaC and NbC. According to the analysis of phase composition, microstructure, and EM wave absorption performance, the prepared high-entropy carbides have formed single-phase solid solutions, and their absorption performance has been improved. It can be noted that (Zr 0.2 Ti 0.2 Hf 0.2 Nb 0.2 Ni 0.2)C has the minimum reflection loss (RL) of − 42.61 dB, and it has the maximum effective absorption bandwidth (E AB) of 3.60 GHz at the thickness of 1.00 mm. Through the analysis of EM parameters, it was found that high-entropy carbides with different compositions changed the dielectric loss, magnetic loss, and their coupling effect. This provides important insights for designing absorbing materials with ultra-thin and good conductivity. [Display omitted] • High-entropy carbide powders containing magnetic elements were successfully prepared. • The electromagnetic wave absorption performance of high-entropy carbides is improved compared to that of metal carbides. • (Zr 0.2 Ti 0.2 Hf 0.2 Nb 0.2 Ni 0.2)C exhibits excellent EM wave absorption performance, with the minimum reflection loss of − 42.61 dB at 5.25 mm, and the maximum effective absorption bandwidth of 3.6 GHz at the ultra-thin thickness of 1.00 mm. [ABSTRACT FROM AUTHOR]