Synthesis, microstructure and electromagnetic wave absorption properties of high-entropy carbide powders

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, (Zr0.2Ti0.2Hf0.2Ta0.2Cr0.2)C, (Zr0.2Ti0.2Hf0.2Ta0.2Ni0.2)C, (Zr0.2Ti0.2Hf0.2Nb0.2Cr0.2)C and (Zr0.2Ti0.2Hf0.2Nb0.2Ni0.2)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 (Zr0.2Ti0.2Hf0.2Nb0.2Ni0.2)C has the minimum reflection loss (RL) of -42.61 dB, and it has the maximum effective absorption bandwidth (EAB) 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.