Investigation on Microstructure, Wave Absorbing Properties and High Temperature Stability for (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O High-entropy Ceramics

In this work, high entropy (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O ceramics were fabricated with three different precursors by conventional sintering method. SEM and XRD analyses revealed the microstructure is related to the precursors while the phase composition is independent with the precursors. Compared with S1 and S2 samples, the S3 samples show well distributed small pores located inside the grain or at the grain boundary. While all the samples exhibit a single rock salt phase. The RL values could reach to -30.5 dB (S3) at 6.8 GHz under the thickness of 4.0 mm, the excellent microwave absorbing properties stem from the bonding interface defects, the micro-pores and many grain boundaries. The (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O ceramics keep stable under 1200 oC for S3. The results demonstrate that (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O ceramics may be a promising candidate for microwave absorption materials at high temperature.