One-step synthesis and electromagnetic absorption properties of high entropy rare earth hexaborides (HE REB6) and high entropy rare earth hexaborides/borates (HE REB6/HE REBO3) composite powders
| Autor: | Biao Zhao, Weiming Zhang, Huimin Xiang, Shijiang Wu, Fu-Zhi Dai, Yanchun Zhou |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
high entropy rare earth hexaborides (HE REB6) Clay industries. Ceramics. Glass chemistry.chemical_element 02 engineering and technology Dielectric Boron carbide Cubic crystal system 010402 general chemistry 01 natural sciences Electromagnetic radiation one-step synthesis electromagnetic wave absorbing properties chemistry.chemical_compound Phase (matter) wide effective absorption bandwidth Ceramic Boron Condensed matter physics Reflection loss 021001 nanoscience & nanotechnology 0104 chemical sciences Electronic Optical and Magnetic Materials TP785-869 synergistic dielectric and magnetic losses chemistry visual_art Ceramics and Composites visual_art.visual_art_medium 0210 nano-technology |
| Zdroj: | Journal of Advanced Ceramics, Vol 10, Iss 1, Pp 62-77 (2020) |
| ISSN: | 2227-8508 2226-4108 |
| DOI: | 10.1007/s40145-020-0417-2 |
| Popis: | Considering the emergence of severe electromagnetic interference problems, it is vital to develop electromagnetic (EM) wave absorbing materials with high dielectric, magnetic loss and optimized impedance matching. However, realizing the synergistic dielectric and magnetic losses in a single phase material is still a challenge. Herein, high entropy (HE) rare earth hexaborides (REB6) powders with coupling of dielectric and magnetic losses were designed and successfully synthesized through a facial one-step boron carbide reduction method, and the effects of high entropy borates intermedia phases on the EM wave absorption properties were investigated. Five HE REB6 ceramics including (Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6, (Ce0.2Eu0.2Sm0.2Er0.2Yb0.2)B6, (Ce0.2Y0.2Eu0.2Er0.2Yb0.2)B6, (Ce0.2Y0.2Sm0.2 Eu0.2Yb0.2)B6, and (Nd0.2Y0.2Sm0.2Eu0.2 Yb0.2)B6 possess CsCl-type cubic crystal structure, and their theoretical densities range from 4.84 to 5.25 g/cm3. (Ce0.2Y0.2Sm0.2Er0.2 Yb0.2)B6 powders with the average particle size of 1.86 µm were found to possess the best EM wave absorption properties among these hexaborides. The RLmin value of (Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6 reaches −33.4 dB at 11.5 GHz at thickness of 2 mm; meanwhile, the optimized effective absorption bandwidth (EAB) is 3.9 GHz from 13.6 to 17.5 GHz with a thickness of 1.5 mm. The introduction of HE REBO3 (RE = Ce, Y, Sm, Eu, Er, Yb) as intermediate phase will give rise to the mismatching impedance, which will further lead to the reduction of reflection loss. Intriguingly, the HEREB6/HEREBO3 still possess wide effective absorption bandwidth of 4.1 GHz with the relative low thickness of 1.7 mm. Considering the better stability, low density, and good EM wave absorption properties, HE REB6 ceramics are promising as a new type of EM wave absorbing materials. |
| Databáze: | OpenAIRE |
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