Excellent electromagnetic wave absorption of MOF/SiBCN nanomaterials at high temperature |
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Institution: | MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an 710072, China |
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Abstract: | Electromagnetic wave absorbing materials at high-temperature are urgently needed for stealth aircrafts or aero-engines worked in harsh environments. In this contribution, cobalt-containing siliconboron carbonitride (MOF/SiBCN) nanomaterials were prepared by pyrolyzing metal–organic framework, i.e. cobalt 2-methylimidazole (ZIF-67), and hyperbranched polyborosilazane. The rhombic dodecahedral ZIF-67 and cobalt element promoted in situ formation of dielectric loss phases, including SiC nanocrystals, CoSi nanocrystals and turbostratic carbons. The ZIF-67/SiBCN nanomaterials showed excellent microwave absorption both at room and elevated temperature. The minimum reflection coefficient (RCmin) was ?51.6 dB and effective absorption bandwidth (EAB) is 3.93 GHz at room temperature. At an elevated temperature of 600 °C, the RCmin reached ?30.29 dB and EAB covered almost the whole X-band (3.95 GHz, 8.45–12.4 GHz). The ZIF-67/SiBCN nanocomposites are promising and useful platform for microwave absorbing materials at high-temperature. It may shed light on the downstream applications in designing next generation areo-engines and stealth aircrafts. |
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Keywords: | Electromagnetic wave absorption High temperature resistance Metal-organic framework Polymer-derived ceramics Siliconboron carbonitride |
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