CoxNi100-x nanoparticles encapsulated by curved graphite layers: controlled in situ metal-catalytic preparation and broadband microwave absorption
CoxNi100-x nanoparticles encapsulated by curved graphite layers: controlled in situ metal-catalytic preparation and broadband microwave absorption
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弯曲石墨层封装的 CoxNi100-x 纳米粒子：受控原位金属催化制备和宽带微波吸收
DOI：
10.1039/c5nr03745j
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发表时间：
2015-01-01
期刊：
影响因子：
6.7
通讯作者：
Zhang, Z. D.
中科院分区：
文献类型：
--
作者：
Wang, H.;Dai, Y. Y.;Zhang, Z. D.
我们报告了一个一步法制备分散的CoxNi 100-x纳米粒子完全封装的弯曲石墨层。采用蒸发Co-Ni合金的方法制备纳米颗粒，通过调节合金中Co的含量，在纳米颗粒表面原位生长金属催化石墨层，并控制石墨层的层数。通过调节磁芯的组成和壳层的层数，这些核/壳结构的磁性能和介电性能同时得到优化，并且它们的磁导率和介电常数得到改善，以获得增强的电磁匹配。结果，纳米电容器的超过-20dB（99%吸收）的反射损耗（RL）的带宽对于S1为9.6GHz，对于S2为12.8GHz，对于S3为13.5GHz，并且对于S4为14.2GHz。在13.2 GHz时，厚度为2.55 mm的吸收体的最佳RL值达到-53 dB。通过控制芯和壳的生长来优化阻抗匹配是这种非凡的微波吸收的原因。
We report a one-step approach for preparing dispersive CoxNi100-x nanoparticles completely encapsulated by curved graphite layers. The nanoparticles were prepared by evaporating Co-Ni alloys and the shell of graphite layers was formed by in situ metal-catalytic growth on the surface of nanoparticles whose layer number was controlled by tuning the Co content of the alloys. By modulating the composition of the magnetic core and the layer number of the shell, the magnetic and dielectric properties of these core/shell structures are simultaneously optimized and their permeability and permittivity were improved to obtain the enhanced electromagnetic match. As a result, the bandwidth of reflection loss (RL) exceeding -20 dB (99% absorption) of the nanocapsules is 9.6 GHz for S1, 12.8 GHz for S2, 13.5 GHz for S3 and 14.2 GHz for S4. The optimal RL value reaches -53 dB at 13.2 GHz for an absorber thickness of 2.55 mm. An optimized impedance match by controlling the growth of the core and shell is responsible for this extraordinary microwave absorption.