Precursor-directed synthesis of porous cobalt assemblies with tunable close-packed hexagonal and face-centered cubic phases for the effective enhancement in microwave absorption
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- 作者：Ying Wang ; Yunchen Du ; Di Guo ; Rong Qiang ; Chunhua Tian…
- 刊名：Journal of Materials Science
- 出版年：2017
- 出版时间：April 2017
- 年：2017
- 卷：52
- 期：8
- 页码：4399-4411
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Materials Science, general; Characterization and Evaluation of Materials; Polymer Sciences; Continuum Mechanics and Mechanics of Materials; Crystallography and Scattering Methods; Classical Mechanics;
- 出版者：Springer US
- ISSN：1573-4803
- 卷排序：52
文摘
Metal cobalt is one of the most promising candidates for high-performance microwave absorbers due to its compatible dielectric loss and magnetic loss abilities. Rational design on the microstructure of metal cobalt became a popular way to upgrade its microwave absorption performance in the past decade, while much less attention has been paid to the electromagnetic functions derived from its different crystal structures. Herein, we report the microwave absorption of porous cobalt assemblies with varied composition of close-packed hexagonal (hcp) and face-centered cubic (fcc) phases. Electromagnetic analysis reveals that the change of phase composition can significantly impact the complex permittivity and complex permeability of metal cobalt, where hcp-cobalt favors high complex permittivity and fcc-cobalt produces high complex permeability. The optimum phase composition in these porous cobalt assemblies will promise well-matched characteristic impedance and good performance in strong reflection loss (−41.0 dB at 9.4 GHz) and wide response bandwidth (4.0–17.4 GHz over −10.0 dB). The enhanced microwave absorption is superior to many cobalt absorbers ever reported. It is believed that these results will provide a new pathway to the design and preparation of highly effective metal cobalt and cobalt-based composites as novel microwave absorbers in the future.