Wen S L, Liu Y, Zhao X C
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
J Chem Phys. 2015 Aug 28;143(8):084707. doi: 10.1063/1.4929842.
Spherical (sample A), chain-like (sample B), and flake-like (sample C) cobalt powders are synthesized on a large scale through simple chemical liquid reduction method. Based on uniformly dispersing samples into a paraffin matrix, morphology-dependent electromagnetic responses in GHz range, including permittivity and permeability, are investigated for these three cobalt powders in the microwave frequency of 2-18 GHz. The calculated reflection loss (RL) indicates as-prepared samples have potential application as a candidate for microwave absorption. The maximum RL of sample A is -15.28 dB at 12.85 GHz with a matching thickness of 2.5 mm. The maximum RL of sample B is -28.05 dB at 5.74 GHz corresponding to a thickness of 2.0 mm, and the maximum RL of sample C is -41.17 dB at 5.10 GHz with a thickness of 2.5 mm. Mechanism of morphology-dependent electromagnetic response and microwave absorption of the Cobalt powders is also discussed in this paper.
通过简单的化学液相还原法大规模合成了球形（样品A）、链状（样品B）和片状（样品C）钴粉。基于将样品均匀分散到石蜡基体中，在2-18 GHz微波频率下研究了这三种钴粉在GHz范围内的形态依赖电磁响应，包括介电常数和磁导率。计算得到的反射损耗（RL）表明，所制备的样品具有作为微波吸收候选材料的潜在应用。样品A在12.85 GHz时的最大RL为-15.28 dB，匹配厚度为2.5 mm。样品B在5.74 GHz时的最大RL为-28.05 dB，对应厚度为2.0 mm，样品C在5.10 GHz时的最大RL为-41.17 dB，厚度为2.5 mm。本文还讨论了钴粉形态依赖电磁响应和微波吸收的机理。
