MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
J Colloid Interface Sci. 2018 Mar 15;514:10-20. doi: 10.1016/j.jcis.2017.12.013. Epub 2017 Dec 6.
A series of magnetic FeCo alloy/carbon composites have been successfully prepared through in situ pyrolysis of Prussian blue analogues (PBAs) with different Fe/Co ratios. The Fe/Co ratio can affect the crystalline phase, particle size, and magnetic property of the FeCo alloy particles, as well as the relative graphitization degree of the carbon frameworks. As a result, the electromagnetic functions of these composites will be highly associated with the Fe/Co ratio, where high Co content is beneficial to the formation of strong dielectric loss and moderate Co content can facilitate the magnetic loss. When Fe/Co ratio reaches 1:1, the as-obtained composite (sample S4) displays excellent reflection loss characteristics with powerful absorption in a very broad frequency range (over -10 dB in 3.2-18.0 GHz), which is superior to those of single magnetic metal (Fe or Co)/carbon composite derived from PBAs, as well as many previously reported FeCo alloy/carbon composites. Electromagnetic analysis reveals that the excellent microwave absorption of sample S4 benefits from its preferable matching of characteristic impedance and good attenuation ability toward incident electromagnetic waves. These results provide new insight into the fabrication of carbon-based magnetic composites with enhanced microwave absorption by rationally manipulating the chemical composition of magnetic components.
通过原位热解不同 Fe/Co 比的普鲁士蓝类似物 (PBA)，成功制备了一系列磁性 FeCo 合金/碳复合材料。Fe/Co 比可以影响 FeCo 合金颗粒的晶相、粒径和磁性，以及碳骨架的相对石墨化程度。因此，这些复合材料的电磁性能与 Fe/Co 比密切相关，其中高 Co 含量有利于形成强介电损耗，而适中的 Co 含量则有利于磁损耗。当 Fe/Co 比达到 1:1 时，所获得的复合材料（样品 S4）在很宽的频率范围内（在 3.2-18.0GHz 范围内超过-10dB）显示出优异的反射损耗特性，具有强大的吸收能力，优于由 PBA 衍生的单一磁性金属（Fe 或 Co）/碳复合材料以及许多先前报道的 FeCo 合金/碳复合材料。电磁分析表明，样品 S4 的优异微波吸收性能得益于其对特征阻抗的较好匹配和对入射电磁波的良好衰减能力。这些结果为通过合理调控磁性组分的化学成分来制备具有增强微波吸收性能的碳基磁性复合材料提供了新的思路。
