Co7Fe3 and Co7Fe3@SiO2 Nanospheres with Tunable Diameters for High-Performance Electromagnetic Wave Absorption
Co7Fe3 and Co7Fe3@SiO2 Nanospheres with Tunable Diameters for High-Performance Electromagnetic Wave Absorption
复制标题
用于高性能电磁波吸收的直径可调的 Co7Fe3 和 Co7Fe3@SiO2 纳米球
DOI：
10.1021/acsami.7b03907
复制
发表时间：
2017-07-05
影响因子：
9.5
通讯作者：
Zhen, Liang
中科院分区：
文献类型：
--
作者：
Chen, Na;Jiang, Jian-Tang;Zhen, Liang
铁磁性金属/合金纳米粒子在电磁波吸收领域的应用引起了广泛的兴趣。然而，铁磁纳米颗粒容易氧化并产生涡流，导致电磁性能恶化。在这项工作中，一个简单的和可扩展的液相还原法合成均匀的Co 7 Fe 3纳米球的直径为350至650 nm的高性能微波吸收应用。然后通过改进的Stober方法制备了SiO2壳厚度为30 nm的Co7Fe3@SiO2核壳纳米球。当作为微波吸收剂进行测试时，直径为350 nm的裸Co 7 Fe 3纳米球在1.59 mm的小厚度下具有78.4 dB的最大反射损耗（RL）和从10到16.7 GHz的RL > 10 dB的有效吸收。SiO2纳米球的微波吸收能力显著增强，有效吸收带宽和向低频的偏移，这归因于Co 7 Fe 3纳米球之间的SiO2壳层的直接接触的保护，以及在退火时改善的结晶度和减少的缺陷。该研究为制备Co 7 Fe 3和Co7Fe3@SiO2纳米球提供了一种简单有效的微波吸收材料，其设计思想也可推广到其他铁磁合金颗粒。
Ferromagnetic metal/alloy nanoparticles have attracted extensive interest for electromagnetic wave-absorbing applications. However, ferromagnetic nanoparticles are prone to oxidization and producing eddy currents, leading to the deterioration of electromagnetic properties. In this work, a simple and scalable liquid-phase reduction method was employed to synthesize uniform Co7Fe3 nanospheres with diameters ranging from 350 to 650 nm for high-performance microwave absorption application. Co7Fe3@SiO2 core-shell nanospheres with SiO2 shell thicknesses of 30 nm were then fabricated via a modified Stober method. When tested as microwave absorbers, bare Co7Fe3 nanospheres with a diameter of 350 nm have a maximum reflection loss (RL) of 78.4 dB and an effective absorption with RL > 10 dB from 10 to 16.7 GHz at a small thickness of 1.59 mm. Co7Fe3@SiO2 nanospheres showed a significantly enhanced microwave absorption Capability for an effective absorption bandwidth and a shift toward a lower frequency, which is ascribed to the protection of the SiO2 shell from direct contact among Co7Fe3 nanospheres, as well as improved crystallinity and decreased defects upon annealing. This work illustrates a simple and effective method to fabricate Co7Fe3 and Co7Fe3@SiO2 nanospheres as promising microwave absorbers, and the design concept can also be extended to other ferromagnetic alloy particles.