Liu Tianhao, Shang Kaixuan, Miao Chao, Ouyang Jing
Key Laboratory for Mineral Materials and Application of Hunan Province, Central South University, Changsha 410083, PR. China; Department of Inorganic Materials, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR. China.
Key Laboratory for Mineral Materials and Application of Hunan Province, Central South University, Changsha 410083, PR. China; Department of Inorganic Materials, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR. China; Key Lab of Clay Mineral Functional Materials in China Building Materials Industry, Central South University, Changsha 410083, China.
J Colloid Interface Sci. 2022 Dec 15;628(Pt A):858-868. doi: 10.1016/j.jcis.2022.07.172. Epub 2022 Aug 5.
Here in this article, a halloysite nanotube/reduced graphene oxide/cobalt nickel composite (HNT/rGO/CoNi) was synthesized by co-precipitation and subsequent calcination processes. The microstructure, morphology, and chemical composition of the as-synthesized samples were characterized by X-ray diffractometer, Raman spectra, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The electromagnetic absorption performances of the composites/paraffin wax hybrids were tested in the frequency range 2-18 GHz. It was found that the synergistic attenuation of electricity and magnetism, as well as the fairly good impedance matching properties together have led to the impressive electromagnetic absorption performance of the optimized product. The maximum reflection loss can reach - 69.77 dB with the thickness of 2.38 mm at 14.72 GHz, and an effective absorption bandwidth of about 7.12 GHz (10.88 GHz-18.00 GHz) can be achieved in the HNT/rGO/CoNi (30) composite. The excellent microwave absorption performance was estimated to originate from the combination of multiple electromagnetic loss mechanisms, including interfacial polarization between graphene and magnetic nanoparticles, dipole orientation polarization caused by the defects of graphene, the natural ferromagnetic resonance, and eddy current of the magnetic nanoparticles. Furthermore, the halloysite plays the roles of improving dispersion of the magnetic nanoparticles as well as adjusting the complex permittivity of the composite. This work provides a new strategy for the design and fabrication of high performance microwave absorbing materials with natural and readily available components.
在本文中，通过共沉淀和后续煅烧工艺合成了一种埃洛石纳米管/还原氧化石墨烯/钴镍复合材料（HNT/rGO/CoNi）。采用X射线衍射仪、拉曼光谱、扫描电子显微镜、透射电子显微镜和X射线光电子能谱对合成样品的微观结构、形态和化学成分进行了表征。在2-18GHz频率范围内测试了复合材料/石蜡混合体的电磁吸收性能。结果发现，电和磁的协同衰减以及相当好的阻抗匹配特性共同导致了优化产物令人印象深刻的电磁吸收性能。在14.72GHz频率下，厚度为2.38mm时，最大反射损耗可达-69.77dB，在HNT/rGO/CoNi（30）复合材料中可实现约7.12GHz（从10.88GHz至18.00GHz）的有效吸收带宽。据估计，优异的微波吸收性能源于多种电磁损耗机制的结合，包括石墨烯与磁性纳米颗粒之间的界面极化、石墨烯缺陷引起的偶极取向极化、天然铁磁共振以及磁性纳米颗粒的涡流。此外，埃洛石起到了改善磁性纳米颗粒分散性以及调节复合材料复介电常数的作用。这项工作为设计和制造具有天然且易于获得成分的高性能微波吸收材料提供了一种新策略。
