Electromagnetic attenuation property of multiphase Fe–Fe₃O₄–Al₂O₃ cermets near percolation threshold

详细信息    查看全文

• 作者：Kai Sun ; Run-Hua Fan ; Zi-Dong Zhang ; Ke-Lan Yan ; Xi-Hua Zhang…
• 关键词：Cermets ; Attenuating materials ; Percolative phenomenon ; Microwave absorption ; Metamaterials
• 刊名：Rare Metals
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：36
• 期：1
• 页码：42-45
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Nanotechnology; Ceramics, Glass, Composites, Natural Materials; Surfaces and Interfaces, Thin Films; Inorganic Chemistry; Physical Chemistry;
• 出版者：Nonferrous Metals Society of China
• ISSN：1867-7185
• 卷排序：36

文摘

Cermets are widely applied as attenuating materials due to high electromagnetic loss and better mechanical properties. In this paper, multiphase cermets composed of iron, iron oxide and alumina were successfully prepared by a two-step in situ synthesis process, which includes pressureless sintering and a selective reduction in hydrogen atmosphere. The phase composition and microstructure of cermets were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It is shown that nanosized cuboid Fe particles and octahedral Fe₃O₄ particles are distributed in alumina matrix. The permittivity and permeability of composites were tested with radio frequency impedance analyzer (0.01–1.00 GHz). The results show that permittivity presents obvious frequency dispersion. Furthermore, dielectric constants of multiphase cermets get enlarged due to the enhancement of interfacial polarization. On the other hand, there is a magnetic loss peak in permeability spectra, which indicates typical relaxation behavior. It is possible to achieve better electromagnetic attenuation property by adjusting process parameters.