Structural phase transition of spinel to hematite of as-prepared Fe2+-Cr nanoferrites by sintering temperature
Structural phase transition of spinel to hematite of as-prepared Fe2+-Cr nanoferrites by sintering temperature
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DOI：
10.1016/j.measurement.2018.09.021
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发表时间：
2019-01-01
期刊：
影响因子：
5.6
通讯作者：
Matsuda, A.
中科院分区：
文献类型：
--
作者：
Elshater, R. E.;Kawamura, G.;Matsuda, A.
本研究介绍了烧结温度对共沉淀法合成的立方尖晶石 Fe2+Cr0.4Fe1.6O4 纳米铁氧体转变过程的影响。除了部分合成样品在环境空气中在温度 T = 300、500、700、900 或 1100 摄氏度下烧结 4 小时外，其他部分在 250 摄氏度下烧结 1、2 和 3 小时。随着温度的升高，样品晶体的结构相从立方尖晶石转变为磁赤铁矿转变为六方赤铁矿。研究了烧结温度和转变过程对样品不同性能的影响。过渡电子的阈值频率和能量随着 T 的变化而减小。比表面积 S 随微晶尺寸 R 的变化而减小，而饱和磁化强度 MS 受 R 和孔隙率 P 的影响。密度表明对弹性波速度 V-S 和 V-L 的影响，而应变 epsilon 的增加增强了带隙能量 E-g。 (C) 2018 年由爱思唯尔有限公司出版。
This investigation presents effect of sintering temperature on the transition processes of as-synthesized cubic spinel Fe2+Cr0.4Fe1.6O4 nanoferrites by the co-precipitation method. In addition to parts of as-synthesized sample were sintered at the temperatures T = 300, 500, 700, 900 or 1100 degrees C in ambient air for 4 h, other parts were sintered at 250 degrees C for 1, 2 and 3 h. The structural phase of sample crystal was converted from cubic spinel-to-maghemite-to-hexagonal hematite with T. The effect of the sintering temperatures and transition process on the different properties of the samples was investigated. The threshold frequency and energy of transition electrons showed decrease against T. The specific surface area S revealed decrease against the crystallite size R, while the saturation magnetization MS was affected by R and porosity P. The density indicated effect on elastic wave velocities, V-S and V-L, while increase of strain epsilon enhanced the band gap energy E-g. (C) 2018 Published by Elsevier Ltd.