Bibliographic Details
| Title: |
Nanostructural M-type barium hexaferrite synthesized by spark plasma sintering method. |
| Authors: |
Wen-Yu Zhao1, Qing-Jie Zhang1 zhangqj@mail.whut.edu.cn, Xin-Feng Tang1, Hai-Bin Cheng1, Peng-Cheng Zhai1 |
| Source: |
Journal of Applied Physics. 4/15/2006, Vol. 99 Issue 8, p08E909. 3p. 2 Black and White Photographs, 1 Graph. |
| Subject Terms: |
*BARIUM, *SINTERING, *NANOSTRUCTURES, *FERRITES, *ELECTROMAGNETIC waves |
| Abstract: |
This investigation shows that the spark plasma sintering (SPS) method may not only absolutely prevent the formation of intermediate phase α-Fe2O3 but also significantly lower the crystallization temperature of M-type barium hexaferrite. A kind of textured sample composed of major phase M-type barium hexaferrite and trace amount of BaFe0.24Fe0.76O2.88 has been successfully synthesized in one step by SPS process at 800 °C for 10 min. Scanning electron microscopy, energy dispersive spectroscopy, x-ray-diffraction, transimission electron microscopy, and vibrating-sample magnetometer techniques are used to study the microstructure, composition, phase formation, crystal orientation, and magnetism of the textured sample, respectively. It is confirmed that nanostructural M-type barium hexaferrites in the holes of the textured sample are in nanobelt and nanorod microstructures; these nanobelts and nanorods are nonstoichiometric and completely random and are characterized by barium or iron surplus, and that their composition may be described as BaFe12+xO19+1.5x (-4.49≤x≤6.60). The prolongation orientation of a nanobelt is parallel to the zone axis [1010]. The values of δs and Hc of the textured sample are 65.52 emu/g and 1412.17 Oe, respectively. The Hc value decreases to one-fourth of that of randomly packed platelike M-type barium hexaferrite with same composition synthesized by sol-gel process at 900 °C for 4 h, while the δs value was independent of the synthesis conditions. This indicates that M-type barium hexaferrite magnets synthesized by SPS process may be applied to electromagnetic wave absorption and/or magnetic recording. [ABSTRACT FROM AUTHOR] |
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