RESEARCH PAPER |
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Preparation and Formation Mechanism of Magnesium Aluminate Spinel Whiskers by Carbothermal Reduction Method |
ZHANG Yanxiang, LI Hongxia, YANG Wengang, LIU Guoqi,
ZHANG Liping, TIAN Xiangyu, SHANG Xinlian
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State Key Laboratory of Advanced Refractories, Sinosteel Luoyang Institute of Refractories Research Co., Ltd., Luoyang 471039 |
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Abstract Aiming at investigating the preparation and formation mechanism of magnesium aluminate spinel whisker, the present work utilized fused magnesia (≤0.074 mm), α-Al2O3(d50=2.5 μm) and flake graphite (≤0.15 mm) as main raw materials and applied a carbon-embedded heat-treatment process at 1 550 ℃ for 3 h to synthesize fibroid whisker-like MgAl2O4, whose phase composition and microstructure were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS), respectively. The results confirmed the spinel phase of the resultant whiskers with the length of up to 10 mm and an average diameter ranging from 5 μm to 20 μm. The spinel whiskers exhibit sharp terminals, and some of the whiskers have branches. The mutual presence of alumina and graphite can lead to a relatively large amount of spinel whiskers. It can also be concluded that the vapor-solid (V-S) mechanism dominates the in-situ growth of the magnesium aluminate spinel whiskers.
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Published: 25 April 2018
Online: 2018-05-11
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