Combined Effects of Boron Carbide, Silicon, and MWCNTs in Alumina-Carbon Refractories on Their Microstructural Evolution

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• 作者：Ning Liao ; Yawei Li ; Shengli Jin ; Yibiao Xu ; Shaobai Sang and Zhaojun Deng
• 刊名：Journal of the American Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：100
• 期：1
• 页码：443-450
• 全文大小：2342K
• ISSN：1551-2916

文摘

The phase and microstructure evolutions of multiwalled carbon nanotubes (MWCNTs) in B₄C- and Si-containing Al₂O₃–C specimens under elevated temperatures were investigated by means of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results show that the incorporation of B₄C decreases the partial pressure of SiO(g) in Al₂O₃–C specimens due to the oxidation of B₄C prior to Si at lower temperature, which prevents the transformation of MWCNTs at 1000°C and suspends the transformation under higher temperature. B₂O₃ vapor resulting from oxidation of B₄C powder reacts with C sources to generate nanoscaled B₄C droplets, which facilitate the catalytic formation of new MWCNTs and nano onion-like carbon. In addition, B-doped MWCNTs and BN tubes with the coexistence of B₂O₃, MWCNTs, and N₂ are obtained under evaluated temperatures.