Effect of B₄C on the properties and microstructure of Al₂O₃ -SiC-C based trough castable refractories

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• 作者：Jun Wu^a ; Naijing Bu^a ; ^{bunaijing@163.com" class="auth_mail" title="E-mail the corresponding author} ; Hongbo Li^b ; Qiang Zhen^a ; ^{qzhen@staff.shu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：In-situ formation ; SiC fibers ; Al2O3-SiC-C castable refractories ; B4C ; Thermodynamic calculations
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1402-1409
• 全文大小：3410 K

文摘

The effect of B₄C addition (0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%) on properties and microstructure of Al₂O₃-SiC-C (ASC) based trough castables was studied in this paper. The results showed that the bulk density of samples after firing at 1450 °C decreased when the addition of B₄C was over 1 wt%. The cold modulus of rupture of samples improved significantly with the addition of B₄C when the treating temperature was over 1100 °C. Among them, sample with 1.5 wt% of B₄C had the best anti-slag performance and thermal shock resistance. The SiC fibers were formed in the non-oxidized zone of ASC castables with addition of B₄C after firing at 1450 °C in air condition. The obtained fibers rooted in the walls of inner micropores of samples with the diameter of 50–200 nm, and the lengths of 10–50 µm. The experiment revealed the nucleation of SiC started at about 1000 °C, and then the growth of SiC fibers happened at higher temperature in a favorable condition. A stepped twin structure perpendicular to the growth direction of fibers could be observed. Finally, the growth mechanism was interpreted by thermodynamic calculations.