Ultra low-density mullite foams by reaction sintering of thermo-foamed alumina-silica powder dispersions in molten sucrose

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• 作者：Sujith Vijayan ; Praveen Wilson ; Kuttan Prabhakaran ; ^{kp2952002@gmail.com} ; ^{kp2952002@yahoo.co.uk}
• 关键词：Foams ; Porosity ; Strength ; Mullite ; Insulators
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：37
• 期：4
• 页码：1657-1664
• 全文大小：3320 K
• 卷排序：37

文摘

Ultra low-density mullite foams are prepared by thermo-foaming followed by reaction sintering of alumina-silica powder dispersions in molten sucrose. The foaming & setting time, foam rise, sintering shrinkage, porosity, cell size and compressive strength are studied as a function of ceramic powder loading, foaming temperature and magnesium nitrate (blowing agent and setting agent) concentration. Phase pure mullite is produced by reaction sintering at 1600 °C. The mullite foams produced without magnesium nitrate have porous struts and cell walls due to improper densification. The magnesium nitrate drastically decreases the foaming & setting time and increases the foam rise and cell interconnectivity. The MgO produced from the magnesium nitrate assists the densification of the mullite as evidenced from the non-porous struts and cell walls at higher magnesium nitrate concentrations. The maximum porosity of 94.92 and 96.28 vol.% achieved without and with magnesium nitrate, respectively, is the highest reported for mullite foams.