Evaluation of the porogenic behavior of aluminum hydroxide particles of different size distributions in castable high-alumina structures

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• 作者：Adriane D.V. Souza ^{anne.damasceno@usp.br" class="auth_mail" title="E-mail the corresponding author} ; Rafael Salomã ; o ; ^{rsalomao@sc.usp.br" class="auth_mail" title="E-mail the corresponding author} ; ^{rflslm@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Aluminum hydroxide ; Aluminum oxide ; Porous structures ; Castable ; Pore generator
• 刊名：Journal of the European Ceramic Society
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：36
• 期：3
• 页码：885-897
• 全文大小：6820 K

文摘

The combination of Al₂O₃ and Al(OH)₃ produces high refractoriness porous structures. The evolution of these ceramics during the first heating is a competition between pore generation by Al(OH)₃ dehydroxilation, and densification by sintering. Previous studies have reported the size of Al(OH)₃ particles affect both events. In this study, we evaluate the porogenic behavior of three grades of α-Al(OH)₃ (gibbsite) of different average particle sizes (0.9, 10 and, 107 μm). The particles were thermally treated (300–1500 °C) for the investigation of changes in their physical properties and microstructures. Amounts of 67.5 vol% of each grade were added to aqueous castable alumina suspensions. After rheological tests and casting, the sintered samples (1100–1500 °C) were tested for porosity, pore size, and strength and examined by electron microscopy. The particles of the three grades exhibited similar evolution during thermal treatment. When they were added to the alumina matrix, structures of different porosity and strength were obtained.