Thermal expansion and mechanical properties of self-reinforced aluminum titanate ceramics with elongated grains

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• 作者：Yutaka Ohya^a ; ^{ohya@gifu-u.ac.jp} ; Shu Yamamoto^a ; ¹ ; Takayuki Ban^a ; Makoto Tanaka^b ; Satoshi Kitaoka^b
• 关键词：Al2TiO5 ceramics ; Thermal expansion ; Fracture ; Microstructure
• 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：1673-1680
• 全文大小：3923 K
• 卷排序：37

文摘

To fabricate aluminum titanate ceramics that possess both low thermal expansion coefficients and excellent mechanical properties, the co-doping of MgO with Y2O3, La2O3 and Nb2O5 was examined. Doping with MgO lowered the formation reaction temperature of aluminum titanate and prevented the formation of oriented grain regions. Liquid-phase sintering at 1500 °C of the MgO-La2O3-doped ceramic resulted in the formation of a minor amount of elongated grains with lengths of approximately 130 μm. This microstructure resulted in a high resistance against crack propagation during the bend test. Grain pull-out and grain bridging mechanisms as well as crack deflection and branching resulted in the high resistance. A low thermal expansion coefficient of 0.7 × 10−6/deg was observed for this ceramic. The co-doping of MgOY2O3 led to high bending strength and moderate low thermal expansion coefficient. The co-doping of MgO-Nb2O5 resulted in an extended grain growth by liquid-phase sintering at 1500 °C and poor mechanical properties.