Effect of solidification path on the microstructure of Al₂O₃-Y₂O₃-ZrO₂ ternary oxide eutectic ceramic system

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• 作者：Haijun Su ; ^{shjnpu@yahoo.com.cn} ; Jun Zhang ; Haifeng Wang ; Kan Song ; Lin Liu ; Hengzhi Fu
• 关键词：Eutectic ceramic ; Solidification ; Microstructure ; Al2O3&ndash ; Y2O3&ndash ; ZrO2 ; DTA ; Oxide composite
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：September, 2012
• 卷：32
• 期：12
• 页码：3137-3142
• 文件大小：2206 K

摘要

The solidification path of the Al₂O₃-Y₂O₃-ZrO₂ ternary oxide eutectic composite ceramic is determined by a high temperature DTA and laser floating zone (LFZ) directional solidification method to investigate the effect of solidification path on the microstructure of the ternary oxide. The DTA and microstructure analyses show that the YAG or Al₂O₃ tends to form as primary phase under the unconstrained solidification conditions, and then the system enters ternary eutectic solidification during cooling from 1950 掳C at rate of 20 掳C/min. The as-solidified composite ceramic shows a divorced irregular eutectic structure consisting of Al₂O₃, YAG and ZrO₂ phases with a random distribution. The primary phases are however completely restrained at the directional solidification conditions with high temperature gradient, and the ternary composite by LFZ presents well coupled eutectic growth with ultra-fine microstructure and directional array. Furthermore, the eutectic transformation and growth mechanism of the composite ceramic under different solidification conditions are discussed.