Effects of Alumina on Cristobalite Crystallization and Properties of Silica-Based Ceramic Cores

作     者：J.J.Liang Q.H.Lin X.Zhang T.Jin Y.Z.Zhou X.F.Sun B.G.Choi I.S.Kim J.H.Do C.Y.Jo 

作者机构：Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Korea Institute of Materials ScienceChangwon 642-831Republic of Korea 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2017年第33卷第2期

页      面：204-209页

核心收录：

学科分类：080503[工学-材料加工工程] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 080201[工学-机械制造及其自动化] 

主　　题：Silica-based ceramic cores Alumina Cristobalite crystallization Properties 

摘      要：In this work, the influences of alumina addition on cristobalite crystallization and properties of injec- tion molded silica-based ceramic cores were investigated. X-ray diffraction （XRD） was used to characterize phase transformations in the samples, and the XRD result indicated that the addition of alumina pro- moted crystallization of fused silica during sintering at 1180-1220 ℃ and thus increases the amount of cristobalite. The increased amount of cristobalite as well as alumina addition led to much more thermal dilation due to their higher coefficients of thermal expansion than that of fused silica. The flexural strengths at room temperature and 1500 ~C were tested, and it was shown that alumina addition could not affect room temperature strength, but decreased the flexural strength at 1500 ℃. In addition, deflection resis- tance during heating to high temperatures was investigated, and the result indicated that alumina addition speeded up high temperature softening of the samples. XRD and scanning electron microscopy equipped with energy dispersive spectrometry （SEMJEDS） analysis suggested that this softening behavior was related with viscous flow sintering which could be accelerated by the reaction of alumina and silica with a product of mullite.