作者：ZENBE-E NAKAGAWA;SHIGEO HAYASHI;OSAMU YAMAMOTO;
作者單位：Akita University
刊名：Journal of the Technical Association of Refractories
ISSN：0285-0028
出版年：2007-01-05
卷：27
期：2
起頁：138
止頁：0
分類號(hào)：TQ175
語種：英文
關(guān)鍵詞：
內(nèi)容簡介The formation of magnesium aluminate spinel from magnesia (periclase) and alumina (corundum) is accompanied by a volume expansion of 8.0 percent (corresponding to the linear expansion of 2.6 percent theoretically) owing to the density difference between reactants and product. It is well known that in the case of powder compacts, although the expansion behaviors have been explained by this expansion value, the expansion behavior differs depending on the formation conditions and/or the environment. The authors calculated the expansion values of powder compacts depending on the migration of the magnesia component during spinel formation and assuming that the expansion of alumina side in the reaction couple essentially determines the whole expansion of the compacts while the shrinkage of magnesia side in the reaction couple does not contribute to the volume change to form voids or spaces". In this report we measured the expansion of powder compacts during spinel formation that depends on the solid solubility of alumina component in spinel by firing at various temperatures and mixture ratios of magnesia and alumina, firing in a water vapor pressure and using various particle sizes. These results were compared with the calculated values on the migration of magnesia component.
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