کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1475983 | 991137 | 2013 | 9 صفحه PDF | دانلود رایگان |
Iron-enriched reference kaolins (KGa-1b, KGa-2 and KF) were used to study the effect of iron on the development of mullite phases during the sintering of kaolin-based materials. Up to 1050 °C, primary mullite formation occurred at earlier temperature within iron-enriched kaolins than in the case of iron-free kaolins. At 1150 °C, the presence of ferric ions tended to promote the transformation of the spinel (γ-Al2O3-like) phase into primary mullite. This action was correlated with an enhancement of the diffusion mechanism of the main constitutive species of the samples (Al, Si). In the range 1300–1400 °C, iron-enriched kaolins exhibited an abnormal grain growth of secondary mullite crystals and a partial reduction of hematite (Fe2O3) into magnetite (Fe3O4). These two iron compounds reacted with mullite and cristobalite, leading to the occurrence of eutectic liquids as expected from phase equilibrium diagrams.
Journal: Journal of the European Ceramic Society - Volume 33, Issue 4, April 2013, Pages 669–677