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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >The devitrification kinetics of silica powder heat-treated in different conditions
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The devitrification kinetics of silica powder heat-treated in different conditions

机译：在不同条件下热处理的二氧化硅粉的失透动力学

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摘要

In the present paper, the devitrification kinetics of silica powder heat-treated in air and in nitrogen were investigated. The heat-treated powders were confirmed to partially crystallize into cristobalite by X-ray diffraction analysis. The devitrification kinetics data of silica powder fitted the Avrami equation very well. The measured value of it was ascertained to be 1.63 and 1.60 when, the silica powder was heat-treated in air and in nitrogen, respectively, corresponding to activation energies of 408 kJ/mol and 529 kJ/mol, respectively. The effect of phenolic resin-derived carbon on crystallization of silica powder was also studied. By adding phenolic resin into silica powder, the devitrification of silica powder was fully restrained up to 1500 degrees C in flowing nitrogen. High concentrations of oxygen vacancies may retard the nucleation of cristobalite on the surface of silica powder. Phenolic resin-derived pyrolysis carbon restrained the nucleation of cristobalite, because it prevented the reactions of oxygen vacancies with H2O and O-2 molecules. (C) 2008 Elsevier B.V. All rights reserved.
机译：在本文中，研究了在空气和氮气中热处理的二氧化硅粉末的失透动力学。通过X射线衍射分析确认热处理后的粉末部分结晶为方石英。二氧化硅粉末的失透动力学数据非常符合Avrami方程。当二氧化硅粉分别在空气和氮气中进行热处理时，测得的测量值为1.63和1.60，分别对应于408 kJ / mol和529 kJ / mol的活化能。还研究了酚醛树脂衍生的碳对二氧化硅粉末结晶的影响。通过将酚醛树脂添加到二氧化硅粉末中，在流动的氮气中将二氧化硅粉末的失透性完全抑制到1500℃。高浓度的氧空位可能会延迟二氧化硅粉末表面上方石英的形核。酚醛树脂衍生的热解碳抑制了方石英的成核，因为它阻止了氧空位与H2O和O-2分子的反应。 （C）2008 Elsevier B.V.保留所有权利。

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