Low-Temperature Diffusion of Oxygen through Ordered Carbon Vacancies in Zr2Cx: The Formation of Ordered Zr2CxOy

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• 作者：Wentao Hu ; Jianyong Xiang ; Shaocun Liu ; Yang Zhang ; Cankun Chen ; Pang Wang ; Haitao Wang ; Fusheng Wen ; Bo Xu ; Julong He ; Dongli Yu ; Yongjun Tian ; Zhongyuan Liu
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：May 7, 2012
• 年：2012
• 卷：51
• 期：9
• 页码：5164-5172
• 全文大小：542K
• 年卷期：v.51,no.9(May 7, 2012)
• ISSN：1520-510X

文摘

Investigations are performed on low-temperature oxygen diffusion in the carbon vacancy ordered ZrC_0.6and thus induced formation of the oxygen atom ordered ZrC_0.6O_0.4. Theoretically, a superstructure of Zr₂CO can be constructed via the complete substitution of carbon vacancies with O atoms in the Zr₂C model. In the ordered ZrC_0.6, the consecutive arrangement of vacancies forms the vacancy channels along some zone axes in the C sublattice. Through these vacancy channels, the thermally activated oxygen diffusion is significantly facilitated. The oxygen atoms diffuse directly into and occupy the vacancies, producing the ordered ZrC_0.6O_0.4. Relative to the ordered ZrC_0.6, the Zr positions are finely tuned in the ordered ZrC_0.6O_0.4 because of the ionic Zr鈥揙 bonds. Because of this fine adjustment of Zr positions and the presence of oxygen atoms, the superstructural reflections are always observable in a selected area electron diffraction (SAED) pattern, despite the invisibility of superstructural reflections in ZrC_0.6 along some special zone axes. Similar to the vacancies in ordered ZrC_0.6, the ordering arrangement of O atoms in the ordered ZrC_0.6O_0.4 is in nanoscale length, thus forming the nano superstructural domains with irregular shapes.