掺杂A2B2O7型陶瓷的有序无序转变与离子传输特性关联研究

项目名称： 掺杂A2B2O7型陶瓷的有序无序转变与离子传输特性关联研究

项目编号： No.51272054

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 欧阳家虎

作者单位： 哈尔滨工业大学

项目金额： 80万元

中文摘要： 掺杂A2B2O7型陶瓷是潜在的中温固体电解质材料，同时具有有序烧绿石型和无序缺陷型萤石相结构，氧空位缺陷浓度、有序无序转变、相界面结构等对其热膨胀性能和电学性能有重要的影响，电导率的最大值在短程无序的烧绿石相内，因此对有序无序转变行为与离子传输特性之间的内在关系进行研究具有重要的科学意义。本项目拟从掺杂A2B2O7型陶瓷材料的设计、氧空位浓度的计算和有序无序转变研究入手，通过不同氧分压气氛烧结及A、B位不同价态阳离子掺杂等手段制备不同类型的阳离子掺杂A2B2O7陶瓷，在研究其物相及界面结构、热膨胀性能和电学性能的基础上，阐明烧绿石型A2B2O7陶瓷中短程无序化转变和缺陷萤石型A2B2O7陶瓷中的短程有序化转变及其机制，揭示氧空位浓度、有序无序转变与热膨胀性能及离子传输性能之间的内在联系，为高性能掺杂A2B2O7型陶瓷在中温燃料电池方面的应用提供理论指导。

中文关键词： 掺杂A2B2O7陶瓷；氧空位；有序无序转变；离子传输；热膨胀

英文摘要： Doped A2B2O7-type zirconate ceramics, which exhibit either ordered pyrochlore- or disordered defective fluorite-type structures depending upon the ionic radius ratio, are potential candidates for applications as intermediate-temperature solid electrolyte materials in SOFCs. There exists an important influences of oxygen vacancy concentration, order-to-disorder transformation and phase interfacial structure on the thermal expansion behavior and electrical properties. The doped rare-earth zirconates show the highest conductivity when there is an optimum carrier density for the relatively low ordered pyrochlore-type phase at the vicinity of the phase boundary between fluorite- and pyrochlore-type phases. Therefore, it is of great significance for us to understand the relationship between the order-to-disorder transformation and the oxide-ion transport properties in the intermediate temperature range. This project provides a new approach to investigate the design and fabrication of doped A2B2O7-type ceramics at different oxygen partial pressure, the calculation of oxygen vacancy concentration, and reveal the order-to-disorder transformation by co-doping metallic cations with different valances and rare-earth cations with different ionic-radius ratios to partially substitute the A or B site cations in A2B2O7 ceramics

英文关键词： Doped A2Zr2O7 ceramics；Oxygen vacancy；Order-disorder transformation；Ionic transport properties；Thermal expansion