Phase Transitions, Chemical Expansion, and Deuteron Sites in the BaZr0.7Ce0.2Y0.1O3−δ Proton Conductor
Phase Transitions, Chemical Expansion, and Deuteron Sites in the BaZr0.7Ce0.2Y0.1O3−δ Proton Conductor
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BaZr0.7Ce0.2Y0.1O3−δ 质子导体中的相变、化学膨胀和氘核位点
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
U. Amador
中科院分区：
文献类型：
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作者：
G. C. Mather;Gemma Heras;C. Ritter;R. O. Fuentes;A. Chinelatto;D. Pérez;U. Amador
技术相关的高温质子导体 BaZr0.7Ce0.2Y0.1O3−δ (BZCY72) 的晶体结构已通过在 10–1173 K 温度范围内对氘化样品进行高分辨率中子粉末衍射研究，并辅以 RT-1173 K 范围内的同步加速器 X 射线衍射。加热时的体积不连续性表明从正交晶系的一级相变（空间群 Imma）在 85 到 150 K 之间转变为菱面体对称性（R3c）。在~570 K 时进一步转变为立方对称性（Pm3m），这表明八面体倾斜角的温度依赖性是二阶的。立方相的稳定场在脱水状态下冷却时扩展至 85 K。分别通过中子衍射和同步加速器 X 射线衍射观察到在低真空和空气中加热时晶胞体积的膨胀/收缩，用涉及水含量和热膨胀的温度依赖性的点缺陷模型进行描述。
The crystal structure of the technologically relevant, high-temperature proton conductor BaZr0.7Ce0.2Y0.1O3−δ (BZCY72) has been studied by high-resolution neutron powder diffraction performed on a deuterated sample in the temperature range 10–1173 K, complemented with synchrotron X-ray diffraction in the range RT-1173 K. A volume discontinuity on heating indicates a first-order phase transition from orthorhombic (space group Imma) to rhombohedral symmetry (R3c) between 85 and 150 K. A further transition to cubic symmetry (Pm3m) takes place at ∼570 K, indicated to be second order from the temperature dependence of the octahedral tilt angle. The stability field of the cubic phase was extended on cooling in the dehydrated state to 85 K. Expansion/contraction of the unit-cell volume on heating in low vacuum and air, respectively observed by neutron diffraction and synchrotron X-ray diffraction, was described with a point-defect model involving the temperature dependence of the water content and thermal expa...