Internal friction in ceria ceramics doped with alkali earth metal oxides
Internal friction in ceria ceramics doped with alkali earth metal oxides
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DOI：
10.1016/0925-8388(94)90524-x
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发表时间：
1994-09
影响因子：
6.2
通讯作者：
K. Matsushita
中科院分区：
文献类型：
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作者：
K. Matsushita
将CeO2和5mol%碱土金属粉末在1673K下于空气中烧成6h，以制备CeO2和碱土金属氧化物固溶体样品。内耗随温度的变化在450K附近出现一个峰值，内耗峰强度强烈依赖于掺杂阳离子的种类。掺杂CaO的CeO2的峰值最大，而掺杂BaO的CeO2的峰值最小。采用Born-Mayer-Huggings类型的Busing近似作为对势，用分子动力学计算分析了离子的运动和结构。当掺杂阳离子半径大于或小于Ce2+离子半径时，碱土金属氧化物掺杂形成的掺杂阳离子和氧离子空位的运动方向和速度分布趋于单向运动和陡峭分布。结果表明，内耗峰取决于离子的运动方向和速度分布。
Ceria and 5 mol% of alkali earth metal powder were fired at 1673 K for 6 h in air in order to prepare specimens containing a solid solution of ceria and alkali earth metal oxide. The internal friction as a function of temperature shows a peak at around 450 K. The internal friction peak intensity observed is strongly dependent on the kind of dopant cation. The peak for ceria doped with CaO was the largest, whereas the peak for ceria doped with BaO was the smallest. The ion motion and structures have been analysed by molecular dynamics calculations using as pair potential the Busing approximation of the Born-Mayer-Huggings type. The directions of motion and velocity distributions of dopant cations and oxygen ion vacancies formed by addition of alkali earth metal oxide tend to unidirectional motion and sharp distributions when the ionic radius of the dopant cation is larger or smaller than that of the cerium ion. It is concluded that the internal friction peaks depend on the direction of motion and velocity distribution of the ions.