快离子导体中的钠沉积

采用电子探针(EPMA)定点轰击法研究了β-,β″-Al₂O₃和Nasicon(Na₃Zr₂Si₂PO₁₂)的钠沉积效应。按照递减离子源的离子迁移和电解沉积机理导出了钠沉积动力学方程式,可以较好地说明快离子导体在电子束轰击下钠计数率随时间的变化。在β-Al₂O₃单晶内有丰富的可迁移钠离子源,曲线上升的延续时间较长;而对于Na关键词：

SODIUM DEPOSITION IN FAST ION CONDUCTORS

Sodium deposition in β-, β"-Al₂O₃ and Nasicon (Na₃Zr₂Si₂PO₁₂) was studied by using EPMA. Based on the mechanism of ion transportation and electrolytic deposition with a diminished carrier concentration, a kinetic equation for sodium deposition has been derived, which can fit well the time dependence of the sodium counts during electron bombardment. Since an abundant source of mobile Na⁺ ions exists in the large single crystal, the rise of the curve of beta-Al₂O₃ extends over a long period of time. However, the crystallites in the Nasicon polycrystal are small (< 10μm), the Na⁺ ion therefore may be provided insufficiently at the electron bombarded point for a prolonged deposition due to the hindrance of the grain boundaries in the ion transport process. The deposition attains its saturation limit rapidly.