【摘要】 β″-Al₂O₃是重要的快离子导体,离子传导由结构中的钠氧层承担,每个β″-Al₂O₃晶胞中含三个尖晶石“基块”,相间三个钠氧传导层（见图1）。有人用高分辨电子显微镜曾观察到,β″-Al₂O₃在电子束作用下其钠氧传导层消失,从而导致相邻的两个尖晶石块直接相连。我们不仅从高分辨象,而且还从电子衍射的结果证实了这种二基块直接相连的现象,并进一步发现:β″-Al₂O₃在电子束作用下,还会产生超结构现象.我们的研究还指出,这类电子辐射损伤还与材料中某些缺陷有关.电子辐射产生大量缺陷,缺陷的产生反过来使辐射损伤进一步加快,在某些区域甚至出现无序化的倾向。更多还原

【Abstract】 The β″-alumina is an important fast ion conductor.The conductive ions are Na⁺from conduction layers in the structure.Its chemical formula is Na₂O·5Al₂O₃.Itbelongs to trigonal system with space group R（?）m.Its lattice parameters are a=5.614（?）,c=33.85（?）.A unit cell contains three spinel-like blocks alternated with three Na⁺conduction layers.Using HREM,Yoshio Matsui and Shigeo Horiuche have observed that underradiation of electron beam,Na⁺ conduction layers in β″-alumina disappear,and twospinel-like blocks nearby directly combine.We have observed this phenomenon not onlyfrom high resolution lattice image but also from the electron diffraction image.Moreover,under the radiation of electron beam,we have also found the superstructuresin which three or four spinel-like blocks and Na⁺ conduction layers have been damagedsimultaneously,and that electron radiation damage in β″-Al₂O₃ is closely related tosome defects in the material.The electron beam radiation produces point defects,thesepoint defects quicken the radiation damage in return,even in some areas of thespecimen appears the tendency of disordering.更多还原