Abstract
The decomposition of α-Al2O3 under 200 keV electron irradiation has been investigated by in situ high-resolution electron microscopy (HREM). It was confirmed that aluminium precipitated from α-Al2O3 under 200 keV electron irradiation for less than 1 min over the temperature range from 700 to 1273 K. The electron dose rate was of the order of 1023 e m−2 s−1 and the vacuum level of the microscope was better than 10−6 Pa. The mechanisms of α-Al2O3 decomposition were discussed based on two possible decomposition models: the thermally activated atom movement and the forced atom displacement.
Acknowledgements
A part of this work was supported by ‘Nanotechnology Network Project of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan’ at the Research Center for Ultrahigh Voltage Electron Microscopy, Osaka University (Handai multi-functional Nano-Foundry). Also a part of this work was supported by Priority Assistance for the Formation of Worldwide Reowned Centers of Research - The Global COE Program (Project: Center of Excellence for Advanced Structural and Functional Materials Design) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The authors would like to thank Mr A. Yabuuchi for part of calculation in the present work.