Modeling Calculation and Synthesis of Alumina Whiskers Based on the Vapor Deposition Process
Abstract
:1. Introduction
2. Simulation and Experimentation
3. Results and Discussion
3.1. Band Structure and Density of States
3.2. Surface Energies Calculation
3.3. Phase Composition and Microstructure of the As-Synthesized Sample
3.4. The Generation Mechanism for Al2O3 Whiskers at High Temperatures
4. Conclusions
- (1)
- Density of States calculation of Al2O3 showed that Al-O bonding exhibited strong ionic characteristics and the direct band gap between the top of the valence band and the bottom of the conduction band is 6.704 eV. The surfaces of (001), (110), and (113) would be terminated and determined by the Al or O layer.
- (2)
- Under oxygen-rich conditions, the surface energies of low Miller index surfaces of Al2O3 followed the sequence of (001)-Al > (110)-Al > (113)-Al > (113)-O > (001)-O > (110)-O. Under oxygen-deficient conditions, the sequence was converted to the trend of (001)-O > (110)-O > (113)-O > (001)-Al > (113)-Al > (110)-Al. The (001) surface possessed the higher surface energy.
- (3)
- The growth experiment of Al2O3 whiskers showed that the whiskers were 50–500 nm in diameter and hundreds of microns in length. The diffraction spots along the alumina whiskers’ axis was the crystal face (003), and its growth direction was parallel to [001], namely, along the c-axis. This analysis was in agreement with the calculation and modeling results based on DOS.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Gong, W.; Li, X.-C.; Zhu, B.-Q. Modeling Calculation and Synthesis of Alumina Whiskers Based on the Vapor Deposition Process. Materials 2017, 10, 1192. https://doi.org/10.3390/ma10101192
Gong W, Li X-C, Zhu B-Q. Modeling Calculation and Synthesis of Alumina Whiskers Based on the Vapor Deposition Process. Materials. 2017; 10(10):1192. https://doi.org/10.3390/ma10101192
Chicago/Turabian StyleGong, Wei, Xiang-Cheng Li, and Bo-Quan Zhu. 2017. "Modeling Calculation and Synthesis of Alumina Whiskers Based on the Vapor Deposition Process" Materials 10, no. 10: 1192. https://doi.org/10.3390/ma10101192
APA StyleGong, W., Li, X.-C., & Zhu, B.-Q. (2017). Modeling Calculation and Synthesis of Alumina Whiskers Based on the Vapor Deposition Process. Materials, 10(10), 1192. https://doi.org/10.3390/ma10101192