Abstract
Examination of small euhedral crystals of α-Al2O3 (sapphire) that were observed following oxidation of aluminum and an aluminum alloy in wet hydrogen at high temperatures showed that growth probably occurs by decomposition of AlO on an Al2O3 surface. Rapid growth occurs on the tips of needles and the edges of platelets at lattice steps formed by intersection of hollow screw dislocations with these surfaces. Screw dislocations were detected by x-ray measurement of the lattice twist they produce in the needle-like crystals or ``whiskers.'' Needles were bent to elastic strains of over 2% corresponding to a strength of 1011 dyne cm−2.
Keywords
SapphireMaterials scienceAlloyCrystallographyAluminiumWhiskersBent molecular geometryLattice (music)Condensed matter physicsComposite materialOpticsChemistry
Affiliated Institutions
Related Publications
Crystalline Ropes of Metallic Carbon Nanotubes
Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation of a laser-vaporized carbon-nickel-cobalt mixture at 1200°C. X-ray diffra...
Comparison of protein structures determined by NMR in solution and by X-ray diffraction in single crystals
Following the first determinations of protein structures in the late 1950s and the early 1960s (see for example Kendrew et al. 1960; Perutz, 1964), the three-dimensional structu...
Preparation and Electrochemical Properties of SnO<sub>2</sub> Nanowires for Application in Lithium‐Ion Batteries
Long and thin: SnO2 nanowires with tetragonal structure were successfully synthesized by a thermal evaporation method without any conventional metal catalysts. The enhanced elec...
Publication Info
- Year
- 1957
- Type
- article
- Volume
- 28
- Issue
- 12
- Pages
- 1449-1454
- Citations
- 109
- Access
- Closed
External Links
Social Impact
Altmetric
PlumX Metrics
Social media, news, blog, policy document mentions
Citation Metrics
109
OpenAlex
Cite This
W. W. Webb,
W. D. Forgeng
(1957).
Growth and Defect Structure of Sapphire Microcrystals.
Journal of Applied Physics
, 28
(12)
, 1449-1454.
https://doi.org/10.1063/1.1722675
Identifiers
- DOI
- 10.1063/1.1722675