Exaggerated grain growth in bixbyite via fast diffusion along planar defects
✍ Scribed by H.-J. Kleebe; S. Lauterbach
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 284 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0232-1300
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✦ Synopsis
Abstract
Naturally occurring bixbyite single crystals from the Maynard claim at Thomas Mountain Range in Utah, USA, show pronounced grain growth, when compared to bixbyite crystals from other locations in close vicinity. These enlarged single crystals reveal characteristic linear surface features, which were initially interpreted as twin boundaries. HRTEM studies in conjunction with EDS analysis and electron diffraction, however, confirmed that these features originate from thin interlayers of braunite, Mn~7~SiO~12~, epitaxially grown within the host crystal. A model for the observed exaggerated grain growth is presented, which is based on the assumption that fast diffusion occurs along the braunite/bixbyite phase boundaries in three dimensions and, more importantly, promote nucleation at surface edges. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)