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Preparation and Cry...
Preparation and Crystal Structure of of U-Phase Ln3(Si3-xAl3+x)O12+xN2-x (x≈0.5, Ln=La,Nd)
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- Käll, Per-Olov (author)
- University of Stockholm
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- Grins, Jekabs (author)
- University of Stockholm
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- Olsson, Per-Olof (author)
- University of Stockholm
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- Liddell, Kath (author)
- University of Stockholm
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- Korgul, Peter (author)
- University of Stockholm
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- Thompson, Derek P. (author)
- University of Stockholm
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(creator_code:org_t)
- 1991
- 1991
- English.
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In: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 1:2, s. 239-244
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
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- U-phase Ln3(Si3 –xAl3 +x)O12 +xN2 –x(Ln = La, Nd) occurs as a crystalline phase in rare-earth sialon ceramics formed by devitrification of grain-boundary glasses at 1000–1400 °C. The crystal structure of Nd U-phase has been determined from Cu-Kα X-ray powder diffractometer data and refined by the Rietveld full-profile technique to RF= 0.028. The space group is P321 and the cell dimensions are a= 7.974(1)Å, c= 4.873(1)Å and V= 268.29 Å3. The structure is isomorphic with the La3Ga5GeO14 structure, and exhibits corner-shared layers of (Si,Al)(O,N)4 tetrahedra interconnected by AlO6 octahedra. The rare-earth cations occupy sites between the tetrahedral layers. Transmission electron microscopy and lattice imaging studies support the X-ray structural findings. The structural relationship of the U-phase to other nitrogen-containing ceramic phases is discussed.
Keyword
- Salon material; Grain boundary phase; Rietveld analysis; Nitrogen ceramic
- NATURAL SCIENCES
- NATURVETENSKAP
Publication and Content Type
- ref (subject category)
- art (subject category)
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