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Temperature Dependence of Lattice Parameters and Anisotropic Thermal Expansion of Bismuth Oxide
Author(s) -
Yashima Masatomo,
Ishimura Daiju,
Ohoyama Kenji
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00432.x
Subject(s) - sesquioxide , thermal expansion , anisotropy , bismuth , lattice constant , lattice (music) , materials science , neutron diffraction , phase transition , condensed matter physics , rietveld refinement , chemistry , diffraction , thermodynamics , crystal structure , crystallography , optics , physics , composite material , metallurgy , acoustics
Temperature dependence of lattice parameters of bismuth sesquioxide (Bi 2 O 3 ) has been obtained between 26° and 778°C by the Rietveld method using neutron powder diffraction data. Lattice parametersand unit‐cell volume of α and δ phases increased, while the β angle of α phase decreased with an increase of temperature. Here thedenotes the lattice parameter a of the α phase on the basis of pseudo‐fluorite lattice. The thermal expansion coefficients of α phase were 26.7, 6.6, and 9.0 (× 10 −6 °C −1 ) forandaxes, respectively, indicating a large anisotropy. The α‐ to ‐δ phase transition of Bi 2 O 3 was confirmed between 721° and 760°C on heating. At the α–δ transition point, the lattice parameters and unit‐cell volume discontinuously changed, indicating that the transition is of the first order.