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In Situ Diffraction from Levitated Solids Under Extreme Conditions—Structure and Thermal Expansion in the Eu 2 O 3 –ZrO 2 System
Author(s) -
Maram Pardha S.,
Ushakov Sergey V.,
Weber Richard J.K.,
Benmore Chris J.,
Navrotsky Alexandra
Publication year - 2015
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/jace.13422
Subject(s) - thermal expansion , pyrochlore , materials science , solid solution , diffraction , phase (matter) , negative thermal expansion , atmospheric temperature range , phase transition , analytical chemistry (journal) , thermodynamics , chemistry , metallurgy , physics , organic chemistry , optics , chromatography
The accurate determination of structure and thermal expansion of refractory materials at temperatures above 1500°C is challenging. Here, for the first time, we demonstrate the ability to reliably refine the structure and thermal expansion coefficient of oxides at temperatures to 2200°C using in situ synchrotron diffraction coupled with aerodynamic levitation. Solid solutions in the Eu 2 O 3 –ZrO 2 binary system were investigated, including the high‐temperature order–disorder transformation in Eu 2 Zr 2 O 7 . The disordered fluorite phase is found to be stable above 1900°C, and a reversible phase transition to the pyrochlore phase is noticed during cooling. Site occupancies in Eu 2 Zr 2 O 7 show a gradual increase in disorder on both cation and anion sublattices with increasing temperature. The thermal expansion coefficients of all cubic solid solutions are relatively similar, falling in the range 8.6–12.0 × 10 −6 C −1 . These studies open new vistas for in situ exploration of complex structural changes in high‐temperature materials.