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Title: Structure and thermal expansion of Lu 2O 3 and Yb 2O 3 up to the melting points

Knowledge of thermal expansion and high temperature phase transformations is essential for prediction and interpretation of materials behavior under the extreme conditions of high temperature and intense radiation encountered in nuclear reactors. We studied the structure and thermal expansion of Lu 2O 3 and Yb 2O 3 were studied in oxygen and argon atmospheres up to their melting temperatures using synchrotron X-ray diffraction on laser heated levitated samples. Both oxides retained the cubic bixbyite C-type structure in oxygen and argon to melting. In contrast to fluorite-type structures, the increase in the unit cell parameter of Yb 2O 3 and Lu 2O 33 with temperature is linear within experimental error from room temperature to the melting point, with mean thermal expansion coefficients (8.5 ± 0.6) · 10 -6 K -1 and (7.7 ± 0.6) · 10 -6 K -1, respectively. There is no indication of a superionic (Bredig) transition in the C-type structure or of a previously suggested Yb 2O 3 phase transformation to hexagonal phase prior to melting.
ORCiD logo [1] ; ORCiD logo [1] ;  [1] ; ORCiD logo [2] ;  [3]
  1. Univ. of California, Davis, CA (United States). Peter A. Rock Thermochemistry Lab., NEAT ORU
  2. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  3. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division; Materials Development Inc., Arlington Heights, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357; DMR-1506229
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 495; Journal Issue: C; Journal ID: ISSN 0022-3115
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
OSTI Identifier: