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Title: Lattice thermal expansion of the solid solutions (La{sub 1−x}Sm{sub x}){sub 2}Ce{sub 2}O{sub 7}

Highlights: • Sm-doped La{sub 2}Ce{sub 2}O{sub 7} was prepared by the coprecipitation–calcination method. • In situ HT-XRD measurements revealed that is much stable than 8YSZ. • Its thermal expansion is better than 8YSZ. - Abstract: A series of solid solutions with the general formula (La{sub 1−x}Sm{sub x}){sub 2}Ce{sub 2}O{sub 7} (0.0 ≤ x ≤ 1.0) were prepared by the coprecipitation–calcination method. The products obtained were characterized by powder X-ray diffraction for phase purity. It was observed that La{sup 3+} and Sm{sup 3+} can form complete solid solution in (La,Sm){sub 2}Ce{sub 2}O{sub 7} with defect-fluorite-type phase. The unit cell parameters of these solutions were calculated by a least squares method and the lattice parameters decreased linearly as x increased. The lattice thermal expansion behavior of (La{sub 1−x}Sm{sub x}){sub 2}Ce{sub 2}O{sub 7} (0.0 ≤ x ≤ 1.0) was investigated by high-temperature X-ray diffraction in the temperature range 298–1623 K. The lattice parameters a{sub T} of all the solutions at different temperature can be expressed as a{sub T} = a + bT + cT{sup 2}. As x < 1, the thermal expansion has a sudden decrease at ca. 473 K. The coefficients of lattice thermal expansion of Sm{sub 2}Ce{sub 2}O{sub 7} were 10.2–13.6more » × 10{sup −6} K{sup −1} from 298 to 1623 K, and without the thermal contraction at low temperature. The materials show positive or negative thermal expansion due to the asymmetric anharmonic vibration.« less
Authors:
;  [1] ;  [2] ; ;  [3]
  1. Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China)
  2. The State Key Laboratory of Refractories and Metallurgy, Wuhan 430081 (China)
  3. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China)
Publication Date:
OSTI Identifier:
22420570
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 57; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCINATION; CERIUM OXIDES; COMPUTERIZED TOMOGRAPHY; CONCENTRATION RATIO; COPRECIPITATION; DOPED MATERIALS; LANTHANUM COMPOUNDS; LANTHANUM IONS; LATTICE PARAMETERS; LEAST SQUARE FIT; SAMARIUM COMPOUNDS; SAMARIUM IONS; SOLID SOLUTIONS; THERMAL EXPANSION; X-RAY DIFFRACTION