Influence of synthesis conditions on the crystal structure of the powder formed in the "hfO2 - CeO2/Ce2O3" system

Influence of synthesis conditions (type of atmosphere: reduction or oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the "HfO2 - CeO2/Ce2O3" system has been investigated by X-ray absorption fine structure spectroscopy combined with Raman spectroscopy, X-ray diffraction and thermogravimetric analysis. It was revealed that isothermal annealing of precursor at temperatures less than 1000°C in air leads to formation of Ce0.5Hf0.5O2 powders with cubic fluorite-type structure (space group Fm-3m). Further increase of annealing temperatures above 1000°C causes decomposition of formed crystal structure into two phases: cubic and monoclinic. Annealing in reduction hydrogen atmosphere causes formation of Ce4+ 2xCe3+ 2-2xHf2O7+x compounds with intermediate oxidation state of cerium, where value of x depends on the reducing conditions and treatment parameters. Annealing in vacuum at 1400°C strongly reduces the content of Ce4+ in a powder samples and leads to formation of pyrochlore structure (space group Fd-3m) with predominant +3 oxidation state of cerium. © Published under licence by IOP Publishing Ltd.

Authors
Popov V.V.1, 2 , Menushenkov A.P.2 , Khubbutdinov R.M.2 , Yastrebtsev A.A.2 , Svetogorov R.D.1 , Zubavichus Y.V.1 , Trigub A.L.1 , Sharapov A.S.2 , Pisarev A.A.2 , Kurilkin V.V. 3 , Tsarenko N.A.4 , Arzhatkina L.A.4
Conference proceedings
Journal of Physics: Conference Series
Publisher
Institute of Physics Publishing
Number of issue
1
Language
English
Status
Published
DOI
10.1088/1742-6596/941/1/012080
Number
012080
Volume
941
Year
2018
Organizations
  • 1 NRC, Kurchatov Institute, pl. Akademika Kurchatova 1, Moscow, 123182, Russian Federation
  • 2 National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, Moscow, 115409, Russian Federation
  • 3 Peoples' Friendship University of Russia, Miklukho-Maklaya st. 6, Moscow, 117198, Russian Federation
  • 4 JSC, Scientific Research Institute of Chemical Technology, Kashirskoe sh. 33, Moscow, 115309, Russian Federation
Keywords
Atmospheric temperature; Cerium; Cerium oxide; Chemical analysis; Fluorspar; Hafnium oxides; Isothermal annealing; Oxidation; Reaction intermediates; Thermogravimetric analysis; X ray absorption; X ray absorption fine structure spectroscopy; X ray diffraction; Annealing in vacuum; Annealing temperatures; Chemical compositions; Hydrogen atmosphere; Pyrochlore structures; Reducing conditions; Synthesis conditions; Treatment parameters; Crystal structure
Date of creation
19.10.2018
Date of change
19.10.2018
Short link
https://repository.rudn.ru/en/records/article/record/6903/
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