Influence of synthesis conditions on the crystal structure of the powder formed in the ZrO2 - Ce2O3/CeO2 system.

2nd Conference on Plasma & Laser Research and Technologies

Popov, V.V.^1,2 ; Menushenkov, A.P.^1 ; Khubbutdinov, R.M.^1 ; Svetogorov, R.D.^2 ; Zubavichus, Ya V.^2 ; Sharapov, A.S.^1 ; Kurilkin, V.V.^3

National Research Nuclear University MEPhI, Moscow Engineering Physics Institute, Kashirskoe sh. 31, Moscow

115409, Russia^1

NRC, Kurchatov Institute, pl. Akademika Kurchatova 1, Moscow

123182, Russia^2

Peoples' Friendship University of Russia, Russia^3

关键词: Annealing in vacuum;    Annealing temperatures;    Chemical compositions;    Hydrogen atmosphere;    Pyrochlore structures;    Reducing conditions;    Synthesis conditions;    Treatment parameters;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/747/1/012041/pdf
DOI  :  10.1088/1742-6596/747/1/012041

来源: IOP

【 摘 要 】

Influence of synthesis conditions (type of atmosphere, reduction and oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the "ZrO2- Ce2O3/ CeO2" system has been investigated by X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It is revealed that isothermal annealing of precursor at temperatures less than 1000 °C in air leads to formation of Ce0.5Zr0.5O2powders with cubic fluorite-type structure (Fm-3m). Further increase of annealing temperatures above 1000 °C causes decomposition of formed crystal structure into two phases: cubic and tetragonal. Annealing in reduction hydrogen atmosphere causes formation of Ce4+ 2xCe3+ 2-2xZr2O7+ x compounds with intermediate valency of cerium, where value of x depends on the reducing conditions and treatment parameters of precursor. 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 practically Ce3+valence state.