Effects of the synthesis procedure, doping and non-stoichiometry on the order-disorder transformation in Ln2Ti2O7 (Ln=Tm-Lu) oxygen-ion conductors

被引:61
作者
Shlyakhtina, AV
Knotko, AV
Boguslavskii, MV
Stefanovich, SY
Peryshkov, DV
Kolbanev, IV
Shcherbakova, LG
机构
[1] Russian Acad Sci, Inst Chem Phys, Moscow 119991, Russia
[2] Moscow MV Lomonosov State Univ, Fac Chem, Moscow, Russia
[3] Karpov Inst Phys Chem, Moscow, Russia
关键词
oxide ion conductor; order-disorder transformation; pyrochlore; fluorite; anti-site defect;
D O I
10.1016/j.ssi.2005.06.005
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The ionic conductivity of the Ln(2)Ti(2)O(7) (Ln=Tm-Lu) pyrochlores is found to correlate with the degree of anti-site cation disordering in these materials. The highest ionic conductivity is exhibited by Ln(2)Ti(2)O(7) containing 3.53-4.5% Ln(Ti)+Ti-Ln anti-structure pairs. This degree of cation disordering can be achieved by heat treatment just below the melting point of the material, by mechanical activation with subsequent high-temperature firing and by doping with small amounts of cations of different sizes (as, e.g., in the case of (Yb0.91Sc0.09)(2)Ti2O7). The Ln(Ti)+Ti-Ln anti-structure pairs seem to interact with oxygen vacancies. The defect structure of Lu2+xTi2-xO7-x/2 (34.5-44 mol% Lu2O3) oxygen-ion conductors is investigated. The materials with x=0.052 (34.5 mol% Lu2O3); 0.096 (35.5 mol% Lu2O3); 0.286 (40 mol% Lu2O3) contain the whole one type of anti-site defect, Lu-Ti, and possess an ionic conductivity of about 10(-3) S/cm at 740 degrees C. The conductivity of the materials containing Lu-Ti defects is lower than that of the stoichiometric materials containing Lu-Ti + Ti-Ln anti-structure pairs. A strong correlation is found between the variable positional parameter X of 0(2) (position 480 in the structure of Lu2+xTi2-xO7-x/2,,Ti-2(-),O7-x/2 (x=0, 0.052, 0.096, 0.286) nanoceramics and the I-311/I-222 and I-331/I-222 intensity ratios in their X-ray diffraction patterns. (c) 2005 Elsevier B.V. All rights reserved.
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页码:2297 / 2304
页数:8
相关论文
共 16 条
[1]  
BERNHARDT J, 2000, SOLID STATE IONICS, V129, P111
[2]   DETERMINATION OF ENERGY YIELD OF MECHANOCHEMICAL REACTIONS [J].
BUTYAGIN, PY ;
PAVLICHEV, IK .
REACTIVITY OF SOLIDS, 1986, 1 (04) :361-372
[3]   Order-disorder transformations induced by composition and temperature change in (SczYb1-z)2Ti2O7 pyrochlores, prospective fuel cell materials [J].
Eberman, KW ;
Wuensch, BJ ;
Jorgensen, JD .
SOLID STATE IONICS, 2002, 148 (3-4) :521-526
[4]   FAST-ION CONDUCTING Y-2(ZRYTI1-Y)(2)O-7 PYROCHLORES - NEUTRON RIETVELD ANALYSIS OF DISORDER-INDUCED BY ZR SUBSTITUTION [J].
HEREMANS, C ;
WUENSCH, BJ ;
STALICK, JK ;
PRINCE, E .
JOURNAL OF SOLID STATE CHEMISTRY, 1995, 117 (01) :108-121
[5]  
IZUMI F, 1993, RIETELD METHOD
[6]   ELECTRICAL AND CATALYTIC PROPERTIES OF SOME OXIDES WITH THE FLUORITE OR PYROCHLORE STRUCTURE - CO OXIDATION ON SOME COMPOUNDS DERIVED FROM GD2ZR2O7 [J].
KORF, SJ ;
KOOPMANS, HJA ;
LIPPENS, BC ;
BURGGRAAF, AJ ;
GELLINGS, PJ .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS I, 1987, 83 :1485-1491
[7]   STUDY OF ORDER-DISORDER TRANSFORMATION OF FLUORITE STRUCTURE WITH PYROCHLORE TYPE PHASES OF FORMULA (1-X) ZRO2-XLN2O3 [J].
MICHEL, D ;
PEREZYJO.M ;
COLLONGUES, R .
MATERIALS RESEARCH BULLETIN, 1974, 9 (11) :1457-1468
[8]  
SHEVCHENKO AV, 1984, INORG MATER+, V20, P1615
[9]   Synthesis and conductivity of Yb2Ti2O7 nanoceramics [J].
Shlyakhtina, AV ;
Abrantes, JCC ;
Larina, LL ;
Shcherbakova, LG .
SOLID STATE IONICS, 2005, 176 (17-18) :1653-1656
[10]   Ionic conduction of a high-temperature modification of Lu2Ti2O7 [J].
Shlyakhtina, AV ;
Ukshe, AE ;
Shcherbakova, LG .
RUSSIAN JOURNAL OF ELECTROCHEMISTRY, 2005, 41 (03) :265-269