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Electronic Conductivity of La‐Doped Ceria Ceramics
Author(s) -
Shimonosono Taro,
Hirata Yoshihiro,
Sameshima Soichiro,
Horita Teruhisa
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00401.x
Subject(s) - analytical chemistry (journal) , partial pressure , lanthanum , conductivity , activation energy , atmospheric temperature range , materials science , sintering , oxygen , doping , thermal conduction , oxide , oxalate , chemistry , inorganic chemistry , thermodynamics , metallurgy , physics , optoelectronics , organic chemistry , chromatography , composite material
Lanthanum‐doped ceria powder with a composition Ce 0.8 La 0.2 O 1.9 was prepared by heating the oxalate solid solution (Ce 0.8 La 0.2 ) 2 (C 2 O 4 ) 3 at 873 K in air. As‐prepared powder was densified to 96%–97% relative density by sintering in air at 1773 K for 4 h. The electronic current of the disk sample was measured in a temperature range from 773 to 1113 K by the direct current polarization method using a Hebb–Wagner ion‐blocking cell. A linear relationship, which was theoretically predicted, was measured between log σ e (electronic conductivity) and E (applied voltage) in the applied voltage range of 0.2–1.0 V. The σ e was proportional to P O2 −1/4.3 ≈ P O2 −1/4.6 in the oxygen partial pressure range of 10 −2 –10 −8 Pa, and to P O2 −1/6.7 ≈ P O2 −1/7.1 in the oxygen partial pressure range of 10 −7.5 –10 −22 Pa. The apparent activation energy of the electronic conduction was 1.87–1.94 eV. The hole conduction was also measured in the P o 2 range of 10 2 –10 5 Pa. The transport number of oxide ion was 0.96–1.00 at 773–1113 K under an oxygen partial pressure of 10 −5 Pa.