Impurity effects and the nonstoichiometric defect characterization of CeO/sub 2-x/ and Ce/sub. 9/Zr/sub. 1/O/sub 2-x/ in the near-stoichiometric composition range

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 1984

OSTI ID:5380018

Chang, E K.C.

The electrical conductivity of CeO/sub 2-x/ was measured in the temperature range 800/sup 0/ to 1000/sup 0/C and 1 to 10/sup -3/ atm of oxygen partial pressures. It was found that the results were consistent with a defect model involving doubly ionized oxygen vacancies arising from both nonstoichiometry and lower valent cation impurities (e.g., Ca/sup +2/). A method of analysis was also developed to determine the equivalent amount of M/sup +2/ impurities. It was found that the effect of lower valent cation impurities can be compensated by counterdoping with Ta/sub 2/O/sub 5/. The completely compensated specimen exhibits the predicted behavior of pure ceria. The partial molal enthalpy change, ..delta..anti H/sub O/sub 2// of CeO/sub 2/ was calculated from the temperature variation of the electrical conductivity with the counterdoped specimen. The value of ..delta..anti H/sub O/sub 2// thus obtained, 9.96 +/- .65 eV, is in good agreement with previously reported results. The electrical conductivity of Ce/sub .9/Zr/sub .1/O/sub 2-x/ was also measured in the temperature range 800/sup 0/C to 1000/sup 0/C and 1 to 10/sup -3/ atm of oxygen pressures. It was found, again, that the results were consistent with a defect model involving doubly ionized oxygen vacancies arising from both lower valent cation impurities and nonstoichiometry.

• Research Organization: Marquette Univ., Milwaukee, WI (USA)
• OSTI ID: 5380018
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
ELECTRIC CONDUCTIVITY
ZIRCONIUM OXIDES
IMPURITIES
PRESSURE EFFECTS
VERY HIGH TEMPERATURE
CERIUM COMPOUNDS
CHALCOGENIDES
ELECTRICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties