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Structural Evolution and Electrical Properties of Sc 2 O 3 ‐Stabilized ZrO 2 Aged at 850°C in Air and Wet‐Forming Gas Ambients
Author(s) -
Du Kui,
Kim ChangHoon,
Heuer Arthur H.,
Goettler Richard,
Liu Zhien
Publication year - 2008
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.1551-2916.2007.02138.x
Subject(s) - tetragonal crystal system , electrical resistivity and conductivity , monoclinic crystal system , materials science , analytical chemistry (journal) , conductivity , activation energy , crystallography , mineralogy , crystal structure , chemistry , electrical engineering , chromatography , engineering
X‐ray diffraction (XRD) and electron microscopy investigations have been performed on Sc 2 O 3 ‐stabilized ZrO 2 as‐sintered and after aging in air or in wet‐forming gas at 850°C for 1000 h. Some tetragonal to monoclinic transformation had occurred in the near‐surface regions of 4 mol% Sc 2 O 3 samples after aging; the phase transition was more severe for samples aged in the forming gas ambient. A decrease of ∼20% in electrical conductivity accompanied the aging. In 6 mol% Sc 2 O 3 samples, although no cubic to tetragonal transformation was detected, both the electrical conductivity and the activation energy for ionic conductivity decreased significantly during aging. Ten mole percent Sc 2 O 3 samples did not show appreciable change in electrical conductivity due to aging, although some near‐surface cubic to rhombohedral transformation did occur. Sharpening of the (400) t XRD peak of Sc 2 O 3 ‐stabilzed tetragonal ZrO 2 accompanies the change(s) in the electrical conductivity.