Effect of dopants on zirconia stabilization -- An x-ray absorption study; 2: Tetravalent dopants

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb05403.x· OSTI ID:7303174

Li, P; Chen, I W; Penner-Hahn, J E ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States)

X-ray absorption spectra at Zr-K, Ce-L[sub m], and Ge-K edges in ZrO[sub 2]-CeO[sub 2] and ZrO[sub 2]-CeO[sub 2] solid solutions have been measured at 10 K. Both Ce and Ge substitute for Zr in the cation network, but CeO[sub 8] and GeO[sub 4] polyhedra are maintained around the dopants. The oversized CeO[sub 8] is compressed to a Ce-O distance of 2.30 [angstrom], which is smaller than the 2.35 [angstrom] seen in fluorite-type CeO[sub 2]. Meanwhile, the distortion of the Zr-cation network is increased and the tetragonality is reduced. The undersized Ge has a Ge-O distance of 1.80 [angstrom], which is much shorter than the Zr-O[sub I] distance of 2.10 [angstrom]. A strong tendency for Ge-Zr ordering in tetragonal solid solutions into locally scheelite-like clusters, even within the solubility limit, is observed. This results in an increase in the tetragonality and a decrease in the distortion of the cation network. Despite the opposite effects on tetragonality, both Ce and Ge doping can stabilize tetragonal zirconia albeit via different mechanisms. The structural origin of the cubic phase is also elucidated.

• OSTI ID: 7303174
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:5; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
CRYSTAL STRUCTURE
DATA
DIAGRAMS
DOPED MATERIALS
EXPERIMENTAL DATA
GERMANIUM COMPOUNDS
GERMANIUM OXIDES
INFORMATION
MATERIALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES