Control of grain-boundary pinning in Al sub 2 O sub 3 /ZrO sub 2 composites with Ce sup 3+ /Ce sup 4+ doping

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1992.tb04147.x· OSTI ID:5132300

Xue, L A; Meyer, K; Chen, D W ^[1]

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1. Dept. of Materials Science and Engineering, Univ. of Michigan, Ann Arbor, MI (US)

In this paper the control of the microstructure of Ce-doped Al{sub 2}O{sub 3}/ZrO{sub 2} composites by the valence change of cerium ion is demonstrated. Two distinctively different types of microstructure, large Al{sub 2}O{sub 3} grains with intragranular ZrO{sub 2} particles and small Al{sub 2}O{sub 3} grains with intergranular ZrO{sub 2} particles, can be obtained under identical presintering processing conditions. At doping levels greater than {approximately}3 mol % with respect to ZrO{sub 2}, Ce{sup 3+} raises the alumina grain-boundary to zirconia particle mobility ratio. This causes the breakaway of grain boundary from particles and the first type of microstructure. On the other hand, Ce{sup 4+} causes no breakaway and produces a normal intergranular ZrO{sub 2} distribution. The dramatic effect of Ce{sup 3+} on the relative mobility ratio is found to be associated with fluxing of the glassy boundary phase and is likewise observed for other large trivalent cation dopants. The ZrO{sub 2} second phase acts as a scavenger for these trivalent cations, provided their solubility limit in ZrO{sub 2} is not exceeded.

• OSTI ID: 5132300
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 75:4; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CERIUM ADDITIONS
CERIUM ALLOYS
CHALCOGENIDES
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
DISLOCATION PINNING
DOPED MATERIALS
GRAIN BOUNDARIES
MATERIALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES