Effect of aqueous processing conditions on the microstructure and transformation behavior in Al[sub 2]O[sub 3]-ZrO[sub 2](CeO[sub 2]) composites

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1992.tb05484.x· OSTI ID:6973396

Bleier, A; Becher, P F; Alexander, K B; Westmoreland, C G ^[1]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

This paper reports on aqueous processing of Al[sub 2]O[sub 3]-ZrO[sub 2] (12 mol% CeO[sub 2]) composites, combined with sintering conditions, which was used to control the microstructure and its influence on the martensitic transformation temperatures of t-ZrO[sub 2] and the transformation-toughening contribution at room temperature. The resultant ZrO[sub 2] grain sizes in the dense composites were related to the transformation-toughening behavior of t-ZrO[sub 2]. The data show that the best processing conditions exist when the electrophoretic mobilities of the two solids are positive, adequately high to ensure colloidal stability, efficient packing, and uniform ZrO[sub 2] distribution, but differ greatly in magnitude, the colloidal stability of ZrO[sub 2] controls the overall stability and the rheological and processing behavior of this mixture, the grain size distribution in dense pieces sintered for 1 h at 1500[degrees] C is comparable to the particle size distribution of the powders, the martensite start temperature for the tetragonal-to-monoclinic transformation in Al[sub 2]O[sub 3] containing 20 and 40 vol% ZrO[sub 2] increases and can approach 0[degrees] C with increasing average ZrO[sub 2] grain size, and, as a result, the fracture toughness values at room temperature are raised from 4-5 MPa [center dot] m[sup [1/2]] to 9-12 MPa [center dot] M[sup [1/2]] for these two compositions.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6973396
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 75:10; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AQUEOUS SOLUTIONS
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DISPERSIONS
FABRICATION
FAILURES
FRACTURES
GRAIN SIZE
MATERIALS
MICROSTRUCTURE
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
RHEOLOGY
SINTERING
SIZE
SOLUTIONS
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES