Tape casting of fine alumina/zirconia powders for composite fabrication

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

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb07109.x· OSTI ID:6988275

Plucknett, K P; Caceres, C H; Wilkinson, D S ^[1]

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1. McMaster Univ., Hamilton, Ontario (Canada). Dept. of Materials Science and Engineering

Ceramic films, containing Al[sub 2]O[sub 3] with up to 40 vol% ZrO[sub 2], have been fabricated using the tape casting process. Finer powders (average mean diameter of 250--300 nm) than have generally been reported for tape casting were used in this study. The optimum formulation for tape casting is affected substantially by decreasing particle size. For example, the amount of dispersant needed is increased. Moreover, the amount of plasticizer/binder must be increased so as to maintain the solids content in the dried tapes below a critical level (about 55 vol% in this case), which decreases with particle size. Rheological studies on the effectiveness of menhaden fish oil and phosphate ester as dispersants show that phosphate ester can be used in lower concentrations, for the preparation of higher solids loading slurries, and was therefore selected for further study. The amount of dispersant required to obtain minimum slurry viscosity was found to be primarily dependent upon the effective particle surface area, defined as that available to the dispersant molecules. In the case of particles composed of agglomerated crystallites (such as the ZrO[sub 2] powder used here), this may be considerably less than that measured by nitrogen absorption. Moreover, the porous internal structure of such powders is filled with solvent, which increases the effective solids loading of the slurry, and thus its viscosity. Particle morphology also influences the packing efficiency; i.e., the green density decreases as ZrO[sub 2] is added.

• OSTI ID: 6988275
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:8; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
COLLOIDS
COMPOSITE MATERIALS
DISPERSIONS
FABRICATION
GRAIN SIZE
MATERIALS
MICROSTRUCTURE
MORPHOLOGY
OXIDES
OXYGEN COMPOUNDS
RHEOLOGY
SIZE
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES