Influence of interparticle forces on the rheological behavior of pressure-consolidated alumina particle slurries

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb06980.x· OSTI ID:142254

Velamakanni, B V; Lange, F F; Zok, F W; Pearson, D S ^[1]

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1. Univ. of California, Santa Barbara, CA (United States). Materials Dept.

The stress relaxation behavior of alumina powder compacts, consolidated from aqueous slurries by pressure filtration, is reported. The interparticle forces were controlled prior to consolidation by changing the pH from 3 to 9 and by adding different amounts of salt (0.1 to 2.0 M NH{sub 4}Cl) to slurries maintained at pH 4. Disk-shaped bodies were rapidly compressed to an axial strain of 2%, and the resulting stress relaxation data were monitored as a function of time. For bodies formed from dispersed slurries (pH {<=} 4 without added salt), the stress relaxation behavior consisted of an irreproducible mixture of plastic and elastic response. The initial stress and the stress retained after long relaxation periods were highest for bodies formed with flocced slurries (pH 9). For bodies formed with coagulated slurries (pH 4 with added salt), the initial stress increased with the addition of 0.1 to 0.5 M salt, but the bodies behaved plastically, with more than 90% of the initial stress relaxing within a short period. These results are consistent with a short-range, repulsive interparticle force that lowers the attractive force between particles. They also suggest that interparticle forces in consolidated bodies can be controlled in a way that should prove useful in preventing damage that occurs during processing and reshaping operations.

• Sponsoring Organization: USDOE
• OSTI ID: 142254
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 77; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPACTING
EXPERIMENTAL DATA
FABRICATION
RHEOLOGY
SLURRIES
STRESS RELAXATION