SiC-whisker-reinforced Al[sub 2]O[sub 3] composites by free sintering of coated powders

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Journal of the American Ceramic Society; (United States)

OSTI ID:5627983

Hu, Chingli; Rahaman, M N ^[1]

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1. Univ. of Missouri, Rolla, MO (United States). Ceramic Engineering Dept.

SiC whiskers were coated with a thick cladding of fine-grained Al[sub 2]O[sub 3] powder by controlled heterogeneous precipitation in a concentrated suspension of whiskers. After calcination, the coated whiskers were compacted by cold isostatic pressing and sintered at a constant heating rate of 5 C/min in a helium atmosphere. The parameters which control the coating process and the sintering characteristics of the consolidated powders are reported. Starting with an initial matrix density of 40--45% of the theoretical, composites containing up to [approx]20 vol% whiskers (aspect ratio [approx]15) were sintered freely to nearly theoretical density below 1800 C. By comparison, a similar composite formed by mechanical mixing of the whiskers and the precipitated Al[sub 2]O[sub 3] powder reached a density of only 68% of the theoretical after sintering under identical conditions. For a fixed whisker content, the sinterability of the composites formed from the coated whiskers shows a fairly strong dependence on the whisker aspect ratio.

• OSTI ID: 5627983
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 76:10; 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
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
COMPOSITE MATERIALS
CRYSTALS
FABRICATION
MATERIALS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
POWDERS
SILICON CARBIDES
SILICON COMPOUNDS
SINTERED MATERIALS
SINTERING
WHISKERS