Improved processing of. alpha. -SiC

Journal Article · Sun May 01 04:00:00 EDT 1988 · Advanced Ceramic Materials; (USA)

DOI:https://doi.org/10.1111/j.1551-2916.1988.tb00213.x· OSTI ID:5943044

Dutta, S ^[1]

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1. NASA-Lewis Research Center, Cleveland, OH (USA)

Improved processing techniques such as slurry pressing and hot isostatic pressing were used to minimize processing defects and to improve strength and reliability in fabricated SiC. For this purpose, compacts were fabricated by various consolidation techniques: (1) dry-pressing and sintering, (2) slurry-pressing and sintering, and (3) slurry-pressing and hot isostatic pressing. High density (>96% of theoretical) was produced by sintering at 2,150{degree} to 2,200{degree}C. By contrast, a much lower temperature (1,875{degree} to 1,900{degree}C) was required for high-density specimens by hot isostatic pressing. The isostatistically hot-pressed {alpha}-SiC exhibited an ultrafine-grained microstructure (0.3 to 3 {mu}m) compared to 1 to 17 {mu}m produced by sintering. Dry-pressing and sintering yielded an average flexure strength (4-point bend) as high as 348 MPa. On the other hand, slurry-pressing resulted in an {approx}25% improvement in strength, 348 to 428 MPa. Further, isostatic hot-pressing of slurry-pressed specimens exhibited an average strength as high as 655 MPa. This value was {approx}90% higher than the dry-pressed/sintered strength and {approx}60% higher than the slurry-pressed/sintered strength.

• OSTI ID: 5943044
• Journal Information: Advanced Ceramic Materials; (USA), Journal Name: Advanced Ceramic Materials; (USA) Vol. 3:3; ISSN 0883-5551; ISSN ACEME
• 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
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
DATA
EXPERIMENTAL DATA
FABRICATION
FLEXURAL STRENGTH
HIGH PRESSURE
HOT PRESSING
INFORMATION
MATERIALS WORKING
MEASURING METHODS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NUMERICAL DATA
PRESSING
SILICON CARBIDES
SILICON COMPOUNDS
SINTERING