Sintering model for SiC(sub)w/Si sub 3 N sub 4 composites

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5784679

Freedman, M R; Kiser, J D; Sanders, W A

Presented is a model which suggests that it should be possible to pressureless sinter a SiC(sub w)/ Si{sub 3}N{sub 4} composite to theoretical density. Prior failure to achieve complete densification by sintering is attributed to the use of compositions which result in a glass deficit. There is one basic premise for this model. The ratio of glass amount to surface area of nonglass constituents must be the same for both composite and sinterable monolithic Si{sub 3}N{sub 4}. This model suggests that whisker and grain sizes and whisker loading influence the glass amount necessary for successful sintering of composites. According to the model, a large glass amount will be necessary for successful sintering of these composites. However, grain boundary thicknesses in the composite will be less than those in the analogous monolithic materials. This suggests that good high temperature strength may still be attained. A recent report supports the predictions of the model.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• OSTI ID: 5784679
• Report Number(s): N-89-10166; NASA-TM--101336; E--4354; NAS--1.15:101336; CONF-880504--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
CARBIDES
CARBON COMPOUNDS
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
CRYSTALS
FABRICATION
GLASS
GRAIN BOUNDARIES
GRAIN SIZE
MATERIALS
MICROSTRUCTURE
MONOCRYSTALS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
SINTERING
SIZE
STRUCTURAL MODELS
WHISKERS