Development of silicon nitride composites with continuous reinforcement

Conference · Thu Jul 01 04:00:00 EDT 1993

OSTI ID:140115

Starr, T L; Mohr, D L; Hanigofsky, J A ^[1]

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1. Georgia Institute of Technology, Atlanta, GA (United States)

Silicon nitride matrix composites are fabricated using the reaction sintering process by combining ceramic fiber with silicon powder and converting the silicon to nitride at high temperature in a nitrogen atmosphere. Critical factors in achieving good composite properties are effective impregnation of the multifilament tows, fiber stability during processing and fiber-matrix interface in the final composite. The authors form tube shapes by passing the Nicalon fiber tow through a slurry of silicon powder, winding the fiber onto a mandrel to form a unidirectional composite. As compared to the previous cloth lay-up method, this fabrication scheme produces better matrix distribution between individual filaments. Nicalon{trademark} fiber stability during processing is enhanced by CVD coating as-received fiber with layers of carbon and silicon carbide prior to slurry impregnation and winding. Flexure bar and C-ring testing produces non-brittle fracture but significant shear failure parallel to the fiber direction.

• Research Organization: Oak Ridge National Lab., TN (United States)
• OSTI ID: 140115
• Report Number(s): ORNL/FMP--93/1; CONF-9305135--; ON: DE94001091
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
COMPOSITE MATERIALS
FABRICATION
FILAMENTS
SILICON NITRIDES