Silicon nitride ceramic fibers from preceramic polymers. Technical report

Technical Report · Mon Jun 01 00:00:00 EDT 1987

OSTI ID:6017303

Laine, R M; Blum, Y D; Chow, A; Schwartz, K S

The program objectives are to develop: (1) Transition metal catalyzed synthetic routes to designed, tractable silicon nitride (Si/sub 3/N/sub 4/) preceramic polymers (polysilazanes) based on SRI developed technology; (2) Methods of spinning the resultant polysilazanes into continuous preceramic fibers; and, (3) Pyrolysis techniques for transforming the preceramic fibers into high strength Si/sub 3/N/sub 4/ and silicon carbide nitride (SiCN) fibers. In the past year, polysilazanes driven from precursors of the type-H/sub 2/SiNMe were prepared, whose viscoelastic properties can be carefully controlled by type of catalyst and/or reaction conditions. This control permitted drawing preceramic fibers of diameters as small as 10 um. Furthermore, pyrolysis methodology was developed from which ceramic yields of 50-70% were obtained with Si/sub 3/N/sub 4/ purities ranging from 80-99%. It was discovered that polymer molecular weight greatly influences the ceramic yield, but only monomer design or pyrolysis under a reactive atmosphere seems to influence selectivity to specific ceramic products.

• Research Organization: SRI International, Menlo Park, CA (USA)
• OSTI ID: 6017303
• Report Number(s): AD-A-183442/3/XAB; TR-8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
FIBERS
PRODUCTION
POLYMERS
PROCESSING
SILICON CARBIDES
SYNTHESIS
SILICON NITRIDES
CATALYSTS
MOLECULAR WEIGHT
MONOMERS
PYROLYSIS
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
DECOMPOSITION
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON COMPOUNDS
THERMOCHEMICAL PROCESSES
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360601 - Other Materials- Preparation & Manufacture