Thermodynamic analysis of grain aspect ratio in fibrous microstructures of silicon nitride

Journal Article · Mon Dec 01 00:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb03262.x· OSTI ID:605772

Raj, R ^[1]; Hoffmann, M J ^[2]

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1. Univ. of Colorado, Boulder, CO (United States). Dept. of Mechanical Engineering
2. Univ. Karlsruhe (Germany). Inst. Keramik and Maschinenbau

Needlelike, free-floating {beta}-crystals of silicon nitride, precipitated within a supersaturated Y-Si-Al-O-N oxynitride glass, apparently approach an equilibrium value of the aspect ratio. An expression that relates this aspect ratio to the anisotropy in the interfacial energies of the longitudinal and transverse interfaces of the crystal is derived. The prediction agrees reasonably well with theoretical estimates of the interfacial energies. Kinetic and stearic effects that often lead to nonequilibrium values of the aspect ratio are discussed.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States)
• OSTI ID: 605772
• Journal Information: Journal of the American Ceramic Society, Vol. 80, Issue 12; Other Information: PBD: Dec 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILICON NITRIDES
MICROSTRUCTURE
GLASS
INTERFACES
FRACTURE PROPERTIES
MECHANICAL PROPERTIES
FIBERS