Effect of vapor-liquid-solid and vapor-solid silicon carbide whiskers on the effective thermal diffusivity/conductivity of silicon nitride matrix composites

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1991.tb06945.x· OSTI ID:5189039

Russell, L M; Donaldson, K Y; Hasselman, D H ^[1]; Corbin, N D ^[2]; Petrovic, J J ^[3]; Rhodes, J F ^[4]

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1. Dept. of Materials Engineering, Virginia Polytechnic Inst., Blacksbury, VA (US)
2. Norton Co., Northborough, MA (US)
3. Los Alamos National Lab., Los Alamos, NM (US)
4. Advanced Composite Materials Corp., Greer, SC (US)

This paper reports on a study that was conducted of relative effect of vapor-liquid-solid (VLS) and vapor-solid (VS) SiC whiskers on the effective thermal diffusivity and conductivity of pressed-densified silicon nitride. It was found that VLS whiskers cause an increase in the thermal diffusivity/conductivity, whereas the opposite effect was found for the VS-SiC whiskers. Comparison with composite theory suggests that the VS-SiC whiskers have a thermal conductivity as low as 25 to 30 W/(m {center dot} K). In contrast the VLS-SiC whiskers appear to have a value for the thermal conductivity of at least about 100 W/(m{center dot} K) to as high as 250 W/(m {center dot} K). These large differences in thermal conductivity for these two types of SiC whiskers are attributed to the much larger density of structural defects in the VS-SiC whiskers, which act as phonon scatterers, thereby lowering the thermal conductivity.

• OSTI ID: 5189039
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 74:4; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
THERMAL CONDUCTIVITY
SILICON CARBIDES
METALLURGICAL EFFECTS
SILICON NITRIDES
THERMAL DIFFUSION
WHISKERS
CARBIDES
CARBON COMPOUNDS
CRYSTALS
DIFFUSION
MATERIALS
MONOCRYSTALS
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
SILICON COMPOUNDS
THERMODYNAMIC PROPERTIES
360603* - Materials- Properties