Synthesis and characterization of SiC whiskers
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)
- High Temperature Materials Laboratory, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
SiC whiskers were synthesized by the carbothermal reduction of silica with an addition of halide (3NaF{center dot}AlF{sub 3} or NaF) as an auxiliary bath. The whiskers were {beta} phase (3C) and grew in the (111) direction. Three distinctive morphologies were observed: (1) Type A: thin and straight; (2) Type B: thick and bamboo-like; and (3) Type C: thick, straight, and smooth. Type A whiskers contained a high density of basal plane (111) stacking faults along their entire length, whereas Type B whiskers showed periodic changes between stacking faults and well-defined single crystals. Type C whiskers showed stacking faults on the other {l brace}111{r brace} planes instead of on the basal (111) plane. Silica formed molten fluorosilicate with halide and SiC grew via a vapor-solid reaction mechanism through gaseous SiO. These reactions can be expressed as (SiO{sub 2})+C(s)=SiO(g)+CO(g) and SiO(g)+3CO(g)=SiC(s)+2CO{sub 2}(g). The effects of processing parameters on the morphology and size of the whiskers were examined and the relationship between the morphological development of the whiskers and the stacking fault energy was determined.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5003611
- Journal Information:
- Journal of Materials Research; (United States), Vol. 7:1; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON CARBIDES
MORPHOLOGY
SYNTHESIS
WHISKERS
CHEMICAL REACTIONS
MONOCRYSTALS
STACKING FAULTS
CARBIDES
CARBON COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
SILICON COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies