Low‐Temperature Fabrication of Porous β‐SiC Ceramics in Sodium Vapor
2007; Wiley; Volume: 91; Issue: 1 Linguagem: Inglês
10.1111/j.1551-2916.2007.02021.x
ISSN1551-2916
AutoresFumihiro Kawamura, Hisanori Yamane, Takahiro Yamada, Shu Yin, Tsugio Sato,
Tópico(s)Boron and Carbon Nanomaterials Research
Resumoβ‐silicon carbide (SiC) porous ceramics were synthesized from pelletized powder mixtures of silicon (Si) and fullerene or Si and amorphous carbon (carbon black) at 1000 K for 24 h in sodium (Na) vapor. The relative density of the ceramics was 29%–34% of the theoretical density of SiC. Scanning electron microscopic observation of the fracture surface showed that the ceramics prepared with fullerene were agglomerates of submicrometer‐sized SiC particles and open spaces. The samples prepared with carbon black had a smooth fracture surface with cavities and voids. Using transmission electron microscopy, grains of over 250 nm and a diffuse electron diffraction ring pattern of β‐SiC were observed for the sample prepared with fullerene, and grains of 10–20 nm with a β‐SiC spot ring pattern for the sample prepared with carbon black. A surface area of 11–17 m 2 /g and a mesopore size distribution in the range of 2–10 nm were shown by a nitrogen adsorption technique. Energy‐dispersive X‐ray analysis detected 1–5 at.% of Na against Si on the fracture surface of the ceramics.
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