Synthesis of Silicon Carbide Powders from Methyl-Modified Silica Aerogels

Autor: Kyoung-Jin Lee, Yanggu Kang, Young Hun Kim, Se Won Baek, Haejin Hwang
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Applied Sciences, Vol 10, Iss 18, p 6161 (2020)
Druh dokumentu: article
ISSN: 2076-3417
DOI: 10.3390/app10186161
Popis: β-silicon carbide (SiC) powders were synthesized by the carbothermal reduction of methyl-modified silica aerogel/carbon mixtures. The correlations between the phase evolution and morphologies of the SiC powders and the C/SiO2 ratio were investigated. At a C/SiO2 ratio of 3, β-SiC formed at 1425 °C and single-phase SiC powders were obtained at 1525 °C. The methyl groups (-CH3) on the silica aerogel surfaces played important roles in the formation of SiC during the carbothermal reduction. SiC could be synthesized from the silica aerogel/carbon mixtures under lower temperature and C/SiO2 ratios than those needed for quartz or hydrophilic silica. The morphology of the SiC powder depended on the C/SiO2 ratio. A low C/SiO2 ratio resulted in β-SiC powder with spherical morphology, while agglomerates consisting of fine SiC particles were obtained at the C/SiO2 ratio of 3. High-purity SiC powder (99.95%) could be obtained with C/SiO2 = 0.5 and 3 at 1525 °C for 5 h.
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