Structural characterization and high-temperature behavior of silicon oxycarbide glasses prepared from sol-gel precursors containing Si-H bonds

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08811.x· OSTI ID:79806

Soraru, G D; D`Andrea, G; Campostrini, R; Mariotto, G ^[1]; Babonneau, F ^[2]

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1. Univ. di Trento (Italy)
2. Univ. Pierre et Marie Curie, Paris (France). Chimie de la Matiere Condensee

Silicon oxycarbide glasses have been synthesized by inert atmosphere pyrolysis at 1,000 C of gel precursors obtained by cohydrolysis of triethoxysilane, HSi(OEt){sub 3}, and methyl-diethoxysilane, HMeSi(OEt){sub 2}. The oxycarbide structures have been carefully characterized by means of different techniques such as {sup 29}Si magic angle spinning nuclear magnetic resonance (MAS-NMR) and Raman spectroscopies, X-ray diffraction (XRD), and chemical analysis. Experimental results clearly indicate that, depending on the composition of the starting gels, the resulting oxycarbide glass either is formed by a pure oxycarbide phase or contains an extra carbon or silicon phase. By increasing the temperature up to 1,500 C, the oxycarbide glasses display compositional and weight stability; however, the amorphous network undergoes structural rearrangements that lead to the precipitation of nano-sized {beta}-SIC crystallites into amorphous silica. Crystallization of metallic silicon is also clearly observed at 1,500C for the samples in which the presence of Si-Si bonds was postulated at 1,000 C.

• Sponsoring Organization: USDOE
• OSTI ID: 79806
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 2 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CHEMICAL ANALYSIS
CRYSTALLIZATION
GLASS
MICROSTRUCTURE
NUCLEAR MAGNETIC RESONANCE
PRECIPITATION
PYROLYSIS
RAMAN SPECTROSCOPY
SILICON
SILICON CARBIDES
SILICON OXIDES
SOL-GEL PROCESS
X-RAY DIFFRACTION