前駆体法によって合成された炭化ケイ素粉末のシリコン-29固体MAS NMRによる研究

概要

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Carbon-silica hybrid precursors were synthesized from the liquid mixtures of tetraethyl orthosilicate and phenol resin by condensation reaction and pyrolysis. The precursors obtained by the pyrolysis at 1273 K yielded silicon carbide powders with various morphology after heat treatments at 1773-1973 K in an Ar atmosphere. Solid state ^<29>Si MAS NMR is used for powder characterization. In the case that the crystallites are held at small size during heat treatments, the powders shows three signals at -16, -20 and -25 ppm in the NMR spectra. After coarsening of the crystallites and grains with heat treatment under no residual carbon, the powder shows the broad signal at -19 ppm with a small spike at -16 ppm. The signal at -19 ppm would correspond to the "β-SiC" structure disordered by somewhat "α-SiC" areas.
社団法人日本セラミックス協会の論文
2000-12-01