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Precursor‐derived Si–(B–)C–N ceramics: thermolysis, amorphous state and crystallization
Author(s) -
Bill Joachim,
Kamphowe Thomas W.,
Müller Anita,
Wichmann Thomas,
Zern Achim,
Jalowieki Artur,
Mayer Joachim,
Weinmann Markus,
Schuhmacher Jörg,
Müller Klaus,
Peng Jianqiang,
Seifert Hans Jürgen,
Aldinger Fritz
Publication year - 2001
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.242
Subject(s) - amorphous solid , ceramic , crystallization , metastability , thermal stability , boron nitride , chemical engineering , chemistry , phase (matter) , carbide , ceramic matrix composite , silicon carbide , thermal decomposition , chemical stability , mineralogy , crystallography , organic chemistry , engineering
The preparation of silicon nitride‐ and carbide‐based ceramics by solid‐state thermolysis of polysilazanes and polysilylcarbodiimides is described. Results on the ceramization of the preceramic compounds and the architecture of the corresponding amorphous states obtained by spectroscopic means and by X‐ray and neutron scattering are reviewed. Fundamental correlations between the composition and structure of the preceramic compounds and the architecture of the amorphous state are revealed. Furthermore, the crystallization behavior of the amorphous precursor‐derived Si–C–N ceramics is treated. Moreover, the influence of boron on the thermal stability of the amorphous state is described. The high‐temperature behavior of these Si–B–C–N solids can be correlated with their phase composition. Ceramic materials with compositions located close to the three‐phase equilibrium SiC + BN + C exhibit a high temperature stability up to 2000 °C. This effect is accompanied by the formation of a metastable solid consisting of Si 3 N 4 and SiC nanocrystals that are embedded in a turbostratic B–C–N matrix phase. Based on thermodynamic considerations, a model for the high‐temperature stability effect is proposed. Copyright © 2001 John Wiley & Sons, Ltd.