Silicon carbonitride ceramics derived from polysilazanes Part I. Investigation of compositional and structural properties

In this paper we report on the compositional and structural properties of ceramics in the Si-C-N system. The amorphous material synthesised by thermally induced ceramisation of an organo-substituted polysilazane crystallises at temperatures exceeding 1450 degrees C in nitrogen atmosphere. Chemical composition solid state structure, microstructure as well as the crystallisation behaviour depend on: (i) the synthesis conditions; (ii) the pyrolysis atmosphere; and (iii) the time and temperature of a final heat treatment. The chemical composition was determined by chemical bulk analysis together with N-15-method and electron energy-loss spectroscopy (EELS). Reaction products formed during the heat treatment were analysed in-situ by thermal gravimetric analysis coupled with mass spectrometry. The hybridisation of carbon in the solid reaction product was determined by X-ray absorption near-edge structure (XANES). The resulting amorphous microstructure was investigated by electron microscopy (HRTEM), while the crystalline phases were analysed by X-ray diffraction (XRD). (C) 2000 Published by Elsevier Science Ltd. All rights reserved.