INVESTIGATIONS ON SURFACE REACTIVITY OF SILICON-CARBONITRIDE POWDERS BY THERMOANALYTICAL METHODS

Fine-grained powders of excellent homogeneity represent a requirement for high performance materials based on silicon nitride and silicon ca rbide. Such powders can be produced by pyrolysis of organometallic pre cursors. The investigated silicon-carbonitride powders were prepared b y gas phase-pyrolysis of disilazane or oligosilazanes under different pyrolysis conditions. On-line coupling of thermogravimetry (TG) with e volved gas analysis (EGA)/mass spectrometry (MS) was applied to charac terize the behaviour of powders during annealing processes. The result s show clearly the influence of pyrolysis conditions and post-treatmen t steps on the surface properties of powders.