Structural characterisation of silicon carbonitride ceramics derived from polymeric precursors

Polymeric precursors with tailored structures were prepared from functional ised chlorosilanes. Pyrolysis under inert atmospheres led to amorphous Si-C -N-(H) ceramics at 1000 degrees C. Further heat treatment caused the transf ormation into the thermodynamically stable crystalline phase assemblage. Th e structural changes associated with crosslinking, pyrolysis and crystallis ation were studied by characterising the solid intermediates between 300 an d 1600 degrees C applying Si-29 and C-13 solid State nuclear magnetic reson ance (NMR) spectroscopy. In addition, Fourier transformed infrared (FTIR) s pectroscopy, X-ray diffraction (XRD), thermoanalytical techniques and densi ty measurements were employed. The combination of these methods and the use of polymeric precursors with tailored structures painted to a correlation of the polymer architecture with the structure of the amorphous ceramic mat erial. (C) 2000 Elsevier Science Ltd. All rights reserved.