Structural characterisation of silicon carbonitride ceramics derived from polymeric precursors

Polymeric precursors with tailored structures were prepared from functionalised chlorosilanes. Pyrolysis under inert atmospheres led to amorphous Si–C–N–(H) ceramics at 1000°C. Further heat treatment caused the transformation into the thermodynamically stable crystalline phase assemblage. The structural changes associated with crosslinking, pyrolysis and crystallisation were studied by characterising the solid intermediates between 300 and 1600°C applying 29Si and 13C solid state nuclear magnetic resonance (NMR) spectroscopy. In addition, Fourier transformed infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermoanalytical techniques and density measurements were employed. The combination of these methods and the use of polymeric precursors with tailored structures pointed to a correlation of the polymer architecture with the structure of the amorphous ceramic material.