Pyrolysis chemistry of polysilazane precursors to silicon carbonitride

Abstract

The cross-linking reactions and the decomposition processes of three different polysilazane precursors to silicon carbonitride have been investigated systematically in the course of pyrolysis to 1400 °C. The polymer to ceramic conversion chemistry was studied for the following precursors: (ViSiHNH) _n (VS), (ViSiHNMe) _n (VNMS), [(ViSiHNH) _0.5 –(MeSiHNH) _0.5 ] _n (VS/MS), by means of thermogravimetry, mass spectrometry, solid-state NMR and IR spectroscopies, elemental analysis and X-ray diffraction. The influence of the structure and the polymer backbone (the nature and distribution of the functional groups) on the conversion chemistry was investigated. The occurrence of the cross-linking reactions, the ceramic yields and the abundance of the free carbon phase are related to the polymeric precursor structures.