Micro-Raman investigation of the nanostructure evolution of Boron-doped SiOC powders after pyrolysis at high temperature

Polymer-derived ceramics, constitute a class of ceramic materials obtained through pyrolysis of pre-ceramic polymers. Initial examples of PDCs were the silicon carbide fibers for high temperature structural applications. Recently, boron doped silicon-based ceramics with enhanced high-temperature stability have attracted great attention [1]. SiOC:B samples, with different B content, were synthesized using the sol gel method at different B concentration and the synthesized samples underwent pyrolysis at 1200°C and 1400°C. Herein, we present the spectroscopic study of thermally treated SiOC:B samples doped with increasing amounts of boron. The study of has been done using micro Raman spectroscopy. In pure SiOC powders, treated at 1400°C , the two D and G bands which are barely visible in SiOC sample treated at 1200°C , turn out in the form of well resolved peaks at about 1332 cm-1 and 1609 cm-1. The temperature evaluation of these two fingerprints indicates that the graphitic component of SiOC powders undergoes an important structural rearrangement. In samples with higher concentration of B, treated at 1400°C, there is a clear evidence of the D’ at 1605 cm-1, G’(2D) at 2658 cm-1 and D+G at 2913 cm-1.The 2D band is sensitive to the stacking of graphene sheets, which becomes well defined at 1400°C .