Nano-SiC implantation into the structure of carbon/graphite materials made by pyrolysis (carbonization) of the precursor system coal tar pitch/poly(dimethylsiloxane) Original Research Article

Conversion of the air-cured poly(dimethylsiloxane) {–O–Si(CH3)2–}n to SiC during co-pyrolysis with a coal tar pitch is studied with reference to the related SiO2/pitch system. Each binary mixture is first homogenized at 160 °C followed by carbonization at 500 °C under argon to afford initial carbonizates. In both cases, one part of the initial carbonizate is further pyrolyzed at 1300 °C and another part at 1650 °C under an argon flow resulting in composite products. All products are studied with FT-IR, XRD, and XPS spectroscopic methods supplemented with SEM and ‘wet’ Si-analyses, when applicable. Carbothermally assisted conversion of both silicon precursors to nanocrystalline SiC embedded in the evolving C-matrix, i.e. nano-SiC/C composites, is evident only after the 1650 °C carbonization stage.