The effect of precursor system on the resistivity and oxidation susceptibility of C/SiC nanocomposites en route to electronic grade nanomaterials

Presented are results of a study on specific technological properties of affordable C/SiC composite nanomaterials obtained via pyrolysis of several pitch/silicon-bearing precursor systems (elemental Si, silica SiO2, poly(carbomethylsilane) [-CH2-Si(H)CH3-]n, commercial SiC). For pyrolysis at 1300 °C, the formation of nanosized SiC is detected in the systems with elemental Si and poly(carbomethylsilane) while 1650 °C pyrolysis is required for silica to achieve such conversion. In situ formed nano-SiC is homogeneously dispersed in the simultaneously evolving graphitic carbon matrix of the composites. Reactivities vs. CO2, electrical resistivities, and surface properties of the nanocomposites are determined. Significant differences and patterns in the properties among the materials obtained from these precursor systems and at the selected pyrolysis temperatures are clearly established. Among others, the data suggest potential for carbon removal from the most reactive nanocomposites via reactions with CO2 to yield unique nano-SiC powder products for further processing towards electronic and ceramic applications.