Mechanical properties and Oxidation resistance of monolithicC/SiO2/SiC nanocomposite aerogels based on Novolac/silica hybridaerogels

In this study, the carbon/silicon carbide (C/SiO2/SiC) nanocomposite aerogels prepared via pyrolysis and carbothermal reduction of Novolac/silica hybrid aerogels. Thermogravimetric analysis and compressive strength measurements are used to investigate thermal and mechanical properties of prepared aerogels, respectively. Scanning electron microscopy results demonstrate that the structural characteristics of fabricated nanocomposite aerogels retained after heat treatment steps. Also, the particles and pore size of prepared aerogels was in the nanometric range. The maximum oxidation rate temperature increased from 588 °C for carbon aerogel to about 750 °C for C/SiO2/SiCaerogels. Compressive strength of C/SiC aerogels is in the range of 1.8–2.3 MPa. This is very impressive as the compressive strength of novolac/silica aerogels is in the range of 0.2–1.4 MPa.

Keywords:

Nanocomposite aerogel , silicon carbide , oxidation resistance , compressive strength