How xerogel carbonization conditions affect the reactivity of highly disperse SiO2–C composites in the sol–gel synthesis of nanocrystalline silicon carbide

摘要: A transparent silicon polymer gel was prepared by sol–gel technology to serve as the base in preparation of highly disperse SiO2–C composites at various temperatures (400, 600, 800, and 1000°C) exposure times (1, 3, 6 h) via pyrolysis under a dynamic vacuum (at residual pressures ~1 × 10–1 1 10–2 mmHg). These were X-ray amorphous; their thermal behavior flowing air range 20–1200°C studied. The encapsulation nascent carbon, which kept it from oxidizing reduced reactivity system SiC synthesis, enhanced carbonization temperature time increased. How xerogel conditions affect micro- mesostructure studied ultra-small-angle neutron scattering (USANS). Both found considerably influence structure formation composites. Dynamic DSC/DTA/TG experiments an inert gas flow showed that increasing significantly carbide yields upon subsequent heating systems 1500°C, 35–39 (400°C) 10–21% (1000°C).