SOL-GEL GLASSES AND NANOMATERIALS ON THE BASE OF SiO_2

摘要

Silica gels containing Ag_2O and PtO_2 have been synthesized. The gels have been heat treated in the 25-1000°C temperature range. It has been established that the temperature of gel to gel-glass transition decreases when the Ag_2O and PtO_2 content in the gels increases. Special attention is paid to the formation of silver and platinum metallic particles in amorphous materials. The sizes of the metal particles are determined to be from 3 to 25 nm. The crystallization processes in the gels heat treated at 1000-1200°C are carried out and besides the silver and platinum particles the crystalline phase of α-crystobalite is separated. It has been shown that nanocomposite materials containing ultrafine silver and platinum particles in SiO_2 amorphous or poly-crystalline matrixes can be obtained.