Investigations of Shock Wave Synthesis of Metastable Compounds.

Abstract : In accordance with the contract requirements the investigation of phase formation in GeO2-SiO2 system under the effect of shock waves has been undertaken with the aim of revealing of possibilities of explosion as a preparative method in the chemistry of metastable compounds as well as of investigating of the mechanism of chemical reactions in shock wave. The system has been taken as a model since no compounds were obtained in it by no one traditional method of synthesis and the existence of binary compounds is contradicted on the basis of counter polarization concept in principle. Besides that the realization of chemical processes in the system is made difficult due to high viscosity and low diffusion coefficients of components in solid and melt states. Nevertheless mixed compounds have been synthesized under the effect of shock waves and the scheme of phase formation has been constructed in relation to the intensity of shock wave effect. One of these compounds of wide homogeneity range (approx. 30-70 mol%) is realized in the form of cubic solid solution of fluorite type structure. Besides that the compound of GeSiO4 composition stabilized by the excess of SiO2 has been obtained. It has been found out that the compounds are metastable, and the scheme of phase formation constructed with data of shock wave synthesis is representative of metastable diagram of state realizing in the system GeO2-SiO2 in the conditions of explosion treatment.