New methods of determining the real structure parameters of special gels and silicate glasses

Abstract

This paper is concerned with the application of new x-ray diffraction methods for studying the structure of gels and silicate glasses. Low- and wide-angle x-ray diffraction methods were applied. The summarized, differential and differentiated by subtraction radial distribution functions were analyzed. Basic structural parameters (interatomic distances, distances between groups of atoms and coordination numbers and zones) internal ordering degree and concentrations of inhomogeneous zones were determined. Structural models approximating the real structure of special gels (SiO 2·xH 2O and SiO 2·xH 2O + R 2O 3) and models of local ordering in silicate glasses (SiO 2, SiO 2 + Na 2O 3 + CaO + MgO + R 2O 3/FeO, Fe 2O 3) are also described. The theory of the structural analysis applied to the materials studied is presented, including a detailed description of the new methods used to determine the parameters of the real structure of the substances studied. The usefulness of the measuring and analysis methods is described also. A comparison is made between data obtained in my laboratory and that available in the literature. The structural models constructed from the structural parameters obtained by the radial function method are considered as to their accuracy and probability to be found. The accuracy of the measurements, both apparatus and numerical calculations, is evaluated. The structural diffraction measurements are supplemented with the analyses of surface layers made by other methods including x-ray spectrometry and microspectrometry, emission electron microscopy, and local microhardness and microplasticity.