Quantitative Phase Analysis of Plasma-Treated High-Silica Materials

Abstract

The paper presents the X-ray diffraction (XRD) analysis of the crystal structure of SiO₂ in two modifications, namely quartzite and quartz sand before and after plasma treatment. Plasma treatment enables the raw material to melt and evaporate after which the material quenches and condenses to form nanoparticles. The Rietveld refinement method is used to identify the lattice parameters of SiO₂ phases. It is found that after plasma treatment SiO₂ oxides are in the amorphous state, which are modeled within the microcanonical ensemble. Experiments show that amorphous phases are stable, and model X-ray reflection intensities approximate the experimental XRD patterns with fine precision. Within the modeling, full information is obtained for SiO₂ crystalline and amorphous phases, which includes atom arrangement, structural parameters, atomic population of silicon and oxygen atoms in lattice sites.