Preparation of phase-separated textures and crystalline phases from two-liquid immiscible melts in the TiO₂-SiO₂ system

Phase-separation textures in two-liquid immiscible melts in the TiO ₂-SiO₂ system were obtained by melting at 1800°C and rapidly quenching TiO₂-SiO₂ samples of various compositions. The chemical compositions studied contained 40-90mass% TiO ₂. The resultant samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystalline phases varied according to the melting conditions and the compositions. The anatase fraction in the samples decreased with increasing TiO₂ content. The difference in the anatase fraction in these samples is attributed to the difference in their microtextures which change from a binodal texture containing a TiO ₂-rich phase dispersed in a SiO₂-rich matrix to a spinodal texture, then to a binodal texture containing a SiO₂-rich phase dispersed in a TiO₂-rich matrix. The phase-separation textures coarsened on melting at higher temperatures, causing a change in the anatase fraction due to the change in the phase-separation texture.