Approach of phase transformations and densification in nanostructured and (Bi2O3, ZnO,TiO2) doped silica ceramics

The low temperature sintering of silica is studied under the influence of sintering aids and nanosized powders using X-Ray Diffractometry (XRD) and high-temperature environmental scanning electron microscopy analyses (HT-ESEM). Two particular aids were chosen to conduct this study, [Bi₂O₃–ZnO]_eutectic and titania. We report a lowering of the crystallization temperature when the former compound is introduced in the silica while a raise is observed when the latter is used. Moreover, the amorphous silica crystallization into cristobalite inhibits drastically the kinetics of densification of silica-based materials.