Preparation of SiO₂ Glass from Model Powder Compacts: II, Sintering

The sintering behavior of powder compacts formed from spherical, nearly monosized SiO₂ particles was investigated. Highly ordered compacts sintered to high density and translucency at 1000°C. In contrast, less homogeneous samples prepared from flocculated suspensions remained highly porous after sintering under the same conditions. Densification kinetics were determined over the temperature range 900° to 1050°C for ordered compacts. The viscosity at each sintering temperature and the activation energy for viscous flow were determined using available sintering models. Sintering of ordered compacts is divided into several stages. Densification, mercury porosimetry, and electron microscopy results indicate that the first stage is dominated by the shrinkage of three‐particle pore channels, whereas the second stage primarily involves the shrinkage of four‐particle pore channels.