A Study of the Influence of Temperature Gradients on Densification of Glass Powder Compacts [Thesis]

In the present study, we are concerned with the influence of temperature gradients on densification during the early stages of sintering in glass powder compacts. Glass was chosen primarily because it is of interest to determine if gradients can enhance densification, not only by diffusion in crystalline particles, but also by viscous flow. A second reason for using glass was that glasses clearly have the isotropic surface energies assumed in sintering models. The assumption that surface energies are isotropic is not always valid for crystalline ceramics and that assumption has been shown to lead predictions for grain growth which are in conflict with observations. Furthermore, grain boundary free energies, which are often neglected in sintering models, are absent when glass is sintered. 12 figs., 5 tabs.