Although particle coarsening has been studied for over a century, it remains an active area of materials science research. The current work presents a theoretical analysis of the degradation of regular arrays of spherical particles through diffusional interaction. In order to understand the onset of coarsening, a linear stability analysis is performed on a simple square lattice of particles. It is predicted that particles will dissolve in a spatially ordered manner. The active transport mechanism plays a strong role in the selection of the coherent growth modes.

Controlled-geometry pore structures were introduced into undoped and Ti-doped sapphire using microfabrication techniques, and subsequently transferred to internal sapphire-sapphire and sapphire-polycrystalline alumina interfaces via hot pressing. The high-temperature evolution of several different types of structures was examined, in order to isolate different surface properties and evolution processes which are of interest during sintering. A study of pore channel breakup showed that Ti strongly stabilizes channels oriented in the sapphire [1100] direction, suggesting a significant alteration of the Wulff plot. In another study, the equilibration rate of isolated pores was enhanced in Ti-doped sapphire; as glassy phases are unlikely in this material, a solid-state diffusion mechanism for this enhancement is suggested. The evolution of pore channels with pre-existent perturbations was also studied, and the results of these studies are presented.

A recently developed technique combining photolithography, ion beam milling, and hot pressing allows the production of submicron-scale controlled-geometry, controlled-crystallography pore structures in controlled misorientation bicrystals, single crystal-polycrystal ensembles, and polycrystal-polycrystal ensembles. Such microdesigned interfacial structures provide a new tool for studying fundamental aspects of microstructural evolution. Current applications of the technique, opportunities for future research, and future extensions and refinements of the technique are described.