ABSTRACT
Nanocrystalline ceramics have attracted considerable interest in recent years because of the promise of new and interesting properties that are sensitive to the crystallite size. These include mechanical, optical, electrical, and magnetic properties, many of them only manifest in dense ceramics. These new properties are linked to the high density of grain boundaries and interfaces that result from their nanoscale structure (characteristic length scale below 100 nm) [1]. Over the past 20 years, nanocrystalline oxide and nonoxide powders of high purity have also become available from a variety of synthetic routes, such as precipitation, sol-gel, inert gas condensation, chemical vapor deposition, high-energy milling, and hydrothermal reactions. As a result, considerable progress has been made in fabricating nanocrystalline ceramics. In the field of electroceramics, this progress is additionally driven by the technological imperative to miniaturize in order to realize reduced device sizes and the increasing desire to impart multifunctionality into a single component. This trend is expected to continue into the foreseeable future; hence the increasing importance of the fabrication processes, such as sintering, that may enable nanotechnology [2].
