ABSTRACT
This chapter provides an outline of major techniques that are available for fabricating dense nanocrystalline ceramics, starting with powders. It emphasizes the importance of agglomeration-free green-body fabrication and two-step sintering (TSS), the latter being a unique, unconventional, yet industrially viable process capable of densification without grain growth. The chapter describes the kinetic of constant structure sintering in yttria and the successful application of TSS approach to several oxide and nonoxide ceramics with outstanding properties. TSS exploits the difference in the kinetics between grain boundary diffusion and grain boundary migration at low temperature, and it has been demonstrated for simple oxides, complex oxides, and liquid-phase sintered zinc oxide and silicon carbide. The simplicity of TSS approach should also make it a useful tool for preparing model systems to study grain-size-dependent properties in nanostructured materials and grain boundary kinetics at low temperatures.
