Chapter 19 - Chemical Preparation of Advanced Ceramic Materials

Abstract

This chapter focuses on the chemical preparation of advanced ceramic materials. From the first use of flint and obsidian during the Stone Age, to the formation of vessels from clay, to the use of refractories in the iron and steel industry, to the fabrication of optical fibers for high-speed communication, ceramics have revolutionized society and technology in many ways. Novel ceramic materials are always surprising us. How to prepare advanced ceramics has become the key point. Conventionally nanostructured ceramics are defined as inorganic materials composed of structural units with a size scale of less than 100 nm in any dimension. Based on dimensions, nanoceramics are classified as zero-dimensional nanocrystals, one-dimensional nanowires and nanotubes, two-dimensional nanofilms and nanowalls, and three-dimensional bulk materials with at least one nanocrystalline phase. Nanoceramics, in particular, bulk nanoceramic materials, exhibit superior and unique properties in comparison to conventional ceramics with coarser structured units. A major challenge in the research on bulk nanoceramics and nanoceramic composites is concerned with the aspect of processing. The basic steps in nanoceramic fabrication mainly involve obtaining unagglomerated nanosized powders with uniform size distribution and sintering to near theoretical density without grain growth. The synthesis of nanocrystalline powders is an essential and first step in the processing of bulk nanoceramics. Efforts have been made to ensure appropriate control of particle size, surface contamination, and degree of agglomeration. Various chemical methods have been adapted to synthesize nanocrystalline powders. The main advantages of chemical synthesis methods lie in their ability to produce a large variety of compositions and ensure homogeneous (atomic level) mixing of the constituent particles.