POWDER SYNTHESIS METHODS

A variety of methods exist for the synthesis of ceramic powders. In this book, we divide them into two categories: mechanical methods and chemical methods.
Mechanical methods are generally used to prepare powders of traditional ceramics from naturally occurring raw materials. Powder preparation by mechanical methods is a fairly mature area of ceramic processing in which the scope for new developments is rather small. However, in recent years, the preparation of fine powders of some advanced ceramics by mechanical methods involving milling at high speeds has received a fair amount of interest.
Chemical methods are generally used to prepare powders of advanced ceramics from synthetic materials or from naturally occurring raw materials that have undergone a considerable degree of chemical refinement. Some of the methods categorized as chemical involve a mechanical milling step as part of the process. The milling step is usually necessary for the breakdown of agglomerates and for the production of the desired physical characteristics of the powder such as average particle size and particle size distribution. Powder preparation by chemical methods is an area of ceramic processing that has seen several new developments in the past 25 years and further new developments are expected in the future. Table 2.1 provides a summary of the common powder preparation methods for ceramics
2-2 POWDER SYNTHESIS BY CHEMICAL METHODS
A wide range of chemical methods exist for the synthesis of ceramic powders and several reviews of the subject are available in the ceramic literature. For convenience, we will consider the methods in three fairly broad categories :( 1) solid-state reactions, (2) synthesis from liquid solutions, and (3) vapor-phase reactions.