ABSTRACT
Historically, solid solution was so common in commercial metallurgical systems that early phase literature in metallurgy almost disregarded the existence of the intermetallic compound. Of course, compound formation and solid solution are equally important in both metal and ceramic systems as far as basic phase relations are concerned. This chapter presents a space model for the complete solid solution or ternary isomorphous system. When discussing the equilibrium crystallization path of any liquid in this system, it is important to realize that ternary liquids will be in equilibrium with ternary solid solutions as the path proceeds through the two phase region. Fosterite refractories and electronic ceramics are of considerable importance and the phase relations in the ternary systems have a bearing on their processing (forming) although the influence of liquifaction is usually less important than for steatite and cordierite. Some ultra pure forsterites are prepared by solid state sintering and little or no glass phase is present.
