Grain boundary segregation in nonstoichiometric compounds and its impact on the development of advanced ceramic materials

The properties of the grain boundry layer of ionic compounds are analyzed in terms of defect chemistry. Experimental data for non-stoichiometric oxides are provided to illustrate the effect of segregation and its impact on properties of ceramic materials. The paper considers several applied aspects of grain boundary engineering such as processing of ceramics, standardization of catalysts, high temperature corrosion of metals and preparation of ceramic gas sensors. It is concluded that further progress in materials science resulting in the development of advanced ceramic materials requires better understanding of grain boundary properties and their effect on materials properties. 62 refs., 38 figs