Grain growth in perovskites: What is the impact of boundary transitions?

Several perovskite ceramics are known to have non-Arrhenius type grain growth and to show grain growth transitions instead. These growth transitions are coupled to bimodal microstructures and seem to be caused by the existence, coexistence and transition of two different grain boundary types. This paper gives a review on the details of the grain growth transitions in perovskite ceramics. A simple mean field approach and standard grain growth experiments are used for quantification. However, this approach is far too simple to understand bimodal anisotropic grain growth completely as apparent in perovskites. Important parameters such as atomistic boundary structure, segregation effects, wetting transitions, faceting, grain boundary stoichiometry, space charge and interfacial drag effects are discussed with respect to their impact on grain growth in perovskites. A summary of open questions and future directions is given.