Ceramic interfaces and reactions

Since the majority of ceramic components are polycrystalline, these materials have many internal interfaces, including those between grains and phases, that greatly affect the properties. The structure and stability of external surfaces are always important, and especially so when the temperature is high and the environment corrosive - situations in which ceramics are often used. A circumstance that amplifies the importance of interfaces is that many ceramics are anisotropic - that is, their crystallography and properties (mechanical, electrical, optical, etc.) are different in different directions.