Grain boundary diffusion metals versus non-stoichiometric compounds

This paper compares the current knowledge of grain boundary diffusion in three classes of materials: metals and metallic alloys, ordered intermetallic compounds, and ionic stoichiometric and non-stoichiometric compounds. Along with fundamentals, the recent progress in grain boundary diffusion studies in these materials is reviewed. The differences and common features of grain boundary diffusion in these materials are pointed out, and the origin of the differences is examined. It is concluded that, despite many differences, the basic features of grain boundary diffusion in metals, intermetallics and ionics are fairly similar. Those basic features are discussed through the paper, and some prospective topics of future research in the area are suggested.