Diffusion-Key Role in Solid State Crystalline Material - A Review

Abstract

Solid-state diffusion is a process which is responsible for the transport of atoms or ions of the solid reactant and product during the reaction and crystal growth of the solid product. The overall kinetics is usually significantly influenced by the relatively slow and highly activated solid–state diffusion. Due to the involvement of nucleation and crystal growth of the solid product, crystallographic properties of the solid reactant and product have a large influence on the overall kinetics as well since those properties determine how nucleation and crystal growth proceed. Diffusion is the net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential) as a result of random motion of the molecules or atoms. The main advantage of diffusion methods is that one can grow crystals of insoluble substances under normal conditions without special apparatus. It is sufficient to cause two substances to diffuse in opposite directions, whereupon the product is formed by reaction.