Aspects of Solid-Solid Reactions

Conventional solid state synthesis techniques involve heating mixtures of two or more solids to form a solid phase product. Unlike gas phase and solution reactions, the limiting factor in solid-solid reactions is usually diffusion.

Fick's law :

Fick's Law stated that for the diffusion of component-A in a binary mixture of A and B: The average distance a diffusing species will travel, <x>, is given by: where t is the time.