Diffusion

POINT DEFECTS AND DIFFUSION

� The transport of atoms in a real crystal takes place through diffusion. Point defects control diffusion through the bulk of the material, down dislocations, and over internal and external surfaces.
� Point defects are thermodynamically favored constituents of materials and increase exponentially in number as temperature increases. Diffusion processes are therefore strongly temperature dependent.
� The diffusion couple illustrated shows materials interpenetration by diffusion processes.

From: Newey & Weaver, "Materials Principles & Practice," Butterworths (1990)