Grain-boundary diffusion - diffusion in solid polycrystalline bodies, concentrated in narrow (several atomic layers thick) zones at the grain boundary with different crystallographic orientations.
Description
Due to the high concentration of defects in the zone of grain contact due to their crystallographic misorientation, diffusion transfer along the grain boundaries proceeds much faster than in their volume, where the concentration of defects is much lower (volume diffusion), but slower than at the interface between the solid and the atmosphere ( surface diffusion ). Grain-boundary diffusion is one of the main mechanisms for the implementation of low-temperature sintering in the production of ceramics and powder metallurgy ; An increase in its contribution is usually attributed to a decrease in sintering temperature with an increase in the dispersion of the starting materials. Grain-boundary diffusion is also one of the mechanisms of deformation of solids.
Literature
- Atkinson A. Grain-boundary Diffusion: An Historical Perspective // J. Chem. Soc. Dalton trans. 1990. V. 86, No. 8. P. 1307-1310.
- Ovidko I.A., Reyzis A. B. Crawling of grain-boundary dislocations and diffusion in nanocrystalline solids // FTT. 2001.Vol. 43, No. 1. S. 35-38.