An investigation was made, of the grain-boundary penetration of Ag+ ions, by using X-ray diffraction and microhardness measurements. The activation energy for penetration was found to be essentially independent of the boundary misorientation angle. For misorientation angles of between 12 and 14º, and temperatures of between 200 and 650C, the data could be described by:

D (cm2/s) = 1 x 10-8 exp[-0.53(eV)/kT]

For misorientation angles of between 1 and 2º, and temperatures of between 200 and 650C, the data could be described by: D (cm2/s) = 5 x 10-8 exp[-0.53(eV)/kT]

Diffusive Penetration of the Boundaries in Akali Halide Crystals. Y.E.Geguzin, E.R.Dobrovinskaya, I.E.Lev, M.D.Melamud: Ukrayinskyi Fizychnyi Zhurnal, 1968, 13[12], 1972-6