An analysis was made of diffusion from an infinite source and into a triple junction shape which was made up of 3 grain boundaries that met along a common line. The diffusion coefficients in all 3 boundaries were assumed to be the same. It was proposed that diffusion into the triple junction occurred first, followed by later penetration into each boundary and then into the bulk of the crystals. This led to 3 diffusion paths with differing diffusion coefficients. Using the present solution, the product of the triple-junction section and the triple-junction diffusion coefficient could be extracted from experimental data.

A.L.Peteline: Materials Science Forum, 1997, 235-238, 469-74