Radio-tracer serial sectioning studies, involving 64Cu, were carried out over a temperature range of 600K. The results revealed that the grain boundary diffusivities, described by:

sD (m3/s) = 1.2 x 10-15 exp[-84.8(kJ/mol)/RT]

were of the same order as the grain boundary self-diffusivity. These were quite different to those for lattice diffusion.

T.Surholt, C.Herzig: Materials Science Forum, 1996, 207-209, 481-4