Bulk and grain-boundary diffusion coefficients were measured for Gd diffusion in nuclear fuel pellets. Between 1500 and 1703C, in a hydrogen atmosphere, the bulk diffusion coefficient could be described by:

D(cm2/s) = 5.3 x 10-3exp[-5.1(eV)/kT]

Over the same temperature range and in the same atmosphere, the grain-boundary coefficient could be described by:

Dδ(cm3/s) = 1,1 x 10-2exp[-6.3(eV)/kT]

W.B.Ferraz, A.C.S.Sabioni: Ceramica, 2006, 52[323], 143-8