The impurity diffusion of Au in polycrystals was investigated by using radio-tracer and serial sectioning techniques, involving 195Au, over a temperature range of 600K. In the type-B Harrison regime,

sD(m3/s) = 2.1 x 10-15exp[-81.2(kJ/mol)/RT]

whereas, in the type-C regime, grain boundaries diffusivities were measured directly and could be described by:

D (m2/s) = 4.9 x 10-6exp[-91.0(kJ/mol)/RT]

T.Surholt, J.M.Mishin, C.Herzig: Solid State Phenomena, 1995, 41, 113-20