The impurity diffusion of Au and Se in polycrystals was investigated by using radio-tracer and serial sectioning techniques, involving 195Au and 75Se, over a temperature range of 600K. In the type-B Harrison regime, sD was found to be described by:

195Au:      sD(m3/s) = 2.1 x 10-15exp[-81.2(kJ/mol)/RT]

75Se:      sD(m3/s) = 6.6 x 10-15exp[-52.8(kJ/mol)/RT]

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

195Au:      D (m2/s) = 4.9 x 10-6exp[-91.0(kJ/mol)/RT]

75Se:      D (m2/s) = 2.6 x 10-7exp[-74.6(kJ/mol)/RT]

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