The temperature dependence of the bulk diffusivity of 186Re in W single crystals was investigated, at 2110 to 2900K, by using the radiometric diffusion-zone sectioning method and materials of at least 4N-purity. It was found that the data:

D (cm2/s) = 4.0 x 100 exp[-142.6(kcal/mol)/RT]

could be explained in terms of the Lazarus-LeClaire vacancy model.

N.K.Arkhipova, S.M.Klotsman, I.P.Polikarpova, G.N.Tatarinova, A.N.Timofeev, L.M.Veretennikov: Physical Review B, 1984, 30[4], 1788-96