The diffusion of 192Ir in single crystals of 4N-purity material was studied by using serial sectioning methods at 911 to 1030C. The results could be described by:

D (cm2/s) = 1.06 x 101 exp[-66.01(kcal/mol)/RT]

S.M.Klotsman, Y.A.Rabovskii, V.K.Talinskii, A.N.Timofeev: Physics of Metals and Metallography, 1978, 45[5], 1104-6 [Russian edition]