The diffusion of Fe was studied by using serial sectioning and autoradiographic techniques at 750 to 1100K. The grain boundary diffusion coefficients were evaluated by using Whipple’s or Suzuoka’s method. The grain boundary diffusivity could be described by:

D (cm2/s) = 1.88 x 10-1 exp[-160.7(kJ/mol)/RT]

A.R.Paul, M.C.Naik, K.N.G.Kaimal: Materials Science and Technology, 1991, 7[1], 8-11