The in-diffusion of radio-active C from 14CO2 was investigated at 723 to 1073K by using serial sectioning methods. It was found that the diffusivity could be described by:

D (m2/s) = 8.72 x 10-6exp[-149.3(kJ/mol)/RT]

J.Cermak, F.Rollert, H.Mehrer: Zeitschrift für Metallkunde, 1990, 81[2], 81-3