The diffusion of Ti and Nb radioactive tracers was studied simultaneously, at 950 to 1511C, by using standard lathe-sectioning techniques. The results for Ti could be described by:

D (cm2/s) = 4.54 x 10-4 exp[-31.30(kcal/mol)/RT]

A.E.Pontau, D.Lazarus: Physical Review B, 1979, 19[8], 4027-37