Dense scales of the tetragonal phase were studied at 1100 to 1300C by using the interruption kinetic (Rosenberg) method. By assuming that O vacancies were the predominant defects, estimates were made of the O self-diffusion coefficient in the oxide at its lower limit of stability. The results were described by:

D (cm2/s) = 2.2 x 10-3 exp[-33.3(kcal/mol)/RT]

B.Oberlander, P.Kofstad, I.Kvernes: Materialwissenschaft und Werkstofftechnik, 1988, 19[6], 190-3

The best linear fit to the solute diffusion data ([468] to [470]) yields:

O: Ln[Do] = 0.27E – 11.7 (R2 = 0.27)