The diffusion of O in α-phase material was determined via internal oxidation measurements, of alloys having various Si contents, at 1073 to 1173K:

0.07wt%Si:     D (cm2/s) = 2.36 x 1011 exp[-87.6(kJ/mol)/RT]

0.12wt%Si:     D (cm2/s) = 2.46 x 1011 exp[-86.2(kJ/mol)/RT]

0.18wt%Si:     D (cm2/s) = 8.97 x 1011 exp[-97.9(kJ/mol)/RT]

0.40wt%Si:     D (cm2/s) = 4.37 x 1011 exp[-89.0(kJ/mol)/RT]

Particular attention was paid to the role which was played by oxide particles in the oxidation layer. The O diffusion coefficient in the layer was calculated by using the rate equation for internal oxidation. It was found to increase with increasing volume fraction of the oxide. This indicated that the existence of oxide particles accelerated O diffusion.

J.Takada, M.Adachi: Journal of Materials Science, 1986, 21[6], 2133-7