The diffusion of 55Fe was measured parallel to the c-axis of single crystals at 708 to 1303C, at an O activity of unity. The tracer penetration profiles were determined by using sectioning techniques. At above 900C, the tracer diffusion (table 97) could be described by:

D (cm2/s) = 1.6 x 109 exp[−6.0(eV)/kT]

and, below 900C, by:

D (cm2/s) = 2.8 x 109 exp[−1.8(eV)/kT]

It was suggested that the high-temperature behaviour was probably characteristic of the pure oxide, while the diffusion at lower temperatures was influenced by impurities. The most likely defects responsible for the diffusion of Fe were expected to be Fe interstitials.

Diffusion of 55Fe in Fe2O3 Single Crystals. A.Atkinson, R.I.Taylor: Journal of Physics and Chemistry of Solids, 1985, 46[4], 469-75

Table 97

Diffusion of 55Fe in Fe2O3