Exchange reactions between 18O2 gas and the oxide were studied at 300 to 700C. From gravimetric data, the surface diffusion behaviour was found to be described by:

D (cm2/s) = 5.04 x 10-16 exp[-10.2(kcal/mol)/RT]

The grain-boundary diffusivity at 700C was estimated to be have the same value.

W.Komatsu, Y.Ikuma: Zeitschrift fur Physikalische Chemie, 1982, 131[1], 79-88

Table 158

Migration Energy of O in NiO