Chemical relaxation experiments were performed at 1000C in order to study variations in

the apparent diffusivity as a function of O partial pressures of between 0.0001 and 1atm. A slow surface reaction was found to be responsible for variations in the apparent diffusivity. In the true diffusional regime, the chemical diffusion coefficient was equal to about 9.2 x 10-7cm2/s (table 56).

F.Morin, R.Dieckmann: Journal of the Physics and Chemistry of Solids, 1990, 51[3], 283-8