The solid-state reaction, ½Y2O3 + ½Cr2O3  YCrO3, was carried out at temperatures of between 1458 and 1719K under an O partial pressure of 0.21atm. It was found that the reaction obeyed a parabolic rate law, and that the diffusion of Y ions controlled the reaction. The diffusion coefficient of Y3+ ions was deduced from the Gibbs free energy change of the reaction and the parabolic rate constant. The diffusivity of the Y ion could be described by:

D(m2/s) = 8.36 x 10-9exp[-272(kJ/mol)/RT]P3/16a1/8

where a was the Cr2O3 activity and P was the O partial pressure.

K.Kawamura, A.Saiki, T.Maruyama, K.Nagata: Journal of the Electrochemical Society, 1995, 142[9], 3073-7