The diffusion of Co in alumina was carried out at 1403 to 1873K in air, with and without the presence of a spinel phase. The penetration profiles were measured by using the secondary-ion mass spectrometry technique or (at the highest temperature) by performing tracer measurements. The results obtained using both methods could be described by:

D (m2/s) = 6.2 x 10-9 exp[-333(kJ/mol)/RT]

E.G.Gontier-Moya, G.Erdélyi, F.Moya, K.Freitag: Philosophical Magazine A, 2001, 81[11], 2665-73