Tracer diffusion coefficients for 93Nb in rutile single crystals were determined using secondary ion mass spectrometry. The coefficients exhibited a temperature dependence, at 21kPa and 1073 to 1573K, of:

D(m2/s) = 4.7 x 10-7exp[-244(kJ/mol)/RT]

L.R.Sheppard, A.J.Atanacio, T.Bak, J.Nowotny, K.E.Prince: Journal of Physical Chemistry B, 2007, 111[28], 8126-30