Chronopotentiometric methods were used to investigate the diffusion of Nb2+ and Nb3+ in equimolecular KCl-NaCl melts. The diffusivity of Nb3+ (0.9 to 1.7%Nb), at temperatures of 700 to 840C, could be described by:

D (cm2/s) = 4.36 x 10-3 exp[-10.5(kcal/mol)/RT]

The diffusivity of Nb2+ could be described by:

D (cm2/s) = 9.2 x 10-3 exp[-9.15(kcal/mol)/RT]

V.F.Pimenov, Y.V.Baimakov: Electrokhimiya, 1968, 4[11], 1357-60