The impurity diffusion of 60Co in V was measured at 5 concentrations; including 0%Co (table 319). The activation energies for these alloys were found to range from 283 to 226kJ/mol in going from 0 to 2at%Co:

0%Co:     D(m2/s) = 0.7 x 10-4 exp[-283(kJ/mol)/RT]

0.5%Co:     D(m2/s) = 0.8 x 10-4 exp[-292(kJ/mol)/RT]

1%Co:     D(m2/s) = 0.4 x 10-4 exp[-281(kJ/mol)/RT]

1.5%Co:     D(m2/s) = 0.1 x 10-4 exp[-263(kJ/mol)/RT]

2%Co:     D(m2/s) = 0.6 x 10-4 exp[-226(kJ/mol)/RT]

The impurity enhancement which was observed was analyzed by using linear, polynomial and exponential functions which related the diffusivity of the solute to its concentration. It appeared that the higher terms in the concentration of the polynomial function could not be neglected in the case of Co diffusion in V.

J.Pelle: Philosophical Magazine A, 1995, 72[6], 1547-57