Impurity Diffusion of Vanadium and Self-Diffusion in Iron

Abstract

Impurity diffusion of /sup 48/V was measured in - and el-iron. In both phases the vanadium diffusion is faster by a factor of 2 to 3 when compared to iron self-diffusion. In the el-phase the diffusion parameters D/sub 0/=(0.62 +- 0.7) cm/sup 2/ s/sup -1/ and Q=(273.5 +- 6.2) kJ mol/sup -1/ correspond to a normal vacancy diffusion mechanism. The fit of the experimental data of vanadium in the paramagnetic -phase to an Arrhenius relation, D/sub 0/=(124 +- 19) cm/sup 2/ s/sup -1/ and Q=(274 +- 6.6) kJ mol/sup -1/, yields a very large frequency factor, like the results of the additionally measured self-diffusion in the paramagnetic -phase, D/sub 0/=(121 +- 4) cm/sup 2/ s/sup -1/ and Q=(281.6 +- 1.7) kJ mol/sup -1/, which can be understood by an influence of the magnetic ordering on lattice diffusion still above the Curie-temperature. The occurrence of ferromagnetic clusters tends to decrease the diffusivity already in the paramagnetic -phase. Thus the calculated results of D/sub 0/ and Q have to be regarded as effective values only.