A Curvature in the Arrhenius Plot for the Diffusion of Iron in Single Crystals of Nickel in the Temperature Range from 1200 to 1400°C

The diffusion of Fe‐59 in single crystals of nickel was measured in the temperature range from 1200 to 1400°C. The Arrhenius plot exhibits a clear curvature. The addition of iron impurities up to 1.5 at% had only a slight influence on the nickel self‐diffusion coefficient, while a measurement of the isotope effect for the diffusion of Fe‐55 and Fe‐59 at 1330°C yielded a quite “normal” value. The curvature in the In D versus 1/ T plot for the diffusion of iron in nickel could not be explained.