Isotope effect in niobium self-diffusion

Measurements of the isotope effect in niobium self-diffusion have been made over the temperature range 1900 °C to near the melting point (2468 °C). The measurements were made by simultaneous diffusion of ⁹⁵Nb and ⁹²Nb isotopes from a thin surface layer and subsequent sectioning. The ratio of ⁹²Nb to ⁹⁵Nb in each section was determined using a well-type Ge(Li) detector of high efficiency. The low values of the measured isotope effect are similar to other bcc metals (Na, α- and δ-Fe,Cr, and β-Zr) however, the temperature dependence is different.