Interdiffusion of 6Li and 7Li in Isotopically Nearly Pure Lithium Metal Melts

Abstract

A capillary-reservoir technique has been used to investigate the interdiffusion of 6Li and 7Li in nearly pure (ca. 94%) 6Li, as well as in nearly pure 7Li. At the melting point the ratio of these diffusion coefficients is about 1.30. Extrapolation to tracer concentrations gives good qualitative agreement with the ratio of the viscosities of 7Li and 6Li. The interdiffusion coefficient ratio of the melts decreases with rising temperature, also in agreement with viscosity results. Quantum effects are likely to be responsible for the strong dependence on isotope mass.