Chemical diffusion coefficients in solid Al-Li alloys at low Li concentrations

The galvanostatic method was used in measurements of the chemical diffusion coefficient in the Al-rich aluminium-lithium alloys. The experiments were performed using electrochemical concentration cells with the liquid electrolytes LiCl-LiF, LiCl-KCl and LiCl-KCl-CsCl at 4 temperatures 568 K, 638 K, 780 K and 863 K. The observed values of the chemical diffusion coefficients in the alpha(Al) solid alloys of the Al-Li system are of the order from 10(-11) cm(2)/s at 568 K to 10(-8) cm(2)/s at 863 K. Taking from the literature the self-diffusion coefficient of aluminium, the self-diffusion coefficients of Li were calculated from the Darken relation. Finally, the Arrhenius equation describing the dependence of the self-diffusion coefficient on temperature was worked out and compared with the earlier published results from different experimental techniques. The empirical relation describing the dependence of the activation energy on the melting temperature of metals was confirmed.