Diffusion of Cd in Sodium Chloride

A new method for evaluating the diffusion coefficient of divalent cation in NaCl is described. The method is based upon the observation of difference in colloidal coloration between pure and impure regions of NaCl. Analysis is done by assuming that the diffusion coefficient of divalent cation in NaCl is proportional to its concentration. This method is applied to the diffusion of Cd in NaCl over the temperature range from 350°C to 600°C. The diffusion coefficient of Cd in NaCl is estimated below 500°C as follows; D =1.2×exp (-0.64/ k T )× c in which c is the molar fraction of Cd in NaCl. Above 500°C it tends to lower value than that expected from the above equation.