An Analytical Method of Calculating Variable Diffusion Coefficients

摘要

The Matanohyphen;Boltzmann method of graphical calculation of diffusion coefficients in solutions is replaced by an analytical method in certain systems. This procedure enables accurate calculation of diffusion coefficients near the concentration extremes. An equation is derived for the diffusion coefficientDas a function of concentrationc.The equation predicts a variation ofDwithcwhich is not exponential in metallic systems, contrary to the proposal of Wagner. Comparison ofDvalues with those obtained graphically, for the system copperhyphen;nickel, indicates that the graphical values may be appreciably in error at that extreme where the diffusion coefficient is greatest.