The sum-rule relation among phenomenological transport coefficients and its consequences in the analysis of collective diffusion problems

In this paper, we discuss the sum-rule that relates the phenomenological coefficients in the multicomponent random alloy system in the case where the isolated vacancy mechanism is operating. We present applications of this sum-rule to intrinsic diffusion in multicomponent alloys, intrinsic diffusion in mixed alkali halides and demixing of multicomponent transition metal oxides in an oxygen potential gradient and an electric field. In each case, a very substantial simplification in the analysis is made possible because of the sum-rule.