Ideal solution interdiffusion

Figure 3-36 The dependence of interdiffusivity on composition for two models (Equations 3-137c versus 3-138b) for ideal solutions and concentration-independent T>a and X>b- The solid curve is for interdiffusion of two ions of identical charge. The dashed curve is for interdiffusion of neutral atomic species such as in an alloy.

Derive the governing equation for composition as a function of position and lime for the case of the interdiffusion of two fluids in which the molar density of the mixture is not constant, but the partial molar volumes of each species are constant and equal to the pore component values, that is, a thermodynamically ideal solution. 

Thus, Pick s Second Law can be rigorously applied for the case of ffie interdiffusion of ideal solutions. For nonideal solutions, the simultaneous soittffon of Eqs. (D) and (B) can be carried out if density versus composition data ate available for the tysiem. ... 

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