The formation of solid solutions in equimolar powder mixtures was studied. The progress of homogenization was monitored by measuring the change in capacitance as a function of time. It was found that the transformation process occurred in 3 stages. These were associated with grain-boundary diffusion, volume diffusion of Cl- ions and volume diffusion of Br- ions. The latter results (figure 19) were in good agreement with the predictions of diffusion theory based upon non-uniform thermodynamics.

Formation of Mixed Crystals in Equimolar KCl-KBr Powder Mixtures. S.Pehkonen, M.Ahtee, O.Inkinen: Journal of Physics D, 1972, 5[1], 767-73

Figure 19

Diffusion of Br in the KCl-KBr System