It was noted that the broadening of X-ray diffraction line profiles, due to compositional variations, could be used as a powerful non-destructive tool for the study of interdiffusion in binary solid solutions. Here, powder samples of high-purity materials were mixed in the ratio, 1:0.1963, by weight. After annealing at various temperatures, the X-ray diffractograms revealed a shift in the KCl and PbCl2 peaks. The powder became amorphous at 550C. Interdiffusion was found to be very rapid at the beginning, and was limited to the surface. The activation energy for this diffusion process was found to be 0.012eV. This low activation energy was explained in terms of a surface diffusion mechanism. An X-Ray Diffraction Study of the Interdiffusion in a KCl:PbCl2 Solid Solution System. L.D.Pradhan, B.S.Acharya: Solid State Ionics, 1987, 24[3], 213-6