An X-ray diffraction study of the interdiffusion in a KCl:PbCl2 solid solution system
Abstract Broadening of X-ray diffraction line profile due to compositional variations can be used as a powerful, non-destructive toll to study the interdiffusion in metallic alloys, binary solid solutions and alloy catalysts. Since powder samples are easy to prepare and have technological importance and KCl, PbCl 2 form solid solution, high purity Aldrich chemicals of KCl and PbCl 2 (-325 mesh, 50 μm) were mixed at a ratio 1:0.1963 by weight. After diffusion anneals at different temperatures, X-ray diffractograms show the shift in KCl and PbCl 2 peaks. The powder becomes amorphous at and above 550°C. Interdiffusion was found to be very fast at the beginning and wask limited to the surface only. The activation energy for such diffusion was found out to be 0.0012 eV. Such a low activation energy has been explained on the basis of surface diffusion mechanism. The degree of interdiffusion ( F ) as well as diffusion coefficient ( D ) were also calculated from the concentric sphere model.