Simultaneous measurements were made of K ion diffusion, using the serial sectioning technique, at temperatures ranging from 400 to 700C (figure 14). The slope of the plot in the impurity region indicated an activation energy of about 0.85eV.
D.C.Parashar: Journal of the Physics and Chemistry of Solids, 1970, 31[12], 2795-7
Figure 14
Diffusion of K in KCl Crystals