A study was made, of the self-diffusion of 42K, by using serial sectioning and conductivity techniques. The samples were pure single crystals, or crystals which were doped with 61ppm of Sr2+ ions (figure 15). The Nernst-Einstein relationship was obeyed at all temperatures, to within experimental error.

M.Bénière, F.Bénière, M.Chemla: Journal de Chimie Physique et de Physicochimie Biologique, 1970, 67[7-8], 1312-21

Figure 15

Diffusion of K in KCl Crystals