Self-Diffusion of Zinc

Self-diffusion measurements in zinc single crystals of various known orientations and polycrystalline zinc have been made by a sectioning method with long-lived radioactive ${\mathrm{Zn}}^{65}$ as an indicator. Measurements on 18 single crystals in the temperature range of 340°C to 410°C enable an investigation of the anisotropy in the diffusion rate. Parallel to the $C$ axis the diffusion rate was found to be 4 × ${10}^3$ exp (2.04 ×${10}^4$ cal. ${\mathrm{mole}}^{-1\mathrm{}}$/RT)${\mathrm{cm}}^2$ ${\mathrm{day}}^{-1\mathrm{}}$ while that parallel to the basal plane was 8 × ${10}^6$ exp (3.1 ×${10}^4$ cal. ${\mathrm{mole}}^{-1\mathrm{}}$/RT) ${\mathrm{cm}}^2$ ${\mathrm{day}}^{-1\mathrm{}}$. Polycrystals gave values between these extremes.