Self-Diffusion in Tin Crystals

Abstract

The rate of self-diffusion in single crystals of white tin of various orientations has been measured using the radio-active isotope Sn113. The ratio of the diffusion coefficients parallel and perpendicular to the tetragonal (c) axis is approximately 2 at 180 �C. and approximately 3 at 223 �C. The diffusion coefficients in both directions at various temperatures are given by the Arrhenius expressions Dc= 1.2 x 10-5e-10,1500/RT cm.2sec.-1 and Da=3.7 X 10-8e-5,900/RT cm.2sec.-l. The anisotropy is discussed in terms of the vacancy mechanism of diffusion.