SULPHUR DIFFUSION IN COPPER - DEPARTURE FROM ARRHENIUS PLOT

A study is made of sulphur diffusion in copper single crystals using 35S between 550 and 1000 °C. The plot log D = f(1/T) was not a straight line. Different models were examined to explain the departure from linearity in the Arrhenius plot. A simple model is proposed, basing on classical mechanisms: monovacancy diffusion and diffusion along randomly distributed dislocations. For T > 800 °C, Q = 2.14 eV, and D0 = 23 cm2 s−1, the unusually high diffusion coefficients do not agree well with the value of Q, similar to that of self diffusion. For T < 800 °C, the dislocation model gives a binding energy of some tenths of an electron‐volt. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim