Diffusion of Cobalt into Single Crystals of Copper

Abstract

The measurements of diffusion coefficient of cobalt into copper have been carried out in the temperature range from 950°C to 700°C using Co⁶⁰ as tracer. The result indicates that the diffusion coefficient is given by the equation D=5.7exp (−55200⁄RT) cm²/sec and, therefore, that the activation energy is appreciably larger than that of copper self-diffusion. From this experiment it has been definitely shown that, for the negative value of excess valency Z, the effect of screening on the solute diffusion in metals plays an effective role in the same manner as the effect observed for the positive value of Z.