The Diffusion of Copper in Cuprous Oxide

Abstract

Cuprous oxide strips were prepared by the oxidation of copper at 1000°C. The diffusion of radiocopper in this material at 800 to 1050° gave a self‐diffusion coefficient, D=0.0436 exp(−36100/RT). Virtually the same D is obtained from experiments in which radiocopper is plated on copper strips, and the distribution of activity measured in the cuprous oxide film formed on oxidation in air. The observed D values are in accord with a predicted relation k/D=4, where k is the parabolic rate constant for copperoxidation. It is suggested that parabolic rate constants with large negative entropies of activation and low heats of activation may be due to grain boundarydiffusion.