Effect of sulphur content and pre-annealing treatments on nickel grain-boundary diffusion in high-purity copper

Anger electron spectroscopy (AES) and radiotracers were used to study the effects of pre-annealing treatments and grain boundary migration on nickel grain-boundary diffusion in pure 5N copper at 718 K in the B-kinetic regime. The diffusion penetration profiles are complex, which can be interpreted by the copresence of stationary and moving grain boundaries. Attempts to emphasize the grain-boundary migration effect were made by the application of different pre-annealing treatments before diffusion. It was shown by AES that this preparation procedure induces a modification in the bulk sulphur content which is a residual impurity in 5N copper. It is shown that a few ppm of sulphur dissolved in the bulk has a pronounced influence on the data; the higher the sulphur content, the lower the triple-product and the grain-boundary migration velocity.