Monovacancy and divacancy contributions to self-diffusion in face-centred cubic metals reanalysis for copper, silver, gold, nickel and platinum

Abstract

Results of the Morrison analysis applied to the curved Arrhenius plots of self-diffusion in copper, silver, gold, nickel and platinum are reported. Both temperature-dependent and temperature-independent energies and entropies are taken into consideration. The analysis is applied to the most reliable diffusion coefficients measured with the aid of macroscopic (serial) and microscopic (chemical and electrochemical etching or ion-beam sputtering) sectioning techniques. The error limits of the obtained monovacancy parameters are small, and those of the divacancy parameters in copper, silver and gold are distinctly smaller than in any earlier analysis. The diffusion parameters obtained for gold differ strongly from those hitherto assumed to be valid. According to the present results, the divacancy contribution at the melting temperature amounts to about 50% in copper, silver and platinum, while in gold and nickel the contribution is about 30 and 20%, respectively. The present results also fit the isotope effect and pressure dependence of the self-diffusion coefficients in silver and gold by use of plausible values for the kinetic-energy factors and the activation volumes of diffusion.