Diffusion und isotopieeffekt von silber in β-Zirkon

Abstract

The impurity diffusion and the isotope effect of silver tracers have been investigated in the total range of existence of β-zirconium. The Arrhenius plot of impurity diffusion is strongly curved in a similar way as for self-diffusion in β-Zr. By additional diffusion experiments dislocations could be excluded to be responsible for enhanced diffusion in the low temperature range. Within the experimental error the isotope effect E is temperature independent. The absolute value is compatible with a monovacancy mechanism. The somewhat smaller curvature of the Arrhenius plot of Ag impurity diffusion as compared to self-diffusion in β-Zr and the nearly constant value of E can be explained by a predominant monovacancy mechanism which partly is supported by phononinduced ω-embryo like complexes, the concentration of which obviously is smaller than for self-diffusion in β-Zr.