1989 Volume 30 Issue 7 Pages 480-486
The tracer diffusion coefficient of 198Au in gold-rich Au–Al alloys containing up to 2 at% Al at 1023 K has been determined by the serial sectioning method. The linear enhancement factor of the solvent diffusivity has been determined to be 53±9. In addition to the above, the interdiffusion and intrinsic diffusion coefficients in gold-rich Au–Al alloys containing up to 6 at% Al at 1023 K have been determined by use of semi-infinite couples and thin-plate sandwiches with the Kirkendall marker. Using the value of self-diffusion coefficient in pure Au and the extrapolated values of interdiffusion coefficient and intrinsic diffusion coefficient of Au to the infinite dilution of Al, the vacancy flow factor has been estimated to be −0.78. From the linear enhancement factor and the vacancy flow factor, an appropriate numerical set of the correlation factor and the jump frequency ratios in the five-frequency model for the impurity diffusion of Al in Au has been evaluated. The result suggests that the attraction between an Al atom and a vacancy in Au is highly strong and that a vacancy makes very many consecutive exchanges with an Al atom rather than with any solvent atom neighboring the vacancy.
