Kenta Kuwayama1, Yoshinori Wakamatsu2, Toshitada Shimozaki2 and Masami Onishi2
1Graduate Student, Kyushu Institute of Technology, Kitakyushu. On leave from TOTO LTD., Kitakyushu
The interdiffusion coefficients were obtained by use of the Au-Pt and Au-α1 (20 at%Pt) diffusion couples annealed in the temperature range between 1243 and 1333 K. The concentration dependence of the coefficients determined with the Au-α1 (20 at%Pt) couple differs from that determined with the Au-Pt couple. The extrapolated values of the coefficients determined with the Au-α1, (20 at%Pt) couple to zero atomic percent of Pt were in good agreement with the impurity diffusitivities of Pt in Au. The array of multiple markers embedded in the Pt part of the Au-Pt couple before diffusion bent to Au-rich side sharp at the α1/α2 phase boundary after diffusion. Both the α1 and α2 phases belong to the same type of the crystal structure (f.c.c.). The bend in this experiment, therefore, indicates that vacancies are created owing to formation of the extra lattice planes at the phase boundary with the same type of the crystal structure.
interdiffusion, gold-platinum system, multiple markers, vacancy creation, two phase boundary
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