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M: Metallphysik

M 7: Glasdynamik

M 7.1: Vortrag

Montag, 8. März 2004, 14:45–15:00, H16

P-32 diffusion in the undercooled melt of Pd₄₃Cu₂₇Ni₁₀P₂₀ — •Alexander Bartsch¹, Klaus Rätzke¹, Volker Zöllmer¹, Andreas Meyer², and Franz Faupel¹ — ¹Technische Fakultät, Univ. Kiel, Kaiserstr.2, 24143 Kiel — ²TU München, Physik Department E13, James-Franck-Str., 85747 Garching

Since the development of bulk metallic glasses the undercooled melt is accessible for diffusion experiments [1]. In an earlier study we have for the first time determined diffusivity and isotope effect for the Pd-Cu-Ni-P alloy from the glass to the melt [2]. While in the equilibrium melt diffusivity and viscosity coincide according to the Stokes Einstein (SE) equation, they diverge with decreasing temperature down to the glassy state up to four orders of magnitude. The following questions remain: At which temperature does the divergence start? Does any constituent determines the viscosity? In the present study the P-32- and Co-57 tracer diffusion were studied simultaneously in the range 550 K to 700 K with the radiotracer technique. The present, preliminary data show: the Co-diffusivities are in the expected range. The P-32 diffusivities are a factor of two smaller. Hence, Phosphorus does not determine the viscosity despite its covalent bonding character.

[1] F. Faupel, W. Frank, M.-P. Macht, H. Mehrer, V. Naundorf, K. Rätzke, H. R. Schober, S. K. Sharma, H. Teichler, Review of Modern Physics 75 (2003) 237 [2] V. Zöllmer, K. Rätzke, F. Faupel, A. Meyer, Phys. Rev. Lett., 90, 195502-1 (2003).