The time and temperature dependences of impurity diffusion were measured in detail for several bulk glasses (tables 352 to 362) over a wide temperature range. It was found that neither the quenched-in free volume nor a small volume fraction of crystals had a significant effect upon the diffusivity. It was shown that the composition of the glasses had a much weaker effect upon the diffusion coefficients than did structural changes in the glass. By using long-term relaxation, a reversible metastable equilibrium of the glass structure could be reached at temperatures below the calorimetric glass transition. A single set of diffusion parameters, activation enthalpies and pre-factors was derived, for this metastable equilibrium state, over the entire temperature range above and below the glass transition. This indicated that the usually observed non-linear Arrhenius behavior of diffusion coefficients in bulk glasses was caused by insufficient structural relaxation at temperatures below the calorimetric glass transition. The Arrhenius diffusion relationships for various compositions in the low-temperature region could be described by:

Fe in Zr41Be22.5Ti14Cu12.5Ni10: D (m2/s) = 1.08 x 10-5exp[-1.91(eV)/kT]

B in Zr41Be22.5Ti14Cu12.5Ni10: D (m2/s) = 1.73 x 10-5exp[-1.80(eV)/kT]

Fe in Zr41Be27.8Ti8.7Cu12.5Ni10: D (m2/s) = 2.05 x 10-2exp[-2.27(eV)/kT]

B in Zr41Be27.8Ti8.7Cu12.5Ni10: D (m2/s) = 3.14 x 10-2exp[-2.18(eV)/kT]

Fe in Zr41Be20Ti16.5Cu12.5Ni10: D (m2/s) = 4.80 x 10-6exp[-1.85(eV)/kT]

B in Zr41Be20Ti16.5Cu12.5Ni10: D (m2/s) = 1.19 x 10-4exp[-1.87(eV)/kT]

Co in Zr46.8Be27.5Ti8.2Cu7.5Ni10: D (m2/s) = 7.3 x 10-4exp[-2.01(eV)/kT]

and those in the high-temperature regime could be described by:

Fe in Zr41Be22.5Ti14Cu12.5Ni10: D (m2/s) = 2.26 x 108exp[-3.48(eV)/kT]

B in Zr41Be22.5Ti14Cu12.5Ni10: D (m2/s) = 1.22 x 105exp[-2.97(eV)/kT]

Fe in Zr41Be27.8Ti8.7Cu12.5Ni10: D (m2/s) = 7.24 x 105exp[-3.17(eV)/kT]

B in Zr41Be27.8Ti8.7Cu12.5Ni10: D (m2/s) = 1.24 x 101exp[-2.50(eV)/kT]

Fe in Zr41Be20Ti16.5Cu12.5Ni10: D (m2/s) = 4.58 x 107exp[-3.44(eV)/kT]

B in Zr41Be20Ti16.5Cu12.5Ni10: D (m2/s) = 2.11 x 103exp[-2.77(eV)/kT]

Co in Zr46.8Be27.5Ti8.2Cu7.5Ni10: D (m2/s) = 3.05 x 105exp[-3.00(eV)/kT]

Al in Zr46.8Be27.5Ti8.2Cu7.5Ni10: D (m2/s) = 3.19 x 1012exp[-4.09(eV)/kT]

Hf in Zr46.8Be27.5Ti8.2Cu7.5Ni10: D (m2/s) = 3.76 x 1010exp[-3.76(eV)/kT]

T.Zumkley, V.Naundorf, M.P.Macht, P.Fielitz, G.Frohberg: Materials Transactions, 2002, 43[8], 1921-30

Table 351

Diffusivity of Fe in Bulk Zr46.8Be27.5Ni10Ti8.2Cu7.5 Glass,

Pre-Annealed for Various Times at 553K