TY - JOUR

T1 - Cation diffusion in soda-lime-silicate glass melts

AU - Behrens, Harald

AU - Haack, Miriam

N1 - Funding Information: This work was supported by the German Science Foundation (DFG Grant Be1720/11). The authors thank Karen Rickers and Gerald Falkenberg for technical assistance during measurements at HASYLAB.

PY - 2007/12/15

Y1 - 2007/12/15

N2 - Cation diffusion was experimentally investigated in soda-lime-silicate glass melts (composition in mol%: 74SiO2-16Na2O-10CaO) at temperatures from 1000 to 1200 °C using the diffusion couple technique. One half of each diffusion couple was doped with 11 trace elements (500 ppm by weight of Rb, Cs, Sr, Zn, Cd, Nd, Eu, In, Sn, Ge and 1000 ppm by weight of Fe). Experiments were performed in an internally heated gas pressure vessel at a confining pressure of 100 MPa to avoid convective fluxes in the diffusion samples. The distribution of major elements was analyzed by electron microprobe. IR spectroscopy was used to quantify concentrations of dissolved water in the run products. Trace element diffusion profiles were measured simultaneously employing synchrotron X-ray fluorescence microanalysis. In all analyzed glasses the highest diffusion coefficients were observed for Rb whereas Nd was always the slowest element, e.g. at 1000 °C the diffusivity decreases from (1.51 ± 0.35) × 10-11 m2/s for Rb to (1.29 ± 0.34) × 10-13 m2/s for Nd. The diffusivity of Nd is close to the chemical diffusivity of network former calculated from viscosity data using the Eyring relationship. Surprisingly, the rare earth elements Nd (3+) and Eu (mixed 2+, 3+) diffuse more slowly than the tetravalent Ge. Activation energies for diffusion increase from (132.1 ± 1.5) kJ/mol for Rb to (205 ± 16) kJ/mol for Eu. Based on the diffusion data for Eu, Sr and Nd we estimated that Eu2+/Eutotal ratios in soda-lime-silicate glass melts are below 0.04 both at reducing and oxidizing conditions.

AB - Cation diffusion was experimentally investigated in soda-lime-silicate glass melts (composition in mol%: 74SiO2-16Na2O-10CaO) at temperatures from 1000 to 1200 °C using the diffusion couple technique. One half of each diffusion couple was doped with 11 trace elements (500 ppm by weight of Rb, Cs, Sr, Zn, Cd, Nd, Eu, In, Sn, Ge and 1000 ppm by weight of Fe). Experiments were performed in an internally heated gas pressure vessel at a confining pressure of 100 MPa to avoid convective fluxes in the diffusion samples. The distribution of major elements was analyzed by electron microprobe. IR spectroscopy was used to quantify concentrations of dissolved water in the run products. Trace element diffusion profiles were measured simultaneously employing synchrotron X-ray fluorescence microanalysis. In all analyzed glasses the highest diffusion coefficients were observed for Rb whereas Nd was always the slowest element, e.g. at 1000 °C the diffusivity decreases from (1.51 ± 0.35) × 10-11 m2/s for Rb to (1.29 ± 0.34) × 10-13 m2/s for Nd. The diffusivity of Nd is close to the chemical diffusivity of network former calculated from viscosity data using the Eyring relationship. Surprisingly, the rare earth elements Nd (3+) and Eu (mixed 2+, 3+) diffuse more slowly than the tetravalent Ge. Activation energies for diffusion increase from (132.1 ± 1.5) kJ/mol for Rb to (205 ± 16) kJ/mol for Eu. Based on the diffusion data for Eu, Sr and Nd we estimated that Eu2+/Eutotal ratios in soda-lime-silicate glass melts are below 0.04 both at reducing and oxidizing conditions.

KW - Diffusion and transport

KW - Oxide glasses

KW - Pressure effects

KW - Rare-earths in glasses

KW - Soda-lime-silica

KW - Viscosity

KW - Water in glass

KW - X-ray fluorescence

UR - http://www.scopus.com/inward/record.url?scp=36549072056&partnerID=8YFLogxK

U2 - 10.1016/j.jnoncrysol.2007.05.178

DO - 10.1016/j.jnoncrysol.2007.05.178

M3 - Article

AN - SCOPUS:36549072056

VL - 353

SP - 4743

EP - 4752

JO - Journal of non-crystalline solids

JF - Journal of non-crystalline solids

SN - 0022-3093

IS - 52-54

ER -