Sodium tracer diffusion in glasses of the type (CaO·Al2O3)x(2SiO2)1−x

Lu, Hongxia; Dieckmann, R.

doi:10.1016/j.jnoncrysol.2007.04.024

Cited by 4 publications

(5 citation statements)

References 39 publications

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“…27,55,56 On the experimental side, it is reported that the tracer diffusivity of 22 Na in 0.2Na 2 O-0.8B 2 O 3 glass increased from B10 À13 cm 2 s À1 to B10 À11 cm 2 s À1 as the temperature increased from B500 K to B600 K. 57 Sodium tracer diffusion coefficients measured in (CaO-Al 2 O 3 ) x (2SiO 2 ) 1Àx glasses at 800 1C decreased from B10 À7.5 cm 2 s À1 to B10 À12.5 cm 2 s À1 as the value of x increased from 0.175 to 0.9. 58 Diffusion energy barriers for Na, Ca and Sr for the low-temperature ranges are reported in Table 3. Na diffusion energy barriers range from 0.55 to 0.83 eV, increasing with B 2 O 3 concentration (Fig.…”

Section: Resultsmentioning

confidence: 99%

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

Ren

Deng

et al. 2018

Phys. Chem. Chem. Phys.

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The effect of B2O3/SiO2 substitution in SrO-containing 55S4.3 bioactive glasses on glass structure and properties, such as ionic diffusion and glass transition temperature, was investigated by combining experiments and molecular dynamics simulations with newly developed potentials. Both short-range (such as bond length and bond angle) and medium-range (such as polyhedral connection and ring size distribution) structures were determined as a function of glass composition. The simulation results were used to explain the experimental results for glass properties such as glass transition temperature and bioactivity. The fraction of bridging oxygen increased linearly with increasing B2O3 content, resulting in an increase in overall glass network connectivity. Ion diffusion behavior was found to be sensitive to changes in glass composition and the trend of the change with the level of substitution is also temperature dependent. The differential scanning calorimetry (DSC) results show a decrease in glass transition temperature (Tg) with increasing B2O3 content. This is explained by the increase in ion diffusion coefficient and decrease in ion diffusion energy barrier in glass melts, as suggested by high-temperature range (above Tg) ion diffusion calculations as B2O3/SiO2 substitution increases. In the low-temperature range (below Tg), the Ea for modifier ions increased with B2O3/SiO2 substitution, which can be explained by the increase in glass network connectivity. Vibrational density of states (VDOS) were calculated and show spectral feature changes as a result of the substitution. The change in bioactivity with B2O3/SiO2 substitution is discussed with the change in pH value and release of boric acid into the solution.

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Section: Resultsmentioning

confidence: 99%

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

Ren

Deng

et al. 2018

Phys. Chem. Chem. Phys.

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“…Diffusivity data sources: determined in this work for soda magnesia silicate composition ; calculated in this work for soda magnesia silicate composition with Eyring relation ( ) from the measured viscosities; D divalent of divalent cations for basaltic composition 9 ; for albite composition 23 ; for jadeite composition 23 ; for soda lime silica (SLS) composition 24 ; for calcium aluminosilicate (CAS) composition. 25 …”

Section: Chemical Aspects Of Inward Diffusionmentioning

confidence: 99%

Inward and Outward Diffusion of Modifying Ions and its Impact on the Properties of Glasses and Glass–Ceramics

Smedskjær

Yue

2011

Int J of Appl Glass Sci

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In this paper, we review our recent findings about both the cationic inward and outward diffusion processes in glasses and glass–ceramics caused by redox reactions. We provide new insights into these findings by mapping the diffusion depth, the thermal reduction temperature, and time in a three dimensional diagram and by looking into the correlation among the glass composition, structure, topology, and the diffusion process in the polyvalent elements containing glasses. We illustrate the link between glassy dynamics (via the liquid fragility index m) and activation energy of diffusion. Furthermore, the inward diffusion approach is used to study percolation phenomena in glass–ceramics. Finally, we show that the diffusion approaches are potential tools for tailoring the surface performances of bulk glasses and glass fibers.

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“…The importance of these percolation pathways makes this kind of diffusion mechanism generally prone to blocking effects. 35,45 Data published in the literature show that in the nominally fully polymerized systems NaAlSi 3 36 sodium tracer diffusivity decreases by 4-6 orders of magnitude upon calcium incorporation at temperatures around 1073 K. In the lithium bearing glasses of our study no impact of blocking divalent cations is expected due to low impurity contents (Li/Ca 4 500, see Table 1). …”

Section: Raman Spectroscopymentioning

confidence: 49%

“…35,45 Data published in the literature show that in the nominally fully polymerized systems NaAlSi 3 O 8 -CaAl 2 Si 2 O 8 (ref. 46) and (CaOÁAl 2 O 3 ) x -(2SiO 2 ) 1Àx , x from 0.17 to 0.90 36 sodium tracer diffusivity decreases by 4-6 orders of magnitude upon calcium incorporation at temperatures around 1073 K. In the lithium bearing glasses of our study no impact of blocking divalent cations is expected due to low impurity contents (Li/Ca 4 500, see Table 1).…”

Section: Raman Spectroscopymentioning

confidence: 58%

“…33 An overview of these models can be found, for instance, in Chakraborty, 34 Mehrer 35 or Lu and Dieckmann. 36 Ideas of the latter two models are combined in the concept of mismatch and relaxation (CMR) of Funke, 37 and are further elaborated in the universality concept of Funke et al 38 Ionconducting materials with quite different kinds of disordered structures have been found to show a striking similarity in their conductivity spectra. The first universality is that, at high temperatures, plots of log conductivity vs. log frequency yield features as shown in Fig.…”

Section: Raman Spectroscopymentioning

confidence: 99%

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Lithium conductivity in glasses of the Li₂O–Al₂O₃–SiO₂system

Ross

Welsch

Behrens

2015

Phys. Chem. Chem. Phys.

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To improve the understanding of Li-dynamics in oxide glasses, i.e. the effect of [AlO 4 ] À tetrahedra and non-bridging oxygens on the potential landscape, electrical conductivity of seven fully polymerized and partly depolymerized lithium aluminosilicate glasses was investigated using impedance spectroscopy (IS).Lithium is the only mobile particle in these materials. Data derived from IS, i.e. activation energies, preexponential factors and diffusivities for lithium, are interpreted in light of Raman spectroscopic analyses of local structures in order to identify building units, which are crucial for lithium dynamics and migration. In polymerized glasses (compositional join LiAlSiO 4 -LiAlSi 4 O 10 ) the direct current (DC) electrical conductivity continuously increases with increasing lithium content while lithium diffusivity is not affected by the Al/Si ratio in the glasses. Hence, the increase in electrical conductivity can be solely assigned to lithium concentration in the glasses. An excess of Li with respect to Al, i.e. the introduction of non-bridging oxygen into the network, causes a decrease in lithium mobility in the glasses. Activation energies in polymerized glasses (66 to 70 kJ mol À1 ) are significantly lower than those in depolymerized networks (76 to 78 kJ mol À1 ) while pre-exponential factors are nearly constant across all compositions. Comparison of the data with results for lithium silicates from the literature indicates a minimum in lithium diffusivity for glasses containing both aluminium tetrahedra and non-bridging oxygens. The findings allow a prediction of DC conductivity for a large variety of lithium aluminosilicate glass compositions.

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Sodium tracer diffusion in glasses of the type (CaO·Al2O3)x(2SiO2)1−x

Cited by 4 publications

References 39 publications

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

Inward and Outward Diffusion of Modifying Ions and its Impact on the Properties of Glasses and Glass–Ceramics

Lithium conductivity in glasses of the Li₂O–Al₂O₃–SiO₂system

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Sodium tracer diffusion in glasses of the type (CaO·Al2O3)x(2SiO2)1−x

Cited by 4 publications

References 39 publications

B2O3/SiO2 substitution effect on structure and properties of Na2O–CaO–SrO–P2O5–SiO2 bioactive glasses from molecular dynamics simulations

B2O3/SiO2 substitution effect on structure and properties of Na2O–CaO–SrO–P2O5–SiO2 bioactive glasses from molecular dynamics simulations

Inward and Outward Diffusion of Modifying Ions and its Impact on the Properties of Glasses and Glass–Ceramics

Lithium conductivity in glasses of the Li2O–Al2O3–SiO2system

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Product

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About

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

B₂O₃/SiO₂ substitution effect on structure and properties of Na₂O–CaO–SrO–P₂O₅–SiO₂ bioactive glasses from molecular dynamics simulations

Lithium conductivity in glasses of the Li₂O–Al₂O₃–SiO₂system