Aluminum speciation, vibrational entropy and short-range order in calcium aluminosilicate glasses

Richet, Pascal; Nidaira, Atsusi; Neuville, Daniel R.; Ataké, Tooru

doi:10.1016/j.gca.2009.03.041

Cited by 21 publications

(18 citation statements)

References 25 publications

(51 reference statements)

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“…Spline fits made to these data have been used to derive the smoothed values and thermodynamic functions of Tables II–IV. For silicates, C p is a linear function of composition at low temperature provided that the used components refer to well‐defined structural species, namely cations with fixed anion coordinations 11,24 . In this case, partial molar heat capacities C p,i ° can be considered as being independent of composition, viz where x i is the mole fraction of component i .…”

Section: Resultsmentioning

confidence: 99%

Boson Peak, Elastic Properties, and Rigidification Induced by the Substitution of Nitrogen for Oxygen in Oxynitride Glasses

Richet

Rouxel

Kawaji

et al. 2010

Journal of the American Ceramic Society

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International audienceThe effects of the substitution of nitrogen for oxygen on the heat capacity and vibrational entropy of three yttrium aluminosilicate glasses with 0, 3.4, and 7.4 mol% Si(3)N(4) have been investigated from 10 to 300 K. The partial molar heat capacity and entropy of Si(3)N(4) calculated from these and previous measurements indicate stronger average bonding than for SiO(2) units, whereas the values derived for Y(2)O(3) are consistent with the dual network modifying and Al3+ charge-compensating role of yttrium. The low-frequency part of the vibrational densities of states g(omega) and the boson peaks g(omega)/omega 2 derived from the inversion of the heat capacities indicate that nitrogen rigidifies the TO(4) (T=Si, Al) tetrahedral network and that yttrium hampers the librational motion of the AlO(4) tetrahedra, which contribute to the excitations associated with the boson peak. Along with data reported previously for borate and silicate glasses, these results for oxynitrides show a general monotonically increasing relation between transverse acoustic velocities and the temperature of the calorimetric boson peak. Illustrating the universal phenomenology of the boson peak, all these data collapse on the same master curve when plotted in a reduced form

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Section: Resultsmentioning

confidence: 99%

Boson Peak, Elastic Properties, and Rigidification Induced by the Substitution of Nitrogen for Oxygen in Oxynitride Glasses

Richet

Rouxel

Kawaji

et al. 2010

Journal of the American Ceramic Society

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“…In spite of such experimental differences, the coherence of the results obtained with both kinds of procedures has been noted in a comprehensive study of calcium aluminosilicate glasses. 26 We thus assume that our calculations are not af- fected by significant bias resulting in particular from systematic differences in thermal history and fictive temperature. In binary alkaline earth silicate melts, liquid immiscibility may be a concern.…”

Section: Methodsmentioning

confidence: 99%

Boson peak of alkali and alkaline earth silicate glasses: Influence of the nature and size of the network-modifying cation

Richet

2012

The Journal of Chemical Physics

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The influence of the size of the alkaline earth cation on the boson peak of binary metasilicate glasses, MSiO(3) (M = Mg, Ca, Sr, Ba), has been investigated from vibrational densities of states determined by inversion of low-temperature heat capacities. As given both by C(p)/T(3) and g(ω)/ω(2), the intensity of the boson peak undergoes a 7-fold increase from Mg to Ba, whereas its temperature and frequency correlatively decrease from 18 to 10 K and from 100 to 20 cm(-1), respectively. The boson peak results from a combination of librations of SiO(4) tetrahedra and localized vibrations of network-modifying cations with non-bridging oxygens whose contribution increases markedly with the ionic radius of the alkaline earth. As a function of ionic radii, the intensity for Sr and Ba varies in the same way as previously found for alkali metasilicate glasses. The localized vibrations involving alkali and heavy alkaline earth cations appear to be insensitive to the overall glass structure. Although the new data are coherent with an almost linear relationship between the temperature of the boson peak and transverse sound velocity, pure SiO(2) and SiO(2)-rich glasses make marked exceptions to this trend because of the weak transverse character of SiO(4) librations. Finally, the universality of the calorimetric boson peak is again borne out because all data for silicate glasses collapse on the same master curve when plotted in a reduced form (C(P)∕/T(3))/(C(P)/T(3))(b) vs. T/T(b).

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“…Table 3 Molar thermodynamic functions of NS 2 Fe red glass. whether Ca 2+ is ''free" or acting as a charge-compensating cation for tetrahedrally coordinated Al 3+ because the coordination of Ca 2+ is about the same in both instances (de Ligny et al, 1996;Richet et al, 2009). But for Na 2 O different entropy values of 85 and 96.7 J/mol K were derived depending on whether Na + is ''free" or charge-compensating tetrahedral Al 3+ , respectively, the difference resulting from the large increase in coordination number from about 5 to about 9 induced by the association of sodium with aluminum (Richet et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

“…For Al 2 O 3 we have used the value of 69.1 J/mol K derived from entropies of alkali and alkaline earth aluminosilicate glasses (Richet et al, 1993). For calcium aluminosilicates, this figure actually represents the weighted average of the values for Al 2 O 3 components in which Al is in four-and five-fold coordination, whose entropies are 72.8 and 48.5 J/mol K, respectively (Richet et al, 2009). Interestingly, fits made with the 72.8 J/mol K derived for IV Al 2 O 3 yield entropies that are too high compared to those obtained from the data of Table 6.…”

Section: Discussionmentioning

confidence: 99%

Entropy and structure of oxidized and reduced iron-bearing silicate glasses

Sipowska

Ataké

Mysen

et al. 2009

Geochimica et Cosmochimica Acta

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Aluminum speciation, vibrational entropy and short-range order in calcium aluminosilicate glasses

Cited by 21 publications

References 25 publications

Boson Peak, Elastic Properties, and Rigidification Induced by the Substitution of Nitrogen for Oxygen in Oxynitride Glasses

Boson Peak, Elastic Properties, and Rigidification Induced by the Substitution of Nitrogen for Oxygen in Oxynitride Glasses

Boson peak of alkali and alkaline earth silicate glasses: Influence of the nature and size of the network-modifying cation

Entropy and structure of oxidized and reduced iron-bearing silicate glasses

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