Configurational heat capacity and entropy of borosilicate melts

Richet, Pascal; Bouhifd, Mohamed Ali; Courtial, P.; Téqui, Christophe

doi:10.1016/s0022-3093(96)00646-1

Cited by 51 publications

(185 citation statements)

References 23 publications

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“…35) Therefore, as suggested by Richet et al, 17) smaller Cp Glass at Tg for the glasses in this study is also attributed to the increase of structural units with lower thermal energy by introduction of the B 2 O 3 in SiO 2 -rich glass. It can be estimated that the effect of B 2 O 3 on the decrease of Tg and Cp Glass at Tg becomes more remarkable with the increase of SiO 2 content.…”

Section: Resultssupporting

confidence: 78%

“…6) 16) In contrast, measurements for borosilicate melts are very limited in spite of their industrial importance. 17), 18) The high-temperature heat capacities of materials can be measured by a differential scanning calorimetry (DSC), a drop calorimetry, an AC calorimetry or a laser flash calorimetry. 19) In these techniques, the AC calorimetry and the laser flash calorimetry for oxide melts are not common because of experimental difficulties.…”

Section: )5)mentioning

confidence: 99%

“…Temperature and composition dependences of heat capacity of borosilicate melts were discussed based on the experimental results and previously reported Cp data. 17), 18) 2. Experimental method…”

Section: )5)mentioning

confidence: 99%

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Heat capacity measurements of 75SiO2–6B2O3–10Al2O3–9MO (M=Mg, Ca, Sr and Ba) glasses and melts

Sugawara

Hamano

Yoshida

et al. 2013

J. Ceram. Soc. Japan

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Heat capacities of 75SiO 2 6B 2 O 3 10Al 2 O 3 9MO (M=Mg,Ca, Sr and Ba) glasses and melts were determined between 345 and 1877 K by differential scanning calorimetry and drop calorimetry. The heat capacities of glasses and melts increase with increasing field strength of alkaline-earth metals. The glass transition takes place when the heat capacity of glass reaches 9597% of Dulong-Petit harmonic limit. The configurational contribution to the melt heat capacity is about 20% and is independent of temperature. The partial molar heat capacity of B 2 O 3 (Cp B2O3 ) in borosilicate melts containing alkaline-earth metals approaches to constant value (110120 J·K ¹1 ·mol ¹1 ) above 1600 K and is consistent with heat capacity of pure B 2 O 3 liquid. This suggests that there are no significant differences in coordination state of boron and in BSi ordering among Mg, Ca, Sr and Ba-bearing alumino-borosilicate melts.

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Section: Resultssupporting

confidence: 78%

Section: )5)mentioning

confidence: 99%

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Heat capacity measurements of 75SiO2–6B2O3–10Al2O3–9MO (M=Mg, Ca, Sr and Ba) glasses and melts

Sugawara

Hamano

Yoshida

et al. 2013

J. Ceram. Soc. Japan

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“…The thermal conductivity k c (T ) is given by [26], (27) Here also T is expressed in Kelvin. The correlation agrees with data reported by Richet et al [28] for c p alone at temperatures between 120 o C and 512 o C assuming a constant density of 2230 kg/m 3 [29].…”

Section: Constitutive Relationshipssupporting

confidence: 91%

Radiative heat transfer in enhanced hydrogen outgassing of glass

Kitamura

Pilon

2009

International Journal of Hydrogen Energy

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This paper explores the physical mechanisms responsible for experimental observations that led to the definition of "photo-induced hydrogen outgassing of glass". Doped borosilicate glass samples were placed inside an evacuated silica tube and heated in a furnace or by an incandescent lamp. It was observed that hydrogen release from the glass sample was faster and stronger when heated by an incandescent lamp than within furnace. Here, sample and silica tube were modeled as planeparallel slabs exposed to furnace or to lamp thermal radiation. Combined conduction, radiation, and mass transfer were accounted for by solving the one-dimensional transient mass and energy conservation equations along with the steady-state radiative transfer equation. All properties were found in the literature. The experimental observations can be qualitatively explained based on conventional thermally activated gas diffusion and by carefully accounting for the participation of the silica tube to radiation transfer along with the spectral properties of the silica tube and the glass samples. In brief, the radiation emitted by the incandescent lamp is concentrated between 0.5 and 3.0 µm and reaches directly the sample since the silica tube is nearly transparent up to 3.5 µm. On the contrary, for furnace heating at 400 o C, the silica tube absorbs a large fraction of the incident radiation which reduces the heating rate and the H 2 release rate. However, between 0.8 and 3.2 µm undoped borosilicate does not absorb significantly. Coincidentally, Fe 3 O 4 doping increases the absorption coefficient and also reacts with H 2 to form ferrous ions which increase the absorption coefficient of the sample by two orders of magnitude. Thus, doped and reacted 1 samples heat up much faster when exposed to the heating lamp resulting in the observed faster response time and larger H 2 release rate.Keywords: hydrogen storage, photo-induced gas diffusion, hollow glass microspheres, outgassing NOMENCLATURE c p Specific heat at constant pressure (J/kg.K)

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“…1(A-D) as a function of composition, temperature and water content. The heat capacity (Cp) measurements were carried out on nominally anhydrous and hydrous samples containing up to 19.9 mol% H2O in the temperature range of 574-1002 K. Except for liquids of some specific composition such as titanosilicates, borosilicates and highly polymerized aluminosilicates (e.g., Bottinga, 1984, 1986;Courtial and Richet, 1993;Lange and Navrotsky, 1993;Richet et al, 1997), it is generally observed that the heat capacity of silicate liquids (Cpliq) is constant with temperature, and this allows for extrapolation over a large T interval (e.g., Richet and Bottinga, 1986;Lange and Navrotsky, 1993;Bouhifd et al, 2006). In the investigate temperature range above Tg, no variation of Cpliq was observed, in agreement with literature studies.…”

Section: Calorimetrymentioning

confidence: 99%

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Genova

Romano

Giordano

et al. 2014

Geochimica et Cosmochimica Acta

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International audienceThe glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results

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Configurational heat capacity and entropy of borosilicate melts

Cited by 51 publications

References 23 publications

Heat capacity measurements of 75SiO<sub>2</sub>–6B<sub>2</sub>O<sub>3</sub>–10Al<sub>2</sub>O<sub>3</sub>–9MO (M=Mg, Ca, Sr and Ba) glasses and melts

Heat capacity measurements of 75SiO<sub>2</sub>–6B<sub>2</sub>O<sub>3</sub>–10Al<sub>2</sub>O<sub>3</sub>–9MO (M=Mg, Ca, Sr and Ba) glasses and melts

Radiative heat transfer in enhanced hydrogen outgassing of glass

Heat capacity, configurational heat capacity and fragility of hydrous magmas

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