Phase equilibria in the K2O-Nb2O5 system

Мешалкин, А. Б.; Каплун, А. Б.; Pyl'neva, N. A.; Tsirkina, N.L.; Kosyakov, V. I.

doi:10.1134/s0036023607100270

Cited by 6 publications

(9 citation statements)

References 3 publications

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“…The calculated T m at P = 0 GPa is higher than that of Na 2 SiO 3 where the experimentally reported melting point was 820 °C . The calculated T m shown in Table reveals that the melting temperature increases with applied pressures.…”

Section: Resultsmentioning

confidence: 69%

“…The calculated T m at P = 0 GPa is higher than that of Na 2 SiO 3 where the experimentally reported melting point was 820 °C. 68 The calculated T m shown in Table 6 reveals that the melting temperature increases with applied pressures. However, one can find that between P = 0–15 GPa the rise on T m with P is very regular, but once P reaches 20 GPa, T m surges to ∼2875 °C.…”

Section: Resultsmentioning

confidence: 97%

“…In this regard, we have calculated the melting temperature (T m ) of Na 2 GeO 2 under different applied pressures by employing the equation given as 66,67 = + ± T C 553 5.911 300 m 11 (10) The calculated T m at P = 0 GPa is higher than that of Na 2 SiO 3 where the experimentally reported melting point was 820 °C. 68 The calculated T m shown in Table 6 reveals that the melting temperature increases with applied pressures. However, one can find that between P = 0−15 GPa the rise on T m with P is very regular, but once P reaches 20 GPa, T m surges to ∼2875 °C.…”

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confidence: 97%

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A Thorough Investigation of Electronic, Optical, Mechanical, and Thermodynamic Properties of Stable Glasslike Sodium Germanate under Compressive Hydrostatic Pressure: Ab Initio Study

et al. 2023

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In this paper, we have tried to elucidate the variation of structural, electronic, and thermodynamic properties of glasslike Na 2 GeO 3 under compressive isotropic pressure within a framework of density functional theory (DFT). The result shows stable structural (orthorhombic → tetragonal) and electronic (indirect → direct) phase transitions at P ∼ 20 GPa. The electronic band gap transition plays a key role in the enhancement of optical properties. The results of the thermodynamic properties have shown that Na 2 GeO 3 follows Debye's lowtemperature specific heat law and the classical thermodynamic of the Dulong−Petit law at high temperature. The pressure sensitivity of the electronic properties led us to compute the piezoelectric tensor (both in relaxed and clamped ions). We have observed significant electric responses in the form of a piezoelectric coefficient under applied pressure. This property suggested that Na 2 GeO 3 could be a potential material for energy harvest in future energy-efficient devices. As expected, Na 2 GeO 3 becomes harder and harder under compressive pressure up to the phase transition pressure (∼20 GPa) which can be read from Pugh's ratio (k H ) > 1.75, however, at pressures above 20 GPa k H < 1.75, which may be due to the formation of fractures at high pressure.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 97%

mentioning

confidence: 97%

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A Thorough Investigation of Electronic, Optical, Mechanical, and Thermodynamic Properties of Stable Glasslike Sodium Germanate under Compressive Hydrostatic Pressure: Ab Initio Study

et al. 2023

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“…Several researchers have extensively investigated the use of sodium silicate solution as an inorganic binder for castings, which forms a slurry with high wettability when mixed with casting sands 23,24 . The kneaded sand is then placed in a mold with a specific shape (to acquire that shape), and the handling and casting are carried out through drying 25,26 . The sodium contained in the sodium silicate lowers the melting point of the glass; however, it reduces the strength of the ceramic core owing to its hygroscopicity.…”

Section: Introductionmentioning

confidence: 99%

“…23,24 The kneaded sand is then placed in a mold with a specific shape (to acquire that shape), and the handling and casting are carried out through drying. 25,26 The sodium contained in the sodium silicate lowers the melting point of the glass; however, it reduces the strength of the ceramic core owing to its hygroscopicity. Therefore, the sodium content in sodium silicate should be reduced.…”

Section: Introductionmentioning

confidence: 99%

Enhancing fracture strength of ceramic core using sodium silicate as the binder

Park

Jung

Kim

et al. 2022

Int J Applied Ceramic Tech

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Ceramic cores used in the casting must exhibit high heat resistance because they come in direct contact with molten metals. Therefore, in this study, ceramic cores with high heat resistance and fracture strength were fabricated using sodium silicate as the binder instead of a commonly used organic binder. In addition, the prepared ceramic core was coated with Si and Si-Na precursors as the inorganic binder to improve the firing strength of the ceramic core. The thermal stability and firing strength of the sample were investigated. The results revealed that the firing strength of the ceramic core was significantly improved up to 15.2 MPa owing to the formation of a glass phase between the ceramic particles, which was formed by the reaction of sodium silicate and the inorganic binder precursor. In addition, the core was completely decomposed in an NaOH solution at a relatively low temperature of 60 • C, indicating the excellent elution properties of the sample. These results indicate that the method proposed in this study is suitable for the preparation of ceramic cores with high fracture strength and excellent elution behavior.

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