Ways of Estimating the Heat Capacity of Crystalline Phases

Uspenskaya, I. A.; Ivanov, Andrey; Konstantinova, Natalia; Куценок, И. Б.

doi:10.1134/s003602442209028x

Cited by 7 publications

(7 citation statements)

References 20 publications

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“…The specific heat capacities of the layers used for the TDTR simulation were 132 J kg –1 K –1 for Pt, 485 J kg –1 K –1 for SrCoO y , 536 J kg –1 K –1 for SrFeO y , and 460 J kg –1 K –1 for YSZ. The specific heat capacities of the SrCo 1– x Fe x O y solid solutions were calculated by the Kopp–Neumann law . Details of the TDTR method are described elsewhere. ,− …”

Section: Experimental Sectionmentioning

confidence: 99%

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Solid-State Electrochemical Thermal Transistors with Strontium Cobaltite–Strontium Ferrite Solid Solutions as the Active Layers

Bian

Yang

Yoshimura

et al. 2023

ACS Appl. Mater. Interfaces

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Thermal transistors have potential as thermal management devices because they can electrically control the thermal conductivity (κ) of the active layer. Recently, we realized solid-state electrochemical thermal transistors by utilizing the electrochemical redox reaction of SrCoO y (2 ≤ y ≤ 3). However, the guiding principle to improve the on/off κ ratio has yet to be clarified because the κ modulation mechanism is unclear. This study systematically modulates κ of SrCo1–x Fe x O y (0 ≤ x ≤ 1, 2 ≤ y ≤ 3) solid solutions used as the active layers in solid-state electrochemical thermal transistors. When y = 3, the lattice κ of SrCo1–x Fe x O y is ∼2.8 W m–1 K–1 and insensitive to x. When x = 0 and y = 3, κ increases to ∼3.8 W m–1 K–1 due to the contribution of the electron κ. When y = 2, κ slightly depends on the ordered atomic arrangement. Materials that are high electrical conductors with highly ordered lattices when the transistor is on but are electrical insulators with disordered lattices when the transistor is off should be well-suited for the active layers of solid-state electrochemical thermal transistors.

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Section: Experimental Sectionmentioning

confidence: 99%

“…The specific heat capacities of the SrCo 1−x Fe x O y solid solutions were calculated by the Kopp−Neumann law. 23 Details of the TDTR method are described elsewhere. 5,24−26 Measurements of XAS.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Solid-State Electrochemical Thermal Transistors with Strontium Cobaltite–Strontium Ferrite Solid Solutions as the Active Layers

Bian

Yang

Yoshimura

et al. 2023

ACS Appl. Mater. Interfaces

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“…Hence, for practical purposes, only one equation should be adequate for integrating all the Cp , m values. Many equations have been reported to better fit the molar heat capacity of alloys and oxides at high temperatures 25,26 . The Maier–Kelley formula show excellent reliability in extrapolating Cp , m value in extremely high‐temperature regions; therefore, they take precedence based on existing literature and have also been adopted in this study 27 .…”

Section: Resultsmentioning

confidence: 99%

“…Many equations have been reported to better fit the molar heat capacity of alloys and oxides at high temperatures. 25,26 The Maier-Kelley formula show excellent reliability in extrapolating Cp, m value in extremely high-temperature regions; therefore, they take precedence based on existing literature and have also been adopted in this study. 27 The enthalpy changes respective to temperature and fitted curves were obtained using a simultaneous linear regression.…”

Section: Thermodynamic Propertiesmentioning

confidence: 99%

High‐temperature phase transformation and thermodynamic properties of Ca₃(VO₄)₂

Pei,

Jiao,

et al. 2024

J Am Ceram Soc.

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Ca3(VO4)2 is a promising candidate for applications in ferroelectric, laser host, and optical materials owing to its unique whitlockite structure and excellent physicochemical properties. In this study, the Ca3(VO4)2 powder was fabricated via a conventional solid‐phase route in air, using V2O5 and CaO as precursors. The trigonal Ca3(VO4)2 belongs to the space group R3c, having unit cell parameters of a = 10.8074 Å, b = 10.8074 Å, and c = 37.98871 Å, respectively. Ca3(VO4)2 melts congruently at 1680 K, as determined from differential scanning calorimetry measurements of the thermal profile of the second heating test. Enthalpy changes in Ca3(VO4)2 were experimentally determined for the first time across temperatures between 573 and 1623 K by drop calorimetry. The temperature‐dependent molar heat capacity of Ca3(VO4)2 was calculated from the enthalpy changes at elevated temperatures. Thermodynamic properties (entropy, enthalpy, and Gibbs free energy changes) were also calculated. The thermodynamic properties measured in this study were further applied to evaluate the appropriate precursors for fabricating Ca3(VO4)2 via solid‐state calcination. The results strongly recommend the use of V2O5 and Ca(OH)2 precursors for preparing the Ca3(VO4)2 samples because of their thermodynamic advantages.

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“…The available data are a bit different [9][10][11][12][13][14][15]. It is known that on the basis of data on the heat capacity C p = f (T ), the temperature dependences of the thermodynamic properties of inorganic substances are determined [16], therefore, the accuracy of the calculation of enthalpy, entropy and Gibbs energy will depend on the accuracy of the obtained heat capacity values. In turn, the error in determining the heat capacity depends not only on the method of its measurement, but also on the reproducibility of the properties of the material under study [16].…”

Section: Introductionmentioning

confidence: 99%