{"title":"Thermodynamic properties of neodymium silicates at high temperature (298.15–1273K) and thermodynamic reassessment of the Nd2O3-SiO2 system","authors":"","doi":"10.1016/j.calphad.2024.102760","DOIUrl":null,"url":null,"abstract":"<div><div>Solid oxide fuel cells (SOFCs) have garnered significant interest due to their potential as alternative electrical power generation systems that offer low pollutant emissions and high energy conversion efficiency. Neodymium silicates have emerged as promising electrolyte materials owing to their high ionic conductivity. To enhance our understanding of their performance in SOFC applications, it is essential to investigate the thermodynamic properties of neodymium silicates. In this study, we measured the heat capacities of the prepared samples over the temperature range of 673–1273 K using a multi-high temperature calorimeter (MHTC) 96 line. The temperature dependence of heat capacities for Nd<sub>2</sub>SiO<sub>5</sub>, Nd<sub>14</sub>Si<sub>9</sub>O<sub>39</sub>, and Nd<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> were modeled as functions: Cp<sub>(Nd2SiO5)</sub> = 194.7 + 0.028 T–4,714,800 T<sup>−2</sup> – 239.75 T<sup>−0.5</sup> + 491568400 T<sup>−3</sup> (J·mol<sup>−1</sup>·K<sup>−1</sup>) (298.15 - 1400K), Cp<sub>(Nd14Si9O39)</sub> =1527.1 + 0.22 T − 40097000 T<sup>−2</sup> – 2150.3 T<sup>−0.5</sup> + 4424200000 T<sup>−3</sup> (J·mol<sup>−1</sup>·K<sup>−1</sup>) (298.15 - 1400K), Cp<sub>(Nd2Si2O7)</sub> =276 + 0.032 T − 8261400 T<sup>−2</sup> – 480 T<sup>−0.5</sup> + 983136800 T<sup>−3</sup> (J mol<sup>−1</sup> K<sup>−1</sup>) (298.15–1400K), and then used for computing changes in entropy and Gibbs free energy. The Nd<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> system was reassessed based on the phase diagram experimental data and measured heat capacities in this work.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0364591624001020","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Solid oxide fuel cells (SOFCs) have garnered significant interest due to their potential as alternative electrical power generation systems that offer low pollutant emissions and high energy conversion efficiency. Neodymium silicates have emerged as promising electrolyte materials owing to their high ionic conductivity. To enhance our understanding of their performance in SOFC applications, it is essential to investigate the thermodynamic properties of neodymium silicates. In this study, we measured the heat capacities of the prepared samples over the temperature range of 673–1273 K using a multi-high temperature calorimeter (MHTC) 96 line. The temperature dependence of heat capacities for Nd2SiO5, Nd14Si9O39, and Nd2Si2O7 were modeled as functions: Cp(Nd2SiO5) = 194.7 + 0.028 T–4,714,800 T−2 – 239.75 T−0.5 + 491568400 T−3 (J·mol−1·K−1) (298.15 - 1400K), Cp(Nd14Si9O39) =1527.1 + 0.22 T − 40097000 T−2 – 2150.3 T−0.5 + 4424200000 T−3 (J·mol−1·K−1) (298.15 - 1400K), Cp(Nd2Si2O7) =276 + 0.032 T − 8261400 T−2 – 480 T−0.5 + 983136800 T−3 (J mol−1 K−1) (298.15–1400K), and then used for computing changes in entropy and Gibbs free energy. The Nd2O3-SiO2 system was reassessed based on the phase diagram experimental data and measured heat capacities in this work.
期刊介绍:
The design of industrial processes requires reliable thermodynamic data. CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) aims to promote computational thermodynamics through development of models to represent thermodynamic properties for various phases which permit prediction of properties of multicomponent systems from those of binary and ternary subsystems, critical assessment of data and their incorporation into self-consistent databases, development of software to optimize and derive thermodynamic parameters and the development and use of databanks for calculations to improve understanding of various industrial and technological processes. This work is disseminated through the CALPHAD journal and its annual conference.