The phase stability of Ca2TiO4 and related Ruddlesden–Popper phases

Ramadan, Amr; Hesselmann, Linda; Souza, Roger A. De

doi:10.1016/j.jpcs.2015.06.022

Cited by 10 publications

(5 citation statements)

References 23 publications

(37 reference statements)

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“…XRD detected C3T2 and C4T3 but no C2T, CT2, C2T5, CT4 or C5T4 compounds were seen. These results are consistent with the reported phase diagrams and the reported phase stability of the compounds . The C5T4 phase reported in the literature should probably be the C4T3 compound, considering their very similar compositions.…”

Section: Resultssupporting

confidence: 92%

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Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Gong

Navrotsky

2017

J Am Ceram Soc

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Phase relations in the CaO–TiO2 system are of considerable interest in geology, metallurgy, and ceramics. Despite a number of studies of phase equilibria in the CaO–TiO2 system, there are still some open questions regarding the stability of intermediate compounds. In this work, a series of specimens with different CaO:TiO2 ratios were prepared by solid‐state reaction. The heat capacities of Ca3Ti2O7 and Ca4Ti3O10 from 300 to 1073 K were measured by differential scanning calorimetry and their formation enthalpies from the component oxides at 298 K were measured by high temperature oxide melt solution calorimetry. Using phase diagram information and thermodynamic data from the literature and the present measurements, thermodynamic optimization of the CaO–TiO2 system was carried out by the CALPHAD technique. The phase diagram and the thermodynamic properties of the CaO–TiO2 system were calculated using the obtained thermodynamic database, which clarify the stable and metastable phase equilibria of the system. The thermodynamic stability of the various compounds was discussed.

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Section: Resultssupporting

confidence: 92%

“…As mentioned above, significant discrepancies occur in the composition range from CT to C3T2, related to the dispute over the intermediate compounds. Other compounds, C2T, CT2, C2T5, and CT4 were also reported in literature although these compounds were not present in the phase diagrams mentioned above …”

Section: Introductionmentioning

confidence: 73%

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Gong

Navrotsky

2017

J Am Ceram Soc

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“…Approximately linear decreases in the enthalpy of formation and increases in the entropy of formation of Sr n+1 Zr n O 3n+1 are observed with increasing n . Similar trends have been reported for the SrO‐TiO 2 and CaO–TiO 2 compounds.…”

Section: Thermodynamic Modelling and Calculationsupporting

confidence: 87%

“…To explore the relationship between the thermodynamic properties and structures, the enthalpies and entropies of formation of Sr n+1 Zr n O 3n+1 (n = 3, 2, 1) from the component oxides at 298 K as a function of the number of layers (n) are plotted in Figure 5. Approximately linear decreases in the enthalpy of formation and increases in the entropy of formation of Sr n+1 Zr n O 3n+1 are observed with increasing n. Similar trends have been reported for the SrO-TiO 2 46,47 and CaO-TiO 2 48 compounds. The Gibbs energy of mixing for the ZrO 2 -SrO system at 1673 K is shown as a function of composition in Figure 6.…”

Section: F I G U R E 3 a Calculatedsupporting

confidence: 80%

Thermochemistry of the ZrO₂–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram

et al. 2019

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The thermodynamics of the ZrO2–SrO system is of interest for the optimization of synthesis and applications of functional materials and high‐temperature structural ceramics. Earlier data on phase relationships and thermodynamic properties of the system are unfortunately scattered and inconsistent. In this study, the compounds Srn+1ZrnO3n+1 (n = 3, 2, and 1) were prepared by solid‐state reaction. Their heat capacities from 573 to 1273 K were measured by differential scanning calorimetry and their enthalpies of formation from component oxides at 298 K were determined by high‐temperature oxide melt solution calorimetry. The CALPHAD method was used to assess the ZrO2–SrO system, using both available literature data and our new measurements. A self‐consistent thermodynamic database and the calculated phase diagram of the ZrO2–SrO system are provided. This work is a prerequisite for accurate predictions of the relationships among the composition, temperature, and microstructure of complex functional and structural materials containing ZrO2 and SrO.

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“…Small-scale materials have optical properties directly related to the presence of defects in their crystalline lattice, making the search for materials with complex structures, such as scheelite, spinel and perovskite gain more attention, due to the greater probability of purposely causing defects [1][2][3]. Titanium-based materials, such as CaTiO 3 , Zn 2 TiO 4 , Ca 2 TiO 4 and others, are considered promising for optical applications [4][5][6]. Mu et al [7] showed that defects generated by Er 3+ and Yb 3+ codoping CaTiO 3 act in a way to restrain upconversion luminescence (UCL).…”

Section: Introductionmentioning

confidence: 99%

Effect of the Eu3+ (x = 0, 1, 2 and 3 mol%) doped Zn2−xTiO4 and Zn2Ti1−xO4 obtained by complex polymerization method: photoluminescent and photocatalytic properties

Nascimento

Neto

Garcia

et al. 2019

J Mater Sci: Mater Electron

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In this work, Zn 2 Eu x Ti 1−x O 4 and Zn 2−x Eu x TiO 4 (x = 0, 1, 2 and 3 mol%) powders were synthesized by complex polymerization method (CPM) and calcined at 1000 °C for 4 h. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy in the visible region and photoluminescence properties (PL). The photocatalytic properties were estimated by degradation of methylene blue (MB) dye when irradiated by UV lamps. X-ray diffraction results demonstrated the existence of Zn 2 TiO 4 as primary phase and ZnO with secondary phase. According to diffractograms, the crystallite size varied between 49 and 67 nm. The Eu 3+ ions introduction provides increased absorption in visible region, but the band-gap remains practically constant. In samples were observed an increased in photocatalysis with the increase in europium concentration, while in the Zn 2 Eu x Ti 1−x O 4 samples, photocatalysis was reduced to europium concentrations greater than 1%. Eu 3+ doped Zn 2 TiO 4 provided a photoluminescent intensity increasing. CIE chromaticity coordinates confirm emission in the red region of the phosphor.

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The phase stability of Ca2TiO4 and related Ruddlesden–Popper phases

Cited by 10 publications

References 23 publications

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Thermochemistry of the ZrO₂–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram

Effect of the Eu3+ (x = 0, 1, 2 and 3 mol%) doped Zn2−xTiO4 and Zn2Ti1−xO4 obtained by complex polymerization method: photoluminescent and photocatalytic properties

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The phase stability of Ca2TiO4 and related Ruddlesden–Popper phases

Cited by 10 publications

References 23 publications

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO2 system

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO2 system

Thermochemistry of the ZrO2–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram

Effect of the Eu3+ (x = 0, 1, 2 and 3 mol%) doped Zn2−xTiO4 and Zn2Ti1−xO4 obtained by complex polymerization method: photoluminescent and photocatalytic properties

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Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Combined experimental and computational investigation of thermodynamics and phase equilibria in the CaO–TiO₂ system

Thermochemistry of the ZrO₂–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram