Experimental investigation and thermodynamic modelling in the ZrO2–La2O3–Y2O3 system

Fabrichnaya, Olga; Savinykh, G.; Schreiber, Gerhard; Dopita, Milan; Seifert, H. J.

doi:10.1016/j.jallcom.2009.12.076

Cited by 26 publications

(6 citation statements)

References 30 publications

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“…The melting of sample materials was investigated using the SETSYS EVOLUTION 2400 (TG‐DTA) in W crucibles in He atmosphere at temperatures up to 2173 K. The heating rate in both instruments was 20 K min −1 up to 1473 K and then 10 K min −1 ; the cooling rate was of 30 K min −1 , which was also the same for both instruments. Temperature calibration of the SETSYS EVOLUTION 1750 was performed using the melting points of Al, Ag, Au, Cu, and Ni, whereas the temperature calibration of the SETSYS EVOLUTION 2400 was made using the melting points of Al, Au, and Al 2 O 3 and the temperature of transformation of LaYO 3 to the monoclinic phase B …”

Section: Methodsmentioning

confidence: 99%

“…Samples were synthesised from precursor solutions in a similar way to that described by Fabrichnaya et al 17,18 The starting chemicals were zirconium acetate solution in acetic acid Zr(CH 3 COO) 4 (99.99%, Sigma-Aldrich), La(NO 3 ) 3 ⋅6H 2 O (99.99%, Alfa Aesar) and Gd(NO 3 ) 3 ⋅6H 2 O (99.9%, Alfa Aesar). In the first step, La(NO 3 ) 3 ⋅6H 2 O and Gd(NO 3 ) 3 ⋅6H 2 O were dissolved in distilled water whereas the Zr(CH 3 COO) 4 solution in acetic acid was also diluted by distilled water.…”

Section: Sample Preparationmentioning

confidence: 99%

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Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling

et al. 2019

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The phase relations in the ZrO2–La2O3–Gd2O3 ternary system were experimentally studied and thermodynamic modeling was performed. Selected compositions were synthesized using the co‐precipitation method, equilibrated at 1673 and 1873 K, and analyzed using X‐ray diffraction (XRD) and scanning electron microscopy (SEM/EDX). The phase transformations were investigated using differential thermal analysis (DTA), and the heat capacities of (La1 − xGdx)2Zr2O7 (x = 0.25, 0.50, 0.75) compounds were measured using differential scanning calorimetry (DSC). Experimental studies showed a substantial extension of the fluorite phase into the ternary system and solid‐state transformations involving phases A (hexagonal), fluorite, B (monoclinic), and pyrochlore at 1845 K (DTA). Additionally, thermodynamic modeling was performed using the CALPHAD (CALculation of PHAse Diagrams) approach. Comparing the new experimental data and the calculations based on ternary extrapolations of the binary systems revealed major inconsistencies. One source of inconsistencies was related to the calculated phase equilibria in the binary La2O3–Gd2O3 system. Additional experimental investigation of the binary system indicated an underestimated solubility of La2O3 in the B phase in the temperature range 1673‐1873 K. Based on these new data, the mixing parameters of the B phase were re‐assessed. The new experimental results for the ternary system were used to optimize the mixing parameters of the fluorite, B and C (cubic) phases. All new experimental data were well reproduced by the improved thermodynamic description of the ternary system.

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Section: Methodsmentioning

confidence: 99%

Section: Sample Preparationmentioning

confidence: 99%

Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling

et al. 2019

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“…It should be noted that ternary extension in these phases was also observed in a similar system ZrO 2 -La 2 O 3 -Y 2 O 3 . [35,36] Based on experimental phase equilibrium information, isothermal sections at 1523, 1673 and 1873 K were constructed, Fig. 7 Fig.…”

Section: Experimental Data For the Zro 2 -Yb 2 O 3 -La 2 O 3 Ternary mentioning

confidence: 99%

“…However, with further increasing of temperature, the phase relations changed. [36] To find the temperature of this transformation, the samples ZLYb-8,-9,-10 were investigated using DTA. The thermal effect at a temperature of about 1858 ± 10 K was observed in all three samples, as shown in Fig.…”

Section: Experimental Data For the Zro 2 -Yb 2 O 3 -La 2 O 3 Ternary mentioning

confidence: 99%

Experimental Investigation of Phase Relations in the ZrO2-La2O3-Yb2O3 System

Ilatovskaia

Sun

Saenko

et al. 2020

J. Phase Equilib. Diffus.

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The phase equilibria in the La 2 O 3-Yb 2 O 3 system were investigated using differential thermal analysis, and the phase transformations temperatures were verified. Microstructure investigation using scanning electron microscopy confirmed the presence of eutectoid reactions in the system. The heat capacity of LaYbO 3 with a perovskite structure was measured in the temperature range from 250 to 1250 K using differential scanning calorimetry. The experimental results of the present work as well as reliable literature data were used to derive a thermodynamic description of the La 2 O 3-Yb 2 O 3 system. Isothermal sections of the ZrO 2-La 2 O 3-Yb 2 O 3 system were constructed based on x-ray and microstructural investigations. The tie-lines change from Pyrochlore ? Yb 2 O 3 C to LaYbO 3 Perovskite ? Fluorite was explained by a solidstate reaction occurring in the range between 1673 and 1873 K. The heat effect observed at 1858 K using DTA confirms the phase transformation, and its temperature was established more precisely at 1808 ± 15 K using stepwise heat treatment. Keywords CALPHAD Á La 2 O 3-Yb 2 O 3 system Á phase diagram Á solid state reaction Á ZrO 2-based system This invited article is part of a special tribute issue of the

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“…It can be an effective additive in various polymers [13][14][15], an important component of new advanced ceramics [16,17], or a component in specialized optical glasses [18,19]. Although there are only a few reports on preparation and luminescence of rare earth doped La 2 O 3 -based phosphors [20][21][22][23][24][25] its low phonon energy ∼ 400 cm −1 , [20] makes them a potential material for up-and down-converting phosphors [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

The concentration quenching of photoluminescence in Eu3+-doped La2O3

Đorđević¹,

Antić²,

Nikolić³

et al. 2013

Journal of Research in Physics

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This work explores the influence of dopant concentration on photoluminescent emission and kinetics of Eu 3+ -doped (0.2−10 at.%) nanocrystalline lanthanumoxide powders. The X-ray diffraction analysis confirmed that all samples crystallize in La 2 O 3 hexagonal phase with space group P3m1. Transmission electron microscopy showed particles with non-uniform shape and diverse size distribution with an average particle size of (95 ± 5) nm. The room temperature photoluminescence spectra of all samples contain characteristic Eu 3+ luminescence lines with the most pronounced red 5 D 0 → 7 F 2 emission at about 626 nm. The maximum intensity of red emission is observed for the sample containing 5 at.% of Eu 3+ ions. The emission kinetics was recorded in the temperature range from 10 K to 300 K. The maximum lifetime value of 0.98 ms obtained for the sample with 0.5 at.% Eu 3+ at room temperature increases up to 1.3 ms at 10 K.

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Experimental investigation and thermodynamic modelling in the ZrO2–La2O3–Y2O3 system

Cited by 26 publications

References 30 publications

Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling

Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling

Experimental Investigation of Phase Relations in the ZrO2-La2O3-Yb2O3 System

The concentration quenching of photoluminescence in Eu3+-doped La2O3

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Experimental investigation and thermodynamic modelling in the ZrO2–La2O3–Y2O3 system

Cited by 26 publications

References 30 publications

Phase relations in the ZrO2–La2O3–Gd2O3 system: Experimental studies and phase modeling

Phase relations in the ZrO2–La2O3–Gd2O3 system: Experimental studies and phase modeling

Experimental Investigation of Phase Relations in the ZrO2-La2O3-Yb2O3 System

The concentration quenching of photoluminescence in Eu3+-doped La2O3

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Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling

Phase relations in the ZrO₂–La₂O₃–Gd₂O₃ system: Experimental studies and phase modeling