Crystallization kinetics of binary La2O3-Al2O3 glass

Prnová, Anna; Plško, Alfonz; Klement, Róbert; Valúchová, Jana; Haladejová, Katarína; Švančárek, Peter; Majerová, M.; Galusek, Dušan

doi:10.1016/j.jnoncrysol.2018.03.001

Cited by 10 publications

(7 citation statements)

References 32 publications

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“…Al 5 Er 3 O 12 crystal lattice constant a = b = c = 11.962 Å. [ 13 ] As shown in Figure 5a, it can be seen that there are continuously distributed bright white particles near the grain boundary. The content of O and Er elements is higher, and the content of Al element is decreased, indicating that the Al 5 Er 3 O 12 phase is formed here.…”

Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Zhang

Yang

et al. 2021

Adv Eng Mater

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A new type of Al–TiO2–C–XEr2O3 aluminum alloy refiner is prepared by exothermic dispersion method, and the effect of different Er2O3 content on the structure and refinement effect of Al–TiO2–C refiner is studied by scanning electron microscope (SEM), X‐ray diffraction (XRD), and other methods. The results show that the refiners are composed of Al3Ti, TiC, Al2O3, Al20Ti2Er, and Al5O12Er3 phases. As the content of Er2O3 increases, the Al3Ti phase changes from flaky to massive. The amount of Al2O3 decreases, and the content of Al5Er3O12 increases and is dispersed in the matrix. When the content of Er2O3 in the refiner is 6%, the Al–5Cu alloy has the best refining effect. The grain size of the Al–5Cu alloy is refined from 500 to 180 μm, and the grain size can be reduced by 64%. At the same time, the tensile strength of Al–5Cu alloy is tested, and the results show that when the content of Er2O3 in the refiner is 6%, the tensile strength is the highest, which is 189.7 MPa. This is consistent with the theoretical results.

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Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Zhang

Yang

et al. 2021

Adv Eng Mater

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“…Arai et al 18 synthesized a La 4 Ti 9 O 24 glass, which exhibited a high refractive index of 2.231 at 1313 nm. Anna Prnová et al 14 prepared binary La 2 O 3 –Al 2 O 3 glass, finding that the crystallization of the 50%La 2 O 3 –50% Al 2 O 3 glass is diffusion‐controlled in two‐dimensional growth, while the 76.2La 2 O 3 –23.8 Al 2 O 3 glass is first grown in two‐dimension, and then, in three‐dimension under diffusion control. In order to meet commercial requirements for La 2 O 3 –TiO 2 –Nb 2 O 5 glass and combine beneficial properties, such as more thermal stability, larger sized fabrication, higher refractive index, and lower wavelength dispersion, the combining multiple oxides is effective.…”

Section: Introductionmentioning

confidence: 99%

Understanding the structure, thermal, and optical properties in Al₂O₃‐incorporated La₂O₃‐TiO₂‐Nb₂O₅ glasses

Yang

Ping

2021

J Am Ceram Soc

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Glasses in the 30La2O3‐40TiO2‐30Nb2O5 system are known to have excellent optical properties such as refractive indices over 2.25 and wide transmittance within the visible to mid‐infrared (MIR) region. However, titanoniobate glasses also tend to crystallize easily, significantly limiting their applications in optical glasses due to processing challenges. Therefore, the 30La2O3‐40TiO2‐(30−x) Nb2O5‐xAl2O3 (LTNA) glass system was successfully synthesized using a aerodynamic containerless technique, which improves glass thermal stability and expands the glass‐forming region. The effects of Al2O3 on the structure, thermal, and optical properties of base composition glasses were investigated by XRD, DSC, NMR, Raman spectroscopy, and optical measurements. DSC results indicated that as the content of Al2O3 increased, the thermal stability of the glasses and glass‐forming ability increased, as the 30La2O3‐40TiO2‐25Nb2O5‐5Al2O3 (Nb‐Al‐5) glass obtained the highest ΔT value (103.5°C). Structural analysis indicates that the proportion of [AlO4] units increases gradually and participates in the glass network structure to increase connectivity, promoting more oxygen to become bridging oxygen and form [AlO4] tetrahedral linkages to [TiO5] and [NbO6] groups. The refractive index values of amorphous glasses remained above 2.1 upon Al2O3 substitution, and a transmittance exceeding 65% in the visible and mid‐infrared range. The crystallization activation energies of 30La2O3‐40TiO2‐30Nb2O5 (Nb‐Al‐0) and Nb‐Al‐5 glasses were calculated to be 611.7 and 561.4 kJ/mol, and the Avrami parameters are 5.28 and 4.96, respectively. These results are useful to design new optical glass with good thermal stability, high refractive index and low wavelength dispersion for optical applications such as lenses, endoscopes, mini size lasers, and optical couplers.

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“…The Johnson-Mehl-Avrami-Kolgomorov (JMAK) model was found to be suitable for description of the kinetics of crystallization of aluminate glasses [30]. Using the JMAK model, Prnova et al [30,31] described the crystallization kinetics of La 2 O 3 -Al 2 O 3 and yttrium aluminate glasses.…”

Section: Introductionmentioning

confidence: 99%

Crystallization kinetics of gehlenite glass microspheres

Majerová

Prnová

Plško

et al. 2020

J Therm Anal Calorim

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The glass of gehlenite composition was prepared by flame synthesis in the form of microspheres. The powder precursor was synthesised by standard solid-state reaction method using SiO 2 , Al 2 O 3 and CaCO 3 . The prepared glasses were characterized from the point of view of surface morphology, phase composition and thermal properties by optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The prepared samples contained only completely re-melted spherical particles. SEM did not reveal any features indicating the presence of crystalline phases. However, traces of crystalline gehlenite were detected by XRD. The high-temperature XRD measurements (HT XRD) were carried out to identify the phase evolution during glass crystallization. In the studied temperature range, gehlenite phase was identified as the main crystalline phase. Non-isothermal DSC analysis of prepared glass microspheres was carried out from room temperature up to 1200 °C at five different heating rates: 2, 4, 6, 8 and 10 °C/ min to determine the thermal properties of microspheres. In order to study the crystallization kinetics, the DSC curves were transformed into dependence of fractional extent of crystallization (α) on temperature. The Johnson-Mehl-Avrami-Kolmogorov model was found to be suitable for description of crystallization kinetics. Frequency factor A = 5.56 × 10 29 ± 1.73 × 10 29 min −1 , apparent activation energy E app = 722 ± 3 kJ mol −1 and the Avrami coefficient m = 2 were determined. In the studied system, the linear temperature dependence of nucleation rate, diffusion controlled crystal growth interface and a 2D crystal growth were confirmed.

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Crystallization kinetics of binary La2O3-Al2O3 glass

Cited by 10 publications

References 32 publications

Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Understanding the structure, thermal, and optical properties in Al₂O₃‐incorporated La₂O₃‐TiO₂‐Nb₂O₅ glasses

Crystallization kinetics of gehlenite glass microspheres

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Crystallization kinetics of binary La2O3-Al2O3 glass

Cited by 10 publications

References 32 publications

Effect of Er2O3 on the Structure and Refinement Effect of Al–TiO2–C Refiner

Effect of Er2O3 on the Structure and Refinement Effect of Al–TiO2–C Refiner

Understanding the structure, thermal, and optical properties in Al2O3‐incorporated La2O3‐TiO2‐Nb2O5 glasses

Crystallization kinetics of gehlenite glass microspheres

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Product

Resources

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Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Effect of Er₂O₃ on the Structure and Refinement Effect of Al–TiO₂–C Refiner

Understanding the structure, thermal, and optical properties in Al₂O₃‐incorporated La₂O₃‐TiO₂‐Nb₂O₅ glasses