Crystallization kinetics analysis of BaF2 and BaGdF5 nanocrystals precipitated from oxyfluoride glass systems: A comparative study

Karmakar, Prantik; Subudhi, Abhijit Kumar; Biswas, Kaushik; Annapurna, K.

doi:10.1016/j.tca.2015.04.019

Cited by 30 publications

(15 citation statements)

References 27 publications

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“…These values correspond to a crystallisation process which starts from a constant number of nuclei and for which crystal growth is diffusion controlled [46]. The same behaviour was also observed for other oxyfluoride GCs [47], [48] and [49]. The addition of Nd 3+ , even in quite varied concentrations, does not influence the crystallisation mechanism but affects the crystallisation kinetics.…”

Section: Optical Characterisationsupporting

confidence: 67%

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Gorni

Velázquez

Mather

et al. 2017

Journal of the European Ceramic Society

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Transparent oxyfluoride nano-glass-ceramics have been prepared by melting-quenching and doped with five different Nd 3+ concentrations (0.1-2 mol%) to obtain the most efficient 4 F 3/2  4 I 11/2,13/2 emission. It was observed by differential thermal analysis (DTA) that the addition of Nd 3+ does not affect the crystallization mechanism which corresponds to a diffusioncontrolled volumetric process that starts from a constant number of nuclei. Nevertheless, the presence of the dopant affects the kinetics due to the progressive increase of T g on increasing the Nd 3+ content. LaF 3 crystals with a size between 9-12 nm are obtained after heat treatments at T g + 20-80 °C as confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis shows the incorporation of Nd 3+ ions into the LaF 3 nano-crystals. Judd-Ofelt analysis from the absorption spectra further demonstrate the incorporation of Nd 3+ ions into the fluoride phase and the most relevant parameters such as radiative lifetime and stimulated emission cross-section are calculated. A detailed optical characterisation clearly shows that Nd 3+ ions in the glass-ceramics are incorporated in both crystalline and amorphous phases. Low temperature site-selective emission and excitation spectra, together with the different lifetime values of the 4 F 3/2 state depending on the excitation and emission wavelengths, allow emission from Nd 3+ ions in the LaF 3 nanocrystals to be identified and correlated with the structural properties. As the Nd 3+ concentration is increased beyond 0.1 mol%, a stronger quenching of lifetime is observed for Nd 3+ ions residing in LaF 3 crystals than for those dispersed in the glass matrix. This strong concentration quenching is explained by the much higher concentration of Nd 3+ ions in the crystalline phase with respect to that in the glass matrix.

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Section: Optical Characterisationsupporting

confidence: 67%

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Gorni

Velázquez

Mather

et al. 2017

Journal of the European Ceramic Society

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“…This model is most suitable to explain a random nucleation and nuclei growth process and the Avrami exponent n= + is based on the nucleation law () and number of dimensions in which nuclei grow () [31]. Low values (0.6-0.9) of Avrami coefficient were obtained here, which are sometimes ascribed to diffusional hindrance [32,33] or 'ingestion' and ' coalescence'…”

Section: Model-based Analysis Of Mass Loss Kineticsmentioning

confidence: 75%

Thermal decomposition of layered double hydroxides: Kinetic modeling and validation

Shamim

Dana

2016

Thermochimica Acta

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“…Inset of Figure B show the DSC curve extended from 200 to 450°C that demonstrate 2 T g behavior of TTL10 glass. Further DSC curve at different heating rates has been used to estimate activation energy by adopting established models such as Kissinger, Augis‐Bennett, and Ozawa . Figure A represents the plot of ln(β/( T P − T 0 ) n ) vs (1000/ T P ) in case of n = 2, 1, 0 for Kissinger, Augis‐Bennett, and Ozawa models, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Further DSC curve at different heating rates has been used to estimate activation energy by adopting established models such as Kissinger, Augis-Bennett, and Ozawa. 35 Figure 9A represents the plot of ln(b/(T P ÀT 0 ) n ) vs (1000/ T P ) in case of n = 2, 1, 0 for Kissinger, Augis-Bennett, and Ozawa models, respectively. Kissinger and Ozawa equation consider T 0 = 0 K, whereas, in Augis-Bennett model T 0 = 300 K. Using slope of ln(b/(T P ÀT 0 ) n ) vs (1000/T P ) plot, the activation energy (E a ) has been calculated to be 233.1 AE 9, 235.9 AE 9, and 246 AE 9 kJ/mol, respectively, for Kissinger, Augis-Bennett, and Ozawa model.…”

Section: Crystallization Kineticsmentioning

confidence: 99%

Mid‐IR transparent TeO₂‐TiO₂‐La₂O₃ glass and its crystallization behavior for photonic applications

et al. 2018

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In this report, effect of enhanced rare earth (La2O3) concentration on substitution of TeO2 within ternary TeO2‐TiO2‐La2O3 (TTL) glass system has been studied with respect to its thermal, structural, mechanical, optical, and crystallization properties with an aim to achieve glass and glass‐ceramics having rare‐earth‐rich crystalline phase for nonlinear optical and infrared photonic applications. DSC analysis (10°C/min) demonstrates a progressive increase in glass‐transition temperature (Tg) from 359 to 452°C with the increase in La2O3 content. Continuous glass network modification with transformation of [TeO4] to [TeO3/TeO3+1] units is evidenced from Raman spectra which is corroborated with XPS studies. While mechanical properties demonstrate enhancement of cross‐linking density in the network. These glasses exhibit optical transmission window extended from 0.4 to 6 μm with calculated zero dispersion wavelength (λZDW) varying from 2.41 to 2.28 μm depending upon La2O3 content. Crystallization kinetics of TTL10 (80TeO2‐10TiO2‐10La2O3 in mol%) glass has been studied via established models. Activation energy (Ea) has been evaluated and dimensionality of crystal growth (m) suggests formation of surface crystals. Glass‐ceramic with crystalline phase of La2Te6O15 has been realized in heat‐treated TTL10 glass samples (at 450°C). As predicted from DSC analysis, FESEM study unveils the formation of surface crystallized glass‐ceramics.

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Crystallization kinetics analysis of BaF2 and BaGdF5 nanocrystals precipitated from oxyfluoride glass systems: A comparative study

Cited by 30 publications

References 27 publications

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Thermal decomposition of layered double hydroxides: Kinetic modeling and validation

Mid‐IR transparent TeO₂‐TiO₂‐La₂O₃ glass and its crystallization behavior for photonic applications

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Crystallization kinetics analysis of BaF2 and BaGdF5 nanocrystals precipitated from oxyfluoride glass systems: A comparative study

Cited by 30 publications

References 27 publications

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Selective excitation in transparent oxyfluoride glass-ceramics doped with Nd3+

Thermal decomposition of layered double hydroxides: Kinetic modeling and validation

Mid‐IR transparent TeO2‐TiO2‐La2O3 glass and its crystallization behavior for photonic applications

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Product

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Mid‐IR transparent TeO₂‐TiO₂‐La₂O₃ glass and its crystallization behavior for photonic applications