scholarly journals Crystallization Kinetics and Structural Properties of the 45S5 Bioactive Glass and Glass-Ceramic Fiber Doped with Eu3+

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1281 ◽  
Author(s):  
Agata Baranowska ◽  
Magdalena Leśniak ◽  
Marcin Kochanowicz ◽  
Jacek Żmojda ◽  
Piotr Miluski ◽  
...  
Keyword(s):  
Bioactive Glass ◽  
Crystallization Kinetics ◽  
Glass Ceramic ◽  
Structural Changes ◽  
Glass Fibers ◽  
Glass Structure ◽  
Glass Ceramics ◽  
Luminescent Properties ◽  
Ceramic Fiber ◽  
Scanning Calorimetry

An investigation of the crystallization kinetics of 45S5 Bioglass® using differential scanning calorimetry is presented in this paper. Thermal analysis was performed using the Friedman method. The activation energy and the Avrami index were calculated. The glass samples were subjected to additional controlled heat treatment at 620 °C in order to obtain bioactive glass-ceramics with enhanced mechanical properties. X-ray powder diffraction (XRD) measurements indicated the formation of the glass-ceramic structures of three cyclosilicates: Na4Ca4(Si6O18) or Na6Ca3(Si6O18) or Na16Ca4(Si12O36). Based on middle infrared region (MIR) results, it can be concluded that the crystalline phase present in the tested materials was Na6Ca3(Si6O18) (combeite). Material was doped with Eu3+ ions, which act as a spectroscopic probe for monitoring the structural changes in the glass matrix. The decreasing value of the fluorescence intensity radio parameter indicated symmetry around the europium ions and, thus, the arrangement of the glass structure. The bioactive properties of the examined glass-ceramics were also determined. The bioactive glass fibers doped with Eu3+ were manufactured using two different methods. Its structural and luminescent properties were examined.

scholarly journals Utilization of discarded foundry sand (DFS) and inorganic waste from cellulose and paper industry for the manufacture of glass-ceramic materials

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 413-420
Author(s):  
L. M. S. e Silva ◽  
R. S. Magalhães ◽  
W. C. Macedo ◽  
G. T. A. Santos ◽  
A. E. S. Albas ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Raw Materials ◽  
Paper Industry ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Foundry Sand ◽  
X Ray ◽  
Glass Ceramic Materials

Abstract Recycling has been pointed out as an alternative to the disposal of waste materials in industrial landfills. In the present study, the transformation of residues (discarded foundry sand - DFS, grits, and lime mud) in glass-ceramic materials is shown. The glasses were obtained by the melting/cooling method. The precursor materials, glasses, and glass-ceramics were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA). The glassy materials were milled, pelleted, and thermally treated at the crystallization temperatures given by DSC data to obtain the glass-ceramics (885, 961, and 1090 ºC). The main formed phases were cristobalite, α-wollastonite (parawollastonite), and β-wollastonite (pseudowollastonite). The glass-ceramics showed very low water absorption and apparent porosity (0.26 to 0.88 wt% and 0.66 to 1.77 vol%, respectively). The results confirmed that the studied residues can be used as raw materials for the manufacture of vitreous and glass-ceramic materials.

scholarly journals Reddish-Orange Luminescence from BaF2:Eu3+ Fluoride Nanocrystals Dispersed in Sol-Gel Materials

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3735 ◽  
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Joanna Pisarska ◽  
Tomasz Goryczka ◽  
Wojciech A. Pisarski
Keyword(s):  
Glass Ceramic ◽  
Structural Changes ◽  
Sol Gel ◽  
Ceramic Materials ◽  
Xrd Analysis ◽  
Luminescence Spectra ◽  
Silica Network ◽  
Scanning Calorimetry ◽  
Glass Ceramic Materials ◽  
Reddish Orange

Nanocrystalline transparent BaF2:Eu3+ glass-ceramic materials emitting reddish-orange light were fabricated using a low-temperature sol-gel method. Several experimental techniques were used to verify structural transformation from precursor xerogels to sol-gel glass-ceramic materials containing fluoride nanocrystals. Thermal degradation of xerogels was analyzed by thermogravimetric analysis (TG) and differential scanning calorimetry method (DSC). The presence of BaF2 nanocrystals dispersed in sol-gel materials was confirmed by the X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). In order to detect structural changes in silica network during annealing process, the infrared spectroscopy (IR-ATR) was carried out. In particular, luminescence spectra of Eu3+ and their decays were examined in detail. Some spectroscopic parameters of Eu3+ ions in glass-ceramics containing BaF2 nanocrystals were determined and compared to the values obtained for precursor xerogels. It was observed, that the intensities of two main red and orange emission bands corresponding to the 5D0→7F2 electric-dipole transition (ED) and the 5D0→7F1 magnetic-dipole (MD) transition are changed significantly during transformation from xerogels to nanocrystalline BaF2:Eu3+ glass-ceramic materials. The luminescence decay analysis clearly indicates that the measured lifetime 5D0 (Eu3+) considerably enhanced in nanocrystalline BaF2:Eu3+ glass-ceramic materials compared to precursor xerogels. The evident changes in luminescence spectra and their decays suggest the successful migration of Eu3+ ions from amorphous silica network to low-phonon BaF2 nanocrystals.

scholarly journals Crystallization kinetics and luminescent properties of chromium-doped borate glass-ceramics

2019 ◽  
Vol 1400 ◽  
pp. 066002
Author(s):  
A N Babkina ◽  
K S Zyryanova ◽  
D A Agafonova ◽  
R K Nuryev ◽  
E V Kolobkova ◽  
...  
Keyword(s):  
Crystallization Kinetics ◽  
Borate Glass ◽  
Glass Ceramics ◽  
Luminescent Properties

Preparation and Crystallization Kinetics of FeSiB Amorphous Ribbons under Non-Isothermal Regime

2014 ◽  
Vol 605 ◽  
pp. 35-38
Author(s):  
Eirini Varouti
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Chemical Composition ◽  
Crystallization Kinetics ◽  
Structural Changes ◽  
Scanning Calorimetry ◽  
Amorphous Ribbons ◽  
Isothermal Regime ◽  
Kinetics Of

The aim of the present work was the preparation and characterization of FeSiB amorphous magnetic ribbons with the following chemical composition: Fe80SixB20-x, x=5,6,8 and Fe75Si15B10. Differential Scanning Calorimetry was employed in order to study the thermal stability and structural changes during the transformations that took place. Much emphasis is placed on the analysis of the crystallization kinetics.

Crystallization Kinetics of β-Spodumene/Cordierite-Based Glass-Ceramics

2016 ◽  
Vol 881 ◽  
pp. 83-88 ◽  
Author(s):  
Rafael Bianchini Nuernberg ◽  
Oscar Rubem Klegues Montedo
Keyword(s):  
Crystallization Kinetics ◽  
Glass Ceramics ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Kinetics Parameters ◽  
Crystalline Phases ◽  
Cordierite Glass ◽  
Thermal And Electrical Properties ◽  
Kinetics Of

This work aims to investigate the crystallization kinetics of β-spodumene/cordierite glass-ceramics. Thus, three glasses with compositions based predominantly on cordierite (C), β-spodumene (L) and in a molar ratio 1:1 of both phases (CL) were prepared. The kinetics parameters such as activation energy for crystallization (ranging from 160 to 358 kJ/mol) and Avrami exponent (ranging from 1.4 to 10.7) were determined by means of non-isothermal methods using differential scanning calorimetry (DSC). Additionally, the samples were crystalized according to DSC analyses and characterized by using x-ray diffraction (XRD). The main detected crystalline phases were β-spodumene to the glass L, cordierite to the glass C and β-quartz, mulite and spinel to the glass CL. Considering the thermal and electrical properties of these crystalline phases, these glass-ceramics have potential use for LTCC (Low Thermal Co-fired Ceramics) applications.

Red and Green Phosphors Glow on the Basis of Oxide Glass-Ceramics Doped with Eu3+ and Tb3+

2015 ◽  
Vol 670 ◽  
pp. 107-112 ◽  
Author(s):  
Seseg Yu. Tsyretarova ◽  
Nina M. Kozhevnikova ◽  
Nina S. Ereminа ◽  
Gennady M. Mokrousov
Keyword(s):  
Emission Spectrum ◽  
Glass Ceramic ◽  
Charge Transfer Band ◽  
Broad Band ◽  
Glass Ceramics ◽  
Green Emission ◽  
Luminescent Properties ◽  
Inorganic Materials ◽  
Oxide Glass ◽  
Excitation Spectra

Glass-ceramics phosphors were obtained by the introduction of the crystalline phase NaMg3Sc (MoO4)5:Eu3+,Tb3+ in the glass composition 8SiO2-20B2O3-5Lu2O3-31Bi2O3-36ZnO. The properties were characterized by X-ray diffraction (XRD), photoluminescence (PL) and photoluminescent excitation spectra (PLE). The XRD patterns were indicated NaMg3Sc (MoO4)5:Eu3+,Tb3+ crystallize well with the novel structure type and were assigned to the triclinic phase (space group PĪ, Z = 6). Glass-ceramic phosphors are well-known and promising as solid electrolytes, laser, luminescent and other inorganic materials. Luminescent properties of the phosphors are performed at room temperature. The excitation spectra of Eu-doped phosphor present strong absorption at 300 nm and the sharp peaks in the 350-500 nm range. Under the 394 nm excitation, intense red emission peak at 616 nm corresponding to 5D0→7F2 transition of Eu3+ is observed in the emission spectrum. The luminescence property indicates that the local symmetry of Eu3+ ion has no inversion center. The excitation spectra of Tb-doped phosphor by monitoring wavelength at 546 nm shows the intense broad band from 260 to 420 nm and the line at 234 nm, which is mainly attributed to charge-transfer band transition in MoO42- group, indicating the existence of energy transfer from MoO42- to Tb3+ in the Tb3+:glass-ceramic. The measured emission spectrum of Tb-doped phosphor has intense green emission at 546 nm corresponding to 5D4→7F5 transition of Tb3+, with λex=368 nm. The as-prepared phosphors may find potential applications in the field such as color displays, light-emitting diodes (LEDs) and optoelectronic devices.

Tb-doped Aluminosilicate Oxyfluoride Scintillating Glass and Glass-ceramic

2009 ◽  
Vol 1164 ◽  
Author(s):  
Zhengda Pan ◽  
K. James ◽  
Y. Cui ◽  
A. Burger ◽  
Nerine Cherepy ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Glass Matrix ◽  
Glass Ceramics ◽  
Light Yield ◽  
Oxyfluoride Glass ◽  
Scanning Calorimetry ◽  
Prepared Glass ◽  
Strong Source ◽  
High Light Yield ◽  
Matrix Differential

AbstractTwo aluminosilicate oxyfluoride glass systems, a lead-cadmium-aluminosilicate oxyfluoride and a lithium-lanthanum-aluminosilicate oxyfluoride, doped with different TbF3 concentrations, have been fabricated and investigated. By appropriate heat treatment of the as-prepared glasses above, transparent glass-ceramics (TGC) were obtained. The glass-ceramics contain Tb:Pb(Cd)F2 or Tb:LaF3 nano-crystals in the glass-matrix. Differential scanning calorimetry, Raman scattering, and luminescence under both UV and β-particle excitation have been investigated on as-prepared glasses and glass-ceramics. It has been found that the terbium-doped lithium-lanthanum-aluminosilicate oxyfluoride glass exhibits good UV excited luminescence and β-induced luminescence. The luminescence yield increases for glass-ceramic compared to that of the as-prepared glass. The including of LaF3 in the glass-matrix is beneficial for a higher Tb-doping concentration and a high light yield. The light yield of lithium-lanthanum-aluminosilicate oxyfluoride glass and glass-ceramic is comparable to that of Schott IQI-301 product. However, the terbium-doped lead-cadmium-aluminosilicate oxyfluoride glass and glass-ceramic have a detrimental luminescence performance. The lead cations in the glass-matrix may create non-bridging oxygen defects, which are a strong source of charge traps, and correlated to a strong Raman “Boson” peak.

scholarly journals Characterization of Li2O-Al2O3-SiO2 glass-ceramics produced from a Brazilian spodumene concentrate

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 366-377 ◽  
Author(s):  
L. B. Rebouças ◽  
M. T. Souza ◽  
F. Raupp-Pereira ◽  
A. P. Novaes de Oliveira
Keyword(s):  
Structural Changes ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Heating Microscopy ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

Abstract Glass-ceramics in the LAS (Li2O-Al2O3-SiO2) system with high thermal shock resistance were successfully obtained using Brazilian spodumene concentrate as the main raw material (80-70 wt%). Two compositions (Li2O.Al2O3.nSiO2) were produced with n= 2 and 4, near to the stoichiometric compositions of β-eucryptite and β-spodumene. The characteristic temperatures of parent glasses were determined by contact dilatometry, differential scanning calorimetry and heating microscopy. The crystallization mechanism and the effect of the nucleating agent (TiO2.2ZrO2) required to promote volume crystallization in the parent glasses were investigated. Microstructural and structural changes with temperature were also evaluated by optical microscopy and X-ray diffraction. The obtained glass-ceramics presented coefficients of thermal expansion between -0.370x10-6 and 4.501x10-6 °C-1 in the 22 to 700 °C range.

Preparation and Characterization of Na2O-Y2O3-P2O5-SiO2 Transparent Glass Ceramics

2018 ◽  
Vol 281 ◽  
pp. 692-698 ◽  
Author(s):  
Meng Jie Zhao ◽  
Xiang Yu Zou ◽  
Qin Lei Wei ◽  
Shuo Meng ◽  
Hong Bo Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Refractive Index ◽  
Glass Ceramic ◽  
Visible Region ◽  
Glass Ceramics ◽  
Scanning Calorimetry ◽  
Transparent Glass ◽  
Diffraction Patterns ◽  
The Impact ◽  
Precursor Glass

Transparent glass ceramics containing Na3.6Y1.8(PO4)3 crystals were successfully synthesized using high temperature melting quenching and subsequent heat treatment of the precursor glass with a composition 15Na2CO3-3Y2O3-45SiO2-31H3BO3- 5.4P2O5-0.6Sb2O3 (mol%). The impact of heat treatment is investigated in detail. The glass sample was tested by differential scanning calorimetry analysis to determine the heat treatment system. The ideal heat-treated condition is at 650°C for 2 h. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and scanning electron microscopy images, which indicate that Na3.6Y1.8(PO4)3 crystal were precipitated homogeneously among the glass matrix. The microstructural of precursor glass and glass ceramic were compared by analyzing FTIR spectra, indicating the formation of phosphate groups in glass ceramic. The refractive index of glass ceramics samples were measured. In the visible region, the transmittance of glass ceramics is up to 85%. Moreover, the relationship between the refractive index of the sample and the transmittance is discussed.

Effects of the Sintering Temperature on Structural and Bioactivity in BaFe12O19-P2O5-CaO-Na2O Bioactive Glass Ceramic

2015 ◽  
Vol 804 ◽  
pp. 147-150
Author(s):  
Pratthana Intawin ◽  
Kamonpan Pengpat ◽  
Wilaiwan Leenakul ◽  
Tawee Tunkasiri
Keyword(s):  
Mechanical Properties ◽  
Bioactive Glass ◽  
Glass Ceramic ◽  
Sintering Temperature ◽  
Glass Ceramics ◽  
Microstructural Properties ◽  
Hardness Testing ◽  
X Ray Diffraction ◽  
X Ray

In this research, the effects of sintering temperatures on structural and bioactivity in BaFe12O19 (BF) /P2O5-CaO-Na2O bioactive glass ceramics were investigated. The BF/P2O5-CaO-Na2O bioactive glass ceramics were fabricated under various sintering temperatures in a range of 550-700 oC. X-ray diffraction (XRD) technique and the scanning electron microscopy (SEM) are used to characterize phase and microstructure. The studied samples were evaluated for mechanical properties by hardness testing. Moreover, the bioactivities of studied samples were studied by using simulated body fluid (SBF) in vitro. It was found that, the sintering temperatures are the most influential parameter on microstructure and mechanical properties of the bioactive glass ceramics. The highest density of studied ceramics was found in the sample sintered at 700 oC. The microstructural properties of the studies samples were investigated and the results were then correlated with the characteristics of sintering temperature as well as the microstructure of the bioactive glass ceramic. Moreover, the covering of bone-like apatite layer on the surface sample after a 7 day immersion in SBF suggested that the BF/P2O5-CaO-Na2O glass ceramics have acceptable bioactivities.

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