scholarly journals Dielectric Properties of La2O3 Doped Composite (PbxSr1−x)TiO3 Borosilicate Glass Ceramic

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
C. R. Gautam ◽  
Devendra Kumar ◽  
Om Parkash ◽  
O. P. Thakur
Keyword(s):  
Dielectric Constant ◽  
Glass Ceramic ◽  
Perovskite Phase ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Effective Dielectric Constant ◽  
Glassy Matrix ◽  
Crystal Glass ◽  
Treatment Schedule ◽  
Ceramic Samples

Ferroelectric (PbxSr1−x)TiO3 (PST) perovskite phase has been crystallized in borosilicate glassy matrix with a suitable choice of composition and heat treatment schedule. La2O3 is a donor dopant for PST and can make it semiconducting. Dispersion of semiconducting perovskite phase in insulating glassy matrix in glass-ceramic samples may lead to the formation of space charge polarization around crystal-glass interface, leading to a high value of effective dielectric constant, εr. Therefore, with the aim of the developing glass ceramics with high dielectric constant, glasses in the system 64[(PbxSr1−x)O·TiO2]-25[2SiO2·B2O3]-5[K2O]-5[BaO]-1[La2O3] have been prepared (0.5≤x≤1). It is found that the addition of La2O3 strongly affected the crystallization and dielectric behavior of glass-ceramic with PST perovskite phase. All glass ceramic samples show a diffuse broad Curie peak in their εr versus T plots. Curie peak temperature, Tc, depends on compositions of the glass-ceramic samples as well as frequency of measurements.

scholarly journals Study of PbTiO3-Based Glass Ceramics Containing SiO2

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
V. K. Deshpande ◽  
V. U. Rahangdale
Keyword(s):  
Dielectric Constant ◽  
Glass Ceramic ◽  
Lead Titanate ◽  
Glass Ceramics ◽  
Treatment Schedule ◽  
Glass Ceramic Sample ◽  
Practical Applications ◽  
Ceramic Samples ◽  
Heat Treatment Schedule ◽  
Stage Heat Treatment

Glass samples with composition 50PbO : 25TiO2 : (25-X) B2O3 : XSiO2 (with X = 0, 1.5, 2.5, 3.5, and 5 mol%) were prepared by conventional quenching technique. These glass samples were converted to glass ceramics by the two-stage heat treatment schedule. Formation of ferroelectric lead titanate phase in the glass ceramics was confirmed from the XRD. The density, CTE, and dielectric constant of the glass and glass-ceramic samples were measured. The glass-ceramic sample containing 2.5 mol% SiO2 exhibited the highest dielectric constant. The SEMs of glass-ceramic samples were studied. The P-E hysteresis loop studies also revealed the highest remnant polarization for this sample, which has a potential for being developed for practical applications.

scholarly journals Crystallization Behavior and Microstructural Analysis of Lead-Rich () Glass Ceramics Containing 1 mole

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
C. R. Gautam ◽  
Devendra Kumar ◽  
Om Parkash
Keyword(s):  
Transition Metal Oxides ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
Perovskite Phase ◽  
Microstructural Analysis ◽  
Glass Ceramics ◽  
Glassy Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature

Solid solution of perovskite Pb,SrTiO3in Pb-rich composition can be crystallized in borosilicate glassy matrix. The addition of rare earth and transition metal oxides is known to influence the crystallization behavior and surface morphology of perovskite crystallites in glassy matrix. In the present paper, the glasses in the lead-rich system 64[(PbxSr1-x)·TiO3]-25[2SiO2·B2O3]-5[K2O]-5[BaO] () with the addition of 1 mol % La2O3were prepared to study its effect on their crystallization behavior. Differential thermal analysis (DTA) patterns show one or more exothermic crystallization sharp peaks, which shift towards higher temperature with increasing concentration of SrO. The glasses were subjected to various heat-treatment schedules for crystallization. X-ray diffraction analysis of these glass ceramic samples shows that major crystalline phase of the entire glass ceramic sample with was found to have tetragonal structure similar to PbTiO3ceramic, and addition of La2O3enhances the crystallization of the perovskite phase and retards the crystallization of minor phases.

scholarly journals Study of Impedance Spectroscopy of Ferroelectric (Pb Sr)TiO3 Glass Ceramic System with Addition of La2O3

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
C. R. Gautam ◽  
D. Kumar ◽  
Prabhakar Singh ◽  
O. Parkash
Keyword(s):  
Impedance Spectroscopy ◽  
Glass Ceramic ◽  
Complex Modulus ◽  
Glassy Matrix ◽  
Treatment Schedule ◽  
Spectroscopic Techniques ◽  
Frequency Range ◽  
Ceramic System ◽  
Ceramic Samples ◽  
Spectroscopy Studies

Various composition of glasses were prepared by melt-quenched method in the glass ceramic system 64[(PbxSr1-x)⋅OTiO2]-25[(2SiO2⋅B2O3)]-7[BaO]-3[K2O] doped with 1 mole % La2O3 (0.0≤x≤0.4). Solid solution of perovskite lead strontium titanate (PST) phase was crystallized in borosilicate glassy matrix with controlled heat treatment schedule. X-ray diffraction analysis of these glass ceramic samples revealed that major crystalline phase of the entire glass ceramic samples bears cubic structure similar to SrTiO3 ceramic. Impedance spectroscopy studies were done in the frequency range 0.01 Hz to 3.0 MHz and in the temperature range 50 to 275°C. Impedance and complex modulus spectroscopic techniques were used to find out the various contributions to the polarization process. Resistive and capacitive contributions of the processes relaxing in the highest frequency range were found to have low values in comparison to the resistive and capacitive contributions for the processes relaxing in lower and intermediate frequencies ranges.

scholarly journals Towards Higher Electric Conductivity and Wider Phase Stability Range via Nanostructured Glass-Ceramics Processing

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1321
Author(s):  
Tomasz K. Pietrzak ◽  
Marek Wasiucionek ◽  
Jerzy E. Garbarczyk
Keyword(s):  
Glass Ceramic ◽  
Electronic Conductivity ◽  
Glass Ceramics ◽  
Temperature Stability ◽  
Ceramic Materials ◽  
Glassy Matrix ◽  
Oxide Glasses ◽  
Thermal Transitions ◽  
Stability Range ◽  
Conductivity Enhancement

This review article presents recent studies on nanostructured glass-ceramic materials with substantially improved electrical (ionic or electronic) conductivity or with an extended temperature stability range of highly conducting high-temperature crystalline phases. Such materials were synthesized by the thermal nanocrystallization of selected electrically conducting oxide glasses. Various nanostructured systems have been described, including glass-ceramics based on ion conductive glasses (silver iodate and bismuth oxide ones) and electronic conductive glasses (vanadate-phosphate and olivine-like ones). Most systems under consideration have been studied with the practical aim of using them as electrode or solid electrolyte materials for rechargeable Li-ion, Na-ion, all-solid batteries, or solid oxide fuel cells. It has been shown that the conductivity enhancement of glass-ceramics is closely correlated with their dual microstructure, consisting of nanocrystallites (5–100 nm) confined in the glassy matrix. The disordered interfacial regions in those materials form “easy conduction” paths. It has also been shown that the glassy matrices may be a suitable environment for phases, which in bulk form are stable at high temperatures, and may exist when confined in nanograins embedded in the glassy matrix even at room temperature. Many complementary experimental techniques probing the electrical conductivity, long- and short-range structure, microstructure at the nanometer scale, or thermal transitions have been used to characterize the glass-ceramic systems under consideration. Their results have helped to explain the correlations between the microstructure and the properties of these systems.

HIPed Tailored Pyrochlore-Rich Glass-Ceramic Waste Forms for the Immobilization of Nuclear Waste

2008 ◽  
Vol 1124 ◽  
Author(s):  
Melody Lyn Carter ◽  
Hui Li ◽  
Yingjie Zhang ◽  
Andrew L Gillen ◽  
Eric R Vance
Keyword(s):  
Nuclear Waste ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Spectroscopic Characterization ◽  
Chemical Durability ◽  
Intermediate Level ◽  
Crystalline Phases ◽  
Waste Forms ◽  
Ceramic Samples

AbstractHot isostatically pressed (HIPed) glass-ceramics for the immobilization of uranium-rich intermediate-level wastes and Hanford K-basin sludges were designed. These were based on pyrochlore-structured Ca(1-x)U(1+y)Ti2O7 in glass, together with minor crystalline phases. Detailed microstructural, diffraction and spectroscopic characterization of selected glass-ceramic samples has been performed, and chemical durability is adequate, as measured by both MCC-1 and PCT-B leach tests.

scholarly journals Photoluminescence of Eu and Ce Activated Oxyfluoride Glass And Glass Ceramics/ Eu Un Ce Jonu Luminiscence Oksifluorīdu Stiklos Un Stikla Keramikā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 44-48
Author(s):  
I. Brice ◽  
U. Rogulis ◽  
E. Elsts ◽  
J. Grūbe
Keyword(s):  
Glass Ceramic ◽  
Glass Ceramics ◽  
Oxyfluoride Glass ◽  
Ceramic Samples ◽  
Activator Ions

Abstract The photoluminescence of SiO2-Al2O3-LiO2-LaF3 oxyfluoride glass and glass ceramic samples doped with Ce3+, Eu2+ and Ce3+/Eu2+ is investigated, and the spectra and fluorescence intensities are compared. The luminescence of samples activated by Eu ions is found to be more intensive than of the samples doped with Ce or Ce/Eu. The luminescence of glass ceramics is higher than that of the corresponding glass, which indicates that a proportion of the activator ions are embedded in the fluoride crystallites.

scholarly journals Synthesis, Crystallization, and Dielectric Behaviour of Lead Bismuth Titanate Borosilicate Glasses with Addition of 1% La2O3

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
C. R. Gautam ◽  
Abhishek Madheshiya ◽  
R. K. Dwivedi
Keyword(s):  
Glass Ceramic ◽  
Bismuth Titanate ◽  
Glass System ◽  
Glassy Matrix ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
Mole Percent ◽  
Ceramic Samples ◽  
Donor Dopant ◽  
Quench Method

Lead bismuth titanate borosilicate glasses were prepared in the glass system 65[(PbxBi1-x)·TiO3]-34[2SiO2·B2O3]-1La2O3 (0.0≤x≤1.0) doped with one mole percent of La2O3 via conventional melt quench method. The amorphous nature of glass samples in this glass system is confirmed by using X-ray diffraction (XRD) study. Differential thermal analysis (DTA) has been employed to determine the glass transition temperature, Tg, as well as crystallization temperature, Tc. DTA measurements were recorded in temperature range from 30 to 1200°C. The prepared glasses were crystallized by regulated controlled heat treatment process on the basis of their DTA results. These samples are carried out for XRD measurements in the 2θ range from 20 to 80° to study the crystallization behaviour and phase formation of the glass ceramic samples. The scanning electron microscopy (SEM) of these glass ceramic samples has been carried out to explore the morphology through nucleation and growth of the crystallites in the glassy matrix. The values of dielectric constant as well as dielectric loss were increased with increasing the temperature within the frequency range from 20 Hz to 100 Hz. The addition of 1 mol% of La2O3 to the lead bismuth titanate glasses enhances the crystallization and acts as donor dopant for this glass system.

scholarly journals Investigation on Structural and Optical Properties of Willemite Doped Mn2+Based Glass-Ceramics Prepared by Conventional Solid-State Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Nur Farhana Samsudin ◽  
Khamirul Amin Matori ◽  
Josephine Ying Chi Liew ◽  
Yap Wing Fen ◽  
Mohd Hafiz Mohd Zaid ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Glass Ceramics ◽  
Structural Evolution ◽  
Emission Spectra ◽  
Soda Lime ◽  
X Ray Diffraction ◽  
Glass Waste ◽  
Solid State Method ◽  
Ceramic Samples ◽  
Zno Crystal

Mn-doped willemite (Zn2SiO4:Mn2+) glass-ceramics derived from ZnO-SLS glass system were prepared by a conventional melt-quenching technique followed by a controlled crystallization step employing the heat treatment process. Soda lime silica (SLS) glass waste, ZnO, and MnO were used as sources of silicon, zinc, and manganese, respectively. The obtained glass-ceramic samples were characterized using the X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR), UV-Visible (UV-Vis), and photoluminescence (PL) spectroscopy. The results of XRD revealed that ZnO crystal and willemite (β-Zn2SiO4) were presented as major embedded crystalline phases. This observation was consistent with the result of FESEM which showed the presence of irregularity in shape and size of willemite crystallites. FTIR spectroscopy exhibits the structural evolution of willemite based glass-ceramics. The optical band gap shows a decreasing trend as the Mn-doping content increased. Photoluminescent technique was applied to characterize the role of Mn2+ions when entering the willemite glass-ceramic structure. By measuring the excitation and emission spectra, the main emission peak of the glass-ceramic samples located at a wavelength of 585 nm after subjecting to 260 nm excitations. The following results indicate that the obtained glass-ceramics can be applied as phosphor materials.

Study on the Preparation and Properties of Piezoelectric Glass-Ceramic Sr0.5Ba0.5Nb2O6

2013 ◽  
Vol 669 ◽  
pp. 204-207
Author(s):  
Shan Jiang ◽  
Jing Wen Lv ◽  
Tao Zheng
Keyword(s):  
Particle Size ◽  
Glass Ceramic ◽  
Crystalline Phase ◽  
Room Temperature ◽  
Glass Ceramics ◽  
Molar Ratio ◽  
Spectral Transmittance ◽  
Melting Method ◽  
Ceramic Samples ◽  
Analytical Reagents

Series of ferroelectric glass-ceramic samples of Sr0.5Ba0.5Nb2O6 were synthesized by melting method. Firstly, analytical reagents were melted for 30 minutes at 1440°C after being grinded evenly according to a certain molar ratio, then annealed for 10 hours from 550°C to room temperature, finally it was sustained for 4 hours at constant temperature about 700°C. The hardness and transmittance parameters of SBN glass-ceramic were tested. Results indicated the sample had the best property when the amount of Nb2O5 was 10mol%, whose hardness reached 506 kg/mm2, and spectral transmittance was higher than 35% . XRD spectra of this sample indicated this SBN glass-ceramics contained a large number of Sr0.5Ba0.5Nb2O6 crystalline phase and a small amount of Sr0.3Ba0.7Nb2O6 phase. The particle size was about 50 nm.

scholarly journals Effect of Different Concentrations of Titanium Oxide (TiO2) Addition on the Crystallization Behaviour and Some Properties of Alkaline Earth Aluminosilicate Glass-Ceramics

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Z.S. Aliyu
Keyword(s):  
Glass Ceramic ◽  
Minimum Weight ◽  
Glass Ceramics ◽  
Aluminosilicate Glass ◽  
Base Glass ◽  
Ceramic Samples ◽  
Melting Technique ◽  
The Matrix ◽  
Quaternary Base ◽  
Tio2 Addition

Glass-ceramics in the CaO-MgO-Al2O3-SiO2 quaternary base glass system was produced via melting technique using feldspar, limestone and magnesite as sources of starting materials. Glass-ceramics production involves making a base glass, annealing and cooling to room temperature and then reheating the base glass to nucleation and crystal growth temperatures. Characterization of the produced glass-ceramics was carried out using a scanning electron microscope (SEM). The effects of the crystallization process on some properties such as hardness, chemical durability in acid and alkali media of samples were determined. The results portrayed that glass-ceramic samples to which various amounts of TiO2 (2,4,6,8 and 10 wt.%) were incorporated showed the formation of crystalline phases dispersed in the matrix of their respective residual glassy phases. Significant improvement in hardness, as well as minimum weight loss, were recorded for all the glass-ceramic samples. On the contrary, the glass samples did not crystallize despite subjecting them to heat treatment, their hardness values were low and they were not resistant to acid (1M HCl) and alkali (1M NaOH) attacks. The inability of TiO2 addition to fully transform them into glass-ceramics remains a shortcoming. However, the glass-ceramic samples obtained from this study can be used for tiling works.

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