scholarly journals Glass-Ceramic Materials Obtained by Sintering of Vitreous Powders from Industrial Waste: Production and Properties

2021 ◽  
Vol 1 (1) ◽  
pp. 63-79
Author(s):  
Diana M. Ayala Ayala Valderrama ◽  
Jairo A. Gómez Cuaspud ◽  
Nicoletta Taniolo ◽  
Aldo R. Boccaccini
Keyword(s):  
Coal Fly Ash ◽  
Amorphous Material ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Xrd Analysis ◽  
Crystalline Phases ◽  
Waste Production ◽  
Nano Crystalline ◽  
Average Size ◽  
Silicate Materials

Glass-ceramics are advanced inorganic silicate materials that can be obtained by sintering glass powders using a careful temperature control to result in the densification, nucleation, and crystallization of the material. In the current work, three different samples were obtained starting from amorphous silicate materials derived from mixtures of metallurgical slag, coal fly ash, and glass cullet, mixed in different proportions. The as-received waste samples were heat-treated to high temperatures to achieve complete melting at 1200, 1300, and 1400 °C for two hours, performing a rapid cooling in order to yield an amorphous material (glass). The obtained frit was ball-milled to a powder, which was then cold pressed to obtain compact pellets. The thermal treatment of pellets was carried out at 800–1100 °C for 2 h followed by a cooling rate of 10 °C/min to obtain the final glass-ceramics. The microstructure of samples was evaluated with scanning electron microscopy (SEM), which showed heterogeneous conglomerates and clusters of ~20 microns. The formation of crystalline phases was corroborated by means of X-ray diffraction (XRD) analysis, showing the presence of anorthite in all samples. Depending on the sample composition, other crystalline phases such as augite, enstatite, and diopside were detected. Using the Debye–Scherrer equation, it was possible to find the average size of the nano-crystalline domains. The quantification of the non-crystalline or amorphous fraction was also performed. Additionally, the density and porosity of the materials were calculated using the procedures defined in the ASTM C373 and ASTM C20 standards, measuring density values in the range 2.2–3.1 g·cm−3. The apparent porosity was approx. 33% in the three materials. Raman spectroscopy analysis showed characteristic signals associated with crystalline phases containing alumina, silica, iron, and calcium. Overall, the study confirmed the possibility of obtaining glass-ceramics with fine (nanometric) crystal sizes from a combination of silicate waste and the capability of modifying the crystalline composition by changing the proportions of the different wastes in the initial formulations.

Effects of Different Content of TiO2 on Crystallization Behavior and Properties of Li2O-ZnO-SiO2 Glass-Ceramics

2014 ◽  
Vol 1035 ◽  
pp. 263-267
Author(s):  
Xiu Quan Zhao ◽  
Zheng Cao ◽  
Yu Teng Wu ◽  
Hong Jiang ◽  
Chang Jiu Li ◽  
...  
Keyword(s):  
Crystallization Behavior ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Xrd Analysis ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Ceramic Materials ◽  
Average Coefficient ◽  
Different Content

Glass-ceramic materials of the Li2O-ZnO-SiO2 system, with various amounts of TiO2 added, have been prepared. The appropriate heat treatment temperatures were selected according to the information provided by the differential thermal analysis (DTA). X-ray diffraction (XRD) analysis demonstrated that in the LZS glass-ceramics system, the main phases are Li2ZnSiO4, cristobalite, tridymite and quartz. The scanning electron microscopy (SEM) revealed that crystals appear as lamellar and spherical particles in the glass-ceramics samples. In addition, the average coefficient of the thermal expansion (CTE) values first decreased, then increased and finally tended to flatten. When the content of TiO2 increased to 6%, the CTE value decreased to 9.15×10-6/K, reached the lowest value. When the content of TiO2 increased to 10%, the CTE value reached highest value 13.90×10-6/K.

scholarly journals Synthesis of SiO2-TiO2:Yb3+ glass-ceramics and characterization of structure and optical properties

2017 ◽  
Vol 1 (T1) ◽  
pp. 114-121
Author(s):  
Thanh Tat Huynh ◽  
Van Thi Thanh Tran
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Silica Matrix ◽  
Photoluminescence Intensity ◽  
Raman Spectroscopic ◽  
Characteristic Emission ◽  
Ft Ir ◽  
Average Size ◽  
20 Nm

In this work, the monoliths of 85 % SiO2-15 % TiO2 doped Yb3+ ions at different contents have been prepared by sol-gel method. The measurement of FT-IR, Raman spectroscopic and XRD analysis show the formation of anatase TiO2 nanocrystals with average size about 15–20 nm in silica matrix. Moreover, the pyrochlore crystals of Yb2Ti2O7 begin to form in the samples when content of Yb3+ reaches to 1 mol %. TiO2 Yb3+ 2F7/2 2F5/2 truyền năng lƣợng kích thích UV EV EC mức khuyết tật 974 nm The energy transferred from TiO2 crystals to Yb3+ ions is proven by the characteristic emission spectrum of Yb3+ at the wavelength of 980 nm when the samples are excited by the wavelength of 300 nm. The photoluminescence intensity is highest at 0.1% mol of Yb3+ and gradually decreases with doping content

Transparent Oxyfluoride Glass-Ceramics Containing CaF2 Nano-Crystalline Phase

2012 ◽  
Vol 512-515 ◽  
pp. 1015-1018 ◽  
Author(s):  
Zhao Xia Hou ◽  
Zhao Lu Xue ◽  
Shao Hong Wang ◽  
Xiao Dan Hu ◽  
Hao Ran Lu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crystalline Phase ◽  
Tellurite Glass ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Glassy Matrix ◽  
The Novel ◽  
X Ray Diffraction ◽  
Oxyfluoride Glass ◽  
Nano Crystalline

Transparent oxyfluoride tellurite glass with the composition of TeO2-SiO2-AlF3-CaO-KF system were prepared by conventional melting and annealing technique, and the transparent oxyfluoride glass-ceramics containing CaF2 nano-crystallines were obtained by controlled heat-treatment. The effect of heat-treatment schedules on the crystallization behavior and the microstructure of the glass-ceramics were analyzed by differential scanning caborimetry (DSC) analysis, X-ray diffraction (XRD) analysis, infrared (IR) spectrum and scanning electron microscopy (SEM). The sole CaF2 crystalline phase was confirmed by XRD, the spherical CaF2 nano-crystallines at about 20~100nm embed homogeneously among the glassy matrix after crystallization by SEM observation. The size of CaF2 grains grew with the increase of crystallization temperature and holding time. Te and Si atoms existed in [TeO3] and [SiO4] forms. Part of Al atoms existed in the form of [AlO4] and formed network together with [SiO4] tetrahedron. The other Al atoms acted as modifiers in the form of [AlO6]. The transmittance of glass-ceramics can reach 85% in visible light and 90% in infrared waveband. The novel transparent oxyfluoride tellurite glass-ceramics are excellent matrix materials in up-conversion luminescence field.

New Silicate Glass-Ceramic Materials and Composites

2010 ◽  
Vol 68 ◽  
pp. 1-12 ◽  
Author(s):  
Dachamir Hotza ◽  
Antonio Pedro Novaes de Oliveira
Keyword(s):  
Silicate Glass ◽  
Glass Ceramic ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Crystalline Phases ◽  
Glass Ceramic Materials ◽  
Thermal And Electrical Properties ◽  
Large Production

New silicate glass-ceramic compositions have been investigated due to their interesting chemical, mechanical, thermal, and electrical properties. LZSA glass-ceramics based on -spodumene (Li2O•Al2O3•4-10SiO2) and zircon (ZrSiO4) crystalline phases have shown good chemical resistance, high bending strength as well as high abrasion resistance, when compared with traditional ceramic materials, and coefficient of thermal expansion from 4.6 to 9.110-6 °C-1. These features basically depend on the nature, size and distribution of the formed crystals as well as on the residual glassy phase. The nature of the formed crystalline phases and consequently the final properties can be controlled by modifying the chemical composition of the parent glass and also by adequate selection of the heat-treatment parameters. The classical fabrication of glass-ceramic materials consists on the preparation of monolithic glass components followed by heat treatments for crystallisation. However, this technology requires high investments and can be justified only for large production. A viable alternative could be the production of glass-ceramics processed from glass powders and consolidated by sintering using the same equipments of traditional ceramic plants. This work reports the manufacturing and characterization of glass-ceramic materials and composites processed by pressing, injection moulding, extrusion, casting, replication, and rapid prototyping.

Determination of the crystallized fractions of a largely amorphous multiphase material by the Rietveld method

2001 ◽  
Vol 34 (2) ◽  
pp. 114-118 ◽  
Author(s):  
X. Orlhac ◽  
C. Fillet ◽  
P. Deniard ◽  
A. M. Dulac ◽  
R. Brec
Keyword(s):  
Rietveld Method ◽  
Amorphous Material ◽  
Effective Means ◽  
Site Occupancy ◽  
Internal Standard ◽  
Ceramic Materials ◽  
Contrast Effects ◽  
Crystalline Phases ◽  
Cell Parameters ◽  
High Level

The Rietveld method has proved to be a very effective means to characterize and quantify the crystalline phases and the amorphous phase in glass ceramic materials using X-ray powder diffraction data. The technique was applied to a borosilicate glass of the type used for high-level nuclear-waste containment, in order to measure the proportions of the crystallized phases after heat treatment and, thus, to qualify the thermal stability of the glass. Six crystalline phases were analysed in this way in an almost entirely (>95 wt%) amorphous material after adding a known proportion of an internal standard (TiO2). The quantitative analyses were corrected to allow for microabsorption effects resulting from grain-size and absorption-contrast effects. In addition to the quantitative data, unit-cell parameters and site-occupancy refinements revealed solid-solution and substitution phenomena in the crystal.

scholarly journals Combination of Na-Ca-phosphate and fluorapatite in wollastonite-diopside glass-ceramic: degradation and biocompatibility

2021 ◽  
Author(s):  
Ebrahim A. Mahdy ◽  
Hanaa Y. Ahmed ◽  
Mohammad Farag
Keyword(s):  
Calcium Phosphate ◽  
Cell Viability ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Vero Cells ◽  
Crystalline Phases ◽  
Sodium Calcium ◽  
Glass Ceramic Materials

Abstract In this study, we investigated the effect of introducing sodium calcium phosphate (NCP), fluorapatite (FA), or the combination of both phases in the wollastonite-diopside (WD) bioactive glass-ceramic system on the crystalline phases formed, microstructure, degradation, and biocompatibility of those materials. The prepared materials were characterized by DTA, XRD, and SEM/EDX. Moreover, the density was measured via Archimede’s method, and the mechanical properties were measured by Vicker’s microhardness indenter. The in vitro bioactivity test was carried out in the simulated body fluid (SBF), and the cell viability test was evaluated using the Vero cells. The results showed that the formed crystalline phases were close to the starting proposed phases. Moreover, NCP-containing WD glass-ceramic was showed the lowest density value due to its low densification, and accordingly, it showed the lowest Vicker`s microhardness value due to the same reason. Furthermore, combining sodium calcium phosphate in WD glass-ceramic was increased cell viability better than that included fluorapatite, whereas, the combination of both crystalline phases in WD glass-ceramic led to an increase in the cytotoxicity to the highest value. In conclusion, different properties of wollastonite-diopside glass-ceramics can be tailored by the combination of NCP or FA, and hence, these glass-ceramic materials can be modified effectively according to the purpose for which it is intended to be applied. The obtained results indicated that different properties of WD glass-ceramic materials can be tailored by the combination of NCP and/or FA. Hence, these glass-ceramics are expected to be useful materials in promising biomedical applications, such as orthopedics and dentistry.

Energy saving technology for sintering of black bricks from high-siliceous clay

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3123-3131
Author(s):  
Mario Flores Nicolas ◽  
Marina Vlasova ◽  
Pedro Antonio Márquez Aguilar ◽  
Mykola Kakazey ◽  
Marcos Mauricio Chávez Cano ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxygen Deficiency ◽  
Glass Ceramics ◽  
Total Content ◽  
Ceramic Materials ◽  
Ternary Mixtures ◽  
High Porosity ◽  
Reducing Conditions ◽  
Binary And Ternary Mixtures ◽  
Dark Color

AbstractThe low-temperature synthesis of bricks prepared from high-siliceous clays by the method of plastic molding of blanks was used. For the preparation of brick blanks, binary and ternary mixtures of high-siliceous clays, black sand, and bottle glass cullet were used. Gray-black low-porosity and high-porosity ceramics was obtained by sintering under conditions of oxygen deficiency. It has been established that to initiate plastic in mixtures containing high-siliceous clay, it is necessary to add montmorillonite/bentonite additives, carry out low-temperature sintering, and introduce low-melting glass additives with a melting point ranging from 750 to 800 °C. The performed investigations have shown that the sintering of mixtures with a total content of iron oxide of about 5 wt% under reducing conditions at Tsint. = 800°C for 8 h leads to the formation of glass ceramics consisting of quartz, feldspars, and a phase. The main sources of the appearance of a dark color is the formation of [Fe3+O4]4- and [Fe3+O6]9- anions in the composition of the glass phase and feldspars. By changing the contents of clay, sand, and glass in sintering, it is possible to obtain two types of ceramic materials: (a) in the form of building bricks and (b) in the form of porous fillers.

scholarly journals Functional Attributes of Myco-Synthesized Silver Nanoparticles from Endophytic Fungi: A New Implication in Biomedical Applications

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 473
Author(s):  
Prabu Kumar Seetharaman ◽  
Rajkuberan Chandrasekaran ◽  
Rajiv Periakaruppan ◽  
Sathishkumar Gnanasekar ◽  
Sivaramakrishnan Sivaperumal ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Culture Filtrate ◽  
Morphological Changes ◽  
Xrd Analysis ◽  
Penicillium Oxalicum ◽  
Breast Cancer Cell Lines ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
X Ray ◽  
Average Size

To develop a benign nanomaterial from biogenic sources, we have attempted to formulate and fabricate silver nanoparticles synthesized from the culture filtrate of an endophytic fungus Penicillium oxalicum strain LA-1 (PoAgNPs). The synthesized PoAgNPs were exclusively characterized through UV–vis absorption spectroscopy, Fourier Transform Infra-Red spectroscopy (FT-IR), X-ray powder diffraction (XRD), and Transmission Electron Microscopy (TEM) with energy dispersive X-ray spectroscopy (EDX). The synthesized nanoparticles showed strong absorbance around 430 nm with surface plasmon resonance (SPR) and exhibited a face-centered cubic crystalline nature in XRD analysis. Proteins presented in the culture filtrate acted as reducing, capping, and stabilization agents to form PoAgNPs. TEM analysis revealed the generation of polydispersed spherical PoAgNPs with an average size of 52.26 nm. The PoAgNPs showed excellent antibacterial activity against bacterial pathogens. The PoAgNPs induced a dose-dependent cytotoxic activity against human adenocarcinoma breast cancer cell lines (MDA-MB-231), and apoptotic morphological changes were observed by dual staining. Additionally, PoAgNPs demonstrated better larvicidal activity against the larvae of Culex quinquefasciatus. Moreover, the hemolytic test indicated that the as-synthesized PoAgNPs are a safe and biocompatible nanomaterial with versatile bio-applications.

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.

Analysis of the Samples of Fe-Cu-Nb-Si-B Amorphous Alloys Obtained by Dynamic Compacting Method

2005 ◽  
Vol 903 ◽  
Author(s):  
Victor A. Golubev ◽  
Andrey V. Strikanov ◽  
Grigory A. Potemkin ◽  
Ludmila V. Zueva ◽  
Aleksey V. Golubev ◽  
...  
Keyword(s):  
Shock Wave ◽  
Amorphous Alloys ◽  
Analysis Data ◽  
Xrd Analysis ◽  
Soft Magnetic ◽  
Scanning Calorimetry ◽  
Soft Magnetic Alloys ◽  
Nano Crystalline ◽  
The Impact ◽  
Magnetic Conductivity

AbstractThe Dynamic Compacting (DC) method is promising method to produce considerable-size nonporous wares. The phenomenon is based on the impact of shock wave on the initial powders of amorphous alloys. Every time when the shock wave propagates through the bulk of substance then the temperature rises substantially. Therefore there is a need of study of the DC’s effect on the structure and properties of the amorphous alloys. The results of the thermal analysis (in particular, Differential Scanning Calorimetry) of the samples of the soft magnetic alloys are presented in the report. These results concern with amorphous alloys of 5BDSR, GM414, 10NSR trademarks before DC and after DC, respectively. It is shown there is single low-temperature endothermic peak (near 300C) and there are several high temperature exothermic peaks (near 540C, 650C, and 700C). The first peak is related to glass-transition, the following peaks are related to formation of nano-crystalline phases. It was proved by XRD analysis data. The optimal regimes of the thermal processing of final wares were chosen on the base of thermal- and XRD-analysis. The study of the effects of these regimes on the properties (magnetic conductivity, specific losses etc.) of the circular magnetic conductors was executed. In particular, thermal- as well as thermo-magnetic processing of magnetic conductors based on 5BDSR amorphous alloy (after DC) essentially improves their magnetic properties. For example, magnetic conductivity fÝ increases approximately by factor 17 with respect to the magnitude before DC.

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