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Mei Zhang - One of the best experts on this subject based on the ideXlab platform.
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crystallization kinetics of Glass Ceramics prepared from high carbon ferrochromium slag
Ceramics International, 2016Co-Authors: Zhitao Bai, Guibo Qiu, Changsheng Yue, Min Guo, Mei ZhangAbstract:Abstract Glass-Ceramics were successfully prepared from high-carbon ferrochromium slag (HCFS), and the optimum heat-treatment conditions were determined by analysis of the crystallization kinetics. The parent Glass is first prepared in five different ratios of HCFS to waste Glass (R(H/W)), then heat-treated separately at five heating rates (α) and monitored by DSC. As the value of R(H/W) increases from 0.60 to 1.67, the crystallization activation energy (E c ) decreases from 253.41 to 183.52 kJ/mol. The nucleation and crystallization temperatures decrease from 641.7 to 612.2 °C, and 822.8–814.7 °C, respectively, and both are lower than that of ordinary metallurgy slag. These results indicate that using HCFS to produce Glass-Ceramics both facilitates its production and saves energy. The crystallization index (n) increases with increasing R(H/W), and when n exceeds 2.32, all of the parent Glass samples with different R(H/W) crystallize as bulk crystallization. The crystallization index (n) increases as the heating rate α decreases from 25 to 5 °C/min, with a maximum value of n (5.94) observed when α is 5 °C/min. These conditions produce the largest aspect ratio and highest density of the crystal grain in the Glass-Ceramics. Our results show the optimal HCFS-based Glass-Ceramics were obtained with a R(H/W) of 1.29 and a 5 °C/min heating rate; under those conditions, the parent Glass nucleates and crystalizes at 627.1 and 820.9 °C, respectively.
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synthesis and characterization of Glass Ceramics prepared from high carbon ferrochromium slag
RSC Advances, 2016Co-Authors: Zhitao Bai, Guibo Qiu, Min Guo, Ben Peng, Mei ZhangAbstract:Glass-Ceramics have been successfully prepared from high-carbon ferrochromium slag (HCFS) and waste Glass (WG), and the microstructural characterization and mechanical properties of the Glass-Ceramics were subsequently investigated. The development of HCFS-based Glass-Ceramics involves the nucleation and crystallization stages from the parent Glass. With the increase in mass ratio of HCFS and WG (R(H/W)) from 0.60 to 1.67, the number of bridging oxygens of Si in the parent Glass is reduced, as shown via Raman spectroscopy. Thus, their degree of polymerization decreases with it, and the temperature of nucleation and crystallization increase, which is consistent with the DSC results. The SEM images and EDS results indicate that the increasing value of R(H/W) decreases the crystal grain size and consequently increases the microhardness of the Glass-Ceramics. But the porosity simultaneously increases, which makes the bending strength increase at first and subsequently decrease. And the optimum properties of HCFS-based Glass-ceramic samples in the present work are obtained when R(H/W) reaches 1.29, that is, a bending strength of 104 MPa and a microhardness of 9860 MPa.
Enrico Bernardo - One of the best experts on this subject based on the ideXlab platform.
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magnetic Glass Ceramics by sintering of borosilicate Glass and inorganic waste
Materials, 2014Co-Authors: Ines Ponsot, Aldo R Boccaccini, Yiannis Pontikes, Giovanni Baldi, R K Chinnam, Rainer Detsch, Enrico BernardoAbstract:Ceramics and Glass Ceramics based on industrial waste have been widely recognized as competitive products for building applications; however, there is a great potential for such materials with novel functionalities. In this paper, we discuss the development of magnetic sintered Glass Ceramics based on two iron-rich slags, coming from non-ferrous metallurgy and recycled borosilicate Glass. The substantial viscous flow of the Glass led to dense products for rapid treatments at relatively low temperatures (900–1000 °C), whereas Glass/slag interactions resulted in the formation of magnetite crystals, providing ferrimagnetism. Such behavior could be exploited for applying the obtained Glass Ceramics as induction heating plates, according to preliminary tests (showing the rapid heating of selected samples, even above 200 °C). The chemical durability and safety of the obtained Glass Ceramics were assessed by both leaching tests and cytotoxicity tests.
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sintered and glazed Glass Ceramics from natural and waste raw materials
Ceramics International, 2014Co-Authors: Mohammed Binhussain, Enrico Bernardo, Mauro Marangoni, Paolo ColomboAbstract:Abstract Monolithic sintered Glass-Ceramics and porous Glass-ceramic components were produced from natural raw materials together with industrial waste. The waste, including fly ash from thermal power plants and metallurgical slags, either was mixed with natural raw materials (e.g., clay and silica sand) and vitrified or was directly sintered, after dry pressing at 40 MPa. Fine powders of waste-derived Glasses were also converted into sinter-crystallized Glass-Ceramics, after dry pressing at 40 MPa and subjection of the pressed powders to controlled heating cycles, producing dense components with bending strength as high as ~80 MPa. The two types of waste-derived materials, namely, ceramic tiles from direct sintering and sinter-crystallized Glass-Ceramics, were combined to obtain double-layered Glass-Ceramics. These featured a dense wear-resistant coating on a porous substrate and possessed mechanical properties that make them suitable, for example, as structural lightweight panels in building facades.
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fast sintered gehlenite Glass Ceramics from plasma vitrified municipal solid waste incinerator fly ashes
Journal of the American Ceramic Society, 2009Co-Authors: Enrico Bernardo, Giovanni Scarinci, Erika Edme, Ulysse Michon, Nicholas PlantyAbstract:Plasma heating is a highly efficient industrial treatment for municipal solid waste incinerator fly ashes, converted into leach-resistant Glass. The viscous flow sintering of Glass powders appears a very promising way for the subsequent conversion of the vitrified waste, not refined and available as Glass flakes, into valuable Glass–Ceramics. Because of the particular Glass composition, the densification of Glass–Ceramics was much hindered by the strong tendency of Glass toward surface crystallization. The crystallization of Glass was successfully coupled to a low porosity, thus yielding strong gehlenite-based Glass–Ceramics (with a bending strength exceeding 100 MPa), by adopting a fast sintering treatment (direct insertion of Glass compacts at 1050°C, with an holding time of 1 h).
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sintered sanidine Glass Ceramics from industrial wastes
Journal of The European Ceramic Society, 2006Co-Authors: Enrico Bernardo, R Castellan, Sandro Hreglich, Isabella LancellottiAbstract:Abstract Glass obtained from melting a mixture of industrial wastes (panel Glass from dismantled cathode ray tubes, mining residues from feldspar excavation and lime from fume abatement systems of the Glass industry) has been employed for the production of sanidine-based Glass-Ceramics. The Glass-Ceramics were developed by a sintering treatment with concurrent crystallization, from fine powders (
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sintered Glass Ceramics and Glass ceramic matrix composites from crt panel Glass
Journal of the American Ceramic Society, 2005Co-Authors: Enrico Bernardo, Fernanda Andreola, Luisa Barbieri, Isabella LancellottiAbstract:Sintering with simultaneous crystallization of powdered Glass represents an interesting processing route for Glass–Ceramics, especially originating from wastes. Highly dense Glass–ceramic samples may be obtained from a simple and short treatment at a relatively low temperature. In addition, Glass–ceramic matrix composites may be obtained by mixing Glass with suitable reinforcements. In this work sintered nepheline Glass–Ceramics, based on panel Glass from cathode ray tubes, are illustrated. A limited addition of Al2O3 platelets caused a significant improvement in the mechanical properties (elastic modulus, bending strength, microhardness, fracture toughness), already remarkable for the un-reinforced Glass–ceramic, compared with traditional nepheline Glass–Ceramics.
Ashutosh Goel - One of the best experts on this subject based on the ideXlab platform.
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Glass Ceramics for nuclear waste immobilization
Mrs Bulletin, 2017Co-Authors: John S Mccloy, Ashutosh GoelAbstract:Crystallization in Glasses is usually considered to be a problem in the Glass industry. However, controlled crystallization of Glasses is an important prerequisite in the development of Glass-Ceramics with tailored useful properties. Similar boundary conditions apply when considering Glass-Ceramics for the immobilization of nuclear waste via vitrification. While uncontrolled crystallization in nuclear-waste Glasses is problematic, chemically durable Glass-Ceramics with significantly high waste loadings can be produced with controlled crystallization of Glasses. This article presents an overview of various aspects of nuclear-waste Glasses where crystallization is either considered to be advantageous or problematic. The classification of Glass-ceramic waste forms and strategies to design Glass-Ceramics for a given waste stream is discussed. Some open and relevant problems faced by researchers developing nuclear-waste Glass-Ceramics are also offered.
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diopside cao mgo 2sio2 fluorapatite 9cao 3p2o5 caf2 Glass Ceramics potential materials for bone tissue engineering
Journal of Materials Chemistry, 2011Co-Authors: Ishu Kansal, Dilshat U Tulyaganov, Ashutosh Goel, M J Pascual, Hyeyoung Lee, Haewon Kim, J M F FerreiraAbstract:Glass-Ceramics in the diopside (CaMgSi2O6)–fluorapatite [Ca5(PO4)3F] system are potential candidates for restorative dental and bone implant materials. In the present study, a series of Glasses along the diopside–fluorapatite binary system have been prepared with varying diopside/fluorapatite ratios for their potential applications in bone tissue engineering. The Glasses were obtained from compositions with fluorapatite contents varying between 0 and 40 wt%. The sintering ability and crystallization kinetics of as obtained amorphous Glasses have been studied through hot-stage microscopy (HSM) and differential thermal analysis (DTA), respectively, while crystalline phase evolution in sintered GCs has been followed by X-ray diffraction (XRD) adjoined with the Rietveld-R.I.R. technique and scanning electron microscopy (SEM). Further, biodegradation and apatite forming ability of Glass-Ceramics were investigated by immersion of Glass-ceramic discs in simulated body fluid (SBF) solution while chemical degradation and weight loss of Glass-Ceramics were studied by immersion in Tris–HCl in accordance with the ISO 10993-14 standard. The addition of fluorapatite (10–25 wt%) in the diopside Glass system significantly enhanced the sintering ability of Glass-Ceramics and improved their apatite forming ability along with their biodegradation behaviour. Moreover, the in vitro cellular responses to Glass-Ceramics showed good cell viability and significant stimulation of osteoblastic differentiation, suggesting the possible use of the Glass-Ceramics for bone regeneration.
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sintering behavior and devitrification kinetics of iron containing clinopyroxene based magnetic Glass Ceramics
Solid State Ionics, 2011Co-Authors: Ashutosh Goel, E R Shaaban, J B Oliveira, M J Pascual, J M F FerreiraAbstract:abstract Article history:Received 5 April 2010Received in revised form 25 December 2010Accepted 21 January 2011Available online 26 February 2011Keywords:Magnetic Glass-ceramicDiopsideClinopyroxeneHyperthermiaSinteringCrystallization The present study deals with the design, synthesis and characterization of magnetic Glass-Ceramics alongdiopside (CaMgSi 2 O 6 )–aegirine (NaFeSi 2 O 6 ) join targeted towards their final application as thermoseeds inhyperthermia. The Glass-Ceramics were prepared from the sintering and crystallization of Glass powdersobtained through melt-quenching technique. The sintering behavior of Glass powders was studied by hot-stage microscopy (HSM) while differential thermal analysis (DTA) was used to study the non-isothermalcrystallization kinetics of the as prepared Glasses. In order to analyze the crystallization behavior of Glasses,the Glass powder compacts were sintered at 900 °C for 1 h under non-isothermal conditions. The qualitativeas well as quantitative crystalline phase analysis of Glass-Ceramics has been made by X-ray diffraction (XRD)-adjoined with Rietveld-RIR technique. Augite crystallized as the primary phase in all the compositions. Thescanning electronmicroscopy (SEM)was usedto shed lighton themicrostructureoftheGlass-Ceramics whilethe magnetic properties of Glass-Ceramics were studied by vibration sample magnetometer (VSM). All theinvestigated Glass-Ceramics exhibited ferromagnetic behavior the intensity of which increased with increaseinFecontentinthesamples.ThedependenceofmagneticpropertiesonthecompositionofGlass-Ceramicshasbeen explained.© 2011 Elsevier B.V. All rights reserved.
Edgar D Zanotto - One of the best experts on this subject based on the ideXlab platform.
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bioactive and inert dental Glass Ceramics
Journal of Biomedical Materials Research Part A, 2017Co-Authors: Maziar Montazerian, Edgar D ZanottoAbstract:The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, Glass or polymer-infiltrated Ceramics, and Glass-Ceramics (GCs) are of great importance. Dental Glass-Ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental Glass-Ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental Glass-Ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental Glass-Ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. This article is protected by copyright. All rights reserved.
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bioactive and inert dental Glass Ceramics
Journal of Biomedical Materials Research Part A, 2017Co-Authors: Maziar Montazerian, Edgar D ZanottoAbstract:The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, Glass or polymer-infiltrated Ceramics, and Glass-Ceramics (GCs) are of great importance. Dental Glass-Ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental Glass-Ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental Glass-Ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental Glass-Ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017.
Zhitao Bai - One of the best experts on this subject based on the ideXlab platform.
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crystallization kinetics of Glass Ceramics prepared from high carbon ferrochromium slag
Ceramics International, 2016Co-Authors: Zhitao Bai, Guibo Qiu, Changsheng Yue, Min Guo, Mei ZhangAbstract:Abstract Glass-Ceramics were successfully prepared from high-carbon ferrochromium slag (HCFS), and the optimum heat-treatment conditions were determined by analysis of the crystallization kinetics. The parent Glass is first prepared in five different ratios of HCFS to waste Glass (R(H/W)), then heat-treated separately at five heating rates (α) and monitored by DSC. As the value of R(H/W) increases from 0.60 to 1.67, the crystallization activation energy (E c ) decreases from 253.41 to 183.52 kJ/mol. The nucleation and crystallization temperatures decrease from 641.7 to 612.2 °C, and 822.8–814.7 °C, respectively, and both are lower than that of ordinary metallurgy slag. These results indicate that using HCFS to produce Glass-Ceramics both facilitates its production and saves energy. The crystallization index (n) increases with increasing R(H/W), and when n exceeds 2.32, all of the parent Glass samples with different R(H/W) crystallize as bulk crystallization. The crystallization index (n) increases as the heating rate α decreases from 25 to 5 °C/min, with a maximum value of n (5.94) observed when α is 5 °C/min. These conditions produce the largest aspect ratio and highest density of the crystal grain in the Glass-Ceramics. Our results show the optimal HCFS-based Glass-Ceramics were obtained with a R(H/W) of 1.29 and a 5 °C/min heating rate; under those conditions, the parent Glass nucleates and crystalizes at 627.1 and 820.9 °C, respectively.
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synthesis and characterization of Glass Ceramics prepared from high carbon ferrochromium slag
RSC Advances, 2016Co-Authors: Zhitao Bai, Guibo Qiu, Min Guo, Ben Peng, Mei ZhangAbstract:Glass-Ceramics have been successfully prepared from high-carbon ferrochromium slag (HCFS) and waste Glass (WG), and the microstructural characterization and mechanical properties of the Glass-Ceramics were subsequently investigated. The development of HCFS-based Glass-Ceramics involves the nucleation and crystallization stages from the parent Glass. With the increase in mass ratio of HCFS and WG (R(H/W)) from 0.60 to 1.67, the number of bridging oxygens of Si in the parent Glass is reduced, as shown via Raman spectroscopy. Thus, their degree of polymerization decreases with it, and the temperature of nucleation and crystallization increase, which is consistent with the DSC results. The SEM images and EDS results indicate that the increasing value of R(H/W) decreases the crystal grain size and consequently increases the microhardness of the Glass-Ceramics. But the porosity simultaneously increases, which makes the bending strength increase at first and subsequently decrease. And the optimum properties of HCFS-based Glass-ceramic samples in the present work are obtained when R(H/W) reaches 1.29, that is, a bending strength of 104 MPa and a microhardness of 9860 MPa.