scholarly journals Sintered Glass-Ceramics, Self-Glazed Materials and Foams from Metallurgical Waste Slag

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2263
Author(s):  
Nicolai B. Jordanov ◽  
Ivan Georgiev ◽  
Alexander Karamanov
Keyword(s):  
Glass Ceramics ◽  
Glass Frit ◽  
Heating Rates ◽  
Good Thermal Stability ◽  
Initial Batch ◽  
Sintered Glass ◽  
Glazed Surface ◽  
Heat Treated ◽  
Different Temperatures ◽  
Materials Used

The materials used for the synthesis of parent glass are 70% wt. metallurgical slag and 30% wt. industrial quartz sand. The initial batch is melted at and then quenched in water. The resulting glass frit is milled bellow 75 microns and pressed 1400 °C into “green” samples. In a next stage, they are heat treated at different temperatures with various heating rates and holding times. As a result, it is demonstrated the possibility for production variations, allowing the manufacture of three types of new materials by using the same pressed glass powders. We highlight the flexibility of the synthesis obtaining namely well densified glass-ceramics at about 950 °C, self-glazed glass-ceramics at about 1000 °C or glass-ceramic foams at approximately 1100 °C. The first set of materials is characterized by very well sintered structure combined with reasonable crystallinity; the second one—by smooth self-glazed surface with an attractive appearance and good properties and the third one—by 80–90% closed porosity and very good thermal stability above 1000 °C.

Study on Low Temperature Sintering Behaviour of CaO-B2O3-SiO2 Glass Ceramics

2010 ◽  
Vol 150-151 ◽  
pp. 350-353
Author(s):  
Peng Fei Wei ◽  
Hong Qing Zhou ◽  
Hai Kui Zhu ◽  
Bin Dai ◽  
Jie Wang
Keyword(s):  
Low Temperature ◽  
Glass Ceramics ◽  
Sintered Sample ◽  
Sintered Glass ◽  
Powder Characteristics ◽  
Sintering Properties ◽  
Median Particle ◽  
Materials Used ◽  
Sintering Behaviour ◽  
The Relationship

CaO-B2O3-SiO2 glass ceramics were prepared by powders of different particle sizes. The relationship between CBS powder characteristics and structures was studied by XRD and SEM, and the effect of powder characteristics on sintering properties, dielectric properties at 10GHz, thermal properties (CTE) were investigated to obtain low-temperature sintered glass ceramics. The results showed that the median particle size of glass powders reduced, sintered temperature and apparent porosity decreased. But at the same time, bulk density and thermal expansivity increased. The sample with the powders of D50=2.34μm could be sintered at 850 with the density about 2.615g•cm-3 and the water absorption about 0.16%. Having a dielectric constant of 6.16 and a dielectric loss of 1.9×10-3 at 9.98GHz, the sintered sample could satisfy the requirements of the substrate materials used in LTCC in some fields.

Improvement of the Mechanical Properties of Glasses Based on the 3CaO.P2O5-SiO2-MgO System after Heat-Treatment

2010 ◽  
Vol 636-637 ◽  
pp. 41-46 ◽  
Author(s):  
J.K.M.F. Daguano ◽  
Claudinei dos Santos ◽  
Paulo Atsushi Suzuki ◽  
Luiz A. Bicalho ◽  
Maria Helena F.V. Fernandes
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Phase Content ◽  
Heat Treated ◽  
Different Temperatures ◽  
Hardness Values ◽  
Crystallization Degree ◽  
Temperature Crystallization

Glasses based on the 3CaO.P2O5-SiO2-MgO system present high bioactivity aiming the use as bone restorations. On the other hand, the low mechanical properties reduce the importance of this glass aiming the use as restoration bulk specimens. In this work, glass-ceramics were obtained by devitrification of this glass using different temperatures. CaCO3, SiO2, MgO and Ca(H2PO4).H2O were used as starting-powders. Powder mixture was milled/homogenized and melted at 1600°C, for 2h and annealed at 700°C for 4h with cooling rate of 3°C/min. Glass specimens of 151550mm3 were characterized by DTA and XRD analysis. Specimens were heat-treated in different temperatures between 7000C and 1050°C, for 4 hours, obtaining glass-ceramics with different crystallized phase content. Hardness and fracture toughness were determined and correlated with crystalline phase content. The results indicated that crystallization-degree increase with the temperature, and the mechanical properties are improved: Hardness values present increases lower than 20% as function of the crystallization. Fracture toughness may increase 100% as function of temperature (crystallization degree).

Second-Generation Aluminium Extraction Residue Used as Devitrification Aid for Glass-Ceramics

2008 ◽  
Vol 587-588 ◽  
pp. 773-777
Author(s):  
M.C. Ferreira ◽  
Wilson Acchar ◽  
Ana M. Segadães ◽  
Sonia Regina Homem de Mello-Castanho
Keyword(s):  
Second Generation ◽  
Glass Ceramics ◽  
Glass Frit ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Before And After ◽  
Devitrification Process ◽  
Extraction Metallurgy

Brazil has one of the world’s most important Bauxite deposits, the raw material for the aluminium extraction metallurgy. This work is focused on finding a suitable application for the white dross residue (WDR), a second-generation waste material produced during the metal recovery from the slag left after the primary extraction of aluminium from the ore. A commercial lime-silica based glass frit was used, to which WDR additions were made (up to 30 wt.%), aimed at studying the devitrification process of the glasses produced. Such mixtures were melted at temperatures varying from 1100 to 1500°C and the resulting fritted glasses were heat treated at 900°C. The starting materials and the mixtures thereof were characterized before and after thermal treatment by differential thermal analysis, X-ray diffraction and fluorescence, and scanning electron microscopy. The results obtained showed that the WDR is easily incorporated into the glass matrix and causes easy devitrification after short heat treatment periods at low temperature.

Study on Thermal Conductivity of SPS-Sintered Si3N4 Ceramics after Heat-Treatment

2005 ◽  
Vol 475-479 ◽  
pp. 1279-1282 ◽  
Author(s):  
Xin Lu ◽  
Xiao Shan Ning ◽  
Wei Xu ◽  
He Ping Zhou ◽  
Ke Xin Chen
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Heating Rate ◽  
Great Influence ◽  
Heating Rates ◽  
Plasma Sintering ◽  
Heat Treated ◽  
Different Temperatures ◽  
Spark Plasma ◽  
Si3n4 Ceramics

α-Si3N4 ceramics were sintered at a low temperature of 1773K by using a spark-plasma-sintering (SPS) method with different heating rates, and then they were further heat-treated at different temperatures from 1773K to 2273K, to study the effect of the heating rate of SPS on the microstructure and the thermal conductivity of Si3N4 ceramics after the heat-treatment. Results show that the heating rate of SPS has great influence on the phase transformation and the microstructure of the β-Si3N4, but it has little influence on the thermal conductivity of the ceramics. This proves that the thermal conductivity of the ceramics does not have an obvious relationship with the ratio and the size of the columnar β-Si3N4 grain.

scholarly journals Synthesis and characterization of sol-gel derived monophasic mullite powder

Cerâmica ◽  
2020 ◽  
Vol 66 (379) ◽  
pp. 307-313
Author(s):  
A. Jana ◽  
D. Ray
Keyword(s):  
Sol Gel ◽  
Grain Morphology ◽  
Precursor Powder ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
X Ray ◽  
Heat Treated ◽  
Different Temperatures

Abstract High-purity microfine mullite precursor powder of stoichiometric chemical composition, 3Al2O3.2SiO2, was synthesized through the sol-gel route using aluminum isopropoxide and tetraethyl orthosilicate. The derived mullite precursor powder was characterized by BET surface area, particle size distribution, Fourier-transform infrared spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy. Phase analysis of the precursor powder and calcined samples at different temperatures was done by XRD. Non-isothermal crystallization kinetics of mullite precursor was studied by TG-DTA in static air using heating rates of 5.0, 7.5, 10.0, 12.5, and 15 K.min-1. Grain morphology was studied by SEM. The results showed that synthesized mullite precursor powder possessed homogeneity of Al and Si components, and the amorphous precursor powder was converted to monophasic mullite crystal when heat-treated at 970 °C. Based on Flynn-Wall-Ozawa and Kissinger equations, the activation energy associated with the crystallization of mullite was determined to be 1189.8 and 1189.0 kJ.mol-1, respectively.

Preparation and Characterization of Superionic Conductive Li2O-Al2O3-La2O3-TiO2-P2O5 Glass-Ceramics

2012 ◽  
Vol 509 ◽  
pp. 314-320 ◽  
Author(s):  
Hong Ping Chen ◽  
Hai Zheng Tao ◽  
Qi De Wu ◽  
Xiu Jian Zhao
Keyword(s):  
Heat Treatment ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Lithium Ion ◽  
Treatment Temperature ◽  
Total Conductivity ◽  
Scanning Calorimetry ◽  
Structural Morphology ◽  
Heat Treated ◽  
Different Temperatures

Li2O-Al2O3(La2O3)-TiO2-P2O5 glass-ceramics were fabricated through heat-treatment of the original glass. The differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical workstation were employed to study the structural, morphology and electrical properties of the samples heat-treated at different temperatures. The results showed that: the glass-ceramics consist of the dominating LiTi2(PO4)3 phases, trifle AlPO4, TiO2 and unknown phases. With the heat-treatment temperature increasing from 700 °C to 1100 °C, the structure of glass-ceramic become denser and grain grew, lithium ion conductivity increased quickly and subsequent cut down gradually. While the specimen was obtained by crystallization at 900 °C for 12 h, the total conductivity of glass-ceramic material come up to the maximum (5.85 ×10-4 S•cm-1) at 25 °C. This inorganic solid electrolyte has a potential application in lithium batteries or other devices.

Optimal Conditions for Preparing Sintered Glass-Ceramics with Glass Frit from a Waste Water Flocculate

2014 ◽  
Vol 563 ◽  
pp. 36-40
Author(s):  
Na Li ◽  
Hong Hai Shen ◽  
Shi Quan Liu
Keyword(s):  
Waste Water ◽  
Glass Ceramics ◽  
High Hardness ◽  
Glass Frit ◽  
Sem Analysis ◽  
Preparation Conditions ◽  
Sintered Glass ◽  
Treatment Conditions ◽  
Short Period ◽  
Size And Morphology

Sintered glass-ceramics have been successfully prepared using glass particles derived from a waste water flocculate. Influence of heat treatment conditions (sintering temperature and soaking time, heating rate) and size of the glass particles on the microstructure and density, hardness of the obtained glass-ceramics has been studied. The results show that the prepared glass-ceramics have gehlenite and anorthite as main crystalline phases. SEM analysis indicates that the size and morphology of the crystallites vary with the preparation conditions. A dense glass-ceramic with a high hardness can be obtained by sintering glass powder sized smaller than 0.075mm with a relatively slow ramping rate (3°C/min) to a temperature higher than the crystallization peak temperature of the parent glass for a short period of 30min to 1h.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

scholarly journals Prediction of Thiol Group Changes in Minced Raw and Cooked Chicken Meat with Plant Extracts—Kinetic and Neural Network Approaches

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1647
Author(s):  
Anna Kaczmarek ◽  
Małgorzata Muzolf-Panek
Keyword(s):  
Plant Extracts ◽  
Predictive Models ◽  
External Validation ◽  
Thiol Group ◽  
Chicken Meat ◽  
Validation Dataset ◽  
Heat Treated ◽  
Different Temperatures ◽  
Meat Samples ◽  
Network Approaches

The aim of the study was to develop predictive models of thiol group (SH) level changes in minced raw and heat-treated chicken meat enriched with selected plant extracts (allspice, basil, bay leaf, black seed, cardamom, caraway, cloves, garlic, nutmeg, onion, oregano, rosemary, and thyme) during storage at different temperatures. Meat samples with extract addition were stored under various temperatures (4, 8, 12, 16, and 20 °C). SH changes were measured spectrophotometrically using Ellman’s reagent. Samples stored at 12 °C were used as the external validation dataset. SH content decreased with storage time and temperature. The dependence of SH changes on temperature was adequately modeled by the Arrhenius equation with average high R2 coefficients for raw meat (R2 = 0.951) and heat-treated meat (R2 = 0.968). Kinetic models and artificial neural networks (ANNs) were used to build the predictive models of thiol group decay during meat storage. The obtained results demonstrate that both kinetic Arrhenius (R2 = 0.853 and 0.872 for raw and cooked meat, respectively) and ANN (R2 = 0.803) models can predict thiol group changes in raw and cooked ground chicken meat during storage.

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