The Experts below are selected from a list of 132 Experts worldwide ranked by ideXlab platform
S. Mukhopadhyay - One of the best experts on this subject based on the ideXlab platform.
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Thermal and thermomechanical characteristics of monolithic Refractory Composite matrix containing surface-modified graphite
Ceramics International, 2016Co-Authors: S. Mukhopadhyay, Kaushik Dana, S. Moitra, S Basumallick, Tapas Kumar MukhopadhyayAbstract:Abstract The thermomechanical analysis (TMA) and thermal characteristics of carbon-containing Refractory castable matrix with 20.0 wt% graphite have been compared with graphite-free high alumina based similar castable matrix. Graphite has been added both in uncoated and coated forms, the latter having a thin sol–gel calcium aluminate coating on as-received graphite flakes. The influence of systematic variation of microfine constituents e.g. reactive alumina, high alumina cement etc in the matrix has been investigated in terms of the heat flow studies obtained by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The densification behavior of graphite-free and graphite-containing castable matrices has been critically estimated by the dimensional changes in dynamic heating regime up to 1500 °C. The role of coated graphite on improved densification behavior of Refractory was explored by microstructure and phase assemblage studies of the respective fired castable. It was further corroborated by the transmission electron microscope (TEM) studies of surface-modified graphites.
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in depth studies on cementitious nanocoatings on graphite for its contribution in corrosion resistance of alumina based Refractory Composite
Ceramics International, 2015Co-Authors: S. Mukhopadhyay, C Mondal, Arijit Chakraborty, D Mali, Soumya GhoshAbstract:Abstract Some newer insights had been reported in this paper on synthesis and application of calcium aluminate coated graphite in alumina–carbon Refractory castables. The course of evolution of AlO 4 (tetrahedral) and AlO 6 (octahedral) units in the nanocoating was investigated by XRD (X-ray diffraction), Raman spectroscopy and FTIR (Fourier transformed infrared spectroscopy) studies. An extended research on the resemblance and disparity between sol–gel and conventional Refractory cements were also explored. FESEM ( Field Emission Scanning Electron Microscopy), XRD of coated and uncoated graphites had been revisited with a special study on ESEM (environmental scanning electron microscopy) of those two. The hydrophilic thin film containing Ca-doped γ-Al 2 O 3 phases rendered a decisive influence on graphite retention in castable matrix. A comparison between pore size distribution and thermogravimetric analysis (TGA) of two fired castable refractories advocated the superiority of the one containing coated graphite. Determination of corrosion and penetration indices by the static slag corrosion test, supplemented with microstructural studies, confirmed that the less porous castable containing coated graphites excelled again in the harsh environment.
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Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic Refractory Composite
Materials Research Bulletin, 2013Co-Authors: S. MukhopadhyayAbstract:Abstract The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in Refractory Composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired Composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of Refractory researchers and producers.
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comparison of solid state and sol gel derived calcium aluminate coated graphite and characterization of prepared Refractory Composite
Ceramics International, 2012Co-Authors: S. Mukhopadhyay, Subir Kumar DuttaAbstract:Abstract This paper entails an extended investigation on sol–gel thin film of calcium aluminate (CaAl 2 O 4 ) over graphite flakes that improved their oxidation resistance and water wettability. The commercial preparation of calcium aluminate has been compared with the sol–gel synthesis by differential thermal analysis (DTA) and X-ray diffraction (XRD) to assess the feasibility of the latter for coating preparation. Poorly crystalline nanostructured Ca-doped γ-Al 2 O 3 is considered to be an important intermediate for this preparation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of the calcined gel have been carried out to ascertain its composition. Quantitative chemical analysis of sol gel derived calcium aluminate was also estimated. Atomic force microscopy (AFM) has been conducted to ensure the evolution of hydrophilic nanosized cementitious phases on graphite. Zeta potential values of coated and uncoated graphites with increasing pH have also been determined to distinguish between their compatibility in a Refractory castable matrix. Improved physical properties of that high alumina castable containing coated graphite, e.g. apparent porosity (AP), bulk density (BD), cold crushing strength (CCS) have been measured to evaluate the Refractory quality. The reasons for its better performance are explored by taking further insight on the microstructural analyses of the fired castable (1500 °C) soaked for an extended period.
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Comparison of solid state and sol–gel derived calcium aluminate coated graphite and characterization of prepared Refractory Composite
Ceramics International, 2012Co-Authors: S. Mukhopadhyay, Subir Kumar DuttaAbstract:Abstract This paper entails an extended investigation on sol–gel thin film of calcium aluminate (CaAl 2 O 4 ) over graphite flakes that improved their oxidation resistance and water wettability. The commercial preparation of calcium aluminate has been compared with the sol–gel synthesis by differential thermal analysis (DTA) and X-ray diffraction (XRD) to assess the feasibility of the latter for coating preparation. Poorly crystalline nanostructured Ca-doped γ-Al 2 O 3 is considered to be an important intermediate for this preparation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of the calcined gel have been carried out to ascertain its composition. Quantitative chemical analysis of sol gel derived calcium aluminate was also estimated. Atomic force microscopy (AFM) has been conducted to ensure the evolution of hydrophilic nanosized cementitious phases on graphite. Zeta potential values of coated and uncoated graphites with increasing pH have also been determined to distinguish between their compatibility in a Refractory castable matrix. Improved physical properties of that high alumina castable containing coated graphite, e.g. apparent porosity (AP), bulk density (BD), cold crushing strength (CCS) have been measured to evaluate the Refractory quality. The reasons for its better performance are explored by taking further insight on the microstructural analyses of the fired castable (1500 °C) soaked for an extended period.
Y. Dutheillet - One of the best experts on this subject based on the ideXlab platform.
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Thermomechanical behaviour analysis and simulation of steel/Refractory Composite linings
Composites Science and Technology, 2001Co-Authors: Alain Gasser, Philippe Boisse, J. Rousseau, Y. DutheilletAbstract:In steel ladles (steel industry) or in coal-fired power plants (energy production), the Refractory linings anchored to the steel structure (casing) are subjected to significant thermal loadings which lead to cracking (owing to the difference between the thermal expansion coefficients). A first approach allows us to analyse the problem at a local scale: a smeared crack model permits the computation of the damage which is observed in an experimental test. But since a structure contains thousand of anchors, it is not possible to compute it with this model. An approach was therefore developed with a two-layered shell equivalent to the anchored lining and the casing. This model is identified with an inverse method and uses results from the first approach, validated by a bending test performed on a Refractory lining specimen. The damage computing of a structure shows that it is very important to take the expansion joints into account.
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Thermomechanical behaviour analysis and simulation of steel/Refractory Composite linings
Composites Science and Technology, 2001Co-Authors: Andres Gasser, J. Rousseau, Philippe Boisse, Y. DutheilletAbstract:In steel ladles (steel industry) or in coal-fired power plants (energy production), the Refractory linings anchored to the steel structure (casing) are subjected to significant thermal loadings which lead to cracking (owing to the difference between the thermal expansion coefficients). A first approach allows us to analyse the problem at a local scale: a smeared crack model permits the computation of the damage which is observed in an experimental test. But since a structure contains thousand of anchors, it is not possible to compute it with this model. An approach was therefore developed with a two-layered shell equivalent to the anchored lining and the casing. This model is identified with an inverse method and uses results from the first approach, validated by a bending test performed on a Refractory lining specimen. The damage computing of a structure shows that it is very important to take the expansion joints into account. © 2001 Elsevier Science Ltd. All rights reserved.
Subir Kumar Dutta - One of the best experts on this subject based on the ideXlab platform.
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comparison of solid state and sol gel derived calcium aluminate coated graphite and characterization of prepared Refractory Composite
Ceramics International, 2012Co-Authors: S. Mukhopadhyay, Subir Kumar DuttaAbstract:Abstract This paper entails an extended investigation on sol–gel thin film of calcium aluminate (CaAl 2 O 4 ) over graphite flakes that improved their oxidation resistance and water wettability. The commercial preparation of calcium aluminate has been compared with the sol–gel synthesis by differential thermal analysis (DTA) and X-ray diffraction (XRD) to assess the feasibility of the latter for coating preparation. Poorly crystalline nanostructured Ca-doped γ-Al 2 O 3 is considered to be an important intermediate for this preparation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of the calcined gel have been carried out to ascertain its composition. Quantitative chemical analysis of sol gel derived calcium aluminate was also estimated. Atomic force microscopy (AFM) has been conducted to ensure the evolution of hydrophilic nanosized cementitious phases on graphite. Zeta potential values of coated and uncoated graphites with increasing pH have also been determined to distinguish between their compatibility in a Refractory castable matrix. Improved physical properties of that high alumina castable containing coated graphite, e.g. apparent porosity (AP), bulk density (BD), cold crushing strength (CCS) have been measured to evaluate the Refractory quality. The reasons for its better performance are explored by taking further insight on the microstructural analyses of the fired castable (1500 °C) soaked for an extended period.
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Comparison of solid state and sol–gel derived calcium aluminate coated graphite and characterization of prepared Refractory Composite
Ceramics International, 2012Co-Authors: S. Mukhopadhyay, Subir Kumar DuttaAbstract:Abstract This paper entails an extended investigation on sol–gel thin film of calcium aluminate (CaAl 2 O 4 ) over graphite flakes that improved their oxidation resistance and water wettability. The commercial preparation of calcium aluminate has been compared with the sol–gel synthesis by differential thermal analysis (DTA) and X-ray diffraction (XRD) to assess the feasibility of the latter for coating preparation. Poorly crystalline nanostructured Ca-doped γ-Al 2 O 3 is considered to be an important intermediate for this preparation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of the calcined gel have been carried out to ascertain its composition. Quantitative chemical analysis of sol gel derived calcium aluminate was also estimated. Atomic force microscopy (AFM) has been conducted to ensure the evolution of hydrophilic nanosized cementitious phases on graphite. Zeta potential values of coated and uncoated graphites with increasing pH have also been determined to distinguish between their compatibility in a Refractory castable matrix. Improved physical properties of that high alumina castable containing coated graphite, e.g. apparent porosity (AP), bulk density (BD), cold crushing strength (CCS) have been measured to evaluate the Refractory quality. The reasons for its better performance are explored by taking further insight on the microstructural analyses of the fired castable (1500 °C) soaked for an extended period.
J A Aguilarmartinez - One of the best experts on this subject based on the ideXlab platform.
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effect of hercynite spinel content on the properties of magnesia calcium zirconate dense Refractory Composite
Journal of The European Ceramic Society, 2015Co-Authors: Eden Rodriguez, A K Limones, J E Contreras, J J Ruizvaldes, R Puenteornelas, A Arato, J A AguilarmartinezAbstract:Abstract Hercynite spinel was added to magnesia–calcium zirconate Refractory compositions in the range of 0–8 wt%. Refractory specimens were obtained by solid state sintering at 1500 °C in an electric furnace. The effect of different contents of spinel (FeAl 2 O 4 ) as a microstructural elastifier in the Refractory matrix was studied. Refractory specimens were characterized by density, porosity, cold crushing strength, crystalline phase formation (XRD), microstructural analysis (SEM), and microhardness. Spinel (0.5 wt%) containing a magnesia–calcium zirconate composition was found to have superior properties. The mechanical behaviour of the MgO–CaZrO 3 was enhanced by c.a. 95% by the hercynite addition.
Eden Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Effect of nano-titania (η-TiO2) content on the mechano-physical properties of a magnesia Refractory Composite
Ceramics International, 2016Co-Authors: Eden Rodriguez, J.j. Ruiz-valdés, R. Puente-ornelas, J.a. Aguilar-martínez, F.h. Moreno, A.e. Montes-mejía, J E ContrerasAbstract:Abstract The mechano-physical properties of a sintered magnesia matrix containing 0–8 wt% nano-titania (η-TiO2) have been investigated. The crystalline phases and microstructure characteristics of the Refractory specimens sintered by solid state at 1500 °C for 4 h in an electric furnace were studied by X-ray diffraction (XRD), and scanning electron microscopy (SEM) with microanalysis (EDS), respectively. The physical properties are reported in terms of density and porosity. The mechanical behavior was evaluated by a cold crushing strength (CCS) test. As a result, it was found that the presence of η-TiO2 in the magnesia matrix induced titanates formation (Mg2TiO4 and CaTiO3), which improved the sintering process. Nano-titania also produced a fine-grained microstructure with intergranular second phase particles, which remain at the boundary and exert a pinning effect. In general, the addition of 5 wt% of η-TiO2 contributed to reach a maximum increment in physical and mechanical properties.
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effect of hercynite spinel content on the properties of magnesia calcium zirconate dense Refractory Composite
Journal of The European Ceramic Society, 2015Co-Authors: Eden Rodriguez, A K Limones, J E Contreras, J J Ruizvaldes, R Puenteornelas, A Arato, J A AguilarmartinezAbstract:Abstract Hercynite spinel was added to magnesia–calcium zirconate Refractory compositions in the range of 0–8 wt%. Refractory specimens were obtained by solid state sintering at 1500 °C in an electric furnace. The effect of different contents of spinel (FeAl 2 O 4 ) as a microstructural elastifier in the Refractory matrix was studied. Refractory specimens were characterized by density, porosity, cold crushing strength, crystalline phase formation (XRD), microstructural analysis (SEM), and microhardness. Spinel (0.5 wt%) containing a magnesia–calcium zirconate composition was found to have superior properties. The mechanical behaviour of the MgO–CaZrO 3 was enhanced by c.a. 95% by the hercynite addition.
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Effect of hercynite spinel content on the properties of magnesia–calcium zirconate dense Refractory Composite
Journal of The European Ceramic Society, 2015Co-Authors: Eden Rodriguez, A K Limones, J E Contreras, A Arato, J.j. Ruiz-valdés, R. Puente-ornelas, J.a. Aguilar-martínezAbstract:Abstract Hercynite spinel was added to magnesia–calcium zirconate Refractory compositions in the range of 0–8 wt%. Refractory specimens were obtained by solid state sintering at 1500 °C in an electric furnace. The effect of different contents of spinel (FeAl 2 O 4 ) as a microstructural elastifier in the Refractory matrix was studied. Refractory specimens were characterized by density, porosity, cold crushing strength, crystalline phase formation (XRD), microstructural analysis (SEM), and microhardness. Spinel (0.5 wt%) containing a magnesia–calcium zirconate composition was found to have superior properties. The mechanical behaviour of the MgO–CaZrO 3 was enhanced by c.a. 95% by the hercynite addition.