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Synthesis of calcium ferrite using microwave susceptor heating
No full textThere is a growing interest in calcium ferrite due to its diverse applications, including catalysis, magnetic storage, and environmental remediation. Conventional synthesis methods often involve prolonged heating processes. Microwave heating offers an intriguing alternative, leveraging its ability to induce rapid material synthesis. However, the response of lime and hematite to microwave heating is highly contrastive. This research delves into the synthesis of calcium ferrite under microwave heating, aiming for rapid and efficient formation. Experiments were conducted with or without a susceptor using an equimolar ratio of pure lime and hematite in the form of a pellet. Susceptor heating is necessary for the substances that do not easily absorb microwaves. The experimental results indicated that the calcium ferrite does not form even if the pellet is heated for 50 min without a susceptor. However, with the use of a susceptor, the calcium ferrite forms in 8 min of heating. The X-ray microtomography analysis reveals that the porosity ratios of 6- and 8 min-treated pellets are 2.34% and 2.65%, respectively. Also, most of the pores for all cases lie within 0-250 mu m. FE-SEM micrographs also support the formation of a highly porous structure of calcium ferrite for 8 min treated pellet.
Il existe un int & eacute;r & ecirc;t grandissant dans la ferrite de calcium en raison de ses applications diverses, notamment la catalyse, le stockage magn & eacute;tique et l'assainissement de l'environnement. Les m & eacute;thodes de synth & egrave;se conventionnelles impliquent souvent des proc & eacute;d & eacute;s de chauffage prolong & eacute;s. Le chauffage par micro-ondes offre un choix int & eacute;ressant, tirant parti de sa capacit & eacute; & agrave; induire une synth & egrave;se rapide des mat & eacute;riaux. Cependant, la r & eacute;ponse de la chaux et de l'h & eacute;matite au chauffage par micro-ondes est hautement contrast & eacute;e. Cette recherche se penche sur la synth & egrave;se de ferrite de calcium sous chauffage par micro-ondes, visant une formation rapide et efficace. On a r & eacute;alis & eacute; les exp & eacute;riences avec ou sans suscepteur en utilisant un rapport & eacute;quimolaire de chaux pure et d'h & eacute;matite sous forme de boulette. Le traitement par micro-ondes assist & eacute; d'un suscepteur implique l'utilisation de mat & eacute;riaux connus comme suscepteurs pour am & eacute;liorer le chauffage des substances qui n'absorbent pas facilement les micro-ondes. Les r & eacute;sultats exp & eacute;rimentaux ont indiqu & eacute; que la ferrite de calcium ne se forme pas m & ecirc;me si la boulette est chauff & eacute;e pendant 50 min sans suscepteur. Cependant, en utilisant un suscepteur, la ferrite de calcium se forme en 8 min de chauffage. L'analyse par microtomographie aux rayons X r & eacute;v & egrave;le que le taux de porosit & eacute; des boulettes trait & eacute;es pendant 6 et 8 min est respectivement de 2.34% et 2.65%. & Eacute;galement, la plupart des pores dans tous les cas se situent entre 0 et 250 mu m. Les micrographeis de FE-MEB supportent & eacute;galement la formation d'une structure hautement poreuse de ferrite de calcium pour la boulette trait & eacute;e pendant 8 min
Sustainable environmental technology to reclaim copper from industrial effluent
No full textElectronic manufacturing industries use copper in highest proportion in metals due to its uniqueproperties. But there is a gap in demand and supply of this metal to the industry due to its hugerequirement and lack of its proper recycling of copper containing equipments. Also, effluentgenerated from these industries carries substantial amount of this metal, which get discharged,and loss of metals to the environment. Present paper discusses about valuable copper metalrecovery from industrial effluent in powder form using novel process flow-sheet. At start, bio-adsorptiontechnique was used to recover copper from industrial effluent due to its advantages likelow cost, feasible method showing faster kinetics. Datura root powder was found to be potentialbio-adsorbent for copper recovery from effluent having 997 mg/g adsorption capacity. Itfollows second-order rate reaction and Freundlich adsorption isotherm with 0.9711 regressioncoefficient. Further, copper-enriched solution obtained from this technique was subjected tocementation process using scrap iron rods to get copper powder. This can be used to producevalue added products using its ingots. This is one of the approaches towards waste to wealthcreation having tremendous potential to get commercialized
Preparation and certification of benzoic acid reference material for calorimetry analysis
No full textBenzoic acid reference material is indispensable for bomb calorimeter instrument calibration and validation of gross calorific value (GCV) analysis of any substance. In this work, we demonstrated the preparation of benzoic acid reference material through a homogeneity study, round-robin analysis, and stability study. Two-factor analysis of variance (ANOVA) test for gross calorific value in the randomly selected sub-samples of benzoic acid exhibits a lower FTS value than the Fcrit value, indicating that the samples are sufficiently homogeneous. The calculated uncertainty of between-bottle (ubb) and uncertainty of homogeneity (uhom) for GCV of benzoic acid in the sub-samples were found as 1.82 and 4.42 cal/g respectively. We found that the observed homogeneity (uhom(Finding)) value is lower than the assumed homogeneity (uhom (Assume)) value for the prepared benzoic acid reference material. Overall observations confirm that the sub-samples are sufficiently homogeneous. Moreover, the round-robin analysis/or inter-laboratory comparison analysis was conducted to assign the gross calorific value and determine the characterization uncertainty. The seventh order of Grubbs' analysis was done using robust estimator Alogoritm A to assign the GCV of benzoic acid. Finally, the measurement uncertainty of the assigned GCV of benzoic acid was calculated with the combined uncertainties from various source
Isothermal High-Temperature Oxidation Behaviour of Nickel-Based Superalloy IN740H
No full textThe isothermal oxidation behavior of IN740H alloy was studied by conducting experiments in a thermogravimetric analyzer in the presence of air and synthetic flue gas in the temperature range of 760-900 degrees C. SEM/XRD/EPMA/Raman spectroscopy was used for analyzing surfaces/cross sections of oxidized/corroded specimens. The oxide layer consists of Ti-doped Cr2O3 and NiCr2O4 in air-oxidized specimens, whereas additional NiO and NiS form in the presence of flue gas at 900 degrees C. Alumina forms at the oxide/matrix interface and at 900 degrees C; it was followed by gamma ' denuded zone with dispersed (Ti, Nb)C. The kinetics of oxidation in a steady state are found to be sub-parabolic for all the conditions
Mechanochemically Assisted Microwave-Induced Plasma Synthesis of a N-Doped Graphitic Porous Carbon-Based Aqueous Symmetric Supercapacitor with Ultrahigh Volumetric Capacitance and Energy Density
No full textIn the realm of affordable and yet efficient energy storage devices required for future portable electronic gadgets and electric vehicles, supercapacitors (SCs) have immense potential; however, the prime bottleneck is the low volumetric capacitance and energy density caused by the sluggish reaction kinetics and a limited potential window (<1.2 V) in aqueous electrolytes. Therefore, to address this challenge, we aim to design suitable biomass-derived nitrogen (N)-doped highly porous graphitic carbon (HP-NGC) via a mechanochemically assisted microwave plasma-induced quick synthesis process to deliver high volumetric capacitance and energy density. Detailed characterization of the developed electrode materials revealed that the structural and functional properties are highly influenced by the crucial role of mechanochemical treatment carried out just before carbonization through microwave irradiation under N-2 plasma. HP-NGC produces an almost 32% higher surface area (820 m(2) g(-1)) than the surface area (620 m(2) g(-1)) of N-doped graphitic carbon (NGC) prepared without mechanochemical treatment. Moreover, HP-NGC shows more N doping (ID/IG similar to 1.01)(IDIG similar to 1.01) than NGC (where N doping is 1.1 atom % and ID/IG is similar to 0.98), which significantly affects their electrochemical storage properties. The HP-NGC electrode exhibited similar to 145% higher volumetric capacitance (840 F cm(-3)) and energy density (168 Wh L-1) than the volumetric capacitance (308 F cm(-3)) and energy density (61.5 Wh L-1) of the NGC electrode within a wide potential window of 1.2 V measured at 0.5 A g(-1) in 6 M KOH. Finally, the assembled aqueous symmetric device (HP-NGC//HP-NGC) made of HP-NGC electrodes exhibits a volumetric capacitance of 630 F cm(-3) with excellent rate performance (similar to 81% capacitance retained even after increasing the current density by 10 times), high-energy density of 32 Wh L-1, and power density of 640 W L-1 at 0.5 A g(-1), which is higher than those of many reported porous carbon-based symmetric devices, making it a promising candidate for commercial applications
Empowering Energy Storage Technology: Recent Breakthroughs and Advancement in Sodium-Ion Batteries
No full textEnergy storage devices have become indispensable for smart and clean energy systems. During the past three decades, lithium-ion battery technologies have grown tremendously and have been exploited for the best energy storage system in portable electronics as well as electric vehicles. However, extensive use and limited abundance of lithium have made researchers explore sodium-ion batteries (SIBs) as an alternative to lithium. Throughout the past few years, the rapid progression of sodium-ion batteries has represented a noteworthy advancement in the field of energy storage technologies. This review discusses recent advancements in SIBs, focusing on methodologies to improve the performance of cathode and anode materials, the evolution of electrolytes toward solvent-free electrolytes, and advancements in fast-charging and low-temperature SIBs. This work also highlights some methodologies that have empowered the electrochemical performance of sodium-ion batteries in the past five years. It also concludes some emerging routes to enhance the overall performance of sodium-ion batteries, leading to a comparable performance with Li-ion batteries for future research
Influence of various contact-materials on the fretting fatigue life of P91 steel
No full textFretting-induced damage is an important failure mechanism in steam generator (SG) tubes in which there will be continuous contact and relative motion between tube and tube-support structures. In this work, the influence of various contact materials on the fretting fatigue (FF) behavior of modified 9Cr-1Mo (P91) steel, a widely used SG material has been studied. The test setup has been configured as a flat-on-flat contact between the fatigue specimen made of P91steel and the contact pad. The three different bridge type contact-pads namely, P91-steel, Inconel718 (IN-718), and aluminized IN-718 were employed. The contact pad applies constant pressure on the specimen while it is undergoing a fatigue cycle. All the tests were carried out at a frequency of 10 Hz, with maximum cyclic stresses ranging from 250 to 525 MPa and a stress ratio of R = 0.1 at a constant contact pressure of 100 MPa. The FF life of the alloy with the contact material made of aluminized IN-718 alloy was observed to be lower in comparison with the IN-718 and P91 contact materials. The life reduction in the former case was investigated through a comparative analysis of the formation and distribution of debris on fretted surfaces, surface roughness, and the fracture surface of the steel. The formation of the oxide phase such as Fe2O3 (hematite) and Fe3O4 (magnetite) was found on the fretted surface of the specimens
Microstructural and mechanical properties evaluation of Calcium and zinc-modified WE43-based nanocomposites through stir casting for biodegradable applications
No full textMagnesium-based alloys and composites have potential as biodegradable materials due to their moderate biodegradability, biocompatibility, and usefulness, but their mechanical strength limits their clinical use. The study synthesized a WE43-based alloy with calcium (Ca) and zinc (Zn), then reinforced it with nano reinforcements (hydroxyapatite, beta-tricalcium phosphate, graphene, and bioglass) through stir casting to create four nanocomposites. The microstructural and mechanical properties were examined to assess Ca and Zn ' s influence and determine the most effective reinforcement. The result showed that Ca and Zn-modified alloys and all nanocomposite materials have two additional phases, LPSO and Ca 2 Mg 6 Zn 3 , compared to the monolithic WE43 alloy. With the addition of Ca and Zn, S-2 saw significant increases in ultimate tensile strength (UTS), tensile yield strength (TYS), and uniform elongation (U.El), reaching -246 MPa, -144 MPa, and -8 %, respectively, while maintaining an elastic modulus of -19 GPa. This resulted in improvements of -29 %, -25 %, and -9 % compared to the as -cast WE43. Graphene-reinforced S-4 demonstrated superior mechanical properties with a UTS of 294 MPa, TYS of 194 MPa, U.El of -8 %, and an elastic modulus of 24 GPa, representing increases of -52 %, -69 %, and 6.05 %, respectively, compared to as -cast WE43. Additionally, S-4 exhibited impressive compressive properties, with an ultimate compressive strength (UCS) of 370 MPa, a compressive yield strength (CYS) of -185 MPa, and an U.El of -26 %. The bioglass-reinforced nanocomposites had a maximum hardness of 74.8 HV, whereas the as-cast WE43 had a maximum toughness of -4 J. These enhancements in mechanical properties are attributed to strengthening processes, including thermal mismatch, orowan, and grain refinement mechanisms. Graphene reinforcement shows promise for biodegradable applications
Doping Engineering in Electrode Material for Boosting the Performance of Sodium Ion Batteries
No full textIn recent years, sodium ion batteries (SIBs) emerged as promising alternative candidates for lithium ion batteries (LIBs) due to the high abundance and low cost of sodium resources. However, their commercialization has been hindered by inherent limitations, such as low energy density and poor cycling stability. To address these issues, doping methodology is one of the most promising approaches to boosting the structural and electrochemical properties of SIB electrodes. This review provides a comprehensive overview of recent advancements in doping strategies, focusing on the improvement of the performance of SIBs. Various dopants including s- and p-block elements, transition metals, oxides, carbonaceous materials, and many more dopants are discussed in terms of their effects on enhancing the electrochemical properties of SIBs. Furthermore, the mechanisms responsible for the improvement in the performance of doped SIBs materials are also discussed. It also highlights the importance of doping sites in the crystal lattice, which also play a crucial role in doping in optimizing electrode structure, enhancing ion diffusion kinetics, and stabilizing electrode/electrolyte interfaces. The review ends by looking at the recent studies in simultaneous multiple heteroatom doping, offering valuable perspectives for a high performance SIB. This study provides valuable insight into the researchers and battery industries striving for advancements in energy storage technologies
Microstructure and Texture Evolution in Thermomechanically Processed FCC Metals and Alloys: a Review
No full textThe stacking fault energy (SFE) of face-centered cubic (FCC) alloys is a critical parameter that controls microstructural and crystallographic texture evolution during deformation and annealing treatments. This review focuses on several FCC alloys, aluminum (Al), copper (Cu), austenitic stainless steels (ASSs), and high entropy alloys (HEAs), all of which exhibit varying SFEs. These alloys are often subjected to thermo-mechanical processing (TMP) to enhance their mechanical properties. TMP leads to the evolution of deformation-induced products, such as shear bands (SBs), strain-induced martensite (SIM), and mechanical/deformation twins (DTs) during plastic deformation, while also influencing crystallographic texture. High-medium SFE materials, such as Al and Cu, typically exhibit the evolution of Copper-type texture during room temperature rolling (RTR), while low SFE materials, such as ASSs and HEAs, display Brass-type texture at high reduction ratios. Moreover, the presence of second-phase particles/precipitates can also impact the microstructure and texture evolution in Al and Cu alloys. Particle-stimulated nucleation (PSN) during the annealing treatment has been reported for Al, Cu, ASSs, and HEAs, which causes texture weakening. Another interesting observation in severely deformed Cu alloys is the room-temperature softening phenomenon, which is discussed in the reviewed work. Additionally, plastic deformation and heat treatment of ASSs result in phase transformation, which was not observed in Al, Cu, or HEAs. Furthermore, the dependence of special boundaries in HEAs on plastic deformation temperature, strain rate, and annealing temperature is also discussed. Thus, this review comprehensively reports on the impact of TMP on microstructural and crystallographic texture evolution during plastic deformation and the annealing treatment of Al, Cu, ASSs, and HEAs FCC materials, using results obtained from electron microscopy