Journal articles: 'Iron oxides Thermal properties'

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Ma, Chuan Guo, Hai Jun Zheng, Xiao Ming Li, and Liang Gao. "Preparation and Microwave Absorbing Properties of Iron Oxides/Carbon Nanotubes Compounds." Advanced Materials Research 548 (July 2012): 133–37. http://dx.doi.org/10.4028/www.scientific.net/amr.548.133.

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A Series of iron oxides/CNTs compounds were prepared using a method of impregnation with iron nitrate solution and followed thermal decomposition. The compounds were characterized by the means of scanning electronic microscope, X-ray diffraction and thermogravimetic analysis. The dielectric and microwave-absorbing properties of EP composites containing the different compounds were further measured in a specific frequency range. The results show that: CNTs show reduction at a high temperature, and can make products of the thermal decomposition of iron nitrate produce iron oxide nanoparticles with different valence states at different temperatures. With increasing decomposition temperature, the iron oxides in CNTs composites in turn are Fe2O3, Fe3O4, FeO and Fe. Compared with pure CNTs, these iron oxides/CNTs composites have better microwave absorbing properties in the wavebands of 7.5GHz ~ 15GHz and 26.5GHz ~ 40GHz. Among those iron oxides /CNTs compounds, Fe3O4/CNTs compound has the best microwave absorbing property.

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Abdel Halim, K. S., M. Ramadan, A. Shawabkeh, and A. S. Alghamdi. "Thermal Techniques for the Production of Fe-M Alloys." Applied Mechanics and Materials 826 (February 2016): 105–10. http://dx.doi.org/10.4028/www.scientific.net/amm.826.105.

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The present manuscript is designed to investigate the possibility of manufacturing iron-metal alloys (Fe-M) via thermal techniques. These techniques are mainly depends on simultaneous reduction-sintering reactions of metal oxides. The reduction of metal oxides is an important property in metallurgical processes. It can be applied to M-Fe-O systems and also is used to develop inter-metallic alloys with specific properties. The produced metallic materials have wide range of applications and are characterized by unique physical and mechanical properties. The composition of the produced alloys is often a key element in optimizing their properties. Iron oxide doped another metal oxide such as nickel oxide is used as starting materials to produce metallic materials containing iron contaminated with nickel metal using thermal techniques. The sintering-reduction reactions of the composite oxide materials are investigated under different operation conditions. The experimental results show that the reduction-sintering thermal techniques are economic and promising routes for the production of different Fe-M alloys. The different factors affecting the rate of reduction such as temperature and ratio of doping materials are investigated. The results obtained are used to demonstrate the kinetics and mechanisms of reduction of metal oxides.

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Ristanovic, Z., A. Kalezic-Glisovic, N. Mitrovic, S. Djukic, D. Kosanovic, and A. Maricic. "The influence of mechanochemical activation and thermal treatment on magnetic properties of the BaTiO3-FexOy powder mixture." Science of Sintering 47, no. 1 (2015): 3–14. http://dx.doi.org/10.2298/sos141121001r.

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Powder mixture of 50 mass % of barium titanate (BaTiO3) and 50 mass % of iron (Fe) was prepared by solid-state reaction technique, i.e. ball milled in air for 60 min, 80 min, 100 min, 120 min and 150 min. During mechanochemical activation it was observed the iron powder transitsion to iron oxides. Depending on the activation time the content of iron oxides FeO, Fe2O3 and Fe3O4 varies. Simultaneously, with the content change of the activated system, magnetic properties change as well. The XRD analysis of milled samples shown that as the activation time increase, the iron oxide percentage increases to, whereby the percentage of BaTiO3 in a total sample mass decreases. The percentage of iron oxides and BaTiO3 in annealed samples changes depending on annealing temperature. The thermomagnetic measurements performed by Faraday method shown that the powder mixture milled for 100 minutes exhibit maximum magnetization prior to annealing. The increase of magnetization maximum was observed after annealing at 540?C with all milled samples, and at room temperature it has enhancement from 10 % to 22 % depending on the activation time. The samples milled for 100 min and 150 min and then sintered at 1200w?C exhibit magnetoelectric properties.

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Cursaru, Laura Madalina, Roxana Mioara Piticescu, Dumitru Valentin Dragut, Ioan Albert Tudor, Victor Kuncser, Nicusor Iacob, and Florentin Stoiciu. "The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials." Nanomaterials 10, no. 1 (January 2, 2020): 85. http://dx.doi.org/10.3390/nano10010085.

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Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

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Mînzatu, Vasile, Corneliu-Mircea Davidescu, Petru Negrea, Mihaela Ciopec, Cornelia Muntean, Iosif Hulka, Cristina Paul, Adina Negrea, and Narcis Duțeanu. "Synthesis, Characterization and Adsorptive Performances of a Composite Material Based on Carbon and Iron Oxide Particles." International Journal of Molecular Sciences 20, no. 7 (March 31, 2019): 1609. http://dx.doi.org/10.3390/ijms20071609.

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The aim of this paper was to produce a new composite material based on carbon and iron oxides, starting from soluble starch and ferric chloride. The composite material was synthesized by simple thermal decomposition of a reaction mass obtained from starch and iron chloride, in an inert atmosphere. Starch used as a carbon source also efficiently stabilizes the iron oxides particles obtained during the thermal decomposition. The reaction mass used for the thermal decomposition was obtained by simultaneously mixing the carbon and iron oxide precursors, without addition of any precipitation agent. The proper composite material can be obtained by rigorously adhering to the stirring time, temperature, and water quantity used during the preparation of the reaction mass, as well as the thermal regime and the controlled atmosphere used during the thermal decomposition. Synthesized materials were characterized using thermogravimetric analysis, X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FT-IR). The performances of the obtained material were highlighted by studying their adsorbent properties and by determining the maximum adsorption capacity for arsenic removal from aqueous solutions.

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Khalid Saeed, Khalid Saeed, Noshi Khan Noshi Khan, and Tariq Shah and Muhammad Sadiq Tariq Shah and Muhammad Sadiq. "Morphology, Properties and Application of Iron Oxide/Polycaprolactone Nanocomposites." Journal of the chemical society of pakistan 43, no. 1 (2021): 34. http://dx.doi.org/10.52568/000553.

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Polycaprolactone (PCL) and Fe2O3/PCL nanocomposites sheets/films were prepared by solution casting method. The morphological study illustrated that Fe2O3 nanoparticles were dispersed and embedded well within the PCL matrix. The size of Fe2O3 nanoparticles were below 250 nm. The thermal stability of Fe2O3/PCL nanocomposites was lower than neat PCL, which might be due to Fe2O3 (act as catalyst during the thermal degradation of PCL). The differential scanning calorimetry (DSC) analyses show that the crystallization temperature of the nanocomposites was slightly enhanced as compared to neat PCL. The polarized optical microscopy (POM) analyses showed that the size of Fe2O3/PCL nanocomposites spherulites were smaller than neat PCL. The photodegradation study presented that the nanocomposites photodegraded higher quantity of rhodamine B dye as compared to neat PCL. The neat PCL degraded about 24 and 72% while Fe2O3 (6 wt%)/PCL nanocomposites degraded about 72 and 98% of dye within 2 and 10 h, respectively.

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Khalid Saeed, Khalid Saeed, Noshi Khan Noshi Khan, and Tariq Shah and Muhammad Sadiq Tariq Shah and Muhammad Sadiq. "Morphology, Properties and Application of Iron Oxide/Polycaprolactone Nanocomposites." Journal of the chemical society of pakistan 43, no. 1 (2021): 34. http://dx.doi.org/10.52568/000553/jcsp/43.01.2021.

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Polycaprolactone (PCL) and Fe2O3/PCL nanocomposites sheets/films were prepared by solution casting method. The morphological study illustrated that Fe2O3 nanoparticles were dispersed and embedded well within the PCL matrix. The size of Fe2O3 nanoparticles were below 250 nm. The thermal stability of Fe2O3/PCL nanocomposites was lower than neat PCL, which might be due to Fe2O3 (act as catalyst during the thermal degradation of PCL). The differential scanning calorimetry (DSC) analyses show that the crystallization temperature of the nanocomposites was slightly enhanced as compared to neat PCL. The polarized optical microscopy (POM) analyses showed that the size of Fe2O3/PCL nanocomposites spherulites were smaller than neat PCL. The photodegradation study presented that the nanocomposites photodegraded higher quantity of rhodamine B dye as compared to neat PCL. The neat PCL degraded about 24 and 72% while Fe2O3 (6 wt%)/PCL nanocomposites degraded about 72 and 98% of dye within 2 and 10 h, respectively.

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Khalid Saeed, Khalid Saeed, Noshi Khan Noshi Khan, and Tariq Shah and Muhammad Sadiq Tariq Shah and Muhammad Sadiq. "Morphology, Properties and Application of Iron Oxide/Polycaprolactone Nanocomposites." Journal of the chemical society of pakistan 43, no. 1 (2021): 34. http://dx.doi.org/10.52568/000012.

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Polycaprolactone (PCL) and Fe2O3/PCL nanocomposites sheets/films were prepared by solution casting method. The morphological study illustrated that Fe2O3 nanoparticles were dispersed and embedded well within the PCL matrix. The size of Fe2O3 nanoparticles were below 250 nm. The thermal stability of Fe2O3/PCL nanocomposites was lower than neat PCL, which might be due to Fe2O3 (act as catalyst during the thermal degradation of PCL). The differential scanning calorimetry (DSC) analyses show that the crystallization temperature of the nanocomposites was slightly enhanced as compared to neat PCL. The polarized optical microscopy (POM) analyses showed that the size of Fe2O3/PCL nanocomposites spherulites were smaller than neat PCL. The photodegradation study presented that the nanocomposites photodegraded higher quantity of rhodamine B dye as compared to neat PCL. The neat PCL degraded about 24 and 72% while Fe2O3 (6 wt%)/PCL nanocomposites degraded about 72 and 98% of dye within 2 and 10 h, respectively.

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Smejda-Krzewicka, Aleksandra, Anna Olejnik, and Krzysztof Strzelec. "The effect of metal oxide on the cure, morphology, thermal and mechanical characteristics of chloroprene and butadiene rubber blends." Polymer Bulletin 77, no. 8 (September 20, 2019): 4131–46. http://dx.doi.org/10.1007/s00289-019-02964-z.

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Abstract This paper discusses the role of metal oxides (MeO) in the cross-linking process and useful properties of chloroprene and butadiene rubber (CR/BR) blends. Iron(III) oxide (Fe2O3), iron(II,III) oxide (Fe3O4), silver(I) oxide (Ag2O) or zinc oxide were used. It has found that every proposed metal oxide can be used as a cross-linking agent of the CR/BR blends. The degree of cross-linking was evaluated by means of vulcametric parameters, equilibrium swelling in selected solvents and Mooney–Rivlin elasticity constants. The properties of the cured CR/BR products, such as tensile strength, stress at elongation, tension set under constant elongation and compression set, were also investigated. The results revealed that all CR/BR/MeO vulcanizates were characterized by a high cross-linking degree and satisfying mechanical properties. The most important advantage of obtained rubber goods is very high resistance to flame. The increase in the oxygen index value for the CR/BR/Fe2O3, CR/BR/Fe3O4 and CR/BR/Ag2O vulcanizates compared to the standard cross-linked chloroprene rubber showed that presented metal oxides provided a positive effect on the resistance to flame of the new CR/BR/MeO composites. Satisfactory properties of the studied blends are related to the presence of the interelastomer bonding of both rubbers in the compositions.

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Pashkevich, Aliaksei V., Ludmila A. Bliznyuk, Alexander K. Fedotov, Vladimir V. Khovaylo, Andrei A. Kharchanka, and Vera V. Fedotova. "Thermal and thermoelectric properties of ceramics based on zinc oxide alloyed with iron." Journal of the Belarusian State University. Physics, no. 3 (October 10, 2022): 56–67. http://dx.doi.org/10.33581/2520-2243-2022-3-56-67.

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In this work, we study the effect of adding iron oxides FeO and Fe2O3 in a ratio of 1 : 9 on the thermal and thermoelectric characteristics of ceramics based on zinc oxide ZnO. The samples themselves were made in two stages based on the ceramic technology of sintering powder mixtures in an open atmosphere. Thermal conductivity studies point to the dominant contribution of lattice thermal conductivity at room temperature. The decrease in thermal conductivity as a result of alloying is due to an increase in phonon scattering at point defects introduced into the ZnO lattice (due to the replacement of zinc ions by iron ions) and at grain boundaries (due to microstructure refinement), as well as an increase in porosity (a decrease in density) and the formation of particles of an additional ZnFe2O4 ferrite phase. Alloying wit iron and the accompanying change in the structure of ceramics (decrease in grain size, increase in porosity, precipitation of the ferrite phase) leads to an increase in the thermoelectric figure of merit ZT by 2 times (due to a decrease in electricalresistivity and thermal conductivity with a relatively small decrease in the thermoelectric coefficient). The results obtained can be used to fabricate ZnO-based ceramics with optimal thermoelectric characteristics.

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Song, Myoung Geun, Jun Young Han, and Chung Wung Bark. "The Effect of Annealing Temperature on the Bandgap of Bi3.25La0.75FeTi2O12 Powders." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 8195–98. http://dx.doi.org/10.1166/jnn.2015.11275.

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In recent years, there has been increasing interest in the bandgap engineering of ferroelectric oxides to improve absorbance of the solar spectrum, which is governed by their band gap. To enhance the photovoltaic efficiency by tuning the optical bandgap of complex oxides, an attempt was recently made to reduce the optical band gap of iron doping of lanthanum-modified Bi4Ti3O12-based oxides (Fe-BLT) using oxygen vacancy doping. To study the tunability of the optical band gap from the generation of oxygen vacancies, the thermal treatment time and temperature were controlled during heat treatment under a vacuum environment. The structural, optical properties of the synthesized podwers were examined by X-ray diffraction, scanning electron microscopy, and ultraviolet-visible spectroscopy. Typically, an oxygen vacancy in a complex oxide can alter their structure very easily. On the other hand, the ultraviolet-visible absorption spectra of iron-doped bismuth titanate ceramics under optimal conditions (12 h, 800 °C) showed a decrease in optical bandgap from 2.02 eV to 1.8 eV without a corresponding change in their crystallographic structure. This study suggests that optimal control of the thermal treatment time and temperature critically effects the optical band gap of complex oxides.

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Nguyen, Martin, and Radomír Sokolář. "Impact of Fly Ash as a Raw Material on the Properties of Refractory Forsterite–Spinel Ceramics." Minerals 10, no. 9 (September 22, 2020): 835. http://dx.doi.org/10.3390/min10090835.

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This article examines the process for the synthesis of forsterite–spinel (2MgO·SiO2/MgO·Al2O3) refractory ceramics from fly ash and alumina as sources of aluminum oxide. Raw materials were milled, mixed in different ratios and sintered at 1500 °C for 2 h. Sintered samples were characterized by XRD, thermal analyses and SEM. Porosity, water absorption, bulk density, refractoriness, refractoriness under load and thermal shock resistance were also investigated. The impact of fly ash as a raw material was investigated in accordance with the resulting properties and microstructure of samples with fly ash and alumina as the raw materials. Due to the positive effect of flux oxides (iron oxides and alkalis) on sintering, the mullite contained in fly ash completely decomposed into silica and alumina, which, together with magnesium oxide, formed spinel. This led to improved microstructural and mechanical properties and thermal shock resistance. In particular, mixtures with 10 wt.% and 20 wt.% of fly ash had the most promising results compared to alumina mixtures. Both modulus of rupture and thermal shock resistance were improved, while the impact on refractory properties was minimal. The novelty of this research lies in the recycling of fly ash, a by-product from coal-burning power plants, into a raw material for the production of forsterite–spinel refractory ceramics.

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Maalem, Badreddine, Djamel Berdjane, Okba Belahssen, Latifa Tairi, Youcef Faci, and Samira Djemili. "IDENTIFICATION OF THERMAL AND MICROSTRUCTURAL PROPERTIES OF HOT ROLLING SCALE." Acta Metallurgica Slovaca 25, no. 4 (December 18, 2019): 291. http://dx.doi.org/10.12776/ams.v25i4.1360.

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<p class="AMSmaintext2">A significant amount of scale is produced during casting of ingots and processing of hot-rolled products. In manufacturing steel, during the various rolling operations, the amount of scale produced is approximately 0.1% of the annual production of the rolling mills. The quality of the thin sheet during rolling is affected by the behavior of the iron oxide layers formed on their surfaces. For this reason, acids and oils are used for the descaling of slabs and billets by means of pressurized water. The calamine, contaminated by these various acids and used oils, is rejected and stored involuntarily on important areas and pollutes soil and groundwater. Micrographic observations as well as X-ray diffraction analysis have shown that calamine consists mainly of iron oxides. Hematite and magnetite become the main components for oxidation times greater than 1 hour. Characterization tests have shown that calamine is dense (ρ = 4.8 g/cm<sup>3</sup>), its particle size is variable depending on the degree of oxidation (from 0.5 to 10 mm). Simultaneous thermal analysis showed that an increase in mass of the calamine sample with a release of heat. Studies are underway for the physico-chemical characterization of the soils of the storage areas.</p>

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Likus, Magdalena, Małgorzata Komorowska-Kaufman, Alina Pruss, Łukasz Zych, and Tomasz Bajda. "Iron-Based Water Treatment Residuals: Phase, Physicochemical Characterization, and Textural Properties." Materials 14, no. 14 (July 14, 2021): 3938. http://dx.doi.org/10.3390/ma14143938.

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Groundwater treatment residuals (GWTRs) are safe waste materials generated during drinking water treatment. GWTRs are mainly deposited in landfills, but the preferred solution should be reused or utilized for some components. To ensure proper sludge management, it is important to provide quality, chemical composition, and texture characteristics of GWTRs. Therefore, in this study, we aimed to investigate and compare the features of GWTRs collected from four water treatment plants. GWTRs were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS); Fourier transform infrared spectroscopy (FTIR); thermogravimetric, differential thermogravimetric, and differential thermal analysis (TG, DTG, and DTA, respectively); X-ray fluorescence (XRF); inductively coupled plasma optical emission spectrometry (ICP-OEP); specific surface area (SBET) measurement; and determination of the isoelectric point (pHIEP). According to the results, GWTRs are poor crystalline materials that are predominantly composed of ferrihydrite with minor calcite and quartz admixture. They formed heterogeneously mixed particles with irregular shapes. They were mainly composed of iron oxides (32–55%), silica (4–28%), calcium oxide (4–17%), and manganese oxides (0.3–4.0%). They were found to be mesoporous with a large specific surface area. Due to their composition and texture characteristics, GWTRs demonstrate good adsorption properties toward different compounds such as heavy metals and metalloids.

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Selivanov, E. N., S. V. Sergeeva, and R. I. Gulyaeva. "Thermal Properties of High-Magnesia Oxidized Nickel Ore." Materials Science Forum 989 (May 2020): 461–67. http://dx.doi.org/10.4028/www.scientific.net/msf.989.461.

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The content of elements in the main mineral components of the ore, such as serpentine, talc, and chlorites, were determined. It was shown that, during heat treatment of the ore, in addition to the decomposition of hydrates and carbonates, serpentine decomposes and new phases (forsterite and enstatite) form. On the bases of analysis of the properties of the ore, patterns of phase transitions during heated in inert and reducing atmosphere were identified. It was found that the coal-thermal reduction of nickel and iron from oxides begins at temperatures above 800 °C, and from serpentines begins at temperatures above 1250 °C. It was found that, when heating the ore above 1200 °C in a mixture with a reducing agent, the metals reduce and form iron-nickel alloy. During electro-thermal smelting, the mode of which was determined by the melting points of slag (SiO2 – MgO – FeO – CaO – Al2O3 system) and ferronickel, the ratio of Ni / Fe in the metallic phase was determined by the consumption of reducing agent (coal, coke).

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Ursu, Luminita Daniela, Adriana Diaconu, Bogdan Alexandru Sava, Lucica Boroica, Ileana Mitiu, Elisabeta Rosu, Dorel Radu, M. Dinulescu, and Mihai Eftimie. "A Study of the Industrial Waste Incorporating in Glass." Advanced Materials Research 39-40 (April 2008): 675–78. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.675.

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The paper presents a study of the industrial waste incorporating in glass in order to obtain decorative colored glasses. The influence of iron and chromium oxides from waste amount is discussed. The samples properties such as density, thermal expansion coefficient and viscosity are investigated. Including different oxides of heavy metals (obtained from sludge that contains chromium and iron) into the vitreous system leads to the obtaining of several decorative glasses. Their colour varies widely, to the added quantity and the atmosphere of the work place.

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Serga, Vera, Regina Burve, Mikhail Maiorov, Aija Krumina, Ramūnas Skaudžius, Aleksej Zarkov, Aivaras Kareiva, and Anatoli I. Popov. "Impact of Gadolinium on the Structure and Magnetic Properties of Nanocrystalline Powders of Iron Oxides Produced by the Extraction-Pyrolytic Method." Materials 13, no. 18 (September 17, 2020): 4147. http://dx.doi.org/10.3390/ma13184147.

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Interest in magnetic nanoparticles is primarily due to their practical use. In this work, for the production of nanocrystalline powders of pure and gadolinium doped iron oxides, the extraction-pyrolytic method (EPM) was used. As a precursor, either iron-containing extract (iron (III) caproate in caproic acid) or its mixture with gadolinium-containing extract (gadolinium (III) valerate in valeric acid) was used. The mixed precursor contained 0.5 mol %, 2.5 mol %, 12.5 mol %, 50 mol %, and 75 mol % gadolinium in relation to the iron content. The formation of iron oxide phases, depending on the preparation conditions, was investigated. According to the results obtained, it was demonstrated that the presence of more than 2.5 mol % gadolinium additive in the mixed precursor inhibits the magnetite-to-hematite transformation process during thermal treatment. Produced samples were characterized by XRD and SEM methods, and the magnetic properties were studied.

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Selivanov, E. N., S. N. Sergeeva, and R. I. Gulyaeva. "Phase composition and thermal properties of the Sakharinskoe deposit oxidized nickel ore." Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy, no. 1 (February 22, 2019): 16–24. http://dx.doi.org/10.17073/0021-3438-2019-1-16-24.

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X-ray diffraction, optical microscopy and X-ray microanalysis were used to determine the composition and distribution of elements in the main mineral constituents of oxidized nickel ore at the Sakhalin deposit (goethite, hematite, serpentine, talc and chlorite). The main fraction of nickel is concentrated in iron oxides, where its content reaches 2,4 %, while in magnesium silicates it does not exceed 0,4 %. The sequence and temperature intervals of transformations were established when heating ore in inert and reducing media by means of thermal analysis methods combined with mass-spectrometric analysis of gases and subsequent X-ray phase analysis of products. The temperature regimes of ore roasting for the reduction of nickel and iron from their minerals were justified. The temperature regimes of sample heating are assumed to be close to the conditions implemented in industrial units (electric furnaces) where the rate of charge heating varies within 5—15 degrees/min, up to the melting point (1450 °С) of ferronickel and slag. It is proposed to use information on material composition, thermal properties and metal forms in ore to select regimes and technologies for their pyro-or hydrometallurgical processing. Nickel and iron recovery from oxides in CO environment occurs above 800 °С, while serpentines remain stable up to 1200 °С. The use of coke as a reducing agent allows reducing iron and nickel from serpentines at temperatures above 1250 °С. The obtained data were used to substantiate the operating conditions of roaster and electric furnaces during ferronickel smelting from oxidized ores. When roasting, resulting ferronickel particles will contain 2—4 % Ni. Completing recovery processes in the electric furnace will ensure metal recovery from magnesium silicates, which will slightly increase the nickel content in ferro-nickel.

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Ghodrat, S., M. Janssen, Roumen H. Petrov, Leo Kestens, and Jilt Sietsma. "Microstructural Evolution of Compacted Graphite Iron under Thermo-Mechanical Fatigue Conditions." Advanced Materials Research 409 (November 2011): 757–62. http://dx.doi.org/10.4028/www.scientific.net/amr.409.757.

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Cast iron components in combustion engines, such as cylinder blocks and heads, are exposed for long periods of time to elevated temperatures and subjected to large numbers of heating and cooling cycles. In complex components, these cycles can lead to localized cracking due to stresses that develop as a result of thermal gradients and thermal mismatch. This phenomenon is known as Thermo-Mechanical Fatigue (TMF). Compacted Graphite Iron (CGI) provides a suitable combination of thermal and mechanical properties to satisfy the performance of engine components. However, TMF conditions cause microstructural changes, accompanied by the formation of oxides at and close to the surface, which together lead to a growth in size of the cast iron. These microstructural changes affect the mechanical properties and accordingly the thermo-mechanical fatigue properties. The aim of this research is to provide insight into the microstructure evolution of CGI, with its complex morphology, under TMF conditions. For this, optical and scanning electron microscopy observations are made after cyclic exposure to air at high temperature, both without and with mechanical loading. It was found that the oxide layers, which develop at elevated temperatures, crack during the cooling cycle of TMF. The cracking results from tensile stresses developing during the cooling cycle. Therefore, paths for easy access of oxygen into the material are formed. Fatigue cracks that develop also show oxidation at their flanks. In order to quantify the oxide layers surrounding the graphite particles, Energy Dispersive X-Ray Analysis (SEM-EDX) and Electron Probe Micro Analysis (EPMA) are used.

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dos Santos Monteiro, Dalila, and Marluce Oliveira da Guarda Souza. "Thermal decomposition of precursors and iron oxide properties." Journal of Thermal Analysis and Calorimetry 123, no. 2 (June 24, 2015): 955–63. http://dx.doi.org/10.1007/s10973-015-4840-5.

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SHEINICH, L., and М. MYKOLAIETS. "THE RESEARCH AND USE IN CONSTRUCTION OF THE BY-PRODUCTS FROM THE THERMAL POWER PLANT HYDRAULICALLY REMOVED ASH CLASSIFICATION." Наука та будівництво 27, no. 1 (April 8, 2021): 3–7. http://dx.doi.org/10.33644/scienceandconstruction.v27i1.1.

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Today the environment protection is one of the most important issues in the world. The utilization of accumulating industrial waste is an up-todate area of construction research. The paper suggests a method for processing an electricity production waste, namely an ash from the hydraulic removal in the thermal power plant (TPP). The special classification by fractions of ashes from the hydraulic removal allows to receive such products as iron-containing product, fine sand (coarse filler), aluminosilicate hollow microsphere, and product with pozzolanic activity (fine filler).The experts of the State Enterprise "The State Research Institute of Building Constructions" and "Engineering Company "Perspective"" have conducted a series of studies on the obtained products properties and chemical composition, as well as on determining the fractional composition of each product. The density and specific surface area were evaluated, and each product binding properties control was performed. It was found that the aluminosilicate hollow microsphere and the product with pozzolanic activity had binding properties, and hardened mortars based on these materials were insoluble in water. Chemical analysis showed that in each of the products, except for iron-containing one, oxides of silicon and aluminum predominated. The iron containing product had a high content of iron oxides and by its composition was close to magnetite.The carried-out studies show that the products obtained during the hydraulic ash removal at TPP have a wide range of applications, both in the construction industry and in the chemical, mining, and metallurgical industries. In construction, these materials can be widely used as active mineral additives in the grinding of cements, or as additives improving the concrete mixtures and concretes properties. The iron-containing product is applicable in the special ultraheavy concretes manufacture.

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Kotsyubynsky, V. O., V. V. Moklyak, and A. B. Hrubiak. "Synthesis and Properties of Superparamagnetic Y-Fe2O3." Journal of Vasyl Stefanyk Precarpathian National University 1, no. 1 (May 5, 2014): 33–39. http://dx.doi.org/10.15330/jpnu.1.1.33-39.

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Method of nanodispersed g-Fe2O3 synthesis by thermal decomposition of iron citrate is proposed. The investigations of obtained oxides crystalline and magnetic structures are done. Nanodispersed g-Fe2O3 with sizes of coherent scattering regions about 4-7 nm was is only one phase after gel sintering at 200, 250 and 300оС; the particles of synthesized materials are in a state of magnetic ordering and in superparamagnetic state. The influence of magnetic dipole interparticles interaction on parameters of Mossbauer spectra is observed. The phenomenological model of the differences between nanodispersed g-Fe2O3 magnetic microstructures obtained after annealing at different temperatures is presented.

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Gónzalez-Gómez, W. S., J. May-Crespo, P. Quintana, A. May-Pat, F. Avilés, J. J. Alvarado-Gil, and B. O. Ortega. "Thermal effects on the physical properties of limestone from the Yucatan Peninsula." MRS Proceedings 1611 (2014): 171–76. http://dx.doi.org/10.1557/opl.2014.775.

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ABSTRACTRocks are composed of minerals, bounding matrix, cracks and pores. The study of changes in the physical properties of rocks as a function of heat treatment is relevant to various engineering and industrial applications. The effect of thermal damage on the compression, strength, ultimate compression strain, color and loss of mass of two different limestones extracted from the Yucatan Peninsula is studied. Different thermal treatments are applied by heating the sample from room temperature up to 600°C, with steps of 100°C. The results show a high correlation between the heat transport characteristics, mechanical properties, content of organic matter and the presence of carbonates and iron oxides in each type of limestone rock.

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Mathur, S., T. Ruegamer, N. Donia, and H. Shen. "Functional Metal Oxide Coatings by Molecule-Based Thermal and Plasma Chemical Vapor Deposition Techniques." Journal of Nanoscience and Nanotechnology 8, no. 5 (May 1, 2008): 2597–603. http://dx.doi.org/10.1166/jnn.2008.633.

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Deposition of thin films through vaccum processes plays an important role in industrial processing of decorative and functional coatings. Many metal oxides have been prepared as thin films using different techniques, however obtaining compositionally uniform phases with a control over grain size and distribution remains an enduring challenge. The difficulties are largely related to complex compositions of functional oxide materials, which makes a control over kinetics of nucleation and growth processes rather difficult to control thus resulting in non-uniform material and inhomogeneous grain size distribution. Application of tailor-made molecular precursors in low pressure or plasma-enhanced chemical vapor deposition (CVD) techniques offers a viable solution for overcoming thermodynamic impediments involved in thin film growth. In this paper molecule-based CVD of functional coatings is demonstrated for iron oxide (Fe2O3, Fe3O4), vanadium oxide (V2O5, VO2) and hafnium oxide (HfO2) phases followed by the characterization of their microstructural, compositional and functional properties which support the advantages of chemical design in simplifying deposition processes and optimizing functional behavior.

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Zboril, Radek, Miroslav Mashlan, and Dimitris Petridis. "Iron(III) Oxides from Thermal ProcessesSynthesis, Structural and Magnetic Properties, Mössbauer Spectroscopy Characterization, and Applications†." Chemistry of Materials 14, no. 3 (March 2002): 969–82. http://dx.doi.org/10.1021/cm0111074.

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Chandrakumara, G. T. D., D. M. S. N. Dissanayake, M. M. M. G. P. G. Mantilaka, R. T. De Silva, H. M. T. G. A. Pitawala, and K. M. Nalin de Silva. "Eco-Friendly, Green Packaging Materials from Akaganeite and Hematite Nanoparticle-Reinforced Chitosan Nanocomposite Films." Journal of Nanomaterials 2019 (December 23, 2019): 1–11. http://dx.doi.org/10.1155/2019/1049142.

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In this study, chitosan nanocomposite thin films were successfully fabricated by incorporating hematite nanoparticles (HNPs) and akaganeite nanoparticles (ANPs) as reinforcing fillers using the solution casting method. HNPs and ANPs were synthesized via a urea-assisted synthesis route using naturally occurring ferruginous laterites. Scanning electron microscopic (SEM) images indicated the spherical to subhexagonal morphology of the HNPs and rice-like morphology of the ANPs. X-ray diffractograms indicate the crystalline structure of iron oxides as hematite and akaganeite. Tensile tests were carried out to evaluate the mechanical properties of the nanocomposite films where maximum tensile stress of the chitosan/HNP composites was improved as high as 35.7% while chitosan/ANP composites indicated 43.5%. Thermal decomposition curves obtained by thermogravimetric analysis (TGA) indicate that the thermal stability of the nanocomposites has improved remarkably compared to neat chitosan films. Furthermore, these nanocomposites exhibited excellent UV barrier properties as identified by UV-visible spectrometry. Fourier-transform infrared (FTIR) spectroscopic results are evident in the presence of Fe-O bond in the wavenumber around 480-500 cm-1, and the result also indicated that the nanofillers interact with the chitosan matrix via hydrogen bonding, which enhanced the physical properties of the nanocomposites. Incorporation of iron oxide nanoparticle varieties into chitosan has led to improvements of certain physical and chemical properties, which make chitosan a promising material for packaging applications.

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Soares, Paula I. P., Diana Machado, César Laia, Laura C. J. Pereira, Joana T. Coutinho, Isabel M. M. Ferreira, Carlos M. M. Novo, and João Paulo Borges. "Thermal and magnetic properties of chitosan-iron oxide nanoparticles." Carbohydrate Polymers 149 (September 2016): 382–90. http://dx.doi.org/10.1016/j.carbpol.2016.04.123.

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Jakubas, Adam, Ewa Łada-Tondyra, Marcin Makówka, and Łukasz Suchecki. "A Study on the Possibility of Using Iron Scale in the Construction of Electromagnetic Field Shields." Energies 15, no. 4 (February 12, 2022): 1332. http://dx.doi.org/10.3390/en15041332.

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Electromagnetic radiation can have a negative effect on electronic circuits, for example, by disrupting their work and communication. Therefore, there is a need to reduce or eliminate electromagnetic interference using shields. This paper focuses on using waste materials in the form of iron scale, which is easy and inexpensive to obtain for shielding. Iron scale is the result of gaseous or aqueous corrosion, due to which a superficial layer of metal oxides formed on the surface of heated metal objects as a result of their contact with air or water during an industrial process is developed. In this study, morphology, chemical, and phase composition measurements were carried out. The results show that all the iron-based materials investigated are mainly composed of iron oxides and pure iron. The polymer–iron composites with different quantitative and qualitative compositions were prepared to verify the shielding effectiveness. The electrical resistance, impact strength, and magnetic properties were measured, and dynamic mechanical thermal analysis and tensile strength tests were performed. The tests confirmed the suitability of iron scale for the construction of electromagnetic field shielding material. Iron scale is cheap and easy to obtain from iron-based waste materials. The developed composites are easy to form and use recycled material.

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Jafari-Soghieh, Fariba, Behrooz Maleki, and Hossein Behniafar. "Effect of dendrimer-functionalized magnetic iron oxide nanoparticles on improving thermal and mechanical properties of DGEBA/IPD epoxy networks." High Performance Polymers 31, no. 1 (December 28, 2017): 24–31. http://dx.doi.org/10.1177/0954008317749020.

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In this work, the effects of dendrimer-functionalized magnetic iron oxide nanoparticles (Fe3O4@D-NH2) on improving thermal and mechanical properties in epoxy networks (ENs) are investigated. Magnetic iron oxide nanoparticles are prepared by coprecipitation of iron (II) chloride tetrahydrate with iron (III) chloride hexahydrate. Poly(amido-amine) dendrimer is synthesized by Michael addition reaction from diethylenetriamine with methyl acrylate. The fabricated dendrimer has been used to stabilize and functionalize magnetic nanoparticles. Then, magnetic iron oxide nanoparticles are encapsulated within the dendrimer and subsequently loaded into diglycidyl ether of bisphenol A (DGEBA) epoxy resin in two different contents, that is, 5 and 10 wt%. The amine groups of dendrimer-functionalized magnetic iron oxide nanoparticles allow them to be covalently linked to the polymer matrix alongside the main amine hardener. The resulting epoxy/magnetic iron oxide nanocomposites are thoroughly characterized by X-ray diffraction analysis, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Probing the thermal behaviors of the epoxy/magnetic iron oxide nanocomposites by thermogravimetric analysis indicated that the temperature of 10% decomposition and the temperatures of the maximum decomposition rate values of Fe3O4@D-NH2@EN series increased up to 20 and 10°C, respectively. Dynamic mechanical thermal analysis also indicated that the organo-magnetic iron oxide nanoparticles can lead to an excellent interaction between the nanoparticles and the resulting DGEBA/isophorone diamine ENs.

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Tsepelev, Vladimir S., Yuri N. Starodubtsev, and Nadezhda P. Tsepeleva. "Thermophysical Properties of Pipe Steel in the Liquid State." Metals 11, no. 7 (July 10, 2021): 1099. http://dx.doi.org/10.3390/met11071099.

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The temperature dependences of the kinematic viscosity and surface tension of liquid pipe steel with different modes of melt preparation were investigated. A transition zone was found on the temperature dependences of the thermophysical properties, which separates the regions with different activation energies of viscous flow and surface tension. At the heating stage in the transition zone, the thermal decomposition of clusters based on cementite Fe3C occurs. As a result of the decomposition, free carbon atoms appear which tend to give a uniform distribution in liquid iron with increasing temperature. At a low content of alloying elements and impurities, a high-temperature melt should have a large-scale cluster structure, which provides a more uniform distribution of chemical elements. The melt after vacuum degassing has a narrow transition zone near 1920 K, in contrast to the wide transition zone of the melt without vacuum degassing. The wider transition zone is shifted to high-temperature and this shift is associated with the thermal decomposition of carbides and oxides. Studies have shown that heating liquid pipe steel above the temperature of the liquid–liquid structural transition makes it possible to obtain a more homogeneous structure with a more uniform distribution of alloying and impurity elements in the melt. The sharp drop in surface tension at temperatures above 1920 K in the melt without vacuum degassing is associated with the diffusion of free S and O atoms, which are released after thermal decomposition of sulfides and oxides.

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Gierl-Mayer, C., T. Stepan, J. Sun, and H. Danninger. "Study on Sintering of Artificially Oxidized Steel Compacts." Powder Metallurgy Progress 19, no. 1 (September 1, 2019): 12–22. http://dx.doi.org/10.1515/pmp-2019-0002.

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AbstractSintering of Cr-prealloyed PM steels requires atmospheres with good quality – low oxygen potential – to achieve satisfactory sintering results. But during heating even the best atmospheres may be oxidizing, the system turns to reducing conditions only at high temperatures, which can be monitored by thermal analysis. During the dewaxing process, oxidizing conditions are favourable for effective dewaxing without sooting and blistering. However, this may result in some oxygen pickup during heating, and then the final properties of the produced parts may be strongly influenced by this intermediate oxidation. This study demonstrates the behaviour of artificially oxidized steels (Fe-C and Fe3Cr-0.5Mo-C) during the sintering process by stepwise sintering. Iron and steel powder were slightly oxidized and then pressed and sintered at different temperatures. In parallel, as a second approach, pressed samples were oxidized and then sintered. Density, hardness and impact energy were measured and dilatometry/MS was used for online monitoring of the sintering process. The starting oxygen content of 0.20 to 0.30 wt% is high enough to change the sintering behaviour of the materials, but still leads to rather good properties. Thermal analysis showed that most of the oxygen picked up was present as iron oxides on the surface which were reduced by hydrogen at rather low temperatures, confirming that these were iron oxides, which also holds for the Cr-prealloyed variant. The biggest influence on the final performance was exerted by the final carbon content and the microstructural development of the material.

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Zárybnická, Lucie, Martin Marek, Radek Ševčík, Radek Stolín, Jaroslav Pokorný, and Jiří Šál. "Effect of Infill Density of the Printed PET-G Structures Containing Iron Oxides on Magnetic Properties." Magnetochemistry 9, no. 1 (December 22, 2022): 2. http://dx.doi.org/10.3390/magnetochemistry9010002.

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This work aims to characterize printing structures with various infill densities composed of a thermoplastic material containing magnetic particles composed of mainly Iron(III) oxides with regard to their possible processing with the additive technology of Fused Filament Fabrication. A polyethylene terephthalate glycol (PET-G) structural thermoplastic with the addition of Iron(III)) oxides has been selected, and correct processing temperatures have been determined using thermal analysis. The paramagnetic properties of printed products consisting of different filling densities have been tested. Relative permeability has been identified to be strongly dependent on the printed internal structures of tested products. The samples composed of the densest structure have shown relative permeability higher by 18% with respect to the sample printed with the least dense structure. Finite Element Modelling (FEM) simulations have been applied to determine magnetic field distributions and, moreover, to calculate the holding forces of all printed samples. The performed simulations confirmed that produced composites might be utilized as magnetic switches and sensors or as more advanced components for homogenizing electric motors’ magnetic fields. Moreover, magnetic properties might be tuned according to the specific needs printing structure with the suitable density.

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Koohestani, Babak, Ahmad Khodadadi Darban, Pozhhan Mokhtari, Esmaeel Darezereshki, Erol Yilmaz, and Elif Yilmaz. "Influence of Hydrofluoric Acid Leaching and Roasting on Mineralogical Phase Transformation of Pyrite in Sulfidic Mine Tailings." Minerals 10, no. 6 (June 1, 2020): 513. http://dx.doi.org/10.3390/min10060513.

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Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering possibility, it is advantageous to remove impurities and increase the pyrite content of mine tailings prior to the roasting procedure. In this case, hydrofluoric acid that has no influence on pyrite can be used to leach most inorganic minerals, including aluminosilicates. Therefore, this study investigated and compared the influence of the roasting process with and without hydrofluoric acid leaching pretreatment on mineralogical phase transformation of pyrite and magnetic properties of thermally generated minerals. Several tests and analyses were performed to study mineralogical phase transformation, morphology, elemental composition, surface characterization, and magnetic properties. Results of this study indicated that without acid leaching pretreatment, pyrite was mainly transformed to hematite. However, via acid leaching, fluorine, as a more electronegative element over oxygen, entered the compound and neglected the role of oxygen in thermal oxidation, instead reducing sulfur content of pyrite to only form pyrrhotite.

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Wang, Ying, Parvin Kaur, Augustine Tuck Lee Tan, Rajveer Singh, Paul Choon Keat Lee, Stuart Victor Springham, Raju V. Ramanujan, and R. S. Rawat. "Iron oxide magnetic nanoparticles synthesized by atmospheric microplasmas." International Journal of Modern Physics: Conference Series 32 (January 2014): 1460343. http://dx.doi.org/10.1142/s2010194514603433.

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This paper presents the synthesis of iron oxide nanoparticles using the atmospheric microplasma (AMP). The properties of iron oxide nanoparticles synthesized using AMP are compared with particles (i) formed in as-prepared solution and (ii) prepared using thermal decomposition method. Iron oxide nanoparticles prepared by all the 3 treatment methods exhibit quite soft ferromagnetic properties with coercivities less than 10 G. The AMP synthesis technique was found to be more efficient and better than thermal decomposition method due to ultra-shorter experiment time (around 2.5 min) as compared to 90 min required for thermal decomposition method. Moreover, AMP synthesized nanoparticles are better isolated and of smaller size than thermal decomposition ones. The effect of plasma discharge timings on synthesized nanoparticles has also been studied in this work. Coercivity of synthesized nanoparticles decreases with the increasing plasma discharge timings from 3 to 10 min. The nanoparticles synthesized using plasma discharge timing of 10 min exhibit the smallest coercivity of around 3 G. This suggests a high possibility of achieving super-paramagnetic nanoparticles by optimizing the plasma discharge timings of AMP.

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Bartolotta, A., G. Di Marco, M. Lanza, and G. Carini. "Polyethylene oxide-iron thiocyanate polymeric complexes: thermal and mechanical properties." Journal of Non-Crystalline Solids 172-174 (September 1994): 1328–33. http://dx.doi.org/10.1016/0022-3093(94)90660-2.

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Halim, K. S. Abdel, A. A. El-Geassy, Mohamed Ramadan, M. I. Nasr, A. Hussein, Naglaa Fathy, and Abdulaziz S. Alghamdi. "Reduction Behavior and Characteristics of Metal Oxides in the Nanoscale." Metals 12, no. 12 (December 18, 2022): 2182. http://dx.doi.org/10.3390/met12122182.

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The development of nanomaterials and nanotechnology enables the production of nanosized metallic alloys with advanced characteristics from their oxides via a thermal reduction technique. The aim of the present work was to produce metallic iron, nickel, and tungsten through the gaseous reduction of nanosized metal oxide powders as a preliminary step towards the fabrication of nanosized heavy tungsten alloys with unique properties. Nanosized NiO, Fe2O3, and WO3 were isothermally and non-isothermally reduced with H2, and the oxygen weight loss was continuously recorded as a function of time. The Thermogravimetric TG-DTA technique was applied in the non-isothermal reduction up to 1000 °C. The reduction extents were calculated from the TG curve, whereas the accompanying heat of the reaction was measured from the DTA curve. The results revealed that NiO was reduced at <420 °C, Fe2O3 was reduced at <600 °C, and WO3 was reduced at >950 °C. In the isothermal process, metal oxides were reduced with H2 at 700–1000 °C; a micro-force balance was used and the O2 weight loss was continuously recorded. At a given temperature, the rate of reduction increased in the order NiO > Fe2O3 > WO3. The nano-oxide powders and the reduced products were physically and chemically characterized. The activation energy (Ea) values were computed from the isothermal reduction in the initial and later stages to elucidate the corresponding reduction mechanism. The Ea values indicated that the reduction of metal oxides was controlled by the gas diffusion mechanism at both the initial and later stages of reduction. The results of the present study determined the optimal operation parameters at which the thermal gaseous reduction technique could be applied for preparing metallic alloys from nanosized metal oxides.

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Stachowska, Joanna D., Monika B. Gamża, Claire Mellor, Ella N. Gibbons, Marta J. Krysmann, Antonios Kelarakis, Elżbieta Gumieniczek-Chłopek, Tomasz Strączek, Czesław Kapusta, and Anna Szwajca. "Carbon Dots/Iron Oxide Nanoparticles with Tuneable Composition and Properties." Nanomaterials 12, no. 4 (February 17, 2022): 674. http://dx.doi.org/10.3390/nano12040674.

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We present a simple strategy to generate a family of carbon dots/iron oxide nanoparticles (C/Fe-NPs) that relies on the thermal decomposition of iron (III) acetylacetonate in the presence of a highly fluorescent carbon-rich precursor (derived via thermal treatment of ethanolamine and citric acid at 180 °C), while polyethylene glycol serves as the passivation agent. By varying the molar ratio of the reactants, a series of C/Fe-NPs have been synthesized with tuneable elemental composition in terms of C, H, O, N and Fe. The quantum yield is enhanced from 6 to 9% as the carbon content increases from 27 to 36 wt%, while the room temperature saturation magnetization is improved from 4.1 to 17.7 emu/g as the iron content is enriched from 17 to 31 wt%. In addition, the C/Fe-NPs show excellent antimicrobial properties, minimal cytotoxicity and demonstrate promising bioimaging capabilities, thus showing great potential for the development of advanced diagnostic tools.

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Music, Denis, and Bastian Stelzer. "Intrinsic Thermal Shock Behavior of Common Rutile Oxides." Physics 1, no. 2 (August 28, 2019): 290–300. http://dx.doi.org/10.3390/physics1020022.

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Rutile TiO2, VO2, CrO2, MnO2, NbO2, RuO2, RhO2, TaO2, OsO2, IrO2, SnO2, PbO2, SiO2, and GeO2 (space group P42/mnm) were explored for thermal shock resistance applications using density functional theory in conjunction with acoustic phonon models. Four relevant thermomechanical properties were calculated, namely thermal conductivity, Poisson’s ratio, the linear coefficient of thermal expansion, and elastic modulus. The thermal conductivity exhibited a parabolic relationship with the linear coefficient of thermal expansion and the extremes were delineated by SiO2 (the smallest linear coefficient of thermal expansion and the largest thermal conductivity) and PbO2 (vice versa). It is suggested that stronger bonding in SiO2 than PbO2 is responsible for such behavior. This also gave rise to the largest elastic modulus of SiO2 in this group of rutile oxides. Finally, the intrinsic thermal shock resistance was the largest for SiO2, exceeding some of the competitive phases such as Al2O3 and nanolaminated Ti3SiC2.

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Ramos-Guivar, Juan A., Diego A. Flores-Cano, and Edson Caetano Passamani. "Differentiating Nanomaghemite and Nanomagnetite and Discussing Their Importance in Arsenic and Lead Removal from Contaminated Effluents: A Critical Review." Nanomaterials 11, no. 9 (September 6, 2021): 2310. http://dx.doi.org/10.3390/nano11092310.

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Arsenic and lead heavy metals are polluting agents still present in water bodies, including surface (lake, river) and underground waters; consequently, the development of new adsorbents is necessary to uptake these metals with high efficiency, quick and clean removal procedures. Magnetic nanoparticles, prepared with iron-oxides, are excellent candidates to achieve this goal due to their ecofriendly features, high catalytic response, specific surface area, and pulling magnetic response that favors an easy removal. In particular, nanomagnetite and maghemite are often found as the core and primary materials regarding magnetic nanoadsorbents. However, these phases show interesting distinct physical properties (especially in their surface magnetic properties) but are not often studied regarding correlations between the surface properties and adsorption applications, for instance. Thus, in this review, we summarize the main characteristics of the co-precipitation and thermal decomposition methods used to prepare the nano-iron-oxides, being the co-precipitation method most promising for scaling up processes. We specifically highlight the main differences between both nano-oxide species based on conventional techniques, such as X-ray diffraction, zero and in-field Mössbauer spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism, the latter two techniques performed with synchrotron light. Therefore, we classify the most recent magnetic nanoadsorbents found in the literature for arsenic and lead removal, discussing in detail their advantages and limitations based on various physicochemical parameters, such as temperature, competitive and coexisting ion effects, i.e., considering the simultaneous adsorption removal (heavy metal–heavy metal competition and heavy metal–organic removal), initial concentration, magnetic adsorbent dose, adsorption mechanism based on pH and zeta potential, and real water adsorption experiments. We also discuss the regeneration/recycling properties, after-adsorption physicochemical properties, and the cost evaluation of these magnetic nanoadsorbents, which are important issues, but less discussed in the literature.

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Klyndyuk, Andrey I., and Ekaterina A. Chizhova. "THERMAL EXPANSION, ELECTROTRANSPORT AND DIELECTRICAL PROPERTIES OF Bi4(Ti,Nb,Fe)3O12 SOLID SOLUTIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 7 (July 21, 2019): 92–98. http://dx.doi.org/10.6060/ivkkt.20196207.5834.

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The Bi4Ti3–2xNbxFexO12 (0.05 ≤ x ≤ 0.15) titanates were prepared using ceramic method. Their structure and physicochemical properties were studied. Compounds were p-type semiconductors, which electrical conductivity, Curie temperature, dielectric constant, and dielectric losses decreased, but lattice constants, thermo-EMF coefficient and sinterability did not changed at partial replacing of titanium by niobium and iron. Introduction of niobium and iron oxides into ceramics based on layered Bi4Ti3O12 lead to the sharp decreasing in its grains size. The transition of ceramics from ferroelectric to paraelectric state was accompanied by a stepwise increase in linear thermal expansion coefficient (LTEC) (from (9.63–9.81)·10–6 K–1 to (12.71-14.67)·10–6 K–1 and by decrease in the activation energy of DC electrical conductivity (from 1.13–1.52 eV to 0.72–0.99 eV). Electrical resistivity of ceramics was determined by electrical resistivity of grains, relaxation processes in it were of a non-Debay type, while the activation energy of relaxation for Bi4Ti3–2xNbxFexO12 titanates, found from impedance spectroscopy (1.01–1.05 eV), was close to the value activation energy of their intragrain conductivity (0.85–0.97 eV). The frequency dependences of AC electrical conductivity obeyed Jonscher’s power law σ ~ νn, where n < 1 and increased with temperature, which indicated that charge transfer in the ceramic was accomplished by ions translating over small distances, which was accompanied by small polarons hopping charge transfer.

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Lao, Xun, Xiao Yan, Jiao Xie, and Ya Li Li. "Fabrication of Iron Carbide and Nitride Ceramics with Controlled Magnetic Properties by the Non-Oxide Sol-Gel Process." Key Engineering Materials 512-515 (June 2012): 1429–33. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.1429.

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The carbodiimide-based non-oxide sol-gel process is a novel route to non-oxide nitride and carbide ceramics. This process has been applied to fabricate ternary or binary silicon based nitride and carbide ceramics. Based on this non-oxide sol-gel process, iron carbide and nitride have been fabricated by reaction of iron trichloride with bis(trimethylsilyl)carbodiimide to form FeCN gel followed by pyrolysis in argon flow at different temperatures. The iron carbide material obtained at 700 °C exhibits hard ferromagnetic properties whereas α-iron along with iron nitride formed at 1300 °C shows soft ferromagnetic properties. Therefore, iron carbide and nitride ceramics with controlled magnetic properties can be obtained along this novel non-oxygen sol-gel process by controlled pyrolysis. The pyrolysis behavior was investigated based on thermal gravimetric analysis coupled with differential scanning calorimetry. The phase structures of the iron carbide and nitride are identified by X-ray diffraction and the magnetic properties of the materials are measured by magnetometer.

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Kozlova, T. V., T. V. Lipkina, and A. V. Sedov. "Electrochemical Oxide Films Corrosion Properties Diagnosis System for the Thermal Power Equipment Heating Surfaces." Materials Science Forum 843 (February 2016): 62–67. http://dx.doi.org/10.4028/www.scientific.net/msf.843.62.

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This article describes the electrochemical diagnosys system of oxide films corrosion properties of the thermal power equipment heating surfaces. It was found that the formation of oxide films on carbon steel surface in boiling water includes active dissolution with subsequent thermal conversion of the dissolution products into iron oxide (II). Forming films properties such as porosity and roughness change in multi repeating way, which includes the alternation of loosening and consolidation processes.

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Hashmi, Syed Usama Mauood, Muhammad Aamir Iqbal, Maria Malik, Muhammad Tariq Qamar, Maham Khan, Abu Zahid, Md Rasidul Islam, Mohammed Al-Bahrani, Kareem Morsy, and Wen-Cheng Lai. "Synthesis and Characterization of Polyvinyl Chloride Matrix Composites with Modified Scrap Iron for Advanced Electronic, Photonic, and Optical Systems." Nanomaterials 12, no. 18 (September 11, 2022): 3147. http://dx.doi.org/10.3390/nano12183147.

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In this study, Fe2O3 powder was synthesized using the co-precipitation method from scrap iron, which was then treated with varying concentrations of copper. Afterwards, the modified Fe2O3 was reinforced in the PVC matrix by using the solution-casting method to synthesize PVC composite films, which were subjected to a UV-visible spectrophotometer, a Fourier transform infrared spectrophotometer, an X-ray diffractometer, and a thermal gravimetric analyzer to evaluate the optical, chemical, structural, and thermal properties. FTIR analysis reveals the formation of the composite through vibrational bands pertaining to both components present, whereas no significant changes in the XRD patterns of PVC were observed after the doping of modified iron oxide, which reveals the compatibility of fillers with the PVC matrix. The optical properties of the copper-doped iron oxide-PVC composites, including absorbance, refractive index, urbach energy, and optical as well as electrical conductivity are measured, and show an increase in optical activity when compared to the pure PVC compound. Moreover, the increased thermal stability of the synthesized composite was also observed and compared with conventional compounds, which, in accordance with all the other mentioned properties, makes the copper-dopped iron oxide-PVC composite an effective material for electronic, photonic, and optical device applications.

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Amara, Daniel, and Shlomo Margel. "Synthesis and characterization of elemental iron and iron oxide nano/microcomposite particles by thermal decomposition of ferrocene." Nanotechnology Reviews 2, no. 3 (June 1, 2013): 333–57. http://dx.doi.org/10.1515/ntrev-2012-0061.

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AbstractThe unique chemical and physical properties of the nano and microscale materials have led to important roles in the several scientific and technological fields. The magnetic nano/microparticles are of great interest because of its potential applications in, e.g., hyperthermia, magnetic resonance imaging (MRI), catalytic applications, etc. The decomposition of iron pentacarbonyl is one of the most common methods for the preparation of magnetic iron oxide and iron nanoparticles. However, Fe(CO)5 is severely toxic and alternative precursors should be used. Here, we describe the recent advances in the synthesis and characterization of the elemental iron and iron oxide nano/microcomposite particles by the thermal decomposition of ferrocene. The described synthesis process is based on simple nontoxic approaches including, for example, a solventless process. The particle size and size distribution as well as their composition, crystallinity, shape, and magnetic properties can be controlled via the synthesis conditions.

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Uderbayev, Saken, Aizhan Dilmanova, Nargul Saktaganova, Aigul Budikova, and Yerik Bessimbayev. "Physical and mechanical properties of ceramic brick using rice husk and ash of thermal power plants." Eastern-European Journal of Enterprise Technologies 6, no. 6 (120) (December 31, 2022): 60–68. http://dx.doi.org/10.15587/1729-4061.2022.269124.

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The paper presents the results of the influence on shrinkage deformations of the adopted composition during the drying and firing of ceramic bricks made using rice husk and ash of the combined heat and power plant of the city of Kyzylorda of the Republic of Kazakhstan. The optimal values of the husk additives content and ash from thermal power plants in the studied compositions were determined. Ash dumps from thermal power plants (TPP) create environmental tension and pose a great threat to both the environment and human health. It was found that the hydro-removal ash from the thermal power plant mainly consists of oxides of silica (45.45…46.37 %) and alumina (16.62…17.70 %), there are oxides of calcium (1.66…2.20 %), magnesium (0.86…1.12 %), iron (2.98…3.41 %) and alkali metals (0.80…1.04 %). The composition of ceramic bricks based on loess-like loam, rice husks, and ash from thermal power plants was studied. The charge composition of the raw components of the “clay, TPP ash, and rice husk” brick: clay is 71…75 %, TPP ash is 18…22 %, and rice husk is 2…6 % of the total mass of the components of the raw mixture of ceramic bricks. The compressive strength of fired ceramic bricks was 11…12 MPa. According to the results of experimental studies, it was found that the increased concentration of rice husks in natural mixtures is characterized by a stable increase in ceramic mass drying cracks. The increase in time until the appearance of drying cracks is 100 up to 160 sec. The resulting ceramic brick in accordance with the developed composition has a low weight, good thermal properties and meets the standard requirements for ceramic bricks according to GOST 530-2012

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Saber, Osama, Nagih M. Shaalan, Faheem Ahmed, Shalendra Kumar, and Adil Alshoaibi. "One-Step Multi-Doping Process for Producing Effective Zinc Oxide Nanofibers to Remove Industrial Pollutants Using Sunlight." Crystals 11, no. 10 (October 19, 2021): 1268. http://dx.doi.org/10.3390/cryst11101268.

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Doping processes for optical materials are one of the driving forces for developing efficient and clean technologies for decontamination of aquatic effluents through lowering their band gap energy to become effective in sunlight. The current study has used a non-conventional technique for doping zinc oxide by multi metals, non-metals and organic dyes through a one-step process. In this trend, Zn-Al nanolayered structures have been used as hosts for building host–guest interactions. Organic dyes that have inorganic species of iron, nitrogen and sulfur have been used as guests in the intercalation reactions of Zn-Al layered double hydroxides. By intercalating green dyes, organic–inorganic nanohybrids were formed as nanolayered structures with expanding interlayered spacing to 2.1 nm. By changing the concentration of green dyes and thermal treatment, series of nanofibers and nanoplates of zinc oxides were formed and doped by aluminum, iron and sulfur in addition to colored species. The optical properties of the multi-doped zinc oxide indicated that it became suitable for solar applications because its band gap energy decreased from 3.30 eV to 2.80 eV. The experimental and kinetic results of the multi-doped zinc oxide concluded that the colored pollutants were effectively removed during 50 min of sunlight irradiation.

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I P Soares, Paula, Frederik Lochte, Coro Echeverria, Laura C J Pereira, Joana T Coutinho, Isabel M M Ferreira, Carlos M M Novo, and João P M R Borges. "Thermal and magnetic properties of iron oxide colloids: influence of surfactants." Nanotechnology 26, no. 42 (September 30, 2015): 425704. http://dx.doi.org/10.1088/0957-4484/26/42/425704.

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Ismail, Syahriza, Nur Syafini Saad, and Jeeferie Abd Razak. "Nanostructured Hematite Prepared by Thermal Oxidation of Iron." Key Engineering Materials 694 (May 2016): 208–12. http://dx.doi.org/10.4028/www.scientific.net/kem.694.208.

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This paper reports on the synthesis of iron oxide nanowires using thermal oxidation of iron. The α-Fe2O3 (hematite) and Fe3O4 (magnetite) were successfully formed using this method. The morphological observation was done through the FESEM, while the XRD, EDX and Raman spectroscopy were used to determine the physical and structural properties of the produced nanostructures. It was found that the peaks intensities relative to the hematite, increased with the extent of oxidation period. The growth and final morphology of hematite was significantly controlled by the heating duration. A surface diffusion mechanism for nano-hematite growth was then proposed to account for the growth phenomena of this nanostructured formation.

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TERESITA, V. MARY, V. JESEENTHARANI, B. AVILA JOSEPHINE, and S. ARUL ANTONY. "SYNTHESIS OF NOVEL NANOSTRUCTURED LANTHANUM COBALT FERRITE MIXED METAL OXIDES BY SOL–GEL." International Journal of Nanoscience 12, no. 01 (February 2013): 1350007. http://dx.doi.org/10.1142/s0219581x13500075.

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Properties of nanoscale materials are very interesting and these are either comparable to or superior to those of bulk. These materials are interesting due to their exciting size dependent optical, electronic, magnetic, thermal, mechanical and chemical properties. Different mole ratios of nanostructured mixed metal oxides of LaCo x Fe 1-x O 3-δ (x = 0 to 1) were prepared by the sol–gel method by varying the mole ratios of iron and cobalt substrates. The compounds were sintered for 700°C in the tubular furnace for 8 h. The purity of the compounds was analyzed by TG-DTA. The compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) studies were employed to study the structural phases, vibrational frequencies, surface morphology of the highest humidity sensing compounds.

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Salas, Ulises Acevedo, Ismail Fourati, Jean Juraszek, Fabienne Richomme, Denis Pelloquin, Antoine Maignan, and Sylvie Hébert. "Impact of the iron substitution on the thermoelectric properties of Co 1− x Fe x S 2 ( x ≤ 0.30)." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2152 (July 8, 2019): 20180337. http://dx.doi.org/10.1098/rsta.2018.0337.

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The strong interplay between magnetism and transport can tune the thermoelectric properties in chalcogenides and oxides. In the case of ferromagnetic CoS 2 pyrite, it was previously shown that the power factor is large at room temperature, reaching 1 mW m −1 K −2 and abruptly increases for temperatures below the Curie transition ( T C ), an increase potentially due to a magnonic effect on the Seebeck ( S ) coefficient. The too large thermal conductivity approximately equal to 10.5 W m −1 K −1 at room temperature prevents this pyrite from being a good thermoelectric material. In this work, samples belonging to the Co 1− x Fe x S 2 pyrite family ( x = 0, 0.15 and 0.30) have thus been investigated in order to modify the thermal properties by the introduction of disorder on the Co site. We show here that the thermal conductivity can indeed be reduced by such a substitution, but that this substitution predominantly induces a reduction of the electronic part of the thermal conductivity and not of the lattice part. Interestingly, the magnonic contribution to S below T C disappears as x increases, while at high T , S tends to a very similar value (close to −42 µV K −1 ) for all the samples investigated. This article is part of a discussion meeting issue ‘Energy materials for a low carbon future’.

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Journal articles on the topic 'Iron oxides Thermal properties'

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