Journal articles: 'Iron aluminde'

1

ADIVI, HAMID GHANBARI, IMAN EBRAHIMZADEH, MORTEZA HADI, and MORTEZA TAYEBI. "THE EFFECT OF ALUMINA NANOPARTICLES ADDITION ON HIGH-TEMPERATURE WEAR BEHAVIOR OF INTERMETALLIC IRON ALUMINIDE PRODUCED BY THE SPARK PLASMA SINTERING PROCESS." Surface Review and Letters 27, no. 11 (June 25, 2020): 2050004. http://dx.doi.org/10.1142/s0218625x20500043.

Full text

Abstract:

The pure iron and aluminum powders were milled with 3[Formula: see text]wt.% and 7[Formula: see text]wt.% of alumina nanoparticles in planetary ball mill in order to produce iron aluminide by mechanical alloying technique. The resulting powder mixture was sintered after the formation of iron aluminide by spark plasma sintering (SPS) method to achieve specimens with the highest densification. SPS technique was utilized on specimens under the condition of 40[Formula: see text]MPa pressure at 950∘C for 5[Formula: see text]min. The microstructures were analyzed after sintering using scanning electron microscopy and EDS analysis. The results indicated that the aluminide iron phase has been produced at high purity. The sintered specimens were treated under hardness and density tests, and it was characterized that the specimen included 3[Formula: see text]wt.% of alumina nanoparticles had the highest microhardness. Likewise, it was revealed that the unreinforced sample had a maximum relative density. The wear behavior of specimens was performed at 600∘C. The results of weight loss showed after 1000[Formula: see text]m of wear test, the weight loss of unreinforced specimen was reduced up to 0.21[Formula: see text]g while the specimen with 3[Formula: see text]wt.% of alumina nanoparticle indicated the lowest weight loss about 0.02[Formula: see text]g. The worn surfaces were evaluated by scanning electron microscopy which indicated that the main wear mechanism at high temperature included adhesive wear and delamination.

APA, Harvard, Vancouver, ISO, and other styles

2

Li, Siwei, Jian Pan, Deqing Zhu, Zhengqi Guo, Yue Shi, Jianlei Chou, and Jiwei Xu. "An Innovative Technique for Comprehensive Utilization of High Aluminum Iron Ore via Pre-Reduced-Smelting Separation-Alkaline Leaching Process: Part I: Pre-Reduced-Smelting Separation to Recover Iron." Metals 10, no. 1 (December 28, 2019): 57. http://dx.doi.org/10.3390/met10010057.

Full text

Abstract:

In this study, a novel process was established for extraction of Fe and Al from a complex high aluminum iron ore (33.43% Fetotal and 19.09% Al2O3). The main steps in the proposed process included pre-reducing high alumina iron ore and subsequent smelting to produce pig iron and rich-alumina slag, followed by alkaline leaching of the slag to obtain sodium aluminate solution and a clean slag. When smelting the pre-reduced high alumina iron ore pellets at 1625 °C for 30 min with a slag basicity of 0.40, the pig iron yielded 97.08% Fe and extracted 0.13% Al2O3, together with an iron recovery of 94.54%. In addition, more than 68.93% Al2O3 was recovered by leaching the slag, which was achieved by firstly roasted the slag at 900 °C for 2 h and then alkaline leaching at 95 °C for 2 h with a liquid-to-solid ratio of 10 mL/g. In addition, the alkaline leaching slag could potentially be used as raw material for construction purpose, which mainly consisted of SiO2 and CaO.

APA, Harvard, Vancouver, ISO, and other styles

3

Dyachkova, L. N., P. A. Vityaz, A. Ph Ilyushchenko, L. J. Voronetskaya, A. I. Letsko, and N. M. Parnitsky. "Influence of the ultrafine iron aluminide additive on the structure and properties of iron and copper powder materials." Doklady of the National Academy of Sciences of Belarus 63, no. 3 (June 28, 2019): 360–69. http://dx.doi.org/10.29235/1561-8323-2019-63-3-360-369.

Full text

Abstract:

The results on the effect of introduction of iron aluminide of various chemical and phase compositions on the structure and mechanical properties of powdered carbon steel and tin bronze are presented. It is shown that the introduction of 0.5 % single-phase iron aluminide Fe3Al leads to an increase in the strength of powdered carbon steel by 30–40 MPa, of biphase Fe2Al5 –FeAl3 – by 80–90 MPa, 1 % – to an insignificant decrease in strength. When a single-phase iron aluminide in the powder steel structure is introduced, a decrease in cementite, differentiation is observed, aluminum diffusion into the substrate occurs, and when two-phase aluminide is introduced, the structure griding occurs as well. It is established that the introduction of 0.5 % single-phase iron aluminide into powder bronzes makes it possible to increase its strength by 80– 100 MPa, two-phase – leads to a reduction in strength by 40–50 MPa. Introduction of 1 % single-phase iron aluminide and 0.2–1 % biphasic aluminide causes a change in the morphology of the structure of the powder bronze due to alloying the copper with aluminum and iron.

APA, Harvard, Vancouver, ISO, and other styles

4

Jin, Jing Yun, Zai Yuan Li, and Yan Wu. "Extraction of Aluminum from High Iron Bauxite by Carbothermal Reduction-Ammonium Sulfate Roasting." Applied Mechanics and Materials 624 (August 2014): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amm.624.3.

Full text

Abstract:

A new preparation of alumina from high iron bauxite, which has not been being made reasonably use of yet, has been studied. Iron in high iron bauxite was removed by carbothermal reduction and aluminum-rich slag could be obtained. Then aluminum was extracted from aluminum-rich slag by ammonium sulfate roasting. After leaching, Al2(SO4)3 was obtained, which can be used for preparation of alumina. The effects of roasting temperature, roasting time, ammonium sulfate/aluminum-rich slag mass ratio were investigated. Optimum roasting conditions from aluminum-rich slag by ammonium sulfate were found as roasting temperature:400°C;roasting time:120min;ammonium sulfate/aluminum-rich slag mass ratio:6. Approximately 98% of aluminum was effectively extracted.

APA, Harvard, Vancouver, ISO, and other styles

5

Badaruddin, Mohammad. "Na₂SO₄ Induced Hot Corrosion of Aluminized Low Carbon Steel at 700 °C." Applied Mechanics and Materials 493 (January 2014): 761–66. http://dx.doi.org/10.4028/www.scientific.net/amm.493.761.

Full text

Abstract:

The oxidation kinetics of hot-dip aluminized AISI 1020 steel with Na2SO4 deposit was investigated at 700 °C for 49 h in static air. The scale morphologies were observed by means of metallograpy, scanning electron miscroscopy (SEM), electron dispersive spectroscopy (EDS) and X-ray analyses. The accelerated oxidation of aluminized steel was attributed to the formation of aluminum-sulphides which allowed the rapid diffusion of Fe ions in the aluminide layer to the formation of iron oxide. In addition, the Al-sulphides precipitations in the alumina scale causes the Al-depletion such that Al2O3 layer fails to form a protective layer. Consequently, the kinetics rate of aluminized was increased.

APA, Harvard, Vancouver, ISO, and other styles

6

Suardana, Putu, I. B. Sujana Manuaba, and Nyoman Wendri. "THE MINERAL OXIDE CONTENTS OF THE TEGAL LENGA BEACH IRON SAND." BULETIN FISIKA 20, no. 2 (November 10, 2019): 31. http://dx.doi.org/10.24843/bf.2019.v20.i02.p05.

Full text

Abstract:

Iron sand samples were taken from the top layer of the Tegal Lenga beach sand. It was purified by the Magnetic Separation method, it was found that the average weight fraction of the Tegal Lenga beach iron sand is 54.71%. With X-ray flouresence (XRF) characterization obtined that the minerals oxide contained in the iron sand of the Tegal Lenga beach are magnesium diiron (III) oxide (MgFe2O4), silicare alumina calcium alumina alumina (Ca (Mg0.5 Al0.5) (Al0.5Si1.5O6)), and iron iron (III) titanium aluminum magnesium vanadium manganese silicon oxide (Fe4.42Fe5.245Ti4.72Al0.7 Mg0.4Cr0.3V0.15Fe7.82Mn0.114Si0.05O6) with the volume fraction of each compound are 62.95%, 39.78%, and 39.74%

APA, Harvard, Vancouver, ISO, and other styles

7

Morris, D. G., and M. A. Muñoz-Morris. "High temperature mechanical properties of iron aluminides." Revista de Metalurgia 37, no. 2 (April 30, 2001): 230–39. http://dx.doi.org/10.3989/revmetalm.2001.v37.i2.471.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Iluțiu-Varvara, Dana-Adriana, Marius Tintelecan, Claudiu Aciu, and Ioana-Monica Sas-Boca. "Reuse of the Steel Mill Scale for Sustainable Industrial Applications." Proceedings 63, no. 1 (December 11, 2020): 14. http://dx.doi.org/10.3390/proceedings2020063014.

Full text

Abstract:

The purpose of our paper is to assess the reuse potential of the steel mill scale for sustainable industrial applications. We have presented the experimental procedures for chemical and mineralogical characterizations. According to the results of the elementary chemical analysis, the steel mill scale contains the following predominant chemical elements: iron, aluminum, silicon, and magnesium. Due to its high iron content, the steel mill scale can be reused as a source of raw material in the sustainable steelmaking industry. The mineralogical phases identified in the steel mill scale are: wüstite (FeO), hematite (Fe2O3), magnetite (Fe3O4), silica (quartz) (SiO2), magnesioferitte (MgFe2O4), and aluminum oxide (corundum) (Al2O3). Silica, alumina, and hematite are the main compounds of the cement and contribute to the formation of the: dicalcium silicate (2CaO·SiO2), tricalcium silicate (3CaO·SiO2), tricalcium aluminate (3CaO·Al2O3), and tetra—calcium aluminoferrite (4CaO·Al2O3·Fe2O3). The results of the paper are promising and encourage the future research for establishing the optimal percentage for the reuse of the steel mill scale in the composition of concrete.

APA, Harvard, Vancouver, ISO, and other styles

9

Sun, Bai, Fangwen Xu, Fei Liu, Hui Wang, Chengfeng Ding, Yunming Cheng, Zhuo Tang, Jie Zhang, Wei Shen, and Shuguang Zhu. "Study on adsorption characteristics and regeneration effect of iron - based alumina composites." E3S Web of Conferences 136 (2019): 06030. http://dx.doi.org/10.1051/e3sconf/201913606030.

Full text

Abstract:

In this paper, an iron-based alumina composite was synthesized by modifying activated alumina with ferric chloride. The adsorption performance of iron-based alumina composite modified with 15% ferric chloride solution reached a certain peak. At lower initial fluoride concentration, the amount of fluoride treated by this composite is much more than that of water samples with higher initial fluoride concentration. To some degree, the slower flow rate of fluoride solution, the better adsorption performance of adsorbent. The iron-based alumina composite expressed a better performance of fluoride adsorption at pH=6.5. The adsorbent treated with aluminum potassium sulfate had the best adsorption performance.

APA, Harvard, Vancouver, ISO, and other styles

10

Wöhrmeyer, Christoph, Jianying Gao, Christopher Parr, Magali Szepizdyn, Rose-Marie Mineau, and Junhui Zhu. "Corrosion Mechanism of A Density-Reduced Steel Ladle Lining Containing Porous Spinel-Calcium Aluminate Aggregates." Ceramics 3, no. 1 (March 23, 2020): 155–70. http://dx.doi.org/10.3390/ceramics3010015.

Full text

Abstract:

Refractory monolithics for steel ladle linings are typically products with low porosities and high bulk densities. They achieve high temperature, penetration, and corrosion resistance. Despite the high density of these products, which is due to the low porosity of the aggregates, their matrices still exhibit a high amount of pores. Since calcium magnesium aluminate (CMA) has already proven its resistance to penetration and corrosion as a binder in the matrix, this paper investigated if alumina spinel refractories containing microporous calcium magnesium aluminate aggregates can withstand conditions that occur in a steel ladle wall. The objective was to reduce the castable density with the advantage of a lower material requirement for a ladle lining and reduced heat and energy losses. This was achieved by replacing dense alumina aggregates by up to 38% of porous CMA aggregates (grains with 30 vol% porosity), which resulted in a bulk density reduction from 3.1 g/cm3 for the dense alumina castable to 2.8 g/cm3 for the 38% CMA aggregates containing castable. However, the despite the higher porosity, penetration, and corrosion resistance and thermomechanical properties were not impacted negatively for a model alumina spinel castable. A postmortem investigation was conducted on a newly developed dry-gunning mix that was installed in a steel ladle wall on top of a slag penetrated castable and that achieved a service life of 31 heats versus only 18 heats for the reference mix that contained dense alumina and spinel aggregates. This new repair mix contained the newly designed porous CMA aggregates, which in this case partly replaced the dense alumina and spinel aggregates. These porous aggregates consisted of magnesium aluminate and calcium aluminate micro-crystals. The postmortem study revealed two important phenomena that can explain the improved performance: at the hot face in contact with steel and slag, a thin densified zone was observed that blocked the slag penetration into the porous matrix and the porous aggregates. Iron oxides were almost completely blocked from penetration, and only some manganese oxide was observed in the penetrated zone together with some silica and lime from the slag. Clusters of calcium aluminate (CA6) and magnesium aluminate (MA) spinel build the refractory back-bone on the hot side of the material and gussets filled with mostly glassy calcium aluminum silicates close to the hot face and gehlenite further inside the penetrated zone. Alumina grains had a reaction rim consisting of CA2 or CA6 and a very intimate connection to the surrounding matrix unlike the CMA-free mix that showed micro cracks around the alumina grains. At the colder side, the gunning mix with CMA aggregates showed a very good connection to the substrate, supported by a hercynite formation in the gunning mix resulting from a cross-reaction with remains of iron oxide on the CMA containing repair mix. Furthermore, macroscopic observations of a CMA aggregate containing alumina magnesia castable in the metal zone of a steel ladle revealed that macro cracks developed only very slowly, which resulted in a superior service life.

APA, Harvard, Vancouver, ISO, and other styles

11

Tam, Panias, and Vassiliadou. "Sintering Optimisation and Recovery of Aluminum and Sodium from Greek Bauxite Residue." Minerals 9, no. 10 (September 20, 2019): 571. http://dx.doi.org/10.3390/min9100571.

Full text

Abstract:

Bauxite residue is treated for the recovery of aluminum and sodium by sintering with the addition of soda, metallurgical coke and other reagents such as CaO, MgO and BaO. A thorough thermodynamic analysis using Factsage 7.0™ software was completed together with XRD mineralogy of sinters with different fluxes and reagents additions. Through both thermodynamic interpretation and mineralogical confirmations, it was observed that the type of desilication product in bauxite residue influences the total aluminum recovery through the sintering process and formation of sodium aluminum silicate exists in equilibrium with sodium aluminate, unless silica is consumed by additives (such as CaO, MgO, BaO etc.) forming other more thermodynamically favorable species and liberating alumina. Addition of barium oxide improves the aluminum and sodium recovery to 75% and 94% respectively. Complex sinter product formation that are triggered due to high calcium content in the Greek bauxite residue reduces aluminum recovery efficiency. Optimised and feasible recovery of aluminum and sodium for Greek bauxite residue was proved to be 70% and 85% respectively, when sintered with 50% excess stoichiometric soda. It was observed that stoichiometric carbon addition in inert atmosphere only assisted recovery up to 75% of aluminum and 83% of sodium, though there are benefits gained from pre-reducing iron from hematite for downstream recovery.

APA, Harvard, Vancouver, ISO, and other styles

12

Zhou, Lvshan, Tongjiang Peng, Hongjuan Sun, Dong Fu, and Chuan Lai. "A novel separation method of the valuable components for activated clay production wastewater." Open Chemistry 19, no. 1 (January 1, 2021): 530–40. http://dx.doi.org/10.1515/chem-2021-0052.

Full text

Abstract:

Abstract The acidic wastewater produced by the wet production of activated clay contains valuable components such as iron and aluminum. The precipitation method was successfully introduced to separate iron and aluminum from the activated clay production wastewater step by step, which can not only recover the valuable components, but also avoid environmental pollution. In the separation process, gypsum, iron aluminum phosphate, alumina, and sodium sulfate were prepared, and the phase compositions of separation products were analyzed by XRD and IR. The main influencing factors in the separation of iron and aluminum components were studied by single factor experiment. The results show that at the optimized conditions, phosphorus/iron molar ratio 6.0, the system pH 3.0, the reaction temperature 343 K, and the reaction time 90 min, the iron(iii) ion in the system can form a sodium-containing aluminum iron phosphate double salt, and the filtrate after separating Fe3+ and part of Al3+ can meet the requirements for forming high-purity Al2O3. During the phosphate precipitation process, the hypothesis should be correct that Al3+ reacts with PO 4 3 − {\text{PO}}_{4}^{3-} to form an AlPO4 skeleton, Fe3+ isomorphically replaces Al3+ in the [AlO4] tetrahedron, and adsorption occurs simultaneously, with Na+ occupying the terminal acid sites, P(Al)–OH.

APA, Harvard, Vancouver, ISO, and other styles

13

Pithawalla, Yezdi B., and Sarojini Deevi. "Chemical synthesis of iron aluminide [FeAl] and iron aluminum carbide [Fe3AlC0.5] nanopowders." Materials Research Bulletin 39, no. 14-15 (December 2004): 2303–16. http://dx.doi.org/10.1016/j.materresbull.2004.07.023.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Botero, Yesica L., Jorge Eliécer López-Rendón, Daniel Ramírez, Dioni Mabel Zapata, and Franklin Jaramillo. "From Clay Minerals to Al2O3 Nanoparticles: Synthesis and Colloidal Stabilization for Optoelectronic Applications." Minerals 10, no. 2 (January 29, 2020): 118. http://dx.doi.org/10.3390/min10020118.

Full text

Abstract:

This research was performed to obtain high-value products from clay materials. High-grade nanometric delta-alumina (δ-Al2O3) was obtained from the modification of clay-based minerals, which could be potentially applied in the form of thin film for novel optoelectronic applications. The selective recovery process of alumina from clay materials presents an important advantage regarding the complete removal of other starting constituents such as silica, iron, titanium, alkali, and alkaline earth metals. To accomplish the selective removal of different species, an acid leaching route was used to extract the aluminum, then the iron impurities were eliminated by alkaline precipitation. The solution was acidized to precipitate the aluminum as aluminum chloride hexahydrate. Finally, the aluminum chloride hexahydrate was calcinated to obtain nano-delta-alumina with purity of over 98.5% Al2O3. The dominating crystalline phase was delta–gamma alumina (δ-phase and γ-phase), with a particle size of <140 nm. Then, these nanoparticles (NPs) were prepared as a stable colloidal dispersion to form a mesoporous layer employing the spin-coating technique. Initially, the synthesized alumina was characterized by atomic force microscopy (AFM) and TEM to determine the particle size and its morphology, whereas the colloidal dispersion was analyzed by rheological measurements. Finally, the findings of this investigation made it possible to get thin films with good porosity, which can be used in optoelectronic applications, specifically in perovskite solar cells.

APA, Harvard, Vancouver, ISO, and other styles

15

Moszner, Peng, Suutala, Jasnau, Damani, and Palm. "Application of Iron Aluminides in the Combustion Chamber of Large Bore 2-Stroke Marine Engines." Metals 9, no. 8 (July 31, 2019): 847. http://dx.doi.org/10.3390/met9080847.

Full text

Abstract:

Iron aluminides possess a unique combination of properties such as attractive corrosion resistance in hot gas and wet chemical environments, a favorable strength to weight ratio, low costs of alloying elements, and they can be processed by conventional methods. For the current study, a promising iron aluminide (Fe-Al-Mo-Ti-B) was employed, which shows the potential to replace costly heat resistant steels or expensive Ni-based alloys for components in large bore two-stroke marine engines. The prechamber, an integral part of the combustion system of dual fuel two-stroke marine engines, which must withstand harsh conditions, was selected as the component. Prototypes made of the novel iron aluminide were manufactured via investment casting and hot isostatic pressing using powder of the intermetallic alloy. The high temperature oxidation behavior, the wet corrosion resistance in acid media, and the mechanical properties up to 700 °C were evaluated. A prototype of the prechamber was tested on a large bore two-stroke dual fuel test engine and post analysis of the tested component was performed. The results show that the employed iron aluminide alloy could be an economic alternative to the currently used Ni-based alloy.

APA, Harvard, Vancouver, ISO, and other styles

16

HUANG, MIN, YU WANG, MENG-XIAN ZHANG, YAN-QIU HUO, and PENG-JIN GAO. "EFFECT OF MAGNETRON-SPUTTERED Al FILM ON LOW-TEMPERATURE PACK-ALUMINIZING COATING FOR OIL CASING STEEL N80." Surface Review and Letters 21, no. 04 (August 2014): 1450053. http://dx.doi.org/10.1142/s0218625x1450053x.

Full text

Abstract:

Low-temperature aluminizing coating was prepared onto the surface of oil casing steel N 80 with a magnetron-sputtered Al film to improve its corrosion resistance. Results show that magnetron-sputtered Al film is able to form gradient aluminide coating, composed of iron aluminide FeAl 3, Fe 2 Al 5 and Fe 3 Al with different contents of aluminum. Both the density and continuity of iron aluminide layer for oil casing steel N 80 with magnetron-sputtered Al film can be improved. Under the same corrosion condition, aluminized oil casing steel N 80 with a magnetron-sputtered Al film shows an outstanding corrosion resistance than those of original and aluminized ones without magnetron-sputtered Al film. The positive effect of Al film is considered as the concentration change of active Al atom for diffusion to form the aluminizing coating during the pack processing.

APA, Harvard, Vancouver, ISO, and other styles

17

Ekstroem, K. E., A. Voll Bugten, C. van der Eijk, A. Lazou, E. Balomenos, and G. Tranell. "Recovery of Iron and Aluminum from Bauxite Residue by Carbothermic Reduction and Slag Leaching." Journal of Sustainable Metallurgy 7, no. 3 (August 20, 2021): 1314–26. http://dx.doi.org/10.1007/s40831-021-00422-7.

Full text

Abstract:

Abstract The recovery of major components of bauxite residue by carbothermic reduction at 1550–1750 °C and subsequent slag leaching in a Na3CO3(aq) solution is studied. Iron recovers primarily to pig-iron and lime is added to tune the calcium aluminate slags towards the highly leachable mayenite phase. The concentration of aluminum in the leachate correlates well with the occurrence of mayenite and aluminum recoveries up to 50–60% are observed. However, slags with low CaO additions are vulnerable to gehlenite formation and display reduced leachabilities. Formation of an inhibiting layer of CaCO3(s) on the reaction surface of calcium-aluminate particles during leaching and immobilization of aluminum in CaTiO3(s) are also suggested to play important roles in limiting the aluminum leachability. Costs related to post-processing may be reduced by achieving disintegrating slags, a behavior which is observed for slags holding high γ- to β-Ca2SiO4 ratios. The disintegration is caused by the large volume expansion associated with the β-to-γ transformation and as such, various factors that are known to stabilize the β-polymorph are discussed. Graphical Abstract

APA, Harvard, Vancouver, ISO, and other styles

18

Zhou, Xianlin, Yanhong Luo, Tiejun Chen, and Deqing Zhu. "Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore." Metals 9, no. 1 (December 22, 2018): 15. http://dx.doi.org/10.3390/met9010015.

Full text

Abstract:

How to utilize low grade complex iron resources is an issue that has attracted much attention due to the continuous and huge consumption of iron ores in China. High-aluminum iron ore is a refractory resource and is difficult to upgrade by separating iron and alumina. An innovative technology involving synergistic reducing and synergistic smelting a high-aluminum iron ore containing 41.92% Fetotal, 13.74% Al2O3, and 13.96% SiO2 with a high-manganese iron ore assaying 9.24% Mntotal is proposed. The synergistic reduction process is presented and its enhancing mechanism is discussed. The results show that the generation of hercynite (FeAl2O4) and fayalite (Fe2SiO4) leads to a low metallization degree of 66.49% of the high-aluminum iron ore. Over 90% of the metallization degree is obtained by synergistic reducing with 60% of the high-manganese iron ore. The mechanism of synergistic reduction can be described as follows: MnO from the high-manganese ore chemically combines with Fe2SiO4 and FeAl2O4 to generate Mn2SiO4, MnAl2O4 and FeO, resulting in higher activity of FeO, which can be reduced to Fe in a CO atmosphere. The main products of the synergistic reduction process consist of Fe, Mn2SiO4, and MnAl2O4.

APA, Harvard, Vancouver, ISO, and other styles

19

Zinoveev, Dmitry, Pavel Grudinsky, Vladimir Korneev, Valery Dyubanov, and Mark Zheleznyi. "Recycling Red Mud of JSC Ural Aluminum Plant with the Recovery of Iron and Construction Materials." Key Engineering Materials 743 (July 2017): 331–37. http://dx.doi.org/10.4028/www.scientific.net/kem.743.331.

Full text

Abstract:

Red mud is a by-product of alumina industry which is currently almost completely stored in landfill sites without further use. It contains considerable amounts of valuable components such as iron, aluminum, titanium and rare-earth metals. The reduction smelting of red mud was carried out in laboratory scale to recover iron and obtain slag suitable for use in the construction industry. It has been shown that it is expedient to obtain pig iron and slag from the unprocessed red mud. Those two are suitable for the subsequent leaching of aluminum, titanium and rare-earth metals. It is practical to process dealkalized red mud, with composition adjustment by CaO and Al2O3 addition, in order to obtain pig iron and slag in the form of aluminous clinker.

APA, Harvard, Vancouver, ISO, and other styles

20

Nofal, Adel, Mohamed Waly, Ahmed Ahmed, and Mohamed Agour. "Selection of Cast Iron Grade for Stub-Anode Fixation in Aluminum Electrolytic Cells." Key Engineering Materials 457 (December 2010): 435–40. http://dx.doi.org/10.4028/www.scientific.net/kem.457.435.

Full text

Abstract:

This work is a trial to reach the optimum composition and structure of cast iron used for anode fixation in the aluminum electrolytic cells. Grey iron with low- and high-phosphorus contents, spheroidal graphite irons with compositions typical of ferritic and pearlitic grades as well as grey iron with different carbon equivalent values were compared. A bench-scale experimental set up was used to simulate the operating conditions at the steel stub/cast iron collar/carbon anode connection. The change in microstructure and electrical resistance was measured at temperatures up to 850°C for 30 days, which correspond to the electrolytic cell operating conditions. The thermal expansion properties of irons were measured using a high precision automatic dilatometer. The electrical resistance at the connection was found to decrease with spheroidal graphite irons. In flake graphite irons the resistance decreases with lower phosphorus content as well as higher CE values due to the enhanced graphitization potential during solidification, which increases the contact pressure at the connection. Decomposition of ledeburitic carbides in the structure plays – to lower extent – some role in increasing the contact pressure. This contact pressure rather than the resistivity of the cast iron seems to play the dominant role in determining the electrical resistance of the connection.

APA, Harvard, Vancouver, ISO, and other styles

21

Zhang, X. F., K. Thaidigsmann, J. Ager, and P. Y. Hou. "Al2O3scale development on iron aluminides." Journal of Materials Research 21, no. 6 (June 1, 2006): 1409–19. http://dx.doi.org/10.1557/jmr.2006.0172.

Full text

Abstract:

The structure and phase of the Al2O3scale that forms on an Fe3Al-based alloy Fe-28Al-5Cr (at.%) was investigated by transmission electron microscopy and photoluminescence spectroscopy. Oxidation was performed at 900 °C and 1000 °C for up to 190 min. Transmission electron microscopy revealed that single-layer scales were formed after short oxidation times. Electron diffraction was used to show that the scales are composed of nanoscale crystallites of the θ, γ, and α phases of alumina. Band-like structure was observed extending along three 120°-separated directions within the surface plane. Textured θ and γ grains were the main components of the bands, whereas mixed α and transient phases were found between the bands. Extended oxidation produced a double-layered scale structure with a continuous α layer at the scale/alloy interface and a γ/θ layer at the gas surface. The mechanism for the formation of Al2O3scales on iron aluminide alloys is discussed and compared with that for nickel aluminide alloys.

APA, Harvard, Vancouver, ISO, and other styles

22

Seiji, Yokoyama, and Nik Hisyamudin Muhd Nor. "Formation of Alumina Inclusions during Counter Diffusion of Aluminum and Oxygen Dissolved in Molten Iron." Applied Mechanics and Materials 315 (April 2013): 260–67. http://dx.doi.org/10.4028/www.scientific.net/amm.315.260.

Full text

Abstract:

The formation of alumina (Al2O3) inclusions was experimentally investigated with the capillary-reservoir method. The inclusions were observed with a SEM (scanning electron microscope). The compositions of iron matrix and inclusion were measured with an EDX (energy dispersive X-ray analysis). The content profile of aluminum was discussed by the counter-diffusion model of aluminum and oxygen with an instantaneous irreversible reaction for alumina formation. The inclusions of spherical and polygonal alumina and spherical hercynite (FeOAl2O3) were observed in the vicinity of the diffusion front of aluminum. The hercynite was detected when the initial oxygen content was 0.075 mass% and higher. When the initial oxygen content was more than 0.045 mass% and higher, dendritic alumina formed at the position that was nearer to the interface than the position of spherical and polygonal inclusions. No inclusion was observed around the interface because of the re-dissolution of the inclusions. The initiating position of the inclusion formation was approximated by the reaction position, Zr, obtained from the model on the assumption that aluminum and oxygen contents at the reaction position were zero. Empirically, 0.9×Zr and 0.17×Zr expressed the initiating positions of formation and re-dissolution of inclusions respectively. The critical supersaturation ratio was estimated to be from 1 to 7.4×105, depending on the initial aluminum and oxygen contents.

APA, Harvard, Vancouver, ISO, and other styles

23

Fuks, David, Simon Dorfman, Vlad Liubich, Larisa Kutsenko, and Helmut Mehrer. "Site Preference Occupation of Ni and V in Fe₃Al-Based Alloys." Materials Science Forum 480-481 (March 2005): 81–88. http://dx.doi.org/10.4028/www.scientific.net/msf.480-481.81.

Full text

Abstract:

Nonempirical study of the site preference occupation for Ni and V substituting in Fe3Al has been carried out in the framework of the coherent potential approximation. Obtained values of total energies show in a full agreement with experiments that Ni atoms in the equilibrium configuration occupy the iron sub-lattice for alloying with 5 at % of Ni in the Fe3Al-based alloy. Calculations of alloys with the V-doped iron aluminide in the D03 phase show differences in bonding and site occupation preferences in comparison with Ni doping. V atoms occupy aluminum sublattice.

APA, Harvard, Vancouver, ISO, and other styles

24

Saxena, Akash, Neera Singh, Bhupendra Singh, Devendra Kumar, Kishor Kumar Sadasivuni, and Pallav Gupta. "Phase, microstructure, and wear behavior of Al2O3-reinforced Fe–Si alloy-based metal matrix nanocomposites." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 3 (December 16, 2019): 467–80. http://dx.doi.org/10.1177/1464420719893387.

Full text

Abstract:

In the present work, phase, microstructure, and wear properties of Al2O3-reinforced Fe–Si alloy-based metal matrix nanocomposites have been studied. Composites using 2 wt.% and 5 wt.% of Si and rest Fe powder mix were synthesized via powder metallurgy and sintered at different temperature schedules. Iron–silicon alloy specimens were found to have high hardness and high wear resistance in comparison to pure iron specimens. Addition of 5 wt.% and 10 wt.% alumina reinforcement in Fe–Si alloy composition helped in developing iron aluminate (FeAl2O4) phase in composites which further improved the mechanical properties i.e. high hardness and wear resistance. Formation of iron aluminate phase occurs due to reactive sintering between Fe and Al2O3 particles. It is expected that the improved behavior of prepared nanocomposites as compared to conventional metals will be helpful in finding their use for wide industrial applications.

APA, Harvard, Vancouver, ISO, and other styles

25

Vafeias, Michail, Amalia Bempelou, Eirini Georgala, Panagiotis Davris, Efthymios Balomenos, and Dimitrios Panias. "Leaching of Ca-Rich Slags Produced from Reductive Smelting of Bauxite Residue with Na2CO3 Solutions for Alumina Extraction: Lab and Pilot Scale Experiments." Minerals 11, no. 8 (August 19, 2021): 896. http://dx.doi.org/10.3390/min11080896.

Full text

Abstract:

Sustainable utilization of Bauxite Residue (BR) is currently one of the greatest challenges being tackled by the alumina industry, due to its high production rates and limited reuse options. The present work is concerned with the use of BR as a candidate metallurgical raw material for iron (Fe) production and aluminum (Al) extraction. In more detail, at first, BR undergoes reductive smelting to extract its Fe content and produce a slag of mainly calcium aluminate composition. In a second step, Al contained in the calcium aluminate phases is extracted hydrometallurgically by leaching with a Na2CO3 aqueous solution. The focus of the current study is the optimization of this leaching process, and it was performed in two stages. The first was a laboratory scale investigation on the main parameters affecting the extraction rate of Al. The second stage was performed in pilot scale and incorporated observations and suggestions based on the laboratory scale investigation. Laboratory work showed that more than 50% of aluminum could be easily extracted in less than 1 h, in 5% S/L, at 70 °C and with an 20% excess of Na2CO3. Pilot scale work, by successfully applying the suggestions derived from laboratory scale work, achieved an average Al extraction of 68% from a 10% S/L pulp, with a slag of optimized composition in relation to the one used in the laboratory scale.

APA, Harvard, Vancouver, ISO, and other styles

26

Fujii, Kenji, Junji Sugishita, Noboru Egami, and Minoru Tabata. "Friction and Wear of Aluminum Alloys Containing Hard Phases." Journal of Tribology 117, no. 2 (April 1, 1995): 321–27. http://dx.doi.org/10.1115/1.2831250.

Full text

Abstract:

Adhesion energy between two surfaces containing intermetallic compounds is low, and adhesive wear is expected to be inhibited in such materials. Accordingly, the effects of intermetallic compounds have to be taken into account in the material design stage as a measure for improving wear resistance. Wear tests for specimens containing intermetallic compound phases, such as FeAl, TiAl and NiAl, were carried out under dry and lubricated conditions. The composite specimens used for the tests were fabricated by using a centrifugal casting method. In dry sliding of iron-aluminide composite materials, adhesion was mitigated and specific wear rate decreased with increases in the area fraction up to 60 percent. The titanium aluminide composite material showed the same trend of wear as that of the iron-aluminide composite materials. Under lubrication, specific wear rates increased due to the surface containing brittle intermetallic compounds. For the nickel aluminide composite material, the adhesion-inhibiting effect was remarkable. For particle reinforced metal matrix composites, friction coefficients depend on the protrusion height of alumina particles from the surface. The coefficient of friction for the surface with particles protruding was higher than that for the surface with embedded particles.

APA, Harvard, Vancouver, ISO, and other styles

27

Yang, H. G., Q. Zhan, W. W. Zhao, X. M. Yuan, Y. Hu, and Z. B. Han. "Study of an iron-aluminide and alumina tritium barrier coating." Journal of Nuclear Materials 417, no. 1-3 (October 2011): 1237–40. http://dx.doi.org/10.1016/j.jnucmat.2011.03.040.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Novák, Pavel, and Kateřina Nová. "Oxidation Behavior of Fe–Al, Fe–Si and Fe–Al–Si Intermetallics." Materials 12, no. 11 (May 29, 2019): 1748. http://dx.doi.org/10.3390/ma12111748.

Full text

Abstract:

Iron aluminides are still deeply investigated materials for their use in power plants, automotive and chemical industry, and other sectors. This paper shows that it is possible to strongly improve their oxidation behavior by the addition of silicon. The description of the synergic effect of aluminum and silicon on the oxidation behavior of Fe–Al–Si alloys at 800 °C in air is presented. The oxidation rate, microstructure, phase, and chemical composition of these ternary alloys are compared with the binary Fe–Al and Fe–Si alloys. Results showed that the oxidation of Fe–Al–Si ternary alloys provides an oxide layer based on aluminum oxide with a low concentration of iron and silicon. Below this oxide layer, there is a layer of silicides formed as a result of depletion by aluminum, which forms a secondary oxidation protection.

APA, Harvard, Vancouver, ISO, and other styles

29

Lin, Xin, Yong Li, Yan Jing Li, Jun Jie Zhang, Chang He Gao, and Ji Li Zhang. "Performance Studies on In Situ Spinel Solid Solution Bonded Periclase Refractories." Key Engineering Materials 633 (November 2014): 245–48. http://dx.doi.org/10.4028/www.scientific.net/kem.633.245.

Full text

Abstract:

Specimens were prepared using iron-rich magnesia (3~1 mm、≤1 mm) and high purity magnesia (≤0.088 mm) as the main starting materials, adding tabular alumina at different size (3~2、2~1、≤1 mm) and content:3%、6%、9%、12%、15% to discover the influence of tabular alumina on sample performance. Phase composition and microstructure were also analyzed. The results show that specimen with content of 6% of corundum possessed the best comprehensive performance:apparent porosity 17%, bulk density 2.95 g·cm-3, cold crushing strength 74 MPa, refractoriness under load 1700 °C, heat shock resistance of up to 18 times. The formations of magnesium aluminate spinel and hercynite solid solution were enhanced by Fe ion at high temperatures in the iron-rich magnesia-corundum system at the presence of iron oxides, which are able to largely dissolved in periclase.

APA, Harvard, Vancouver, ISO, and other styles

30

Numluk, Paweena, and Aphiruk Chaisena. "Sulfuric Acid and Ammonium Sulfate Leaching of Alumina from Lampang Clay." E-Journal of Chemistry 9, no. 3 (2012): 1364–72. http://dx.doi.org/10.1155/2012/758296.

Full text

Abstract:

The rapid development of the global alumina industry has led to a considerable increase in the production alumina and processing of alumina from non-bauxitic sources. Lampang clays comprise various minerals that contain about 22.70 wt% of extractable alumina. Local clay was ground, activated by calcination and treated with sulfuric acid to extract alumina. In the activation step, the effects of temperature and time on the extraction of alumina and iron were investigated. The leaching experiments were performed on clay samples with particle sizes less than 200 mesh. The samples were calcined at different temperatures, ranging from 450°C to 1050°C, and for different periods, ranging from 30 to 150 min. The optimum conditions for the extraction of alumina from Lampang clay include grinding the clay to pass through a 200 mesh sieve, calcining the ground clay at 750°C for 30 min, extracting the alumina from the calcined clay by leaching with 3M sulfuric acid, and using an acid to clay ratio of 80 wt% at 100°C for 120 min. An aluminum dissolution efficiency of 95.1 % was achieved under the conditions that resulted in the maximum dissolution efficiency of iron (26.6 %).

APA, Harvard, Vancouver, ISO, and other styles

31

Loginova, Irina V., and Aleksei V. Kyrchikov. "The Study of the Magnetic Properties of Red Mud from Alumina Production after Alkaline Treatment." Solid State Phenomena 316 (April 2021): 673–77. http://dx.doi.org/10.4028/www.scientific.net/ssp.316.673.

Full text

Abstract:

In Russia, the main feedstock for producing aluminum is bauxite. During the processing of 1 ton of bauxite into alumina (Al2O3), up to 0.5–0.6 ton of techno-genic waste is formed, that is red mud. It is not currently disposed of and accumulated in mud tailing dumps. It contains valuable components: Al – 8 %; Fe – 25 %; Ti – 2.4 % and it can be considered as a potential raw material for ferrous metallurgy and as a source of vanadium, titanium, and rare-earth elements (REE) Sc, Y, La. The paper shows the possibility of obtaining red mud with an increased iron content of up to 36 %, with an additional extraction of aluminum. Red mud from the Ural Aluminum Plant (Russia) is considered. It is proposed to direct this mud to the production of pellets for the production of cast iron. To extract aluminum from red mud, it is proposed to process the mud in a highly alkaline medium by sintering in the temperature range 300–600 °C. The resulting sinter is leached with water or a slightly alkaline solution with the conversion of aluminum compounds into solution. The red mud, obtained this way, exhibits magnetic properties. A magnetic separation was carried out, and the yield of the magnetic fraction is 79.87 %. The iron content increases by 25 % and amounts to 51.88 % of Fe2O3.

APA, Harvard, Vancouver, ISO, and other styles

32

Horton, J. A., C. T. Liu, and M. L. Santella. "Microstructures of Ni3Al alloyed with iron." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 210–11. http://dx.doi.org/10.1017/s0424820100125956.

Full text

Abstract:

The nickel aluminide, Ni3Al, is an ordered intermetallic alloy that exhibits an increase in yield stress with an increase in temperature. Recent efforts have alleviated the inherent grain boundary brittleness by microalloying with boron. Alloying additions such as iron can be used to further increase the high temperature yield stress.Microstructures and phase relationships in the aluminides were studied by transmission electron microscopy. A Ni3Al alloy with 10 at.% iron was single phase with the ordered Ll2 structure. Two alloys with 15% iron were found to contain a two-phase, γ + γ', cellular structure that consisted of small islands of crystallographically aligned ordered γ', surrounded by a “web” of disordered γ, Fig. 1. At 20% iron, the cellular structure encompasses nearly the entire specimen. Figure 2, a bright-field, dark-field pair of micrographs, shows the dislocation-cell structures (2a) and the ordered cellular structure (2b) present after tensile deformation at 600°C.

APA, Harvard, Vancouver, ISO, and other styles

33

Sharma, Shyam, Rupal Jain, Vineet Rawat, Prateek Rajeev Hundekar, Neera Singh, Devendra Kumar, and Pallav Gupta. "Structural and mechanical characterization of re-pressed and annealed iron-alumina metal matrix nanocomposites." Journal of Composite Materials 52, no. 11 (August 17, 2017): 1541–56. http://dx.doi.org/10.1177/0021998317726589.

Full text

Abstract:

In this study, structural and mechanical properties of re-pressed and annealed iron (Fe)-alumina (Al2O3) metal matrix nanocomposites (MMNCs) was investigated. Composite composition with 5 wt.% of alumina to iron was fabricated using ball milling technique. Cylindrical sintered specimens were pressed at a load of 10, 12.5, and 15 kN in a die of similar diameter so as to have maximum deformation internally at grain as well as at grain boundary. These specimens were heat treated at 900, 1000, and 1100℃ for 1 h to anneal the stresses as well as to enhance the bonding between grains. Synthesized specimens were characterized for their microstructure, density and hardness respectively. Scanning electron microscopic images of the synthesized specimens revealed the formation of dense phase microstructure along with the presence of nano-dispersion of iron aluminate (FeAl2O4) phase. Secondary processing of metal matrix nanocomposites resulted in an increase in density of prepared specimens from 4.6960 to 5.5035 g/cm3 and the hardness values increased from 63 to 94 HRH.

APA, Harvard, Vancouver, ISO, and other styles

34

SIMON, S., I. ARDELEAN, M. PETEANU, M. POP, and R. STEFAN. "EPR STUDY OF Fe3+ AND Mn2+ DOPED AMORPHOUS AND CRYSTALLINE ALUMINUM BORATES." Modern Physics Letters B 14, no. 01 (January 10, 2000): 1–6. http://dx.doi.org/10.1142/s0217984900000021.

Full text

Abstract:

Amorphous and crystalline aluminum borates prepared by sol–gel method doped with iron and manganese were studied by electron paramagnetic resonance in order to determine the matrix effects on Fe3+ and Mn2+ environments during their consolidation by heat treatment up to 860°C. In amorphous matrices, after heat treatments up to 600°C, the Fe3+ environment is almost unaffected but the vicinity of Mn2+ ions is relatively strongly disordered. In partial crystalline alumina and aluminum borate samples, obtained after heat treatments applied at 860°C, the Fe3+ sites are subjected to completely different crystalline fields, as regards intensity and symmetry. If in crystalline alumina we have both sites typical for α and γ phases in crystalline aluminum borate, the well-known spectrum of Fe3+ in disordered systems seems to be solved, suggesting more than one well-defined site. In the case of manganese-doped samples, only a diminishing of hyperfine resolution with increasing heat treatment temperature is observed as a result of environment distortion by improvement of alumina borate sample crystallinity.

APA, Harvard, Vancouver, ISO, and other styles

35

Narayan, P. B. "Ultramicrotomy in the Analysis of Magnetic Recording Media." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 212–13. http://dx.doi.org/10.1017/s0424820100117984.

Full text

Abstract:

Particulate magnetic recording media is widely used to store information in computer memory applications. The media consists of submicron-size gamma iron oxide and alumina particles held together by a binder resin onto a substrate (mylar for floppy disks and aluminum for rigid disks). The electrical properties of media depend on the physical characteristics (like size and shape), dispersion and orientation of iron oxide. Well- dispersed and optimum-sized alumina improvies wear resistance of the relatively soft media. Transmission electron microscopy (TEM), with its excellent spatial resolution, is found to be very useful in analyzing media. Ultramicrotomy can be conveniently used to prepare cross-sections of the media for TEM study The major advantage of ultramicrotomy is that it provides a large amount of uniformly thin area relatively quickly.

APA, Harvard, Vancouver, ISO, and other styles

36

Zinoveev, Dmitry, Pavel Grudinsky, Andrey Zakunov, Artem Semenov, Maria Panova, Dmitry Valeev, Alex Kondratiev, Valery Dyubanov, and Alexander Petelin. "Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud." Metals 9, no. 12 (December 6, 2019): 1313. http://dx.doi.org/10.3390/met9121313.

Full text

Abstract:

Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.

APA, Harvard, Vancouver, ISO, and other styles

37

Lazou, Adamantia, Casper Van Der Eijk, Kai Tang, Efthymios Balomenos, Leiv Kolbeinsen, and Jafar Safarian. "The Utilization of Bauxite Residue with a Calcite-Rich Bauxite Ore in the Pedersen Process for Iron and Alumina Extraction." Metallurgical and Materials Transactions B 52, no. 3 (March 8, 2021): 1255–66. http://dx.doi.org/10.1007/s11663-021-02086-w.

Full text

Abstract:

AbstractMetallurgical grade alumina is produced worldwide through the well-known Bayer process, which unavoidably generates bauxite residue (BR, also known as red mud) in almost equal amounts to alumina. This study aims the valorization of BR through a smelting-reduction process to obtain calcium aluminate slags that can be a proper feed for alumina recovery via the Pedersen process. It investigates the thermodynamics and characteristics of the slags and pig iron produced from mixtures of BR, a bauxite beneficiation byproduct, and lime. In this context, the evolution of the different phases in the slags is studied with advanced analytical techniques and thermodynamic calculations. According to the results, a CaO/Al2O3 mass ratio within 1.3 to 1.4 in the slags can yield more Al2O3-containing leachable phases, such as CaO·Al2O3 and 12CaO·7Al2O3. The cooling dictates the amount and the characteristics of these phases, and the slower cooling rate yields improved slag characteristics. The distribution of the elements between the slag and metal phases shows that iron is separated, and the majority of the P, Cr, Ni, and V are distributed in the produced pig iron, while S, Ti, and Si are mostly concentrated in the slags.

APA, Harvard, Vancouver, ISO, and other styles

38

Ahmadian, M., M. Reid, Rian Dippenaar, Tara Chandra, David Wexler, and Andrzej Calka. "In Situ Observations of the Densification Behavior of WC-FeAl-B Composites during Liquid Phase Sintering." Materials Science Forum 638-642 (January 2010): 921–26. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.921.

Full text

Abstract:

The densification behavior of WC composites based on iron aluminide binder was investigated using laser scanning confocal mi¬croscopy (LSCM). Doped Fe60Al40 alloys with boron levels ranging from 0 to 0.1 wt% were used as the aluminide binders. The aluminide binders were prepared using controlled atmosphere ring grinding and then blended with WC powder. The composite powder compacted in an alumina crucible and held in a platinum holder in the confocal microscope. The temperature increased from ambient temperature up to 1500 °C under high purity argon. The presence of boron was found to facilitate compaction of the composites and improve the wetting between WC and FeAl binder during liquid phase sintering. Increasing the amount of boron in the binder resulted in the melting of binder at lower temperature and increasing of the compacting of the intermetallic tungsten carbide composites.

APA, Harvard, Vancouver, ISO, and other styles

39

Liu, Zheng-Gen, Man-Sheng Chu, Zheng Wang, Wei Zhao, and Jue Tang. "Study on Metallized Reduction and Magnetic Separation of Iron from Fine Particles of High Iron Bauxite Ore." High Temperature Materials and Processes 36, no. 1 (January 1, 2017): 79–88. http://dx.doi.org/10.1515/htmp-2015-0005.

Full text

Abstract:

AbstractHigh iron bauxite ore is a typical unmanageable polyparagenetic resource and owns high comprehensive utilization value. Separation of iron from fine particles of high iron bauxite ore by the process of metallized reduction and magnetic dressing was researched systemically. The effect of magnetic field intensity, reduction temperature, reduction time, mole ratio of fixed carbon to reducible oxygen (FC/O) and ore particles size on separation indexes was researched. The results show that, with the conditions of reduction temperature of 1,400 °C, reduction time of 180 min, FC/O of 2.0, ore particle size of –2.0 mm and magnetic field intensity of 40 KA/m, about 89.24 % of the iron could be removed from high iron bauxite ore as metallic iron. Meanwhile, 86.09 % of the aluminum is stayed in non-magnetic fraction as alumina. However, the formation of hercynite (FeAl2O4) limits the reduction rate of iron oxides to metallic iron. The lower reduction conditions and higher recovery ratio of iron could be achieved with adopting ore-coal composite agglomerates or adding catalyst.

APA, Harvard, Vancouver, ISO, and other styles

40

Levi, George, and Wayne D. Kaplan. "Iron as an Oxygen Tracer at the Aluminum-Alumina Interface." Journal of the American Ceramic Society 85, no. 6 (June 2002): 1601–6. http://dx.doi.org/10.1111/j.1151-2916.2002.tb00318.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Palaci, Yuksel, and Guven Gonca. "The effects of different engine material properties on the performance of a diesel engine at maximum combustion temperatures." Thermal Science 24, no. 1 Part A (2020): 183–91. http://dx.doi.org/10.2298/tsci180916164p.

Full text

Abstract:

In this study, the influences of various engine materials such as palladium, titanium, thorium, zirconium, vanadium, alumina, aluminum bronze, copper, iron (gray cast), manganese, nickel, cobalt, and carbon steel on the effective efficiency and effective power with respect to the variation of equivalence ratio at the maximum combustion temperatures. In-cylinder gas temperatures have been determined with respect to the melting temperatures and the performance values have been calculated with respect to the variation of the gas temperatures. The results indicated that alumina provides the maximum performance values as aluminum bronze gives the minimum performance values due to the combustion temperatures. Further-more, the equivalence ratios which give the maximum performance characteristics have been parametrically described. The obtained results can be assessed by engine designers and manufacturers to choose suitable engine material.

APA, Harvard, Vancouver, ISO, and other styles

42

Kerdbua, Panya, Mohammad Hassan Shirani Bidabadi, Walairat Chandra-ambhorn, and Somrerk Chandra-ambhorn. "High Temperature Corrosion Behaviour of Aluminide-Coated Cast Iron for an Exhaust Manifold Application." Coatings 10, no. 8 (July 22, 2020): 705. http://dx.doi.org/10.3390/coatings10080705.

Full text

Abstract:

To reduce the pollution emission from vehicles, an improvement on the combustion process is expected, leading to increased exhaust gas temperature. As a result, the development of new materials for an exhaust manifold used at higher temperatures is required. A cost-effective cast iron exhaust manifold treated by aluminising pack cementation was developed in the present work to combat the high temperature corrosion. Its kinetics under cyclic oxidation in N2–12%O2–10%H2O at 850 °C was parabolic with the rate constant (kp) of 5.66 × 10−12 g2 cm–4 s–1, about two orders of magnitude lower than that of the bare cast iron, which indicated the protectiveness of the applied coating. These results relate to the protective alumina formation for the aluminised cast iron and the formation of the less protective iron oxides for the bare cast iron after oxidation, as evidenced by the XRD and Raman spectroscopy results. The addition of 10% water vapour to N2–12%O2 thickened the aluminide layer from 344 μm for the sample oxidised in dry atmosphere to 409 μm for the sample oxidised humidified one. It accelerated the oxidation rate of the aluminised cast iron as the kp value increased by 8.5 times, and also increased the hardness of the aluminised surface, as it was 364 HV for the sample exposed to dry atmosphere and 420 HV for the sample exposed to humidified one. The latter result implied the possibility of the hydrogen dissolution into the metal surface. The roles of hydroxyl ion and dissolved hydrogen on the oxidation and evolution of the aluminide layer after exposure to water vapour were proposed.

APA, Harvard, Vancouver, ISO, and other styles

43

Chen, Shou Gang, Wei Wei Sun, Shuai Qin Yu, Xun Jun Yin, and Yan Sheng Yin. "Electronic Structure of Bimetallic Fe_mAl_n (m+n=6) Clusters." Advanced Materials Research 79-82 (August 2009): 1333–36. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1333.

Full text

Abstract:

Theoretical study on the electronic structure of small FemAln(m+n=6) clusters has been carried out at the BPW91 level, and the electronic structures, binding energy and vertical ionization potential of clusters were evaluated. For the stable clusters, the iron atoms gather together and form a maximum of Fe-Fe bonds, and the aluminum atoms locate around Fe core with a maximum of Fe-Al bonds. The binding energy and vertical ionization potential show that the Fe5Al, Fe4Al2 and Fe3Al3 clusters have higher stability, which results provide insight into the properties of iron-aluminides can be obtained from a finite size cluster model.

APA, Harvard, Vancouver, ISO, and other styles

44

Sun, Kai, Zhong Yang Wang, Pei Tao Xie, and Run Hua Fan. "Dielectric and Magnetic Properties of Cermets with Iron-Aluminum Dual Metallic Particles." Materials Science Forum 898 (June 2017): 1655–60. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1655.

Full text

Abstract:

The dual metallic components, i.e., iron-aluminum particles were distributed in alumina matrix to fabricate lossy cermets. The electromagnetic parameters including ac conductivity, the complex permittivity and permeability were investigated. With the increase of filler fractions, the conductive carriers instead of the dipoles played a primary role in conductive and dielectric properties. Hopefully, the cermets composites could be promising candidates for electromagnetic wave attenuation and shielding.

APA, Harvard, Vancouver, ISO, and other styles

45

Palm, Martin, Frank Stein, and Gerhard Dehm. "Iron Aluminides." Annual Review of Materials Research 49, no. 1 (July 2019): 297–326. http://dx.doi.org/10.1146/annurev-matsci-070218-125911.

Full text

Abstract:

The iron aluminides discussed here are Fe–Al-based alloys, in which the matrix consists of the disordered bcc (Fe,Al) solid solution (A2) or the ordered intermetallic phases FeAl (B2) and Fe3Al (D03). These alloys possess outstanding corrosion resistance and high wear resistance and are lightweight materials relative to steels and nickel-based superalloys. These materials are evoking new interest for industrial applications because they are an economic alternative to other materials, and substantial progress in strengthening these alloys at high temperatures has recently been achieved by applying new alloy concepts. Research on iron aluminides started more than a century ago and has led to many fundamental findings. This article summarizes the current knowledge of this field in continuation of previous reviews.

APA, Harvard, Vancouver, ISO, and other styles

46

Huang, E.-Wen, Tu-Ngoc Lam, I.-Ling Chang, Wei-Jhih Hong, Tian-Yu Lin, Chun-Jen Su, Peter Liaw, Louis Santodonato, Jain Jayant, and Morris Fine. "Plasticity Enhancement by Fe-Addition on NiAl Alloy: A Synchrotron X-ray Diffraction Mapping and Molecular Dynamics Simulation Study." Quantum Beam Science 2, no. 3 (September 19, 2018): 18. http://dx.doi.org/10.3390/qubs2030018.

Full text

Abstract:

Unalloyed nickel aluminide has important applications but lacks ductility at room temperature. In this study, iron-added nickel aluminide alloys exhibit plasticity enhancement. The nickel aluminide alloys are prepared with different iron contents (0, 0.25, and 1 at%) to study their plasticity. The indentation-induced deformed areas are mapped by the synchrotron X-ray diffraction to compare their plastic zones. A complimentary tight binding calculation and generalized embedded atom method demonstrate how the Fe-addition enhances the plasticity of the iron-added nickel aluminide alloys.

APA, Harvard, Vancouver, ISO, and other styles

47

Berman, Diana, Yuchen Sha, and Elena V. Shevchenko. "Effect of Polymer Removal on the Morphology and Phase of the Nanoparticles in All-Inorganic Heterostructures Synthesized via Two-Step Polymer Infiltration." Molecules 26, no. 3 (January 28, 2021): 679. http://dx.doi.org/10.3390/molecules26030679.

Full text

Abstract:

Polymer templates play an essential role in the robust infiltration-based synthesis of functional multicomponent heterostructures with controlled structure, porosity, and composition. Such heterostructures are be used as hybrid organic–inorganic composites or as all-inorganic systems once the polymer templates are removed. Using iron oxide/alumina heterostructures formed by two-step infiltration of polystyrene-block-polyvinyl pyridine block copolymer with iron and aluminum precursors from the solution and vapor-phases, respectively, we show that the phase and morphology of iron oxide nanoparticles dramatically depend on the approach used to remove the polymer. We demonstrate that thermal and plasma oxidative treatments result in iron oxide nanoparticles with either solid or hollow morphologies, respectively, that lead to different magnetic properties of the resulting materials. Our study extends the boundaries of structure manipulations in multicomponent heterostructures synthesized using polymer infiltration synthesis, and hence their properties.

APA, Harvard, Vancouver, ISO, and other styles

48

Wierzba, Bartłomiej, Sébastien Chevalier, Olivier Politano, and Marek Danielewski. "Numerical Determination of Intrinsic Diffusion Coefficient of Aluminide Coatings on Metals." Defect and Diffusion Forum 289-292 (April 2009): 269–76. http://dx.doi.org/10.4028/www.scientific.net/ddf.289-292.269.

Full text

Abstract:

This paper presents a numerical method to determine the composition dependent diffusivities and to predict the concentration profile during the interdiffusion process. The intrinsic diffusion coefficients in diffusion aluminide coatings (Fe-Al) were determined at 1000oC. The obtained diffusion coefficient for iron in Fe3Al or FeAl is in the range 10-10 to 10-9 cm2.s-1. The aluminum diffusion coefficient varies from 10-11 to 10-7 cm2.s-1 in the same phases.The present approach also permits to model the reactive diffusion in the Fe-Al systems.

APA, Harvard, Vancouver, ISO, and other styles

49

Boyarintsev, A. V., M. M. Aung, K. Yi Aung, and S. I. Stepanov. "Aluminium leaching from red muds for their complexing reprocessing." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 3 (December 17, 2018): 317–22. http://dx.doi.org/10.20914/2310-1202-2018-3-317-322.

Full text

Abstract:

Complexing processing of «red muds» (R.M.) - waste of bauxite reprocessing by the Bayer's method, is one of the important tasks of toxic industrial waste utilization. Studied the possibility of aluminum leaching from the R.M. which content reach 14 %, received from Bogoslovsky aluminum plant of JSC «Siberian-Urals Aluminium Company» by aqueous solutions of NaOH. The process was carried out at atmospheric pressure and temperatures near to the boiling point of leaching solutions with the utilization of the residual alkali. The time’s dependence of the aluminum leaching degree from the R.M. by aqueous solutions of NaOH passes through the maximum due to the formation of secondary precipitation of aluminum. The cause of secondary sedimentation is the interaction of silicon with aluminum with formation of insoluble aluminosilicates, for example, Nа2Аl2Si2O8·2Н2O. The conditions of leaching, under which the formation of stable aluminate solutions during the time do not form of secondary precipitations were established. The maximum achieved values of the aluminum leaching degree in autoclave-free conditions was reach 20-25 %. The removal of alkali and part of aluminum under the first stage of complexing processing of R.M. leads to their enrichment in iron. The cakes from aluminum leaching and next carbonate scandium leaching can be used for pyrometallurgical recovery of iron and slag, in which untreated elements are passed, including residual aluminum, scandium, sum of rare earth elements, titanium and zirconium. A significant decrease in the volume of slag opens more opportunities for further isolation their components by acidic methods.

APA, Harvard, Vancouver, ISO, and other styles

50

Imurai, S., Ch Thanachayanont, J. T. H. Pearce, and T. Chairuangsri. "Microstructure And Erosion-Corrosion Behaviour Of As-Cast High Chromium White Irons Containing Molybdenum In Aqueous Sulfuric-Acid Slurry." Archives of Metallurgy and Materials 60, no. 2 (June 1, 2015): 919–23. http://dx.doi.org/10.1515/amm-2015-0230.

Full text

Abstract:

Abstract Microstructure and erosion-corrosion behaviour of as-cast high chromium white irons containing molybdenum in aqueous sulfuric-acid slurry was studied. The experimental irons contained 28 wt.%Cr with a Cr:C ratio of about 10 and up to 10 wt.%Mo. The irons with up to 6 wt.%Mo are hypoeutectic, whereas the iron with 10 wt.%Mo becomes eutectic/peritectic. Mo addition promotes formation of M23C6 and M6C, instead of typical M7C3. Erosion-corrosion testing was performed in aqueous sulfuric-acid slurry containing alumina particles. The hypoeutectic Fe-28Cr-2.7C-1Mo with mainly M7C3 and the eutectic/peritectic Fe-28Cr-2.6C-10Mo showed reduced wear rates of about 30% and 7% of that of the reference iron without Mo addition, respectively. The reduction of the carbide-matrix hardness difference, the increase of corrosion resistance of the matrices, and the increase of macro-hardness are determining factors for the improvement of erosion-corrosion resistance of the irons.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Iron aluminde'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles