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Sample records for ti mn fe

  1. Hydrogen storage in Ti-Mn-(FeV) BCC alloys

    International Nuclear Information System (INIS)

    Santos, S.F.; Huot, J.

    2009-01-01

    Recently, the replacement of vanadium by the less expensive (FeV) commercial alloy has been investigated in Ti-Cr-V BCC solid solutions and promising results were reported. In the present work, this approach of using (FeV) alloys is adopted to synthesize alloys of the Ti-Mn-V system. Compared to the V-containing alloys, the alloys containing (FeV) have a smaller hydrogen storage capacity but a larger reversible hydrogen storage capacity, which is caused by the increase of the plateau pressure of desorption. Correlations between the structure and the hydrogen storage properties of the alloys are also discussed.

  2. Band gap depiction of quaternary FeMnTiAl alloy using Hubbard (U) potential

    Science.gov (United States)

    Bhat, Tahir Mohiuddin; Yousuf, Saleem; Khandy, Shakeel Ahmad; Gupta, Dinesh C.

    2018-05-01

    We have employed self-consistent ab-initio calculations to investigate new quaternary alloy FeMnTiAl by applying Hubbard potential (U). The alloy is found to be stable in ferromagnetic phase with cubic structure. The alloy shows half-metallic (HM) ferromagnet character. The values of minority band gap FeMnTiAl are found to be 0.33 eV respectively. Electronic charge density reveals that both types of bonds covalent as well as ionic are present in the alloy. Thus the new quaternary alloy can be proved as vital contender for spin valves and spin generator devices.

  3. Defect annealing in Mn/Fe-implanted TiO2 (rutile)

    International Nuclear Information System (INIS)

    Gunnlaugsson, H P; Svane, A; Weyer, G; Mantovan, R; Masenda, H; Naidoo, D; Mølholt, T E; Gislason, H; Ólafsson, S; Johnston, K; Bharuth-Ram, K; Langouche, G

    2014-01-01

    A study of the annealing processes and charge state of dilute Fe in rutile TiO 2 single crystals was performed in the temperature range 143–662 K, utilizing online 57 Fe emission Mössbauer spectroscopy following low concentrations (<10 −3  at%) implantation of 57 Mn (T 1/2  = 1.5 min). Both Fe 3+ and Fe 2+ were detected throughout the temperature range. Three annealing stages were distinguished: (i) a broad annealing stage below room temperature leading to an increased Fe 3+ fraction; (ii) a sharp annealing stage at ∼330 K characterized by conversion of Fe 3+ to Fe 2+ and changes in the hyperfine parameters of Fe 2+ , attributed to the annealing of Ti vacancies in the vicinity of the probe atoms; and (iii) an annealing stage in the temperature range from 550 to 600 K, where all Fe ions are transformed to Fe 3+ , attributed to the annealing of the nearby O vacancies. The dissociation energy of Mn Ti –V O pairs was estimated to be 1.60(15) eV. Fe 2+ is found in an environment where it can probe the lattice structure through the nuclear quadrupole interaction evidencing the extreme radiation hardness of rutile TiO 2 . Fe 3+ is found in a paramagnetic state with slow spin–lattice relaxation which follows a ∼T n temperature dependence with 4.1 < n < 6.3 at T > 350 K. (paper)

  4. The centralized control of elemental mercury emission from the flue gas by a magnetic rengenerable Fe-Ti-Mn spinel.

    Science.gov (United States)

    Liao, Yong; Xiong, Shangchao; Dang, Hao; Xiao, Xin; Yang, Shijian; Wong, Po Keung

    2015-12-15

    A magnetic Fe-Ti-Mn spinel was developed to adsorb gaseous Hg(0) in our previous study. However, it is currently extremely restricted in the control of Hg(0) emission from the flue gas for at least three reasons: sorbent recovery, sorbent regeneration and the interference of the chemical composition in the flue gas. Therefore, the effect of SO2 and H2O on the adsorption of gaseous Hg(0) on the Fe-Ti-Mn spinel and the regeneration of spent Fe-Ti-Mn spinel were investigated in this study. Meanwhile, the procedure of the centralized control of Hg(0) emission from the flue gas by the magnetic Fe-Ti-Mn spinel has been analyzed for industrial application. The spent Fe-Ti-Mn spinel can be regenerated by water washing followed by the thermal treatment at 450 °C with no obvious decrease of its ability for Hg(0) capture. Meanwhile, gaseous Hg(0) in the flue gas can be remarkably concentrated during the regeneration, facilitating its safe disposal. Initial pilot test demonstrated that gaseous Hg(0) in the real flue gas can be concentrated at least 100 times by the Fe-Ti-Mn spinel. Therefore, Fe-Ti-Mn spinel was a novel magnetic regenerable sorbent, which can be used for the centralized control of Hg(0) emission from the flue gas. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Thermodynamics of oxygen solutions in Fe-40% Ni-15% Cr melts containing Mn, Si, Ti, Al

    International Nuclear Information System (INIS)

    Dashevskij, V.Ya.; Makarova, N.N.; Grigorovich, K.V.; Kashin, V.I.; Polikarpova, N.V.

    2000-01-01

    Thermodynamic analysis and experimental studied are performed for oxygen solutions in Fe-40% Ni-15% Cr melts where Mn, Si, Ti, Al are used as reducing agents. It is revealed that in the alloys studied the affinity of reducing agents to oxygen essentially lower than in liquid iron, nickel and Fe-40% Ni alloy. This is explained by the fact that the oxygen activity in melts noticeably decreases due to a high chromium content whereas the activity of reducing elements increases in a rather less degree. The agreement between analytical and experimental results confirms the validity of the calculation technique [ru

  6. Spin-polarized electron gas in Co2MSi/SrTiO3(M= Ti, V, Cr, Mn, and Fe) heterostructures

    KAUST Repository

    Nazir, S.; Schwingenschlö gl, Udo

    2016-01-01

    Spin-polarized density functional theory is used to study the TiO2 terminated interfaces between the magnetic Heusler alloys Co2Si (M = Ti, V, Cr, Mn, and Fe) and the non-polar band insulator SrTiO3. The structural relaxation at the interface turns

  7. Shape memory and pseudoelastic properties of Fe-Mn-Si and Ti-Ni based alloys

    International Nuclear Information System (INIS)

    Guenin, G.

    1997-01-01

    The aim of this presentation is to analyse and discuss some recent advances in shape memory and pseudoelastic properties of different alloys. Experimental work in connection with theoretical ones will be reviewed. The first part is devoted to the microstructural origin of shape memory properties of Fe-Mn-Si based alloys (γ-ε transformation); the second part is a synthetic analysis of the effects of thermomechanical treatments on shape memory and pseudoelastic effects in Ti-Ni alloys, with some focus on the behaviour of the R phase introduced. (orig.)

  8. Spin-polarized electron gas in Co2MSi/SrTiO3(M= Ti, V, Cr, Mn, and Fe) heterostructures

    KAUST Repository

    Nazir, S.

    2016-06-08

    Spin-polarized density functional theory is used to study the TiO2 terminated interfaces between the magnetic Heusler alloys Co2Si (M = Ti, V, Cr, Mn, and Fe) and the non-polar band insulator SrTiO3. The structural relaxation at the interface turns out to depend systematically on the lattice mis- match. Charge transfer from the Heusler alloys (mainly the M 3d orbitals) to the Ti dxy orbitals of the TiO2 interface layer is found to gradually grow from M = Ti to Fe, resulting in an electron gas with increasing density of spin-polarized charge carriers. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  9. The design of an Fe-12Mn-O.2Ti alloy steel for low temperature use

    Science.gov (United States)

    Hwang, S. K.; Morris, J. W., Jr.

    1977-01-01

    An investigation was made to improve the low temperature mechanical properties of Fe-8 approximately 12% Mn-O 2Ti alloy steels. A two-phase(alpha + gamma) tempering in combination with cold working or hot working was identified as an effective treatment. A potential application as a Ni-free cryogenic steel was shown for this alloy. It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated martensitic structure and absence of epsilon phase. A significant reduction of the ductile-brittle transition temperature was obtained in this alloy. The nature and origin of brittle fracture in Fe-Mn alloys were also investigated. Two embrittling regions were found in a cooling curve of an Fe-12Mn-O 2Ti steel which was shown to be responsible for intergranular fracture. Auger electron spectroscopy identified no segregation during solution-annealing treatment. Avoiding the embrittling zones by controlled cooling led to a high cryogenic toughness in a solution-annealed condition.

  10. The effects of Ni, Mo, Ti and Si on the mechanical properties of Cr free Mn steel (Fe-25Mn-5Al-2C)

    International Nuclear Information System (INIS)

    Schuon, S.R.

    1982-01-01

    The FeMnAlC alloys may hold potential as Cr-free replacements for high strategic material iron base superalloys, but little is known about their intermediate temperature (650 C to 870 C) mechanical properties. The effects of alloying elements on the mechanical properties of model FeMnAlC alloys were studied. Results showed that modified FeMnAlC alloys had promising short term, intermediate temperature properties but had relatively poor stress rupture lives at 172 MPa and 788 C. Room temperature and 788 C tensile strength of FeMnAlC alloys were better than common cast stainless steels. Changes in room temperature tensile and 788 C tensile strength and ductility, and 788 C stress rupture life were correlated with changes in Ni, Mo, Ti, and Si levels due to alloying effects on interstitial carbon levels and carbide morphology. Fe-25Mn-5Al-2C had a very poor stress rupture life at 172 MPa and 788 C. Addition of carbide-forming elements improved the stress rupture life

  11. Fabrication of Mg-X-O (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn) barriers for magnetic tunnel junctions

    Science.gov (United States)

    Yakushiji, K.; Kitagawa, E.; Ochiai, T.; Kubota, H.; Shimomura, N.; Ito, J.; Yoda, H.; Yuasa, S.

    2018-05-01

    We fabricated magnetic tunnel junctions with a 3d-transition material(X)-doped MgO (Mg-X-O) barrier, and evaluated the effect of the doping on magnetoresistance (MR) and microstructure. Among the variations of X (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn), X = Fe and Mn showed a high MR ratio of more than 100%, even at a low resistance-area product of 3 Ωμm2. The microstructure analysis revealed that (001) textured orientation formed for X = Fe and Mn despite substantial doping (about 10 at%). The elemental mappings indicated that Fe atoms in the Mg-Fe-O barrier were segregated at the interfaces, while Mn atoms were evenly involved in the Mg-Mn-O barrier. This suggests that MgO has high adaptability for Fe and Mn dopants in terms of high MR ratio.

  12. Defect annealing in Mn/Fe-implanted TiO2(rutile)

    CERN Document Server

    Gunnlaugsson, H P; Masenda, H; Mølholt, T E; Johnston, K; Bharuth-Ram, K; Gislason, H; Langouche, G; Naidoo, D; Ólafsson, S; Svane, A; Weyer, G

    2014-01-01

    A study of the annealing processes and charge state of dilute Fe in rutile TiO2 single crystals was performed in the temperature range 143-662 K, utilizing online 57Fe emission Mossbauer spectroscopy following low concentrations ( 350 K.

  13. Effect of Mn and AlTiB Addition and Heattreatment on the Microstructures and Mechanical Properties of Al-Si-Fe-Cu-Zr Alloy.

    Science.gov (United States)

    Yoo, Hyo-Sang; Kim, Yong-Ho; Lee, Seong-Hee; Son, Hyeon-Taek

    2018-09-01

    The microstructure and mechanical properties of as-extruded Al-0.1 wt%Si-0.2 wt%Fe- 0.4 wt%Cu-0.04 wt%Zr-xMn-xAlTiB (x = 1.0 wt%) alloys under various annealing processes were investigated and compared. After the as-cast billets were kept at 400 °C for 1 hr, hot extrusion was carried out with a reduction ratio of 38:1. In the case of the as-extruded Al-Si-Fe-Cu-Zr alloy at annealed at 620 °C, large equiaxed grain was observed. When the Mn content is 1.0 wt%, the phase exhibits a skeleton morphology, the phase formation in which Mn participated. Also, the volume fraction of the intermetallic compounds increased with Mn and AlTiB addition. For the Al-0.1Si-0.2Fe-0.4Cu-0.04Zr alloy with Mn and AlTiB addition from 1.0 wt%, the ultimate tensile strength increased from 100.47 to 119.41 to 110.49 MPa. The tensile strength of the as-extruded alloys improved with the addition of Mn and AlTiB due to the formation of Mn and AlTiB-containing intermetallic compounds.

  14. Conduction Mechanism by Using CBH Model in Fe3+ and Mn3+ Ion Modified Pb(Zr0.65−xAxTi0.35O3 (A = Mn3+/Fe3+ Ceramics

    Directory of Open Access Journals (Sweden)

    Niranjan Sahu

    2013-01-01

    Full Text Available Polycrystalline samples of manganese and iron substituted lead zirconium titanate (PZT with general formula Pb(Zr0.65−xAxTi0.35O3 (A = Mn3+ and Fe3+ ceramics have been synthesized by high temperature solid state reaction technique. X-ray diffraction (XRD patterns were recorded at room temperature to study the crystal structure. All the patterns could be refined by employing the Rietveld method to R3c space group with rhombohedral symmetry. Microstructural properties of the materials were analyzed by scanning electron microscope (SEM, and compositional analysis was carried out by energy dispersive spectrum (EDS measurements. All the materials exhibit ferroelectric to paraelectric transition. The variation of dielectric constant and loss tangent with temperature and frequency is investigated. The decrease of activation energy and increases of AC conductivity with the Fe3+ or Mn3+ ion concentration have been observed. The AC conductivity has been analyzed by the power law. The frequency exponent with the function of temperature has been analyzed by assuming that the AC conduction mechanism is the correlated barrier hopping (CBH model. The conduction in the present sample is found to be of bipolaron type for Mn3+ ion-doped sample. However, the conduction mechanism could not be explained by CBH model for Fe3+ ion-doped sample.

  15. Structural, dielectric and magnetic properties of Mn modified xBiFeO{sub 3}-(1−x)BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Zhonghua, E-mail: zhdai@mail.xjtu.edu.cn [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Liu, Lu; Ying, Guobing; Yuan, Ming [College of Mechanics and Materials, Hohai University, Nanjing 210098 (China); Ren, Xiaobing [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2017-07-15

    Manganese doped xBiFeO{sub 3}-(1−x)BaTiO{sub 3}(x=0.67–0.82) ceramics were prepared by solid-state method. The structural, dielectric and magnetic properties were investigated after annealing in vacuum at 773 K. X-ray diffraction analysis indicated that all samples crystallized in pure perovskite structure. The ceramics displays a typical ferroelectric loop, with a max remnant polarization P{sub r} of 25.6 µC/cm{sup 2}. The piezoelectric coefficient d{sub 33} of Manganese doped 0.67BiFeO{sub 3}0.33BaTiO{sub 3} is 139 pC/N and its temperature dependence of dielectric constant exhibits a broad anomaly. The Manganese doped 0.75BiFeO{sub 3}0.25BaTiO{sub 3} ceramic shows ferrimagnetism at room temperature, with remnant magnetization M{sub r} of 0.31 emu/g and ferrimagnetic transition temperature T{sub N} of ~420 °C. - Highlights: • In this manuscript, a technique combined Mn doping which is able to fabricate point defects and annealing in vacuum which can stabilize the unstable ion was investigated. We studied the electrical properties of Mn doped BiFeO{sub 3}-BaTiO{sub 3} ceramics after vacuum annealing treatment at appropriate temperature. • Our result is that Mn modification and heat treatment are effective methods to solve the problem of high leakage of BiFeO{sub 3}-BaTiO{sub 3} system ceramic prepared by solid-state method. It exhibited a enhanced field-induced ferromagnetic ordering with promising potential in spintronics and recording media applications.

  16. Mn/TiO2 and Mn–Fe/TiO2 catalysts synthesized by deposition precipitation—promising for selective catalytic reduction of NO with NH3 at low temperatures

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Schill, Leonhard; Jensen, Anker Degn

    2015-01-01

    Mn/TiO2and Mn–Fe/TiO2catalysts have been prepared by impregnation (IMP) and deposition-precipitation (DP) techniques and characterized by N2 physisorption, XRPD, NH3-TPD, H2-TPR, XPS and TGA. 25 wt% Mn0.75Fe0.25Ti-DP catalyst, prepared by deposition precipitation with ammonium carbamate (AC......) as a precipitating agent, showed superior low-temperature SCR (selective catalytic reduction) of NO with NH3. The superior catalytic activity of the 25 wt% Mn0.75Fe0.25Ti-DP catalyst is probably due to the presence of amorphous phases of manganese oxide, iron oxide, high surface area, high total acidity......, acidstrength and ease of reduction of manganese oxide and iron oxide on TiO2in addition to formation of an SCR active MnOx phase with high content of chemisorbed oxygen (Oα). The optimum catalyst might beused as tail-end SCR catalysts in, e.g., biomass-fired power plants and waste incineration plants....

  17. High-pressure studies on electronic and mechanical properties of FeBO3 (B = Ti, Mn, Cr) ceramics - a first-principles study

    Science.gov (United States)

    Kishore, N.; Nagarajan, V.; Chandiramouli, R.

    2018-04-01

    Using the density functional theory (DFT) method, the electronic and mechanical properties of perovskites FeBO3 (B = Ti, Mn, Cr) nanostructures were studied in the pressure range of 0-100 GPa. The band structure studies show the change in the band structure upon substitution of different B cation in FeBO3 perovskite structure. The density of states spectrum gives the perception of change in the electronic properties of FeBO3 with the substitution of B cation. The bulk, shear and Young's moduli were calculated and an increase in the moduli is noticed. Moreover, the hardness increases under high pressure. The high-pressure studies of FeBO3 perovskite nanostructures are explored at atomistic level. The findings show that ductility and hardness of FeBO3 get increased upon an increase in the applied pressure. The substitution of Ti, Mn and Cr on FeBO3 shows a significant change in the electronic and mechanical properties.

  18. Grain Refinement of Al-Si-Fe-Cu-Zn-Mn Based Alloy by Al-Ti-B Alloy and Its Effect on Mechanical Properties.

    Science.gov (United States)

    Yoo, Hyo-Sang; Kim, Yong-Ho; Jung, Chang-Gi; Lee, Sang-Chan; Lee, Seong-Hee; Son, Hyeon-Taek

    2018-03-01

    We investigated the effects of Al-5.0wt%Ti-1.0wt%B addition on the microstructure and mechanical properties of the as-extruded Al-0.15wt%Si-0.2wt%Fe-0.3wt%Cu-0.15wt%Zn-0.9wt%Mn based alloys. The Aluminum alloy melt was held at 800 °C and then poured into a mould at 200 °C. Aluminum alloys were hot-extruded into a rod that was 12 mm in thickness with a reduction ratio of 38:1. AlTiB addition to Al-0.15Si-0.2Fe-0.3Cu-0.15Zn-0.9Mn based alloys resulted in the formation of Al3Ti and TiB2 intermetallic compounds and grain refinement. With increasing of addition AlTiB, ultimate tensile strength increased from 93.38 to 99.02 to 100.01 MPa. The tensile strength of the as-extruded alloys was improved due to the formation of intermetallic compounds and grain refinement.

  19. Structure and cation distribution of (Mn0.5Zn0.5)Fe2O4 thin films on SrTiO3(001)

    Science.gov (United States)

    Welke, M.; Brachwitz, K.; Lorenz, M.; Grundmann, M.; Schindler, K.-M.; Chassé, A.; Denecke, R.

    2017-06-01

    A comprehensive study on growth of ferrimagnetic manganese zinc ferrite (Mn0.5Zn0.5Fe2O4) films on single crystalline strontium titanate(001) (SrTiO3) substrates was carried out. Under the optimized conditions, a thin film with a layer thickness of 200 nm was deposited, and the structural properties were investigated. Contrary to data published in literature, no buffer layer was necessary to achieve epitaxial growth of a poorly lattice-matched layer. This was confirmed for Mn0.5Zn0.5Fe2O4(001) on SrTiO3(001) by x-ray diffraction and the adjoined phi scans, which also revealed a lattice compression of 1.2% of the manganese zinc ferrite film in the out-of-plane direction. Using x-ray photoelectron spectroscopy, the near surface stoichiometry of the film could be shown to agree with the intended one within the uncertainty of the method. X-ray absorption spectroscopy showed an electronic structure close to that published for bulk samples. Additional x-ray magnetic circular dichroism investigations were performed to answer detailed structural questions by a comparison of experimental data with the calculated ones. The calculations took into account ion sites (tetrahedral vs. octahedral coordination) as well as the charge of Fe ions (Fe2+ vs. Fe3+). Contrary to the expectation for a perfect normal spinel that only Fe3+ ions are present in octahedral sites, hints regarding the presence of additional Fe2+ in octahedral sites as well as Fe3+ ions in tetrahedral sites have been obtained. Altogether, the layer could be shown to be mostly in a normal spinel configuration.

  20. Enhancement in electrical and magnetic properties with Ti-doping in Bi0.5La0.5Fe0.5Mn0.5O3

    Science.gov (United States)

    Singh, Rahul; Gupta, Prince Kumar; Kumar, Shiv; Joshi, Amish G.; Ghosh, A. K.; Patil, S.; Chatterjee, Sandip

    2017-04-01

    In this investigation, we have synthesized Bi0.5La0.5Fe0.5Mn0.5-xTixO3 (where x = 0 and 0.05) samples. The Rietveld refinement of X-ray diffraction (XRD) patterns shows that the systems crystallize in the orthorhombic phase with the Pnma space group. The observed Raman modes support the XRD results. The appearance of prominent A1-3 and weak E-2 modes in Bi0.5La0.5Fe0.5Mn0.45Ti0.05O3 indicates the presence of chemically more active Bi-O covalent bonds. Ferromagnetism of Bi0.5La0.5Fe0.5Mn0.5O3 is enhanced by Ti doping at the Mn-site, indicating that these particular samples might be interesting for device applications.

  1. Characterisation of a natural quartz crystal as a reference material for microanalytical determination of Ti, Al, Li, Fe, Mn, Ga and Ge

    Science.gov (United States)

    Audetat, Andreas; Garbe-Schonberg, Dieter; Kronz, Andreas; Pettke, Thomas; Rusk, Brian G.; Donovan, John J.; Lowers, Heather

    2015-01-01

    A natural smoky quartz crystal from Shandong province, China, was characterised by laser ablation ICP-MS, electron probe microanalysis (EPMA) and solution ICP-MS to determine the concentration of twenty-four trace and ultra trace elements. Our main focus was on Ti quantification because of the increased use of this element for titanium-in-quartz (TitaniQ) thermobarometry. Pieces of a uniform growth zone of 9 mm thickness within the quartz crystal were analysed in four different LA-ICP-MS laboratories, three EPMA laboratories and one solution-ICP-MS laboratory. The results reveal reproducible concentrations of Ti (57 ± 4 μg g-1), Al (154 ± 15 μg g-1), Li (30 ± 2 μg g-1), Fe (2.2 ± 0.3 μg g-1), Mn (0.34 ± 0.04 μg g-1), Ge (1.7 ± 0.2 μg g-1) and Ga (0.020 ± 0.002 μg g-1) and detectable, but less reproducible, concentrations of Be, B, Na, Cu, Zr, Sn and Pb. Concentrations of K, Ca, Sr, Mo, Ag, Sb, Ba and Au were below the limits of detection of all three techniques. The uncertainties on the average concentration determinations by multiple techniques and laboratories for Ti, Al, Li, Fe, Mn, Ga and Ge are low; hence, this quartz can serve as a reference material or a secondary reference material for microanalytical applications involving the quantification of trace elements in quartz.

  2. Molecular orbital (SCF-X-α-SW) theory of Fe2+-Mn3+, Fe3+-Mn2+, and Fe3+-Mn3+ charge transfer and magnetic exchange in oxides and silicates

    Science.gov (United States)

    Sherman, David M.

    1990-01-01

    Metal-metal charge-transfer and magnetic exchange interactions have important effects on the optical spectra, crystal chemistry, and physics of minerals. Previous molecular orbital calculations have provided insight on the nature of Fe2+-Fe3+ and Fe2+-Ti4+ charge-transfer transitions in oxides and silicates. In this work, spin-unrestricted molecular orbital calculations on (FeMnO10) clusters are used to study the nature of magnetic exchange and electron delocalization (charge transfer) associated with Fe3+-Mn2+, Fe3+-Mn3+, and Fe2+-Mn3+ interactions in oxides and silicates. 

  3. Proton induced reactions on Ti, V, Mn, Fe, Co and Ni. Measurement and hybrid model analysis of integral excitation functions and their application in model calculation for the production of cosmogenic nuclides

    International Nuclear Information System (INIS)

    Stueck, R.

    1983-01-01

    By means of the stacked foil technique 67 excitation functions of p induced reactions on the target elements Ti, V, Mn, Fe, Co, and Ni were measured in the energy range between 45 and 200 MeV. For residual nuclei with 42 [de

  4. Electrochemical activity of Li{sub 2}FeTiO{sub 4} and Li{sub 2}MnTiO{sub 4} as potential active materials for Li ion batteries: A comparison with Li{sub 2}NiTiO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kuezma, Mirjana; Dominko, Robert; Bele, Marjan; Jamnik, Janko [National Institute of Chemistry, Ljubljana (Slovenia); Meden, Anton [Faculty of Chemistry and Chemical Technology, University of Ljubljana (Slovenia); Makovec, Darko [Jozef Stefan Institute, Ljubljana (Slovenia); Gaberscek, Miran [National Institute of Chemistry, Ljubljana (Slovenia); Faculty of Chemistry and Chemical Technology, University of Ljubljana (Slovenia)

    2009-04-01

    We demonstrate, for the first time, a considerable electrochemical activity of two members of lithium transition element titanates: Li{sub 2}FeTiO{sub 4} and Li{sub 2}MnTiO{sub 4}. Both materials consist of 10-20 nm particles embedded in a conductive carbon coating. We show that not the coating but the small particle size is decisive for materials' activity. Li{sub 2}FeTiO{sub 4} shows a stable reversible capacity of up to 123 mA hg{sup -1} at C/20 and 60 C which is 83% of the theoretical value for exchange of 1 electron (148 mA hg{sup -1}). Li{sub 2}MnTiO{sub 4} could only be prepared in a nanosized form that contained about 30% of impurities. The capacity of the whole material (including impurities) is comparable to that of Li{sub 2}FeTiO{sub 4} but the cycling stability is much poorer. In contrast to the Fe and Mn analogues, the third member of the titanate family, Li{sub 2}NiTiO{sub 4}, shows a good electrochemistry even when the particle size is much larger (about 100 nm). During initial cycles at C/10 and 60 C, exchange of more than 1 electron per compound formula has been observed. The cycling stability at high temperatures, however, is poor. (author)

  5. Solid-state reactions during mechanical alloying of ternary Fe-Al-X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems: A review

    Science.gov (United States)

    Hadef, Fatma

    2016-12-01

    The last decade has witnessed an intensive research in the field of nanocrystalline materials due to their enhanced properties. A lot of processing techniques were developed in order to synthesis these novel materials, among them mechanical alloying or high-energy ball milling. In fact, mechanical alloying is one of the most common operations in the processing of solids. It can be used to quickly and easily synthesize a variety of technologically useful materials which are very difficult to manufacture by other techniques. One advantage of MA over many other techniques is that is a solid state technique and consequently problems associated with melting and solidification are bypassed. Special attention is being paid to the synthesis of alloys through reactions mainly occurring in solid state in many metallic ternary Fe-Al-X systems, in order to improve mainly Fe-Al structural and mechanical properties. The results show that nanocrystallization is the common result occurring in all systems during MA process. The aim of this work is to illustrate the uniqueness of MA process to induce phase transformation in metallic Fe-Al-X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems.

  6. Initial oxidation of TiFe{sub 1−x}Mn{sub x} (x = 0–0.3) by low dose exposures to H{sub 2}O and O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Shwartz, A. [Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Shamir, N., E-mail: noah.shamir@gmail.com [Nuclear research Center – Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel); Froumin, N. [Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Zalkind, S.; Edry, I.; Haim, A. [Nuclear research Center – Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel); Mintz, M.H. [Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Nuclear research Center – Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel)

    2014-10-15

    Highlights: • Thermodynamics of adsorption and initial oxidation of TiFe{sub 1−x}Mn{sub x} by H{sub 2}O versus O{sub 2}. • Explanation of different oxide formations. • Explanation of the role of the different constituents of the alloys in the processes. - Abstract: The very initial room-temperature oxidation processes of the ternary pseudo-binary TiFe{sub 1−x}Mn{sub x} (x = 0–0.3) intermetallics by trace amounts of H{sub 2}O vapor and O{sub 2} were studied utilizing XPS and AES techniques. Different reactivities of the two gases were obtained, with a lower oxidation ability of H{sub 2}O, relative to O{sub 2}, as anticipated from thermodynamic considerations. The exposure to O{sub 2} results in a two stage oxidation of the Ti ingredient, which first converts into a divalent TiO (up to exposures of about 2 L), then proceeds into a tetravalent TiO{sub 2} form. Unlike oxygen, water exposure produces only the divalent oxide through the whole exposure range studied (11 L). The Mn component in these compounds is oxidized only by O{sub 2} and not by H{sub 2}O. The Fe ingredient is not oxidized at all and remains in its metallic form up to exposures of 30 L.

  7. First-Principles Study on the Structural Stability and Segregation Behavior of γ-Fe/Cr2N Interface with Alloying Additives M (M = Mn, V, Ti, Mo, and Ni

    Directory of Open Access Journals (Sweden)

    Hui Huang

    2016-07-01

    Full Text Available This study investigated the structural stability and electrochemical properties of alloying additives M (M = Mn, V, Ti, Mo, or Ni at the γ-Fe(111/Cr2N(0001 interface by the first-principles method. Results indicated that V and Ti were easily segregated at the γ-Fe(111/Cr2N(0001 interface and enhanced interfacial adhesive strength. By contrast, Ni and Mo were difficult to segregate at the γ-Fe(111/Cr2N(0001 interface. Moreover, the results of the work function demonstrated that alloying additives Mn reduced local electrochemical corrosion behavior of the γ-Fe(111/Cr2N(0001 interface by cutting down Volta potential difference (VPD between clean γ-Fe(111 and Cr2N(0001, while alloying additives V, Ti, Mo, and Ni at the γ-Fe(111/Cr2N(0001 interface magnified VPD between clean γ-Fe(111 and Cr2N(0001, which were low-potential sites that usually serve as local attack initiation points.

  8. Catalytic Oxidation of Propene over Pd Catalysts Supported on CeO2, TiO2, Al2O3 and M/Al2O3 Oxides (M = Ce, Ti, Fe, Mn

    Directory of Open Access Journals (Sweden)

    Sonia Gil

    2015-04-01

    Full Text Available In the following work, the catalytic behavior of Pd catalysts prepared using different oxides as support (Al2O3, CeO2 and TiO2 in the catalytic combustion of propene, in low concentration in excess of oxygen, to mimic the conditions of catalytic decomposition of a volatile organic compound of hydrocarbon-type is reported. In addition, the influence of different promoters (Ce, Ti, Fe and Mn when added to a Pd/Al2O3 catalyst was analyzed. Catalysts were prepared by the impregnation method and were characterized by ICP-OES, N2 adsorption, temperature-programmed reduction, temperature-programmed oxidation, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. Catalyst prepared using CeO2 as the support was less easily reducible, due to the stabilization effect of CeO2 over the palladium oxides. Small PdO particles and, therefore, high Pd dispersion were observed for all of the catalysts, as confirmed by XRD and TEM. The addition of Ce to the Pd/Al2O3 catalysts increased the metal-support interaction and the formation of highly-dispersed Pd species. The addition of Ce and Fe improved the catalytic behavior of the Pd/Al2O3 catalyst; however, the addition of Mn and Ti decreased the catalytic activity in the propene oxidation. Pd/TiO2 showed the highest catalytic activity, probably due to the high capacity of this catalyst to reoxidize Pd into PdO, as has been found in the temperature-programmed oxidation (TPO experiments.

  9. Monte Carlo and Ab-initio calculation of TM (Ti, V, Cr, Mn, Fe, Co, Ni) doped MgH{sub 2} hydride: GGA and SIC approximation

    Energy Technology Data Exchange (ETDEWEB)

    Salmani, E., E-mail: elmehdisalmani@gmail.com [LMPHE (URAC12), Faculty of Sciences, Mohammed V University in Rabat (Morocco); Laghrissi, A.; Lamouri, R. [LMPHE (URAC12), Faculty of Sciences, Mohammed V University in Rabat (Morocco); Benchafia, E. [Department of Materials Science and Engineering, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Ez-Zahraouy, H. [LMPHE (URAC12), Faculty of Sciences, Mohammed V University in Rabat (Morocco); Benyoussef, A. [Institute for Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco)

    2017-02-15

    MgH{sub 2}: TM (TM: V, Cr, Mn, Fe, Co, Ni) based dilute magnetic semiconductors (DMS) are investigated using first principle calculations. Our results show that the ferromagnetic state is stable when TM introduces magnetic moments as well as intrinsic carriers in TM: Co, V, Cr, Ti; Mg{sub 0.95}TM{sub 0.05}H{sub 2}. Some of the DMS Ferro magnets under study exhibit a half-metallic behavior, which make them suitable for spintronic applications. The double exchange is shown to be the underlying mechanism responsible for the magnetism of such materials. The exchange interactions obtained from first principle calculations and used in a classical Ising model by a Monte Carlo approach resulted in ferromagnetic states with Curie temperatures within the ambient conditions. - Highlights: • The half-metallic aspect was proven to take place for Ti, Cr, Co and Ni. • The TM impurities are shown to introduce the magnetic moment that makes MgH{sub 2} good candidates for spintronic applications.

  10. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming

    2013-09-07

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  11. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming; Zhou, Wenke; Zhu, Xinhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

    2013-01-01

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  12. Substitution studies of Mn and Fe in Ln{sub 6}W{sub 4}Al{sub 43} (Ln=Gd, Yb) and the structure of Yb{sub 6}Ti{sub 4}Al{sub 43}

    Energy Technology Data Exchange (ETDEWEB)

    Treadwell, LaRico J.; Watkins-Curry, Pilanda [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080 (United States); McAlpin, Jacob D. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Prestigiacomo, Joseph; Stadler, Shane [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Chan, Julia Y., E-mail: Julia.Chan@utdallas.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2014-02-15

    The synthesis and characterization of Mn- and Fe-substituted Ln{sub 6}W{sub 4}Al{sub 43} (Ln=Gd, Yb) and Yb{sub 6}Ti{sub 4}Al{sub 43} are reported. The compounds adopt the Ho{sub 6}Mo{sub 4}Al{sub 43} structure type with lattice parameters of a∼11 Å and c∼17.8 Å with structural site preferences for Mn and Fe. The magnetization of Yb{sub 6}W{sub 4}Al{sub 43} is sensitive to Mn and Fe doping, which is evident by an increase in the field dependent magnetization. Gd{sub 6}W{sub 4}Al{sub 43}, Gd{sub 6}W{sub 4}Al{sub 42.31(11)}Mn{sub 0.69(11)}, and Gd{sub 6}W{sub 4}Al{sub 41.69(12)}Fe{sub 1.30(12)} order antiferromagnetically in the ab- and c-directions at 15, 14, and 13 K, respectively, with positive Weiss constants, suggesting the presence of ferromagnetic exchange interactions. Anisotropic magnetization data of Gd{sub 6}W{sub 4}Al{sub 43−y}T{sub y} (T=Mn, Fe) analogs are discussed. - Graphical abstract: The magnetic susceptibility of Ln{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} (Ln = Gd, Yb; T= Mn, Fe). Display Omitted - Highlights: • Single crystals of Ln{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} were grown with Al-flux. • Anisotropic magnetic behavior were determined on single crystals. • Gd{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} (T=Mn, Fe) analogs order antiferromagnetically.

  13. Ab initio study of the magnetic ordering in the semiconductors Mn{sub x}Ti{sub 1-x}O{sub 2}, Co{sub x}Ti{sub 1-x}O{sub 2} and Fe{sub x}Ti{sub 1-x}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Errico, L.A. [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900, La Plata (Argentina)]. E-mail: errico@fisica.unlp.edu.ar; Weissmann, M. [Departamento de Fisica, Comision Nacional de Energia Atomica, Avda. del Libertador 8250, 1429 Buenos Aires (Argentina); Renteria, M. [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900, La Plata (Argentina)

    2004-12-31

    In this work we present a set of density-functional-theory calculations in the systems Mn{sub x}Ti{sub 1-x}O{sub 2}, Fe{sub x}Ti{sub 1-x}O{sub 2}, and Co{sub x}Ti{sub 1-x}O{sub 2}. The calculations were performed with the full-potential linearized augmented plane wave method, assuming that the magnetic impurities substitutionally replace the Ti ions and considering different distributions of them in the host lattice. Our results show that the system Co{sub x}Ti{sub 1-x}O{sub 2} is ferromagnetic, while Mn{sub x}Ti{sub 1-x}O{sub 2} is antiferromagnetic. In both cases, this is independent of the distribution of the impurities in the TiO{sub 2} lattice. First results obtained in the system Fe{sub x}Ti{sub 1-x}O{sub 2} are also presented.

  14. Gaseous Phase and Electrochemical Hydrogen Storage Properties of Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu for Nickel Metal Hydride Battery Applications

    Directory of Open Access Journals (Sweden)

    Jean Nei

    2016-07-01

    Full Text Available Structural, gaseous phase hydrogen storage, and electrochemical properties of a series of the Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu metal hydride alloys were studied. X-ray diffraction (XRD and scanning electron microscopy (SEM revealed the multi-phase nature of all alloys, which were composed of a stoichiometric TiNi matrix, a hyperstoichiometric TiNi minor phase, and a Ti2Ni secondary phase. Improvement in synergetic effects between the main TiNi and secondary Ti2Ni phases, determined by the amount of distorted lattice region in TiNi near Ti2Ni, was accomplished by the substitution of an element with a higher work function, which consequently causes a dramatic increase in gaseous phase hydrogen storage capacity compared to the Ti50Zr1Ni49 base alloy. Capacity performance is further enhanced in the electrochemical environment, especially in the cases of the Ti50Zr1Ni49 base alloy and Ti50Zr1Ni44Co5 alloy. Although the TiNi-based alloys in the current study show poorer high-rate performances compared to the commonly used AB5, AB2, and A2B7 alloys, they have adequate capacity performances and also excel in terms of cost and cycle stability. Among the alloys investigated, the Ti50Zr1Ni44Fe5 alloy demonstrated the best balance among capacity (394 mAh·g−1, high-rate performance, activation, and cycle stability and is recommended for follow-up full-cell testing and as the base composition for future formula optimization. A review of previous research works regarding the TiNi metal hydride alloys is also included.

  15. Processing and characterization of AlCoFeNiXTi{sub 0,5} (X = Mn, V) high entropy alloys; Processamento e caracterizacao de ligas de alta entropia AlCoFeNixTi{sub 0,5} (X = Mn, V)

    Energy Technology Data Exchange (ETDEWEB)

    Triveno Rios, C., E-mail: carlos.triveno@ufabc.edu.br [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Engenharia de Materiais; Lopes, E.S.N.; Caram, R. [Universidade Estadual de Campinas (FEM/DEMA/UNICAMP), Campinas, SP (Brazil); Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), Sao Carlos, SP (Brazil). Departamento de Engenharia de Materiais

    2014-07-01

    The microstructure of high entropy alloys consists of solid solution phases with FC and BCC simple structures, contrary to classical metallurgy where they form complex structures of intermetallic compounds. Because of this they have several attractive properties for engineering applications. In this work the AlCoFeNiMnTi{sub 0,5} and AlCoFeNiVTi{sub 0,5} alloys were processed by melting arc. Since the main objective was the microstructural and mechanical characterization of ingots as-cast. The alloys were characterized by scanning electron microscopy, X-ray diffraction, microhardness and cold compression test. The results showed that the microstructure consists mainly of dendrites and interdendritic regions consisting of metastable crystalline phases. It was also observed that the AlCoFeNiVTi{sub 0,5} alloy showed better mechanical properties than the AlCoFeNiMnTi{sub 0,5} alloy. This may be associated with differences in the parameters of formation of simple solid solution phases between the two alloys. (author)

  16. Photoionization study of Ne-like K9+, Ca10+, Sc11+, Ti12+, V13+, Cr14+, Mn15+, and Fe16+ ions using the screening constant by unit nuclear charge method

    International Nuclear Information System (INIS)

    Goyal, Arun; Khatri, Indu; Sow, Malick; Sakho, Ibrahima; Aggarwal, Sunny; Singh, A.K.; Mohan, Man

    2016-01-01

    Photoionization of the 2s 2 2p 6 ( 1 S 0 ) ground state of the Ne-like (Z=19–29) ions is presented in this paper. Resonance energies and total natural width of the 2s2p 6 np 1 P series of the Ne-like K 9+ , Ca 10+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , Mn 15+ , and Fe 16+ are reported. All the calculations are made using the Screening constant by unit nuclear charge (SCUNC) formalism. New data for Ne-like K 9+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , and Mn 15+ ions are tabulated. Good agreements are found with available literature data. - Highlights: • Photoionization of ground state of the Ne-like (Z=19–29) presented. • good agreements with scarce literature data. • New data for Ne-like K 9+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , and Mn 15+ ions. • Useful guidelines for application in laboratory, astrophysics, and plasma physics.

  17. Magnetically tunable dielectric, impedance and magnetoelectric response in MnFe{sub 2}O{sub 4}/(Pb{sub 1−x}Sr{sub x})TiO{sub 3} composites thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bala, Kanchan, E-mail: bala.kanchan1987@gmail.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Kotnala, R.K. [CSIR, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Negi, N.S., E-mail: nsn_phy_hpu@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

    2017-02-15

    We have synthesized piezomagnetic–piezoelectric composites thin films MnFe{sub 2}O{sub 4}/(Pb{sub 1−x}Sr{sub x})TiO{sub 3}, where x=0.1, 0.2, and 0.3, using the metalorganic deposition (MOD) reaction method. The structural and microstructural analysis using the X-ray diffraction (XRD), AFM, and SEM reveals the presence of homogenous growth of both pervoskite and spinel phases in the composite films. Our results show that all the composites films exhibit good multiferroic as well as considerable magnetoelectric coupling. The impedance (Z′ and Z″) and electrical modulus (M′ and M″) Nyquist plots show distinct electrical responses with the magnetic field. Our analyses suggest that this electrical response arises due to the coexistence of the high resistive phase and the comparatively conductive phase in the MFO/PST composite films. The maximum magnetoelectric coefficient (α) is found to be 4.29 V Oe{sup −1} cm{sup −1} and 2.82 V Oe{sup −1} cm{sup −1} for compositions x=0.1 and 0.2. These values are substantially larger than those reported for bilayer composites thin films in literature and make them interesting for room temperature device applications. - Highlights: • Influence of Sr doping on multiferroic and magnetoelectric properties composites thin films of MnFe{sub 2}O{sub 4} and (Pb, Sr)TiO{sub 3}. • Dielectric constant and dielectric loss with application of magnetic field. • Magnetically tunable AC electrical properties. • Magnetoelectric coupling in MnFe{sub 2}O{sub 4}/(Pb, Sr)TiO{sub 3} composite films by passive method.

  18. The microstructure and composition analysis of (Ba,Sr)O.6Fe_2_1_-_X)(Mn,Ti)_xO_3 (X = 0, 0,25; and 0,5)

    International Nuclear Information System (INIS)

    Wisnu Ari Adi; Azwar Manaf

    2010-01-01

    The raw materials were BaCO_3_' srCO_3_' Fe_2O_3_' MnCO_3 and TiO_2. The compound was synthesized by a solid state reaction method. The finely mixed powder was compacted at 5000 psi into pellets. These pellets were sintered in the electric chamber furnace THERMOLYNE at 1050 °C for 15 h with a heating cycle of 5°C/min ramp rate and cooled in the furnace to room temperature. The result showed that the X-ray diffraction pattern obtained can be identified as the SrO.6Fe_2O3 single phase (ICDD PDF 33-1340) for all samples according to the Hanawalt table. The microstructure analyses showed that the particle shapes are polygonal with the varied particle sizes of 2-5 μm distributed homogeneously on the surface of the samples. The element analysis showed that the compound compositions have already suitable to expectation. It is concluded that a single phase Mn-Ti substituted (Ba,Sr)O.6Fe_2O_3 have been made successfully suitable of compound composition was expected. (author)

  19. Swelling of Fe-Mn and Fe-Cr-Mn alloys at high neutron fluence

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.

    1986-06-01

    Swelling data on neutron-irradiated simple Fe-Cr-Mn and Fe-Mn alloys, as well as commercial Fe-Cr-Mn base alloys are now becoming available at exposure levels approaching 50 dpa. The swelling rate decreases from the ∼1%/dpa found at lower exposures, probably due to the extensive formation of ferritic phases. As expected, commercial alloys swell less than the simple alloys

  20. Multi-walled carbon nanotubes functionalized by carboxylic groups: Activation of TiO{sub 2} (anatase) and phosphate olivines (LiMnPO{sub 4}; LiFePO{sub 4}) for electrochemical Li-storage

    Energy Technology Data Exchange (ETDEWEB)

    Kavan, Ladislav; Zukalova, Marketa [J. Heyrovsky Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223 Prague 8 (Czech Republic); Bacsa, Revathi; Tunckol, Meltem; Serp, Philippe [Laboratoire de Chimie de Coordination, UPR CNRS 8241, composante ENSIACET, Universite de Toulouse UPS-INP-LCC 4, Allee Emile Monso, BP 74233, 31432, Toulouse (France); Zakeeruddin, Shaik M.; Le Formal, Florian; Graetzel, Michael [Laboratoire de Photonique et Interfaces, EPFL, Ecublens, CH-1015 Lausanne (Switzerland)

    2010-08-15

    Multi-walled carbon nanotubes functionalized by carboxylic groups, exhibit better affinity towards TiO{sub 2} (P90, Degussa) as compared to that of pristine nanotubes. Also the electrochemical performance of TiO{sub 2} is improved by nanotube networking, but the Li-storage capacity of TiO{sub 2} is unchanged. Whereas the composite of TiO{sub 2} with non-functionalized nanotubes demonstrates simple superposition of the behavior of pure components, the composite with functionalized nanotubes shows unique faradaic pseudocapacitance which is specific for this composite only. The surface functionalization of nanotubes enhances charge storage capacity and reversibility of a composite with LiMnPO{sub 4} (olivine), but mediates also the electrolyte breakdown at potentials >4.2 V. Whereas the electrochemical activation of LiMnPO{sub 4} (olivine) by functionalized nanotubes is quite modest, excellent performance was found for LiFePO{sub 4} (olivine) in composite materials containing only 2 wt% of functionalized nanotubes. (author)

  1. Laachite, (Ca,Mn){sub 2}Zr{sub 2}Nb{sub 2}TiFeO{sub 14}, a new zirconolite-related mineral from the Eifel volcanic region, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Chukanov, Nikita V. [Institute of Problems of Chemical Physics, Chernogolovka (Russian Federation); Krivovichev, Sergey V.; Pakhomova, Anna S. [St. Petersburg State Univ. (Russian Federation). Faculty of Crystallography; Pekov, Igor V.; Vigasina, Marina F. [Moscow State Univ. (Russian Federation). Faculty of Geology; Schaefer, Christof [Suedwestdeutsche Salzwerke AG, Heilbronn (Germany); Van, Konstantin V. [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Experimental Mineralogy

    2014-02-15

    The new mineral laachite was discovered in a sanidinite specimen from the Laach Lake (Laacher See) volcano, Eifel region, Rheinland-Pfalz, Germany. Associated minerals are sanidine, allanite-(Ce), baddeleyite, hau¨yne, hedenbergite, intermediate members of the jacobsite-magnetite series, phlogopite, rhodonite, spessartine, tephroite, thorite, zircon, and a pyrochlore-group mineral. Laachite is deep brownish-red, has an adamantine lustre, and is translucent; the streak is brownish red. It forms longprismatic crystals up to 0.02 x 0.04 x 0.5 mm, which are present as random intergrowths and twins in cavities within sanidinite. The density calculated from the empirical formula is 5.417 g/cm{sup 3}. The mean refractive index calculated from the Gladstone-Dale relationship is 2.26. The Raman spectrum shows the absence of hydrogen-bearing groups. The chemical composition is (electron microprobe, mean of 5 analyses, wt. %): CaO 4.29, MnO 9.42, FeO 5.73, Y{sub 2}O{sub 3} 2.56, La{sub 2}O{sub 3} 2.00, Ce{sub 2}O{sub 3} 6.37, Nd{sub 2}O{sub 3} 2.22, Al{sub 2}O{sub 3} 0.99, ThO{sub 2} 7.75, TiO{sub 2} 10.98, ZrO{sub 2} 19.39, Nb{sub 2}O{sub 5} 27.82, total 99.52. The empirical formula based on 14 O atoms is: (Ca{sub 0.66}Mn{sub 0.37}Th{sub 0.25}Y{sub 0.20}La{sub 0.11}Ce{sub 0.34}Nd{sub 0.11})(Zr{sub 1.3} {sub 6}Mn{sub 0.64})(Nb{sub 1.81}Ti{sub 1.19})(Fe{sub 0.69}Al{sub 0.17}Mn{sub 0.14})O{sub 14.00}. The simplified formula, taking into account the structural data, is: (Ca,Mn){sub 2}(Zr,Mn){sub 2}Nb{sub 2}TiFeO{sub 14}. Laachite is monoclinic, space group C2/c, a = 7.3119(5), b = 14.1790(10), c = 10.1700(7)Aa, β = 90.072(2), V = 1054.38(1) Aa{sup 3}, Z = 4. The crystal structure was solved using single-crystal X-ray diffraction data. Laachite is a monoclinic analogue of zirconolite-3O, CaZrTi{sub 2}O{sub 7}, with Nb dominant over Ti in the octahedral sites Nb1 and Nb2 and Fe dominant in a site with four-fold coordination. The strongest lines of the powder X-ray diffraction

  2. Magnetocrystalline anisotropy and magnetic domain structure of ErFe11Ti and HoFe11Ti compounds

    International Nuclear Information System (INIS)

    Pastushenkov, Yury G.; Skokov, Konstantin P.; Skourski, Yury; Lebedeva, Ludmila; Ivanova, Tatyana; Grushichev, Anton; Mueller, Karl-Hartmut

    2006-01-01

    Tetragonal ThMn 12 -type single crystalline ErFe 11 Ti and HoFe 11 Ti samples have been investigated by magnetization measurements and by observations of the magnetic domain structure at various temperatures between 10 and 300K. The magnetic structure of ErFe 11 Ti changes from room temperature 'easy axis' (c-axis) type to conical at spin-reorientation temperature T SR =50K. The HoFe 11 Ti has a metastable anisotropy energy minimum in the a-direction at T<40K. It leads to a first-order magnetization process detected by magnetization measurements along the a-axis in this temperature region

  3. Hydrothermal synthesis and characterizations of Ti substituted Mn-ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Nasser Y., E-mail: nmost69@yahoo.com [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Hessien, M.M. [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Advanced materials Division-Central metallurgical R and D Institute (CMRDI), P.O. Box 87 Helwan, Cairo (Egypt); Shaltout, Abdallah A. [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo (Egypt)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Hydrothermal synthesized of well-crystallized Ti-substituted MnFe{sub 2}O{sub 4} nanoparticles at 180 Degree-Sign C without any calcination step. The chemical composition was represented by Mn{sub 1-2x}Ti{sub x}Fe{sub 2}O{sub 4} with x having values 0.0, 0.1, 0.2, 0.3 and 0.4. Black-Right-Pointing-Pointer The change in lattice parameter and saturation magnetization with increasing Ti-substitution was investigated and explained. Black-Right-Pointing-Pointer The change in microstructure due to Ti{sup 4+} ions substitutions was investigated using TEM analysis. - Abstarct: A series of well-crystallized Mn{sub 1-2x}Ti{sub x}Fe{sub 2}O{sub 4} nanoparticles with x values of 0.0, 0.1, 0.2, 0.3 and 0.4 have been synthesized by hydrothermal route at 180 Degree-Sign C in the presence of NaOH as mineralizer. The obtained ferrite samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x up to 0.2. However, samples with x > 0.2 showed traces of unreacted anatase. The increase in Ti-substitution up to x = 0.2 leads to an increase in the lattice parameter of the prepared ferrites. On the other hand, the increase in Ti-substitution over x = 0.2 leads to a decrease in the lattice parameter. The average crystallite size was in the range of 39-57 nm, where it is increased by increasing the Ti-substitution up to x = 0.3, then decreased for x = 0.4. According to VSM results, the saturation magnetization increased with Ti ion substitution of x = 0.1 and decreased for x > 0.1.

  4. Effect of Metal (Mn, Ti) Doping on NCA Cathode Materials for Lithium Ion Batteries

    OpenAIRE

    Wan, Dao Yong; Fan, Zhi Yu; Dong, Yong Xiang; Baasanjav, Erdenebayar; Jun, Hang-Bae; Jin, Bo; Jin, En Mei; Jeong, Sang Mun

    2018-01-01

    NCA (LiNi0.85Co0.10Al0.05-x MxO2, M=Mn or Ti, x < 0.01) cathode materials are prepared by a hydrothermal reaction at 170°C and doped with Mn and Ti to improve their electrochemical properties. The crystalline phases and morphologies of various NCA cathode materials are characterized by XRD, FE-SEM, and particle size distribution analysis. The CV, EIS, and galvanostatic charge/discharge test are employed to determine the electrochemical properties of the cathode materials. Mn and Ti doping res...

  5. Preparation and Mechanical Properties of TiC-Fe Cermets and TiC-Fe/Fe Bilayer Composites

    Science.gov (United States)

    Zheng, Yong; Zhou, Yang; Li, Runfeng; Wang, Jiaqi; Chen, Lulu; Li, Shibo

    2017-10-01

    TiC-Fe cermets and TiC-Fe/Fe bilayer composites consisting of a pure Fe layer and a TiC-Fe cermets layer were fabricated by hot-pressing sintering. The pure Fe layer contributes to the toughness of composites, and the TiC-Fe cermets layer endows the composites with an improved tensile strength and hardness. The effect of TiC contents (30-60 vol.%) on the mechanical properties of TiC-Fe cermets and TiC-Fe/Fe bilayer composites was investigated. Among the TiC-Fe cermets, the 40 vol.% TiC-Fe cermets possessed the highest tensile strength of 581 MPa and Vickers hardness of 5.1 GPa. The maximum fracture toughness of 17.0 MPa m1/2 was achieved for the TiC-Fe cermets with 30 vol.% TiC. For the TiC-Fe/Fe bilayer composites, the 40 vol.% TiC-Fe/Fe bilayer composite owns the maximum tensile strength of 588 MPa, which is higher than that of 40 vol.% TiC-Fe cermets. In addition, the 33.5% increment of tensile strength of 30 vol.% TiC-Fe/Fe bilayer composite comparing with the 30 vol.% TiC-Fe cermets, which is attributed to the 30 vol.% TiC-Fe/Fe bilayer composite exhibited the largest interlaminar shear strength of 335 MPa. The bilayer composites are expected to be used as wear resistance components in some heavy wear conditions.

  6. Density functional study of the stability and magnetic behaviour of Au{sub n}TM{sup +} clusters (TM=Au,Sc,Ti,V,Cr,Mn,Fe; 1{<=}n{<=}9)

    Energy Technology Data Exchange (ETDEWEB)

    Torres, M.B. [Dpto. de Matematicas y Computacion, Univ. de Burgos, Avda. de Cantabria s/n, 09006-Burgos (Spain); Fernandez, E.M.; Balbas, L.C. [Dpto. de Fisica Teorica, Univ. de Valladolid, Prado de la Magdalena s/n, 47011-Valladolid (Spain)

    2005-03-01

    We study the element- and size-dependent electron stability of Au{sub n}TM{sup +} clusters (TM=Sc,Ti,V,Cr,Mn,Fe,Au; 1{<=}n{<=}9) by means of first-principles density functional calculations. The interplay between the cluster atomic arrangements and their electronic and magnetic structure is investigated for the few lower energy isomeric-states in dependence of the TM-atom and its environment in the cluster. We explain the experimental magic-numbers, observed recently, as well as the trend of the impurity local magnetic moment in dependence with the size of the cluster and the position of the impurity in the host. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Highly (002) textured large grain bcc Cr{sub 80}Mn{sub 20} seed layer on Cr{sub 50}Ti{sub 50} amorphous layer for FePt-C granular film

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Jae, E-mail: jsjigst@ecei.tohoku.ac.jp; Saito, Shin [Department of Electronic Engineering, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Hinata, Shintaro [Department of Electronic Engineering, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Japan Society for the Promotion of Science Research Fellow (PD), 5-3-1, Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Takahashi, Migaku [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2015-05-07

    Effect of bcc Cr{sub 80}Mn{sub 20} seed layer and Cr{sub 50}Ti{sub 50} amorphous texture inducing layer on the heteroepitaxy system in FePt-C granular film was studied by introducing a new concept of the layered structure. The concept suggested that the large grain seed layer in which the crystallographic texture was initially formed on an amorphous layer in the layered structure can reduce the angular distribution of (002) c-axis crystal orientation in the FePt-C granular film owing to heteroepitaxial growth. Structure analysis by X-ray diffraction revealed that (1) when the substrate heating temperature was elevated from 300 °C to 500 °C, grain size in the seed layer increased from 9.8 nm to 11.6 nm, and then decreased with further increasing the substrate temperature. The reduction of the grain size over 500 °C corresponds to the crystallization of the amorphous texture inducing layer, (2) when the grain size increased from 9.8 nm to 11.6 nm, the angular distribution of the (002) orientation in the seed layer dramatically decreased from 13.7° to 4.1°. It was shown that the large grain seed layer increased the perpendicular hysteresis in FePt-C granular film.

  8. L1{sub 0} stacked binaries as candidates for hard-magnets. FePt, MnAl and MnGa

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Yu-ichiro [Max-Planck Institut fuer Microstrukture Physics, Halle (Germany); Department of Applied Physics, The University of Tokyo (Japan); Madjarova, Galia [Max-Planck Institut fuer Microstrukture Physics, Halle (Germany); Department of Physical Chemistry, Faculty of Chemistry and Pharmacy, Sofia University (Bulgaria); Flores-Livas, Jose A. [Department of Physics, Universitaet Basel (Switzerland); Dewhurst, J.K.; Gross, E.K.U. [Max-Planck Institut fuer Microstrukture Physics, Halle (Germany); Felser, C. [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Sharma, S. [Max-Planck Institut fuer Microstrukture Physics, Halle (Germany); Department of Physics, Indian Institute of Technology, Roorkee, Uttarkhand (India)

    2017-08-15

    We present a novel approach for designing new hard magnets by forming stacks of existing binary magnets to enhance the magneto crystalline anisotropy. This is followed by an attempt at reducing the amount of expensive metal in these stacks by replacing it with cheaper metal with similar ionic radius. This strategy is explored using examples of FePt, MnAl and MnGa. In this study a few promising materials are suggested as good candidates for hard magnets: stacked binary FePt{sub 2}MnGa{sub 2} in structure where each magnetic layer is separated by two non-magnetic layers, FePtMnGa and FePtMnAl in hexagonally distorted Heusler structures and FePt{sub 0.5}Ti{sub 0.5}MnAl. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Electronic structure of homoleptic transition metal hydrides: TiH4, VH4, CrH4, MnH4, FeH4, CoH4, and NiH4

    International Nuclear Information System (INIS)

    Hood, D.M.; Pitzer, R.M.; Schaefer III, H.F.

    1979-01-01

    Ab initio molecular electronic structure theory has been applied to the family of transition metal tetrahydrides TiH 4 through NiH 4 . For the TiH 4 molecule a wide range of contracted Gaussian basis sets has been tested at the self-consistent-field (SCF) level of theory. The largest basis, labeled M(14s 11p 6d/10s 8p 3d), H(5s 1p/3s 1p), was used for all members of the series and should yield wave functions approaching true Hartree-Fock quality. Predicted SCF dissociation energies (relative to M+4H) and M--H bond distances are TiH 4 132 kcal, 1.70 A; VH 4 86 kcal, 1.64 A; CrH 4 65 kcal, 1.59 A; MnH 4 -- 36 kcal, 1.58 A; FeH 4 0 kcal, 1.58 A; CoH 4 27 kcal, 1.61 A; and NiH 4 18 kcal, 1.75 A. It should be noted immediately that each of these SCF dissociation energies will be increased by electron correlation effects by perhaps as much as 90 kcal. For all of these molecules except TiH 4 excited states have also been studied. One of the most interesting trends seen for these excited states is the shortening of the M--H bond as electrons are transferred from the antibonding 4t 2 orbital to the nonbonding 1e orbitals

  10. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

    Science.gov (United States)

    Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

    2016-01-01

    Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (Al–5Mg–Mn alloy with low Fe content (Al6(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al6(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al–5Mg–Mn alloys (0.5 wt % Fe), intermetallic Al6(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn) to become the primary phase at a lower Mn content. PMID:28787888

  11. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al-5Mg-Mn Alloys Solidified Under Near-Rapid Cooling.

    Science.gov (United States)

    Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

    2016-01-29

    Mn was an important alloying element used in Al-Mg-Mn alloys. However, it had to be limited to a low level (Al-5Mg-Mn alloy with low Fe content (Al₆(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al₆(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al-5Mg-Mn alloys (0.5 wt % Fe), intermetallic Al₆(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al₆(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al₆(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al₆(Fe,Mn) to become the primary phase at a lower Mn content.

  12. Magnetic properties of Fe-rich rare-earth intermetallic compounds with a ThMn12 structure

    International Nuclear Information System (INIS)

    Ohashi, K.; Tawara, Y.; Osugi, R.; Shimao, M.

    1988-01-01

    Sm(Fe/sub 1-//sub x/M/sub x/) 12 ternary compounds based on the tetragonal ThMn 12 structure where M is Ti, Si, V, Cr, and Mo were investigated. M atoms have a preference for site occupation. Ti atoms occupy the 8i or 8j site and Cr atoms occupy the 8i site. Curie temperatures on Sm(M,Fe) 12 compounds are around 590 K except for the SmMo 2 Fe 10 compound (T/sub c/ = 483 K). The SmTiFe 11 and SmSi 2 Fe 10 compounds have a high saturation magnetization and magnetic anisotropy

  13. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

    Directory of Open Access Journals (Sweden)

    Yulin Liu

    2016-01-01

    Full Text Available Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (<1.0 wt % to avoid the formation of coarse intermetallics. In order to take full advantage of the benefits of Mn, research was carried out to investigate the possibility of increasing the content of Mn by studying the effect of cooling rate on the formation of Fe- and Mn-rich intermetallics at different content levels of Mn and Fe. The results indicated that in Al–5Mg–Mn alloy with low Fe content (<0.1 wt %, intermetallic Al6(Fe,Mn was small in size and amount. With increasing Mn content, intermetallic Al6(Fe,Mn increased, but in limited amount. In high-Fe-containing Al–5Mg–Mn alloys (0.5 wt % Fe, intermetallic Al6(Fe,Mn became the dominant phase, even in the alloy with low Mn content (0.39 wt %. Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn to become the primary phase at a lower Mn content.

  14. Microstructure, Piezoelectric, and Ferroelectric Properties of BZT-Modified BiFeO3-BaTiO3 Multiferroic Ceramics with MnO2 and CuO Addition

    Science.gov (United States)

    Guan, Shibo; Yang, Huabin; Chen, Guangcong; Zhang, Rui

    2018-02-01

    A new lead-free piezoelectric ceramic, 0.67BiFeO3-0.33BaTiO3-xBi(Zn0.5Ti0.5) O3 + 0.0035MnO2 + 0.004CuO, was prepared through the solid-state reaction route. The ceramic was sintered in the 950-990°C range. In this paper, the crystal structure of the sample is pure perovskite structure with a pseudo-cubic structure in the range of x = 0-0.05, and does not change greatly with the increase of x. The grain size increases first and then decreases with the increase of x. The addition of Bi(Zn0.5Ti0.5) O3(BZT) promoted the grain growth of the sample. The piezoelectric constant reached the maximum value of d 33 = 188 pC/N, electromechanical coupling coefficient k p = 0.301 and the remanent polarization P r = 61.20 μC/cm2 at x = 0.03. It has a high Curie temperature of T c = 420°C. On the other hand, the depolarization temperature reaches the maximum value, T d = 426°C, at x = 0. A small amount of BZT doping can improve the piezoelectric, dielectric, and ferroelectric properties of the samples. Therefore, this material can be considered as a promising lead-free piezoelectric ceramic material in the application field of high-temperature materials.

  15. Fe-Mn-Si based shape memory alloys

    International Nuclear Information System (INIS)

    Hsu, T.Y.

    2000-01-01

    Characteristics of martensitic transformation fcc(γ)→hcp(ε) in Fe-Mn-Si based alloys are briefly reviewed. By analyzing the influences of constituents and treatments on shape memory effect (SME) in Fe-Mn-Si, the main factors controlling SME are summarized as austenite strengthening, stacking fault energy (probability) and antiferromagnetic temperature. Contribution of thermomechanical training to SME is introduced. The Fe-Mn-Si-RE (rare earth elements) and Fe-Mn-Si-Cr-N alloys are recommended as two novel shape memory alloys with superior SME. (orig.)

  16. Exchange biased FeNi/FeMn bilayers with coercivity and switching field enhanced by FeMn surface oxidation

    Directory of Open Access Journals (Sweden)

    A. V. Svalov

    2013-09-01

    Full Text Available FeNi/FeMn bilayers were grown in a magnetic field and subjected to heat treatments at temperatures of 50 to 350 °C in vacuum or in a gas mixture containing oxygen. In the as-deposited state, the hysteresis loop of 30 nm FeNi layer was shifted. Low temperature annealing leads to a decrease of the exchange bias field. Heat treatments at higher temperatures in gas mixture result in partial oxidation of 20 nm thick FeMn layer leading to a nonlinear dependence of coercivity and a switching field of FeNi layer on annealing temperature. The maximum of coercivity and switching field were observed after annealing at 300 °C.

  17. Sulfide phase in the Fe-Ti-S and Fe-C-Ti-S alloys

    International Nuclear Information System (INIS)

    Malinochka, Ya.N.; Balakina, N.A.; Shmelev, Yu.S.

    1976-01-01

    The nature of the sulfide phases in Fe-Ti-S and Fe-C-Ti-S alloys was studied. The carbide and the sulfide phase were identified the aid of X-ray spectral microanalysis. It was established that for a small content of titanium and sulfur in ternary Fe-Ti-S alloys the solidification of the γ-solution on the boundaries of dendritic branches is accompanied, along with the precipitation of a sulfide rich in iron of the (Fe, Ti) S type where a small quantity of titanium is dissolved, by the formation of a titanium-bearing sulfide eutectic γ + TiS. The amount of the sulfide eutectic increases with the contents of titanium and sulfur until a purely eutectic alloy is formed. Both carbides and sulfides may be formed in the solidification of quaternary alloys Fe-C-Ti-S

  18. Effect of Metal (Mn, Ti Doping on NCA Cathode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Dao Yong Wan

    2018-01-01

    Full Text Available NCA (LiNi0.85Co0.10Al0.05-x MxO2, M=Mn or Ti, x < 0.01 cathode materials are prepared by a hydrothermal reaction at 170°C and doped with Mn and Ti to improve their electrochemical properties. The crystalline phases and morphologies of various NCA cathode materials are characterized by XRD, FE-SEM, and particle size distribution analysis. The CV, EIS, and galvanostatic charge/discharge test are employed to determine the electrochemical properties of the cathode materials. Mn and Ti doping resulted in cell volume expansion. This larger volume also improved the electrochemical properties of the cathode materials because Mn4+ and Ti4+ were introduced into the octahedral lattice space occupied by the Li-ions to expand the Li layer spacing and, thereby, improved the lithium diffusion kinetics. As a result, the NCA-Ti electrode exhibited superior performance with a high discharge capacity of 179.6 mAh g−1 after the first cycle, almost 23 mAh g−1 higher than that obtained with the undoped NCA electrode, and 166.7 mAh g−1 after 30 cycles. A good coulombic efficiency of 88.6% for the NCA-Ti electrode is observed based on calculations in the first charge and discharge capacities. In addition, the NCA-Ti cathode material exhibited the best cycling stability of 93% up to 30 cycles.

  19. Nonstoichiometry of Epitaxial FeTiO(3+delta) Films

    Science.gov (United States)

    2003-01-01

    nonstoichiometry of the FeTiO3 +8 films was probably produced by cation vacancies and disarrangement of Fe3+ and Ti4 ions, which randomly occupied both interstitial...and substitutional sites of the FeTiO 3 related structure. INTRODUCTION Solid solutions of ot-Fe20 3- FeTiO3 (hematite-ilmenite) series are known to...tried to confirm preparation conditions of stoichiometric FeTiO 3 films. According to a literature on bulk crystal growth of FeTiO3 [5], very low oxygen

  20. The Fe/Mn constraint on precursors of basaltic achondrites

    Science.gov (United States)

    Delaney, Jeremy S.; Boesenberg, Joseph S.

    1993-01-01

    Most achondritic meteorites have Fe/Mn ratios that are lower than those of carbonaceous chondrites and of course are lower than the solar system abundance ratio of these elements. Models of the origin of achondritic assemblages must, therefore, account for these ratios. Fe/Mn ratios are suggested to be distinctive for samples from each achondrite parent body and for the Earth and Moon, but the correspondence between the Fe/Mn systematics of achondrites and chondritic precursors is unclear. Most models of achondrite genesis involve magmatic differentiation of chondritic precursors. The Fe/Mn difference between achondrites and chondrites is particularly significant since Fe and Mn are geochemically similar elements with similar partitioning behavior in familiar magmatic systems and are generally coupled during crystal-liquid fractionation. In contrast, however, Mn is more volatile than Fe in a nebular setting. Variation of Fe/Mn ratios based on the relative volatility of these elements in the early nebula provides a constraint for models by which the basaltic achondrites (with Fe/Mn ratios approximately = 25-50) are derived from mixtures of nebular components that were enriched in volatile components such as Mn. However, such volatile enriched components have not been identified in chondrites. When the abundance in achondrites of elements of similar volatility is examined, anomalies appear. For example, Na is massively depleted in basaltic achondrites when compared to Mn. These anomalies might be explained using current models but the alternative hypothesis, that Fe/Mn ratio is controlled not by nebular volatility constraints, but by planetary differentiation should be explored.

  1. Magnetocrystalline anisotropy and magnetic domain structure of ErFe{sub 11}Ti and HoFe{sub 11}Ti compounds

    Energy Technology Data Exchange (ETDEWEB)

    Pastushenkov, Yury G. [Physics Department of Tver State University, 17000 Tver (Russian Federation); Skokov, Konstantin P. [Physics Department of Tver State University, 17000 Tver (Russian Federation); Skourski, Yury [Leibniz-Institute for Solid State and Material Research, 01171 Dresden (Germany); Lebedeva, Ludmila [Physics Department of Tver State University, 17000 Tver (Russian Federation); Ivanova, Tatyana [Physics Department of Moscow Stae University, 119889 Moscow (Russian Federation); Grushichev, Anton [Physics Department of Tver State University, 17000 Tver (Russian Federation)]. E-mail: yupast@tversu.ru; Mueller, Karl-Hartmut [Leibniz-Institute for Solid State and Material Research, 01171 Dresden (Germany)

    2006-05-15

    Tetragonal ThMn{sub 12}-type single crystalline ErFe{sub 11}Ti and HoFe{sub 11}Ti samples have been investigated by magnetization measurements and by observations of the magnetic domain structure at various temperatures between 10 and 300K. The magnetic structure of ErFe{sub 11}Ti changes from room temperature 'easy axis' (c-axis) type to conical at spin-reorientation temperature T{sub SR}=50K. The HoFe{sub 11}Ti has a metastable anisotropy energy minimum in the a-direction at T<40K. It leads to a first-order magnetization process detected by magnetization measurements along the a-axis in this temperature region.

  2. Effect of Fe-Mn addition on microstructure and magnetic properties of NdFeB magnetic powders

    Science.gov (United States)

    Kurniawan, C.; Purba, A. S.; Setiadi, E. A.; Simbolon, S.; Warman, A.; Sebayang, P.

    2018-03-01

    In this paper, the effect of Fe-Mn alloy addition on microstructures and magnetic properties of NdFeB magnetic powders was investigated. Varied Fe-Mn compositions of 1, 5, and 10 wt% were mixed with commercial NdFeB type MQA powders for 15 minutes using shaker mill. The characterizations were performed by powder density, PSA, XRD, SEM, and VSM. The Fe-Mn addition increased the powder density of NdFeB/Fe-Mn powders. On the other side, particle size distribution slightly decreased as the Fe-Mn composition increases. Magnetic properties of NdFeB/Fe-Mn powders changed with the increasing of Fe-Mn content. SEM analysis showed the particle size of NdFeB/Fe-Mn powder was smaller as the Fe-Mn composition increases. It showed that NdFeB/Fe-Mn particles have different size and shape for NdFeB and Fe-Mn particles separately. The optimum magnetic properties of NdFeB/Fe-Mn powder was achieved on the 5 wt% Fe-Mn composition with remanence M r = 49.45 emu/g, coercivity H c = 2.201 kOe, and energy product, BH max = 2.15 MGOe.

  3. Exchange interaction in MnPt/FeCo sputtered multilayers

    International Nuclear Information System (INIS)

    Honda, S.; Nawate, M.; Norikane, T.

    2000-01-01

    MnPt single-layer films have been prepared on glass substrates by RF magnetron sputtering for studying the composition dependencies of resistivity and crystalline structure. In the as-deposited state, the resistivity increases with Mn content and reaches the maximum at 69 at%. By annealing, the resistivity of the films having the Mn content around 51 at% increases, closely relating to the growth of the ordered CuAu FCT-type MnPt crystals. For the both film structures of the glass/Cu/FeCo/MnPt/Cu and the glass/MnPt/FeCo/Cu, which have been sputter-deposited on glass substrates, the exchange interaction between MnPt and FeCo layers, and the coercivity of the FeCo layer have been examined as functions of the Mn content, the layer thickness and the annealing temperature. In the as-deposited state, the exchange field (H ex ) is nearly zero up to 75 at% of Mn content, above which the value of H ex increases and shows the maximum at 85 at%, in which the blocking temperature is about 100 deg. C. By annealing, the value of H ex increases for the films of Mn content around 40-60 at%, exhibiting the higher blocking temperature than 360 deg. C. The temperature stability has also been examined using the Rutherford backscattering spectrometry

  4. Dissimilatory Fe(III) and Mn(IV) reduction.

    Science.gov (United States)

    Lovley, D R

    1991-06-01

    The oxidation of organic matter coupled to the reduction of Fe(III) or Mn(IV) is one of the most important biogeochemical reactions in aquatic sediments, soils, and groundwater. This process, which may have been the first globally significant mechanism for the oxidation of organic matter to carbon dioxide, plays an important role in the oxidation of natural and contaminant organic compounds in a variety of environments and contributes to other phenomena of widespread significance such as the release of metals and nutrients into water supplies, the magnetization of sediments, and the corrosion of metal. Until recently, much of the Fe(III) and Mn(IV) reduction in sedimentary environments was considered to be the result of nonenzymatic processes. However, microorganisms which can effectively couple the oxidation of organic compounds to the reduction of Fe(III) or Mn(IV) have recently been discovered. With Fe(III) or Mn(IV) as the sole electron acceptor, these organisms can completely oxidize fatty acids, hydrogen, or a variety of monoaromatic compounds. This metabolism provides energy to support growth. Sugars and amino acids can be completely oxidized by the cooperative activity of fermentative microorganisms and hydrogen- and fatty-acid-oxidizing Fe(III) and Mn(IV) reducers. This provides a microbial mechanism for the oxidation of the complex assemblage of sedimentary organic matter in Fe(III)- or Mn(IV)-reducing environments. The available evidence indicates that this enzymatic reduction of Fe(III) or Mn(IV) accounts for most of the oxidation of organic matter coupled to reduction of Fe(III) and Mn(IV) in sedimentary environments. Little is known about the diversity and ecology of the microorganisms responsible for Fe(III) and Mn(IV) reduction, and only preliminary studies have been conducted on the physiology and biochemistry of this process.

  5. Rietveld analysis, dielectric and impedance behaviour of Mn /Fe ion ...

    Indian Academy of Sciences (India)

    Figure 1 compares X-ray diffraction patterns of pow- ders calcined at temperature .... ground, absorption coefficient, atomic positions, two theta zero error, thermal ... attributed to segregation of Mn and Fe at grain boundaries. (Dai et al 1995).

  6. Determination of hyperfine fields and atomic ordering in NiMnFeGe exhibiting martensitic transformation

    Directory of Open Access Journals (Sweden)

    Satuła Dariusz

    2015-03-01

    Full Text Available The hyperfine fields and atomic ordering in Ni1−xFexMnGe (x = 0.1, 0.2, 0.3 alloys were investigated using X-ray diffraction and Mössbauer spectroscopy at room temperature. The X-ray diffraction measurements show that the samples with x = 0.2, 0.3 crystallized in the hexagonal Ni2In-type of structure, whereas in the sample with x = 0.1, the coexistence of two phases, Ni2In- and orthorhombic TiNiSi-type of structures, were found. The Mössbauer spectra measured with x = 0.2, 0.3 show three doublets with different values of isomer shift (IS and quadrupole splitting (QS related to three different local surroundings of Fe atoms in the hexagonal Ni2In-type structure. It was shown that Fe atoms in the hexagonal Ni2In-type structure of as-cast Ni1−xFexMnGe alloys are preferentially located in Ni sites and small amount of Fe is located in Mn and probably in Ge sites. The spectrum for x = 0.1 shows the doublets in the central part of spectrum and a broad sextet. The doublets originate from the Fe atoms in the paramagnetic state of hexagonal Ni2In-type structure, whereas the sextet results from the Fe atoms in orthorhombic TiNiSi-type structure.

  7. Synthesis of Nano-Ilmenite (FeTiO3) doped TiO2/Ti Electrode for Photoelectrocatalytic System

    Science.gov (United States)

    Hikmawati; Watoni, A. H.; Wibowo, D.; Maulidiyah; Nurdin, M.

    2017-11-01

    Ilmenite (FeTiO3) doped on Ti and TiO2/Ti electrodes were successfully prepared by using the sol-gel method. The structure, morphology, and optical properties of FeTiO3 are characterized by XRD, UV-Vis DRS, and SEM. The FeTiO3 and TiO2 greatly affect the photoelectrocatalysis performance characterized by Linear Sweep Voltammetry (LSV) and Cyclic Voltammetry (CV). The characterization result shows a band gap of FeTiO3 is 2.94 eV. XRD data showed that FeTiO3 formed at 2θ were 35.1° (110), 49.9° (024), and 61.2° (214). The morphology of FeTiO3/Ti and FeTiO3.TiO2/Ti using SEM shows that the formation of FeTiO3 thin layer signifies the Liquid Phase Deposition method effectively in the coating process. Photoelectrochemical (PEC) test showed that FeTiO3.TiO2/Ti electrode was highly oxidation responsive under visible light compared to the FeTiO3/Ti electrodes i.e. 7.87×10-4 A and 9.87×10-5 A. Degradation test of FeTiO3/Ti and FeTiO3.TiO2/Ti electrodes on titan yellow showed that the percentages of degradation with photoelectrocatalysis at 0.5 mg/L were 41% and 43%, respectively.

  8. Moessbauer and magnetic investigation of Fe-Mn alloy

    International Nuclear Information System (INIS)

    Yousif, A.A.

    1994-01-01

    Moessbauer, X-ray, magnetization and susceptibility measurements were performed to study Fe 100-x Mn x , x = 5, 15, 39, 50. The different phases of Fe-Mn were identified, and hyperfine interaction parameters and average magnetic moments of some samples were determined. The average hyperfine field and average magnetic moment decrease as x increases. The influence of the Mn neighbourhood on the derived parameters is discussed in the light of calculations using the first principle discrete variational method in the local density approximation. (orig.)

  9. Influence of Fe underlayers on stress evolution of Ti in Ti/Fe multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Li; Thompson, Gregory, E-mail: gthompson@eng.ua.edu [Department of Metallurgical Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0202 (United States)

    2016-11-15

    A series of 40–2 nm bilayer spacing Ti/Fe multilayers were sputter-deposited. As the length scale of individual Ti layers equaled to 2 nm, Ti phase transforms from a hexagonal close packed (hcp)-to-body centered cubic (bcc) crystal structures for equal layer thicknesses in Ti/Fe multilayers. Further equal reductions in bilayer spacing to less than 1 nm resulted in an additional transformation from a crystalline to amorphous structure. Atom probe tomography reveals significant intermixing between layers which contributes to the observed phase transformations. Real-time, intrinsic growth stress measurements were also performed to relate the adatom mobility to these phase transformations. For the hcp Ti/bcc Fe multilayers of equivalent volume fractions, the multilayers undergo an overall tensile stress state to a compressive stress state with decreasing bilayer thickness for the multilayers. When the above phase transformations occurred, a modest reduction in the overall compressive stress of the multilayer was noted. Depending on the Fe thickness, the Ti growth was observed to be a tensile to compressive growth change to a purely compressive growth for thinner bilayer spacing. Fe retained a tensile growth stress regardless of the bilayer spacing studied.

  10. Phase relationships in the Er-Mn-Ti ternary system at 773 K

    International Nuclear Information System (INIS)

    Liu Jingqi; Wang Xina; Tang Mengqi; Su Kunpeng; Yang Xiaomao; Li Chunhui; Li Xueqiang

    2009-01-01

    The Phase relationship in the Er-Mn-Ti ternary system at 773 K has been investigated by X-ray powder diffraction analysis with the aid of differential thermal analysis and optical microanalysis techniques in this work. The existence of eight binary compounds Mn 15 Ti 85, αMnTi, βMnTi, Mn 2 Ti, Mn 5 Ti, ErMn 12, Er 6 Mn 23 and ErMn 2 has been confirmed at 773 K in this system. The maximum solid solubility of Ti in Mn is about 8 at%Ti. The homogeneity range of Mn 2 Ti extends from about 31 at% to 39 at% Ti. The maximum solid solubility of Er in Mn 2 Ti phase is about less than 1 at% Er. No ternary compounds were found in this ternary system at 773K. At 773 K, the isothermal section of phase diagram of Er-Mn-Ti ternary system consists of 11 single-phase regions, 19 two-phase regions and 9 three-phase regions.

  11. Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

    2017-09-15

    We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

  12. A new magnet material with ThMn{sub 12} structure: (Nd{sub 1−x}Zr{sub x})(Fe{sub 1−y}Co{sub y}){sub 11+z}Ti{sub 1−z}N{sub α} (α=0.6–1.3)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S.; Kuno, T.; Urushibata, K. [Shizuoka Institute of Science and Technology, 2200-2 Toyosawa, Fukuroi, Shizuoka 437-8555 (Japan); Kobayashi, K., E-mail: koba@ms.sist.ac.jp [Shizuoka Institute of Science and Technology, 2200-2 Toyosawa, Fukuroi, Shizuoka 437-8555 (Japan); Sakuma, N.; Washio, K.; Yano, M.; Kato, A.; Manabe, A. [Toyota Mortor Corporation, 1 Toyota-cho, Toyota 471-8572, Aichi (Japan)

    2016-03-01

    We previously reported a new compound for permanent magnets, (Nd{sub 0.7}Zr{sub 0.3})(Fe{sub 0.75}Co{sub 0.25}){sub 11.5}Ti{sub 0.5}N{sub 0.56}, which has a high saturation polarization (J{sub s}) of 1.68 T and a high magnetocrystalline anisotropy field (H{sub a}) of 2.88–4.0 MA/m. Here, we examined the effects of substituting Co and Ti at the Fe sites and Zr at the Nd sites. J{sub s} increased with Co substitution at the Fe sites, and higher Fe and Co content could be achieved by decreasing the Ti content to −Ti{sub 0.5}. The ThMn{sub 12} structure with high Fe and Co content (i.e. low Ti content) was stabilized mainly by −Zr{sub 0.3} substitution at the Nd sites. The Zr substitution resolves the local mismatch in atomic size in the structure. Specifically, the atomic radius of Zr is about 88% that of Nd, so the local structure surrounding Nd (2a site) shrinks as a result of the substitution and resolves the size mismatch in the three types of local Fe six-fold symmetric hexagons in the structure. The effect of the α-(Fe, Co) phase on J{sub s} was evaluated from the phase's volume fraction measurement of 7.7% (8.1 wt%) by electron backscatter diffraction. Nitrogenation of the starting alloy also resulted in augmentation of the c-axis magnetocrystalline anisotropy. Finally, we confirmed a high J{sub s}(−N{sub 1.3}) of 1.71T (=1.67 T, −0.04 T for the α-(Fe, Co) phase) and H{sub a} of 2.9–5.25 MA/m (H{sub a}(−N{sub 1.3})=5.25 MA/m) in the (Nd{sub 0.7}Zr{sub 0.3})(Fe{sub 0.75}Co{sub 0.25}){sub 11.5}Ti{sub 0.5}N{sub α} (α=0.60–1.30) compounds. - Highlights: • We found a new compound of composition of (Nd,Zr)(Fe,Co){sub 11.5}Ti{sub 0.5}N{sub x} (x=0.6–1.3). • The compound shows high saturation polarization of 1.67T. • The Curie temperature of compound is above 840K, and anisotropy field is nearly 6.6 T. • The basic physical properties such as inner fields of each Fe site were measured. • The reasons of stabilization of 1–12

  13. Moessbauer spectroscopy of Fe-Mn-Cu alloys

    International Nuclear Information System (INIS)

    Paduani, Clederson; Krause, Joao Carlos; Yoschida, M.I. Soares

    2004-01-01

    Full text: Although a continuous series of solid solutions exists between Cu and Mn, Fe and Cu are miscible only a few percent at higher temperatures. In moderately concentrated Cu-Mn alloys the Mn moments are bound to the long ranged antiferromagnetic order and the perpendicular components form an X-Y spin glass. Copper alloys are largely employed in various industrial applications. In this work we study the magnetic properties of iron-rich disordered Fe-Mn-Cu alloys with the bcc structure with the experimental techniques of X-ray diffraction (XRD), Moessbauer spectroscopy (MS) and thermogravimetry (TGA). We investigate the formation of a solid solution with the bcc structure as well as the effect of the composition on the structural and magnetic properties of these alloys. A Rietveld analysis of the XRD diffractograms indicate that all prepared samples are single phase and are well crystallized with a bcc structure. (author)

  14. Mianningite, (□,Pb,Ce,Na) (U{sup 4+},Mn,U{sup 6+}) Fe{sup 3+}{sub 2}(Ti,Fe{sup 3+}){sub 18}O{sub 38}, a new member of the crichtonite group from Maoniuping REE deposit, Mianning county, southwest Sichuan, China

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Xiangkun; Fan, Guang; Chen, Zhangru; Ai, Yujie [Beijing Research Institute of Uranium Geology, Beijing (China); Li, Guowu [China Univ. of Geosciences, Beijing (China). Lab. of Crystal Structure; Shen, Ganfu [Chengdu Institute of Geology and Mineral Resources, Chengdu (China)

    2017-05-15

    Mianningite (IMA 2014-072), ideally (□,Pb,Ce,Na)(U{sup 4+},Mn,U{sup 6+}) Fe{sup 3+}{sub 2}(Ti,Fe{sup 3+}){sub 18}O{sub 38}, is a new member of the crichtonite group from the Maoniuping REE deposit, Mianning county, Sichuan province, China. It was found in fractures of lamprophyre veins and in the contact between lamprophyre and a later quartz-alkali feldspar syenite dyke with REE mineralization, and is named after its type locality. Associated minerals are microcline, albite, quartz, iron-rich phlogopite, augite, muscovite, calcite, baryte, fluorite, epidote, pyrite, magnetite, hematite, galena, hydroxylapatite, titanite, ilmenite, rutile, garnet-group minerals, zircon, allanite-(Ce), monazite-(Ce), bastnaesite-(Ce), parisite-(Ce), maoniupingite-(Ce), thorite, pyrochlore-group minerals and chlorite. Mianningite occurs as opaque subhedral to euhedral tabular crystals, up to 1-2 mm in size, black in color and streak, and with a submetallic luster. Mianningite is brittle, with a conchoidal fracture. Its average micro-indentation hardness is 83.8 kg/mm{sup 2} (load 0.2 kg), which is equivalent to ∝6 on the Mohs hardness scale. Its measured and calculated densities are 4.62 (8) g/cm{sup 3} and 4.77 g/cm{sup 3}, respectively. Under reflected light, mianningite is grayish white, with no internal reflections. It appears isotropic and exhibits neither bireflectance nor pleochroism. The empirical formula, calculated on the basis of 38 O atoms per formula unit (apfu), is [□{sub 0.322}(Pb{sub 0.215}Ba{sub 0.037}Sr{sub 0.036}Ca{sub 0.010}){sub Σ0.298}(Ce{sub 0.128}La{sub 0.077}Nd{sub 0.012}){sub Σ0.217} (Na{sub 0.127}K{sub 0.036}){sub Σ0.163}]{sub Σ01.000}(U{sup 4+}{sub 0.447}Mn{sub 00.293}U{sup 6} {sup +}{sub 0.112}Y{sub 0.091}Zr{sub 0.023}Th{sub 0.011}){sub Σ0.977}(Fe{sup 3+}{sub 1.224}Fe{sup 2+}{sub 0.243}Mg{sub 0.023}P{sub 0.008}Si{sub 0.006} □{sub 0.496}){sub Σ2.000}(Ti{sub 12.464}Fe{sup 3+}{sub 5.292}V{sup 5+}{sub 0.118}Nb{sub 0.083}Al{sub 0.026}Cr{sup 3

  15. Mianningite, (□,Pb,Ce,Na) (U"4"+,Mn,U"6"+) Fe"3"+_2(Ti,Fe"3"+)_1_8O_3_8, a new member of the crichtonite group from Maoniuping REE deposit, Mianning county, southwest Sichuan, China

    International Nuclear Information System (INIS)

    Ge, Xiangkun; Fan, Guang; Chen, Zhangru; Ai, Yujie; Li, Guowu

    2017-01-01

    Mianningite (IMA 2014-072), ideally (□,Pb,Ce,Na)(U"4"+,Mn,U"6"+) Fe"3"+_2(Ti,Fe"3"+)_1_8O_3_8, is a new member of the crichtonite group from the Maoniuping REE deposit, Mianning county, Sichuan province, China. It was found in fractures of lamprophyre veins and in the contact between lamprophyre and a later quartz-alkali feldspar syenite dyke with REE mineralization, and is named after its type locality. Associated minerals are microcline, albite, quartz, iron-rich phlogopite, augite, muscovite, calcite, baryte, fluorite, epidote, pyrite, magnetite, hematite, galena, hydroxylapatite, titanite, ilmenite, rutile, garnet-group minerals, zircon, allanite-(Ce), monazite-(Ce), bastnaesite-(Ce), parisite-(Ce), maoniupingite-(Ce), thorite, pyrochlore-group minerals and chlorite. Mianningite occurs as opaque subhedral to euhedral tabular crystals, up to 1-2 mm in size, black in color and streak, and with a submetallic luster. Mianningite is brittle, with a conchoidal fracture. Its average micro-indentation hardness is 83.8 kg/mm"2 (load 0.2 kg), which is equivalent to ∝6 on the Mohs hardness scale. Its measured and calculated densities are 4.62 (8) g/cm"3 and 4.77 g/cm"3, respectively. Under reflected light, mianningite is grayish white, with no internal reflections. It appears isotropic and exhibits neither bireflectance nor pleochroism. The empirical formula, calculated on the basis of 38 O atoms per formula unit (apfu), is [□_0_._3_2_2(Pb_0_._2_1_5Ba_0_._0_3_7Sr_0_._0_3_6Ca_0_._0_1_0)_Σ_0_._2_9_8(Ce_0_._1_2_8La_0_._0_7_7Nd_0_._0_1_2)_Σ_0_._2_1_7 (Na_0_._1_2_7K_0_._0_3_6)_Σ_0_._1_6_3]_Σ_0_1_._0_0_0(U"4"+_0_._4_4_7Mn_0_0_._2_9_3U"6 "+_0_._1_1_2Y_0_._0_9_1Zr_0_._0_2_3Th_0_._0_1_1)_Σ_0_._9_7_7(Fe"3"+_1_._2_2_4Fe"2"+_0_._2_4_3Mg_0_._0_2_3P_0_._0_0_8Si_0_._0_0_6 □_0_._4_9_6)_Σ_2_._0_0_0(Ti_1_2_._4_6_4Fe"3"+_5_._2_9_2V"5"+_0_._1_1_8Nb_0_._0_8_3Al_0_._0_2_6Cr"3"+_0_._0_1_7)_Σ_1_8_._0_0_0O_3_8. Mianningite is trigonal, belongs to the space group R anti 3, and has

  16. Moessbauer spectroscopic investigations of Fe/Mn-Fischer-Tropsch-catalysts

    International Nuclear Information System (INIS)

    Deppe, P.; Papp, H.; Rosenberg, M.

    1986-01-01

    The phase composition of Fe/Mn oxide catalysts of different compositions after 200 h of Fischer-Tropsch synthesis have been investigated by Moessbauer spectroscopy at room temperature, 77 K and 5 K. The final composition of the bulk catalysts depends strongly on the Mn content and the temperature of reduction before the synthesis. Catalytic activity and selectivity are partly correlated to this phase composition. (Auth.)

  17. Study of intergranular embrittlement in Fe-12Mn alloys

    International Nuclear Information System (INIS)

    Lee, H.J.

    1982-06-01

    A high resolution scanning Auger microscopic study has been performed on the intergranular fracture surfaces of Fe-12Mn steels in the as-austenitized condition. Fracture mode below the ductile-brittle transition temperature was intergranular whenever the alloy was quenched from the austenite field. The intergranular fracture surface failed to reveal any consistent segregation of P, S, As, O, or N. The occasional appearance of S or O on the fracture surface was found to be due to a low density precipitation of MnS and MnO 2 along the prior austenite boundaries. An AES study with Ar + ion-sputtering showed no evidence of manganese enrichment along the prior austenite boundaries, but a slight segregation of carbon which does not appear to be implicated in the tendency toward intergranular fracture. Addition of 0.002% B with a 1000 0 C/1h/WQ treatment yielded a high Charpy impact energy at liquid nitrogen temperature, preventing the intergranular fracture. High resolution AES studies showed that 3 at. % B on the prior austenite grain boundaries is most effective in increasing the grain boundary cohesive strength in an Fe-12Mn alloy. Trace additions of Mg, Zr, or V had negligible effects on the intergranular embrittlement. A 450 0 C temper of the boron-modified alloys was found to cause tempered martensite embrittlement, leading to intergranular fracture. The embrittling treatment of the Fe-12Mn alloys with and without boron additions raised the ductile-brittle transition by 150 0 C. This tempered martensite embrittlement was found to be due to the Mn enrichment of the fracture surface to 32 at. % Mn in the boron-modified alloy and 38 at. % Mn in the unmodified alloy. The Mn-enriched region along the prior austenite grain boundaries upon further tempering is believed to cause nucleation of austenite and to change the chemistry of the intergranular fracture surfaces. 61 figures

  18. Direct evidence of the existence of Mn3+ ions in MnTiO3

    Science.gov (United States)

    Maurya, R. K.; Sharma, Priyamedha; Patel, Ashutosh; Bindu, R.

    2017-08-01

    We investigate the room temperature electronic properties of MnTiO3 synthesised by different preparation conditions. For this purpose, we prepared MnTiO3 under two different cooling rates, one is naturally cooled while the other is quenched in liq.nitrogen. The samples were studied using optical absorbance, photoemission spectroscopy and band structure calculations. We observe significant changes in the structural parameters as a result of quenching. Interestingly, in the parent compound, our combined core level, valence band and optical absorbance studies give evidence of the Mn existence in both 2+ and 3+ states. The fraction of Mn3+ ions has been found to increase on quenching MnTiO3 suggests an increase in oxygen non-stoichiometry. The increase in the fraction of the Mn3+ ions has been manifested a) as slight enhancement in the intensity of the optical absorbance in the visible region. There occurs persistent photo-resistance when the incident light is terminated after shining; b) in the behaviour of the features (close to Fermi level) in the valence band spectra. Hence, the combined analysis of the core level, valence band and optical absorbance spectra suggests that the charge carriers are hole like which further leads to the increase in the electrical conductivity of the quenched sample. The present results provide a recipe to tune the optical absorption in the visible range for its applications in optical sensors, solar cell, etc.

  19. Shape memory effect of Fe-17%Mn-X alloys

    International Nuclear Information System (INIS)

    Lee, S.-H.; Kim, H.-J.; Choi, C.-S.; Baik, S.-H.

    2000-01-01

    SME of Fe-17%Mn-X alloy decreased with increasing Ni and Cr contents. This is because the occurrence of stress-induced martensite transformation of γ to ε is difficult due to the increase in stability of retained austenite with increasing Ni and Cr contents. SME of Fe-17%Mn-X alloy increased with increasing the number of thermal cycles. The reason is that the prior bending deformation for SME is associated with coalescence of the pre-existing ε plates due to their rearrangement, thereby the more the ε content, the greater the SME. (orig.)

  20. Shape memory effect in Fe-Mn-Ni-Si-C alloys with low Mn contents

    Energy Technology Data Exchange (ETDEWEB)

    Min, X.H., E-mail: MIN.Xiaohua@nims.go.jp [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Sawaguchi, T.; Ogawa, K. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Maruyama, T. [Awaji Materia Co., Ltd. 2-3-13, Kanda ogawamachi, Chiyoda, Tokyo 101-0052 (Japan); Yin, F.X. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Tsuzaki, K. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-0047 (Japan)

    2011-06-15

    Highlights: {yields} A class of new Fe-Mn-Ni-Si-C shape memory alloys with low Mn contents has been designed. {yields} A Mn content for the onset of the {alpha}' martensite is less than 13 mass%, and the {epsilon} martensite still exists in the alloy with a 9 mass% Mn. {yields} The shape recovery strain decreases considerably when the Mn content is reduced from 13 to 11 mass%. {yields} The sudden decrease in the shape recovery strain is mainly caused by the formation of {alpha}' martensite. - Abstract: An attempt was made to develop a new Fe-Mn-Si-based shape memory alloy from a Fe-17Mn-6Si-0.3C (mass%) shape memory alloy, which was previously reported to show a superior shape memory effect without any costly training treatment, by lowering its Mn content. The shape memory effect and the phase transformation behavior were investigated for the as-solution treated Fe-(17-2x)Mn-6Si-0.3C-xNi (x = 0, 1, 2, 3, 4) polycrystalline alloys. The shape recovery strain exceeded 2% in the alloys with x = 0-2, which is sufficient for an industrially applicable shape memory effect; however, it suddenly decreased in the alloys between x = 2 and 3 although the significant shape recovery strain still exceeded 1%. In the alloys with x = 3 and 4, X-ray diffraction analysis and transmission electron microscope observation revealed the existence of {alpha}' martensite, which forms at the intersection of the {epsilon} martensite plates and suppresses the crystallographic reversibility of the {gamma} austenite to {epsilon} martensitic transformation.

  1. Exchange bias variations of the seed and top NiFe layers in NiFe/FeMn/NiFe trilayer as a function of seed layer thickness

    International Nuclear Information System (INIS)

    Sankaranarayanan, V.K.; Yoon, S.M.; Kim, C.G.; Kim, C.O.

    2005-01-01

    Development of exchange bias at the seed and top NiFe layers in the NiFe (t nm)/FeMn(10 nm)/NiFe(5 nm) trilayer structure is investigated as a function of seed layer thickness, in the range of 2-20 nm. The seed NiFe layer shows maximum exchange bias at 4 nm seed layer thickness. The bias shows inverse thickness dependence with increasing thickness. The top NiFe layer on the other hand shows only half the bias of the seed layer which is retained even after the sharp fall in seed layer bias. The much smaller bias for the top NiFe layer is related to the difference in crystalline texture and spin orientations at the top FeMn/NiFe interface, in comparison to the bottom NiFe/FeMn interface which grows on a saturated NiFe layer with (1 1 1) orientation

  2. Structural investigation and microwave characteristics of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Manaf, Azwar [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Indonesia of University (Indonesia); Adi, Wisnu Ari, E-mail: dwisnuaa@batan.go.id [Center for Technology of Nuclear Industry Material, National Nuclear Energy Agency (Indonesia)

    2014-03-24

    Synthesis and characterization of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing material by mechanical alloying process has been performed. The absorbing material was prepared by oxide materials, namely BaCO{sub 3}, La{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, and MnCO{sub 3}. The mixture was milled for 10 h and then sintered at a temperature of 1000 ° C for 10 h. The refinement results of x-ray diffraction pattern of lanthanum manganite substituted with barium showed that the sample consisted of two phases, namely, La{sub 0.9125}MnO{sub 3} phase which has a structure monoclinic (I12/a1) with lattice parameters a = 5.527(1) Å, b = 5.572(1) Å and c = 7.810(1) Å, α = γ = 90° and β = 89.88(5)°, the unit cell volume of V = 240.57(8) Å{sup 3}, and the atomic density of ρ = 6.238 gr.cm{sup −3}. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes of 1 ∼ 3 μm distributed homogeneously on the surface of the samples. The results of the electromagnetic wave absorption curve analysis by using a vector network analyzer (VNA) showed that the sample can absorb microwaves in the frequency range of 8-15 GHz with a very wide absorption bandwidth. It indicates that the as prepared absorber presents potential absorbing property in X and Ku-band. We concluded that the (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} material can be applied as a candidate absorber material of microwaves or electromagnetic wave.

  3. Internal Friction of Austenitic Fe-Mn-C-Al Alloys

    Science.gov (United States)

    Lee, Young-Kook; Jeong, Sohee; Kang, Jee-Hyun; Lee, Sang-Min

    2017-12-01

    The internal friction (IF) spectra of Fe-Mn-C-Al alloys with a face-centered-cubic (fcc) austenitic phase were measured at a wide range of temperature and frequency ( f) to understand the mechanisms of anelastic relaxations occurring particularly in Fe-Mn-C twinning-induced plasticity steels. Four IF peaks were observed at 346 K (73 °C) (P1), 389 K (116 °C) (P2), 511 K (238 °C) (P3), and 634 K (361 °C) (P4) when f was 0.1 Hz. However, when f increased to 100 Hz, whereas P1, P2, and P4 disappeared, only P3 remained without the change in peak height, but with the increased peak temperature. P3 matches well with the IF peak of Fe-high Mn-C alloys reported in the literature. The effects of chemical composition and vacancy (v) on the four IF peaks were also investigated using various alloys with different concentrations of C, Mn, Al, and vacancy. As a result, the defect pair responsible for each IF peak was found as follows: a v-v pair for P1, a C-v pair for P2, a C-C pair for P3, and a C-C-v complex (major effect) + a Mn-C pair (minor effect) for P4. These results showed that the IF peaks of Fe-Mn-C-Al alloys reported previously were caused by the reorientation of C in C-C pairs, not by the reorientation of C in Mn-C pairs.

  4. Determination of hydrogen solubility in Fe-Mn-C melts

    Energy Technology Data Exchange (ETDEWEB)

    Lob, Alexander; Senk, Dieter [Institute of Ferrous Metallurgy (IEHK), RWTH Aachen University (Germany); Hallstedt, Bengt [Materials Chemistry (MCh), RWTH Aachen University (Germany)

    2011-02-15

    High manganese steels are supposed to be sensitive to hydrogen embrittlement. This can be explained by increased hydrogen solubility in comparison to unalloyed steels. To minimise hydrogen pick up during melting operations, it is necessary to know accurately the hydrogen solubility as function of hydrogen partial pressure, temperature and Mn content. In this work in situ measurements of hydrogen content at 12, 18 and 23 wt.% Mn (and 0.6 wt.% C) using the Hydris {sup registered} system are compared to pin-tube measurements. Below about 7 ppm [H] both methods gave the same results and above 7 ppm [H] the in situ measurement showed slightly higher hydrogen contents because some hydrogen is lost during quenching with the pin-tube method. The measured solubilities were compared with thermodynamic calculations. Using dilute solution theory with data developed for alloyed Fe-based melts with up to 10 wt.% Mn gives reasonable results except that the hydrogen solubility is slightly underestimated for the presently investigated Mn contents. This could be compensated by using an interaction parameter of e{sup Mn}{sub H}=-0.004 instead of e{sup Mn}{sub H}=-0.0012. A Calphad type extrapolation from the binary Fe-H, Mn-H and Fe-Mn systems gave results very close to the experimental ones. This work is a contribution from the collaborative research centre SFB 761 ''Steel - ab initio''. (Copyright copyright 2011 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Influence of Zr substitution on the stabilization of ThMn12-type (Nd1−αZrα(Fe0.75Co0.2511.25Ti0.75N1.2−1.4 (α = 0–0.3 compounds

    Directory of Open Access Journals (Sweden)

    N. Sakuma

    2016-05-01

    Full Text Available The influence of Zr substitution in ThMn12 compounds was investigated using strip casting alloys. It was found that Zr substitution stabilized (Nd1−αZrα(Fe0.75Co0.2511.25Ti0.75N1.2−1.4 (α = 0–0.3 compounds. Specifically, a reduction in the lattice constant along the a-axis was observed. Energy-dispersive X-ray spectroscopy mapping combined with Cs-corrected scanning transmission electron microscopy indicated that Zr atoms preferentially occupied Nd 2a sites. Both the magnetic anisotropy field and saturation polarization were maximum at Zr substitution ratio α = 0.1. The (Nd1−αZrα(Fe0.75Co0.2511.25Ti0.75N1.2−1.4 (α = 0–0.3 compounds displayed higher saturation polarization than Nd2Fe14B at high temperatures.

  6. Influence of Zr substitution on the stabilization of ThMn{sub 12}-type (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, N.; Yano, M.; Kato, A. [Toyota Motor Corporation, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Technology Research Association of Magnetic Materials for High-Efficiency Motors (MagHEM) Higashifuji-Branch, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Suzuki, S.; Kuno, T.; Urushibata, K.; Kobayashi, K. [Shizuoka Institute of Science and Technology, 2200-2 Toyosawa, Fukuroi, Shizuoka 437-8555 (Japan); Manabe, A. [Technology Research Association of Magnetic Materials for High-Efficiency Motors (MagHEM) Higashifuji-Branch, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan)

    2016-05-15

    The influence of Zr substitution in ThMn{sub 12} compounds was investigated using strip casting alloys. It was found that Zr substitution stabilized (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds. Specifically, a reduction in the lattice constant along the a-axis was observed. Energy-dispersive X-ray spectroscopy mapping combined with Cs-corrected scanning transmission electron microscopy indicated that Zr atoms preferentially occupied Nd 2a sites. Both the magnetic anisotropy field and saturation polarization were maximum at Zr substitution ratio α = 0.1. The (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds displayed higher saturation polarization than Nd{sub 2}Fe{sub 14}B at high temperatures.

  7. Catalytic Oxidation of NO over MnOx–CeO2 and MnOx–TiO2 Catalysts

    Directory of Open Access Journals (Sweden)

    Xiaolan Zeng

    2016-11-01

    Full Text Available A series of MnOx–CeO2 and MnOx–TiO2 catalysts were prepared by a homogeneous precipitation method and their catalytic activities for the NO oxidation in the absence or presence of SO2 were evaluated. Results show that the optimal molar ratio of Mn/Ce and Mn/Ti are 0.7 and 0.5, respectively. The MnOx–CeO2 catalyst exhibits higher catalytic activity and better resistance to SO2 poisoning than the MnOx–TiO2 catalyst. On the basis of Brunauer–Emmett–Teller (BET, X-ray diffraction (XRD, and scanning transmission electron microscope with mapping (STEM-mapping analyses, it is seen that the MnOx–CeO2 catalyst possesses higher BET surface area and better dispersion of MnOx over the catalyst than MnOx–TiO2 catalyst. X-ray photoelectron spectroscopy (XPS measurements reveal that MnOx–CeO2 catalyst provides the abundance of Mn3+ and more surface adsorbed oxygen, and SO2 might be preferentially adsorbed to the surface of CeO2 to form sulfate species, which provides a protection of MnOx active sites from being poisoned. In contrast, MnOx active sites over the MnOx–TiO2 catalyst are easily and quickly sulfated, leading to rapid deactivation of the catalyst for NO oxidation. Furthermore, temperature programmed desorption with NO and O2 (NO + O2-TPD and in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS characterizations results show that the MnOx–CeO2 catalyst displays much stronger ability to adsorb NOx than the MnOx–TiO2 catalyst, especially after SO2 poisoning.

  8. Study of phase transformations in Fe-Mn-Cr Alloys

    International Nuclear Information System (INIS)

    Schule, W.; Panzarasa, A.; Lang, E.

    1988-01-01

    Nickel free alloys for fusion reactor applications are examined. Phase changes in fifteen, mainly austenitic iron-manganese-chromium-alloys of different compositions were investigated in the temperature range between -196 0 C and 1000 0 C after different thermo-mechanical treatments. A range of different physical measuring techniques was employed to investigate the structural changes occurring during heating and cooling and after cold-work: electrical resistivity techniques, differential thermal analysis, magnetic response, Vickers hardness and XRD measurement. The phase boundary between the α Fe-phase and the γ-phase of the iron manganese alloy is approximately maintained if chromium is added to the two component materials. Consequently all the alloy materials for contents of manganese smaller than about 30% Mn are not stable below 500 0 C. This concerns also the AMCR alloys. However the α Fe-phase is not formed during slow cooling from 1000 0 C to ambient temperature and is only obtained if nucleation sites are provided and after very long anneals. A cubic α Mn-type-phase is found for alloys with 18% Cr and 15% Mn, with 13% Cr and 25% Mn, with 10% Cr and 30% Mn, and with 10% Cr and 40% Mn. For these reasons the γ-phase field of the iron-chromium-manganese alloys is very small below 600 0 C and much narrower than reported in the literature. 95 figs. 22 refs

  9. Spin structure of exchange biased heterostructures. Fe/MnF{sub 2} and Fe/FeF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, B

    2006-12-18

    In this work, the {sup 57}Fe probe layer technique is used in order to investigate the depth- and temperature-dependent Fe-layer spin structure of exchange biased Fe/MnF{sub 2} and Fe/FeF{sub 2} (pseudo-twinned) antiferromagnetic (AFM) systems by conversion electron Moessbauer spectroscopy (CEMS) and nuclear resonant scattering (NRS) of synchrotron radiation. Two kinds of samples with a 10 A {sup 57}Fe probe layer directly at or 35 A away from the interface, labeled as interface and center sample, respectively, were studied in this work. The results obtained by CEMS for Fe/MnF{sub 2} suggests that, at 80 K, i.e., above T{sub N}=67 K of MnF{sub 2}, the remanent state Fe-layer spin structure of the two studied samples are slightly different due to their different microstructure. In the temperature range from 300 K to 80 K, the Fe-layer spin structure does not change just by zero-field cooling the sample in remanence. For Fe/FeF{sub 2}, a continuous non-monotonic change of the remanent-state Fe spin structure was observed by cooling from 300 K to 18 K. NRS of synchrotron radiation was used to investigate the temperature- and depth-dependent Fe-layer spin structure during magnetization reversal in pseudo-twinned Fe/MnF{sub 2}. A depthdependent Fe spin structure in an applied magnetic field (applied along the bisector of the twin domains) was observed at 10 K, where the Fe spins closer to the interface are not aligned along the field direction. The depth-dependence disappears at 150 K. (orig.)

  10. Cavitation erosion of Ti-Ni shape memory alloy deposited coatings and Fe base shape memory alloy solid

    International Nuclear Information System (INIS)

    Hattori, Shuji; Fujisawa, Seiji; Owa, Tomonobu

    2007-01-01

    In this study, cavitation erosion tests were carried out by using thermal spraying and deposition of Ti-Ni shape memory alloy for the surface coating. The results show the test speciment of Ti-Ni thermal spraying has many initial defects, so that the erosion resistance is very low. The erosion resistance of Ti-Ni deposit is about 5-10 times higher than that of SUS 304, thus erosion resistance of Ti-Ni deposit is better than that of Ti-Ni thermal spraying. The cavitation erosion tests were carried out by using Fe-Mn-Si with shape memory and gunmetal with low elastic modulus. The erosion resistance of Fe-Mn-Si shape memory alloy solid is about 9 times higher than that of SUS 304. The erosion resistance of gunmetal is almost the same as SUS 304, because the test specimen of gunmetal has many small defects on the original surface. (author)

  11. Precipitation sensitivity to alloy composition in Fe-Cr-Mn austenitic steels developed for reduced activation for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Klueh, R.L.

    1988-01-01

    Special austenitic steels are being designed in which alloying elements like Mo, Nb, and Ni are replaced with Mn, W, V, Ti, and/or Ta to reduce the long-term radioactivity induced by fusion reactor irradiation. However, the new steels still need to have properties otherwise similar to commercial steels like type 316. Precipitation strongly affects strength and radiation-resistance in austenitic steels during irradiation at 400--600/degree/C, and precipitation is also usually quite sensitive to alloy composition. The initial stage of development was to define a base Fe-Cr-Mn-C composition that formed stable austenite after annealing and cold-working, and resisted recovery or excessive formation of coarse carbide and intermetallic phases during elevated temperature annealing. These studies produced a Fe-12Cr-20Mn-0.25C base alloy. The next stage was to add the minor alloying elements W, Ti, V, P, and B for more strength and radiation-resistance. One of the goals was to produce fine MC precipitation behavior similar to the Ti-modified Fe-Cr-Ni prime candidate alloy (PCA). Additions of Ti+V+P+B produced fine MC precipitation along network dislocations and recovery/recrystallization resistance in 20% cold worked material aged at 800/degree/C for 166h, whereas W, Ti, W+Ti, or Ti+P+B additions did not. Addition of W+Ti+V+P+B also produced fine MC, but caused some σ phase formation and more recrystallization as well. 29 refs., 14 figs., 9 tabs

  12. Hydrogen storage performance of Ti-V-based BCC phase alloys with various Fe content

    International Nuclear Information System (INIS)

    Yu, X.B.; Feng, S.L.; Wu, Z.; Xia, B.J.; Xu, N.X.

    2005-01-01

    The effect of Fe content on hydrogen storage characteristics of Ti-10Cr-18Mn-(32-x)V-xFe (x = 0, 2, 3, 4, 5) alloys has been investigated at 353 K. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images of the alloys present BCC and C14 two-phase structures for all of the Fe-containing alloys. With the increasing Fe content, the lattice parameters of the BCC phase decrease, which results in an increase of the hydrogen desorption plateau pressure of the alloys. Among the studied alloys, Ti-10Cr-18Mn-27V-5Fe alloy exhibits the smallest PCT plateau slope and a more suitable plateau pressure (0.1 MPa equ <1 MPa). The maximum and effective capacities of the alloy are 3.32 wt.% and 2.26 wt.%, respectively, which are higher than other reported Fe-containing BCC phase alloys. In addition, the V/Fe ratio in this alloy is close to that of (VFe) alloy, whose cost is much lower than that of pure V

  13. Relationships between environment and characteristics of marine Fe-Mn deposits in the Romanche trench

    International Nuclear Information System (INIS)

    Bonte, Philippe.

    1981-11-01

    The geological characteristics and Fe-Mn deposits from the North wall of the Romanche trench (Atlantic ocean) were studied in order to investigate possible relationships of these deposits with hydrothermalism. The results indicate diffuse hydrothermal activity in all of the rock samples which may explain the notable mineralogical associations observed, such as talc-dolomite-hematite-serpentine. All rock outcrops were covered with Fe-Mn deposits, but no such deposits were noted on sedimentary platforms. The variations in average chemical composition are very low among the different deposits. Hence, the phenomenon which produces these deposits is not localized. From this study, we conclude that marine Fe-Mn deposits result from the continuous supply of terrigenous iron and discontinuous supply of manganese, probably hydrothermal in origin. Detrital particles and numerous chemical elements are scavenged during the accretion process itself, whereas some trace elements, among the least soluble (Co, Ti, Th, Ce), are adsorbed on these deposits, independently of the accretion. This explains the inverse variation of the content of these elements versus deposit thickness [fr

  14. Thin film nano-photocatalyts with low band gap energy for gas phase degradation of p-xylene: TiO2 doped Cr, UiO66-NH2 and LaBO3 (B  =  Fe, Mn, and Co)

    Science.gov (United States)

    Loc Luu, Cam; Thuy Van Nguyen, Thi; Nguyen, Tri; Nguyen, Phung Anh; Hoang, Tien Cuong; Ha, Cam Anh

    2018-03-01

    By dip-coating technique the thin films of nano-photocatalysts TiO2, Cr-doped TiO2, LaBO3 perovskites (B  =  Fe, Mn, and Co) prepared by sol-gel method, and UiO66-NH2 prepared by a solvothermal were obtained and employed for gas phase degradation of p-xylene. Physicochemical characteristics of the catalysts were examined by the methods of BET, SEM, TEM, XRD, FT-IR, TGA, Raman and UV-vis spectroscopies. The thickness of film was determined by a Veeco-American Dektek 6M instrument. The activity of catalysts was evaluated in deep photooxidation of p-xylene in a microflow reactor at room temperature with the radiation sources of a UV (λ  =  365 nm) and LED lamps (λ  =  400-510 nm). The obtained results showed that TiO2 and TiO2 doped Cr thin films was featured by an anatase phase with nanoparticles of 10-100 nm. Doping TiO2 with 0.1%mol Cr2O3 led to reduce band gap energy from 3.01 down to 1.99 eV and extend the spectrum of photon absorption to the visible region (λ  =  622 nm). LaBO3 perovkite thin films were also featured by a crystal phase with average particle nanosize of 8-40 nm, a BET surface area of 17.6-32.7 m2 g-1 and band gap energy of 1.87-2.20 eV. UiO66-NH2 was obtained in the ball shape of 100-200 nm, a BET surface area of 576 m2 g-1 and a band gap energy of 2.83 eV. The low band gap energy nano-photocatalysts based on Cr-doped TiO2 and LaBO3 perovskites exhibited highly stable and active for photo-degradation of p-xylene in the gas phase under radiation of UV-vis light. Perovskite LaFeO3 and Cr-TiO2 thin films were the best photocatalysts with a decomposition yield being reached up to 1.70 g p-xylene/g cat.

  15. Obtention of the TiFe compound by high-energy milling of Ti+Fe and TiH{sub 2}+Fe powder mixtures; Obtencao do composto TiFe a partir da moagem de alta energia de misturas Ti+Fe e TiH{sub 2}+Fe

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, R.B.; Dammann, E.D.C.C.; Rocha, C.J.; Leal Neto, R.M., E-mail: railson.falcao@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais. Lab. de Intermetalicos

    2010-07-01

    In this work TiFe compound was obtained by two process routes involving high-energy ball milling: mechanical alloying from Ti and Fe powders (route 1) and mechanical milling from TiH{sub 2} and Fe powders, both followed by an annealing heat treatment. Shaker and planetary ball mills were utilized for times varying from 1-25 hours. Milled and annealed powders were characterized by SEM and X-ray diffraction analyses. TiFe compound was formed in both routes. A strong powder adherence in the milling vial and balls occurred with route 1 in both mills. Powder adherence was significantly reduced by using TiH{sub 2} (route 2) mainly in the planetary mill, in spite of TiFe formation has only occurred after the annealing treatment. (author)

  16. Cross sections for the reactions 54Fe(n,α)51Cr, 54Fe(n,p)54Mn, and 56Fe(n,p)56Mn

    International Nuclear Information System (INIS)

    Paulsen, A.; Widera, R.; Arnotte, F.; Liskien, H.

    1979-01-01

    Ratios of cross sections for the reactions 54 Fe(n,α) 51 Cr, 54 Fe(n,p) 54 Mn, and 56 Fe(n,p) 56 Mn were measured by the activation technique. In the 6- to 10-MeV energy range, quasi-monoenergetic neutrons produced by the D(d,n) source reaction were used, while additional data were obtained between 12 and 17 MeV by use of the T(d,n) source reaction. The cross-section ratios have accuracies between 1.5 and 4.5%. 1 figure, 3 tables

  17. Phase relations in the pseudobinary systems RAO3-R2Ti2O7 (R: rare earth element and Y, A: Fe, Ga, Al, Cr and Mn) and syntheses of new compounds R(A1-xTix)O3+x/2 (2/3≤x≤3/4) at elevated temperatures in air

    Science.gov (United States)

    Brown, Francisco; Jacobo-Herrera, Ivan; Alvarez-Montaño, Victor; Kimizuka, Noboru; Kurashina, Keiji; Michiue, Yuichi; Matsuo, Yoji; Mori, Shigeo; Ikeda, Naoshi; Medrano, Felipe

    2017-07-01

    Phase relations in the pseudo-binary systems RFeO3-R2Ti2O7 (R: Lu, Ho and Dy), RGaO3-R2Ti2O7 (R: Lu and Er), LuAlO3-Lu2Ti2O7 and RAO3-R2Ti2O7 (R: Lu and Yb. A: Cr and Mn) at elevated temperatures in air were determined by means of a classic quenching method. There exist Lu(Fe1-xTix)O3+x/2, R(Ga1-xTix)O3+x/2 (R: Lu and Er) and Lu(Al1-xTix)O3+x/2 (2/3≤ x≤3/4) having the Yb(Fe1-xTix)O3+x/2-type of crystal structure (x=0.72, space group: R3m, a(Å)=17.9773 and c(Å)=16.978 as a hexagonal setting) in these pseudo binary systems. Eighteen compounds R(A1-xTix)O3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) were newly synthesized and their lattice constants as a hexagonal setting were measured by means of the X-ray powder diffraction method. The R occupies the octahedral site and both A and Ti does the trigonalbipyramidal one in these compounds. Relation between lattice constants for the rhombic R(A1-xTix)O3+x/2 and the monoclinic In(A1-xTix)O3+x/2 are as follows, ah≈5 x bm, ch≈3 x cm x sin β and am=31/2 x bm, where ah and ch are the lattice constants as a hexagonal setting for R(A1-xTix)O3+x/2 and am, bm, cm and β are those of the monoclinic In(A1-xTix)O3+x/2. Crystal structural relationships among α-InGaO3 (hexagonal, high pressure form, space group: P63/mmc), InGaO3 (rhombic, hypothetical), (RAO3)n(BO)m and RAO3(ZnO)m (R: Lu-Ho, Y and In, A: Fe, Ga, and Al, B: divalent cation element, m, n: natural number), the orthorhombic-and monoclinic In(A1-xTix)O3+x/2 (A: Fe, Ga, Al, Cr and Mn) and the hexagonal-and rhombic R(A1-xTix)O3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) are schematically presented. We concluded that the crystal structures of both the α-InGaO3 (high pressure form, hexagonal, space group: P63/mmc) and the hypothetical InGaO3 (rhombic) are the key structures for constructing the crystal structures of these compounds having the cations with CN=5.

  18. Effect of Ni, Fe and Mn in different proportions on microstructure and pollutant-catalyzed properties of Ni-Fe-Mn-O negative temperature coefficient ceramic nanocompositions

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yonglin, E-mail: leiyonglin@163.com [Engineering Research Center of Biomass Materials, Ministry of Education, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Lin, Xiaoyan, E-mail: linxy@swust.edu.cn [Engineering Research Center of Biomass Materials, Ministry of Education, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Liao, Huiwei, E-mail: liaohw@swust.edu.cn [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China)

    2017-06-15

    The effect of Ni, Fe and Mn in different proportions on microstructure and pollutant-catalyzed properties of Ni-Fe-Mn-O negative temperature coefficient ceramic nanocompositions was studied. Structural and physical characterization of all the samples was carried out by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) method, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric (TG). The results revealed that the interplanar spacing decreased with increasing Fe content, the grain size decreased with increasing Ni content, the substitution of Ni{sup 2+} in the tetrahedral sites by Fe{sup 2+} increased with increasing Fe content. And increase of iron could improve Ni-Fe-Mn-O high temperature stability. The low-temperature thermal removal efficiencies of 30 mg/L methyl orange solution for NiFeMnO{sub 4}, Ni{sub 0.6}Fe{sub 0.9}Mn{sub 1.5}O{sub 4,} Ni{sub 0.6}Fe{sub 1.8}Mn{sub 0.6}O{sub 4} and Ni{sub 0.3}Fe{sub 2.1}Mn{sub 0.6}O{sub 4} systems were 83.8%, 75.2%, 78.5% and 60.3% at 2400 min, respectively. And the microwave combining with H{sub 2}O{sub 2} removal efficiencies of 30 mg/L methyl orange solution for NiFeMnO{sub 4}, Ni{sub 0.6}Fe{sub 0.9}Mn{sub 1.5}O{sub 4,} Ni{sub 0.6}Fe{sub 1.8}Mn{sub 0.6}O{sub 4} and Ni{sub 0.3}Fe{sub 2.1}Mn{sub 0.6}O{sub 4} systems were 96.5%,93.8%, 98.7% and 98% at 6.0 min, respectively. These results indicated that the Ni-Fe-Mn-O ceramics with appropriate increase of iron were useful for industrial applications on degrading organic pollute. - Highlights: • The relationship of composition and catalytic properties of Ni-Fe-Mn-O was proposed. • The interplanar spacing decreased with increasing Fe content. • The grain size decreased with increasing Ni content. • The substitution of Ni{sup 2+} in the tetrahedral site by Fe{sup 2+} with increasing Fe content.

  19. New procedure of quantitative mapping of Ti and Al released from dental implant and Mg, Ca, Fe, Zn, Cu, Mn as physiological elements in oral mucosa by LA-ICP-MS.

    Science.gov (United States)

    Sajnóg, Adam; Hanć, Anetta; Koczorowski, Ryszard; Barałkiewicz, Danuta

    2017-12-01

    A new procedure for determination of elements derived from titanium implants and physiological elements in soft tissues by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented. The analytical procedure was developed which involved preparation of in-house matrix matched solid standards with analyte addition based on certified reference material (CRM) MODAS-4 Cormorant Tissue. Addition of gelatin, serving as a binding agent, essentially improved physical properties of standards. Performance of the analytical method was assayed and validated by calculating parameters like precision, detection limits, trueness and recovery of analyte addition using additional CRM - ERM-BB184 Bovine Muscle. Analyte addition was additionally confirmed by microwave digestion of solid standards and analysis by solution nebulization ICP-MS. The detection limits are in range 1.8μgg -1 to 450μgg -1 for Mn and Ca respectively. The precision values range from 7.3% to 42% for Al and Zn respectively. The estimated recoveries of analyte addition line within scope of 83%-153% for Mn and Cu respectively. Oral mucosa samples taken from patients treated with titanium dental implants were examined using developed analytical method. Standards and tissue samples were cryocut into 30µm thin sections. LA-ICP-MS allowed to obtain two-dimensional maps of distribution of elements in tested samples which revealed high content of Ti and Al derived from implants. Photographs from optical microscope displayed numerous particles with µm size in oral mucosa samples which suggests that they are residues from implantation procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Photoelectrochemical Performance Observed in Mn-Doped BiFeO3 Heterostructured Thin Films

    Directory of Open Access Journals (Sweden)

    Hao-Min Xu

    2016-11-01

    Full Text Available Pure BiFeO3 and heterostructured BiFeO3/BiFe0.95Mn0.05O3 (5% Mn-doped BiFeO3 thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO3 films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm−2. By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe0.95Mn0.05O3 layer and an internal field being built in the BiFeO3/BiFe0.95Mn0.05O3 interface. BiFeO3/BiFe0.95Mn0.05O3 and BiFe0.95Mn0.05O3 thin films demonstrated poor photo activity compared with pure BiFeO3 films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe0.95Mn0.05O3 layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.

  1. Giant magnetoresistance in CrFeMn alloys

    International Nuclear Information System (INIS)

    Xu, W.M.; Zheng, P.; Chen, Z.J.

    1997-01-01

    The electrical resistance and longitudinal magnetoresistance of Cr 75 (Fe x Mn 1-x ) 25 alloys, x=0.64, 0.72, are studied in the temperature range 1.5-270 K in applied field up to 7.5 T. The magnetoresistance is negative and strongly correlated with the spin reorientation. In the temperature range where the antiferromagnetic and ferromagnetic domains coexist, the samples display giant magnetoresistance which follows a H n -law at high field. (orig.)

  2. High damping Fe-Mn martensitic alloys for engineering applications

    International Nuclear Information System (INIS)

    Baik, S.-H.

    2000-01-01

    Conventional methods for reducing vibration in engineering designs (i.e. by stiffening or detuning) may be undesirable or inadequate in conditions where size or weight must be minimized or where complex vibration spectra exist. Alloys which combine high damping capacity with good mechanical properties can provide attractive technical and economic solutions to problems involving seismic, shock and vibration isolation. To meet these trends, we have developed a new high damping Fe-17%Mn alloy. Also, the alloy has advantages of good mechanical properties and is more economical than any other known damping alloys (a quarter the cost of non-ferrous damping alloy). Thus, the high damping Fe-17%Mn alloy can be widely applied to household appliances, automobiles, industrial facilities and power plant components with its excellent damping capacity (SDC, 30%) and mechanical property (T.S. 700 MPa). It is the purpose of this paper to introduce the characterization of the high damping Fe-17%Mn alloy and the results of retrofit of several such applications. (orig.)

  3. A -Site Ordered Double Perovskite CaMnTi 2 O 6 as a Multifunctional Piezoelectric and Ferroelectric–Photovoltaic Material

    Energy Technology Data Exchange (ETDEWEB)

    Gou, Gaoyang [Frontier Institute; Charles, Nenian [Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States; Shi, Jing [MOE Key Laboratory; Rondinelli, James M. [Department; Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States

    2017-09-11

    The double perovskite CaMnTi2O6, is a rare A site ordered perovskite oxide that exhibits a sizable ferroelectric polarization and relatively high Curie temperature. Using first-principles calculations combined with detailed symmetry analyses, we identify the origin of the ferroelectricity in CaMnTi2O6. We further explore the material properties of CaMnTi2O6, including its ferroelectric polarization, dielectric and piezoelectric responses, magnetic order, electronic structure, and optical absorption coefficient. It is found that CaMnTi2O6 exhibits room-temperature-stable ferroelectricity and moderate piezoelectric responses. Moreover, CaMnTi2O6 is predicted to have a semiconducting energy band gap similar to that of BiFeO3, and its band gap can further be tuned-via distortions of the planar Mn-O bond lengths. CaMnTi2O6 exemplifies a new class of single-phase semiconducting ferroelectric perovskites for potential applications in ferroelectric photovoltaic solar cells.

  4. XAFS Studies of Fe Doped PhTiO3 Nanoparticles

    International Nuclear Information System (INIS)

    Shibata, Tomohiro; Chattopadhyay, Soma; Lin Bin; Palkar, V. R.

    2007-01-01

    Fe K and Ti K edge XAFS studies are reported on Fe doped PbTiO3 nanoparticles down to the 10 nm size. Fe forms Fe3+ ions and substitute for Ti4+ ions. For 18 nm nanoparticles, the Fe and Ti environment is found to be quite different. For PbFe0.5Ti0.5O3, locally the structure remains distorted from bulk to 10 nm size although the average structure changes

  5. Kinetics and mechanism of diclofenac removal using ferrate(VI): roles of Fe3+, Fe2+, and Mn2.

    Science.gov (United States)

    Zhao, Junfeng; Wang, Qun; Fu, Yongsheng; Peng, Bo; Zhou, Gaofeng

    2018-06-01

    In this study, the effect of Fe 3+ , Fe 2+ , and Mn 2+ dose, solution pH, reaction temperature, background water matrix (i.e., inorganic anions, cations, and natural organic matters (NOM)), and the kinetics and mechanism for the reaction system of Fe(VI)/Fe 3+ , Fe(VI)/Fe 2+ , and Fe(VI)/Mn 2+ were investigated systematically. Traces of Fe 3+ , Fe 2+ , and Mn 2+ promoted the DCF removal by Fe(VI) significantly. The pseudo-first-order rate constant (k obs ) of DCF increased with decreasing pH (9-6) and increasing temperature (10-30 °C) due to the gradually reduced stability and enhanced reactivity of Fe(VI). Cu 2+ and Zn 2+ ions evidently improved the DCF removal, while CO 3 2- restrained it. Besides, SO 4 2- , Cl - , NO 3 - , Mg 2+ , and Ca 2+ almost had no influence on the degradation of DCF by Fe(VI)/Fe 3+ , Fe(VI)/Fe 2+ , and Fe(VI)/Mn 2+ within the tested concentration. The addition of 5 or 20 mg L -1 NOM decreased the removal efficiency of DCF. Moreover, Fe 2 O 3 and Fe(OH) 3 , the by-products of Fe(VI), slightly inhibited the DCF removal, while α-FeOOH, another by-product of Fe(VI), showed no influence at pH 7. In addition, MnO 2 and MnO 4 - , the by-products of Mn 2+ , enhanced the DCF degradation due to catalysis and superposition of oxidation capacity, respectively. This study indicates that Fe 3+ and Fe 2+ promoted the DCF removal mainly via the self-catalysis for Fe(VI), and meanwhile, the catalysis of Mn 2+ and the effect of its by-products (i.e., MnO 2 and MnO 4 - ) contributed synchronously for DCF degradation. Graphical abstract ᅟ.

  6. Synthesis and characterization of FeTiO3 ceramics

    OpenAIRE

    Anil B. Gambhire; Machhindra K. Lande; Sandip B. Rathod; Balasaheb R. Arbad; Kaluram N. Vidhate; Ramakrishna S. Gholap; Kashinath R. Patil

    2016-01-01

    Nanocrystalline FeTiO3 ceramic powders were prepared by the sol–gel process combined with a surfactant-assisted template method. The resulting powders were calcined at different temperatures ranging from 150 °C to 600 °C for 2 h in air. The results revealed that a pure hexagonal phase of FeTiO3 could be obtained at a low temperature, 600 °C. The phase evolution of FeTiO3 was investigated by X-ray diffraction patterns (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelect...

  7. Amorphous surface layers in Ti-implanted Fe

    International Nuclear Information System (INIS)

    Knapp, J.A.; Follstaedt, D.M.; Picraux, S.T.

    1979-01-01

    Implanting Ti into high-purity Fe results in an amorphous surface layer which is composed of not only Fe and Ti, but also C. Implantations were carried out at room temperature over the energy range 90 to 190 keV and fluence range 1 to 2 x 10 16 at/cm 2 . The Ti-implanted Fe system has been characterized using transmission electron microscopy (TEM), ion backscattering and channeling analysis, and (d,p) nuclear reaction analysis. The amorphous layer was observed to form at the surface and grow inward with increasing Ti fluence. For an implant of 1 x 10 17 Ti/cm 2 at 180 keV the layer thickness was 150 A, while the measured range of the implanted Ti was approx. 550 A. This difference is due to the incorporation of C into the amorphous alloy by C being deposited on the surface during implantation and subsequently diffusing into the solid. Our results indicate that C is an essential constituent of the amorphous phase for Ti concentrations less than or equal to 10 at. %. For the 1 x 10 17 Ti/cm 2 implant, the concentration of C in the amorphous phase was approx. 25 at. %, while that of Ti was only approx. 3 at. %. A higher fluence implant of 2 x 10 17 Ti/cm 2 produced an amorphous layer with a lower C concentration of approx. 10 at. % and a Ti concentration of approx. 20 at. %

  8. Molecular magnetism of a linear Fe(III)-Mn(II)-Fe(III) complex. Influence of long-range exchange interaction

    International Nuclear Information System (INIS)

    Lengen, M.; Chaudhuri, P.

    1994-01-01

    The magnetic properties of [L-Fe(III)-dmg 3 Mn(II)-Fe(III)-L] (ClO 4 ) 2 have been characterized by magnetic susceptibility, EPR, and Moessbauer studies. L represents 1,4,7-trimethyl-,1,4,7-triazacyclononane and dmg represents dimethylglyoxime. X-ray diffraction measurements yield that the arrangement of the three metal centers is strictly linear with atomic distances d Fe-Mn 0.35 nm and d Fe-Fe = 0.7 nm. Magnetic susceptibility measurements (3-295 K) were analyzed in the framework of the spin-Hamiltonian formalism considering Heisenberg exchange and Zeeman interaction: H = J Fe-Mn (S Fe1 + S Fe2 )S Mn + J Fe-Fe S Fe1 S Fe2 + gμ B S total B. The spins S Fe1 = S Fe2 = S Mn = 5/2 of the complex are antiferromagnetically coupled, yielding a total spin of S total = 5/2 with exchange coupling constants F Fe-Mn = 13.4 cm -1 and J Fe-Fe = 4.5 cm -1 . Magnetically split Moessbauer spectra were recorded at 1.5 K under various applied fields (20 mT, 170 mT, 4 T). The spin-Hamiltonian analysis of these spectra yields isotropic magnetic hyperfine coupling with A total /(g N μ N ) = -18.5 T. The corresponding local component A Fe is related to A total via spin-projection: A total = (6/7)A Fe . The resulting A Fe /(g N μ N ) -21.6 T is in agreement with standard values of ferric high-spin complexes. Spin-Hamiltonian parameters as obtained from Moessbauer studies and exchange coupling constants as derived from susceptibility measurements are corroborated by temperature-dependent EPR studies. (orig.)

  9. Effects of homogenization on microstructures and properties of a new type Al-Mg-Mn-Zr-Ti-Er alloy

    International Nuclear Information System (INIS)

    He, L.Z.; Li, X.H.; Liu, X.T.; Wang, X.J.; Zhang, H.T.; Cui, J.Z.

    2010-01-01

    Research highlights: These new type alloys are very potential for increased use in aerospace and automobile industries. However, most of published reports have focused on the effects of Cu, Sc, Zr, Ag, rare metals and Si additions, Portevin-LeChatelier effect, corrosion properties, friction stir welding and superplasticity in 5000-series aluminum alloy, few investigated on Er and stepped homogenization on the precipitation of dispersoids in Al-Mg-Mn alloy. The purpose of this work was to study the effects of Er and homogenization treatment on mechanical properties and microstructural evolution in new type Al-Mg-Mn-Er alloy. - Abstract: Microstructural evolutions and mechanical properties of Al-Mg-Mn-Zr-Ti-Er alloy after homogenization were investigated in detail by optical microscope (OM), scanning electronic microscope (SEM), transmission electronic microscope (TEM), energy dispersive spectrum (EDS) and tensile test. A maximum tensile strength is obtained when the alloy homogenized at 510 deg. C for 16 h. With increasing preheating temperature (200-400 deg. C), the strength of the alloy finial homogenized at 490 deg. C for 16 h increases. When the preheating temperature is ≥300 deg. C, the strengths of the two-step homogenized alloys are higher than those of the single homogenized alloys. The preheating stage plays an important role in the microstructures and properties of the final homogenized alloy. Many fine (Mn,Fe)Al 6 precipitates when the preheating temperature is 400 deg. C. ErAl 3 phase cannot be observed during preheating stage. Plenty of fine (Mn,Fe)Al 6 and ErAl 3 precipitate in finial homogenized alloy when the preheating temperature is ≥300 deg. C. The Al-Mg-Mn-Zr-Ti-Er alloy is effectively strengthened by substructure and dispersoids of (Mn,Fe)Al 6 and ErAl 3 .

  10. Superplasticity in a lean Fe-Mn-Al steel.

    Science.gov (United States)

    Han, Jeongho; Kang, Seok-Hyeon; Lee, Seung-Joon; Kawasaki, Megumi; Lee, Han-Joo; Ponge, Dirk; Raabe, Dierk; Lee, Young-Kook

    2017-09-29

    Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here we introduce a new compositionally lean (Fe-6.6Mn-2.3Al, wt.%) superplastic medium Mn steel that resolves these limitations. The medium Mn steel is characterized by ultrafine grains, low material costs, simple fabrication, i.e., conventional hot and cold rolling, low deformation temperature (ca. 650 °C) and superior ductility above 1300% at 850 °C. We suggest that this ultrafine-grained medium Mn steel may accelerate the commercialization of superplastic ferrous alloys.Research in new alloy compositions and treatments may allow the increased strength of mass-produced, intricately shaped parts. Here authors introduce a superplastic medium manganese steel which has an inexpensive lean chemical composition and which is suited for conventional manufacturing processes.

  11. Phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC and the formation of TiC in Fe3Al-based alloys

    International Nuclear Information System (INIS)

    Kobayashi, Satoru; Schneider, Andre; Zaefferer, Stefan; Frommeyer, Georg; Raabe, Dierk

    2005-01-01

    In the context of the development of high-strength Fe 3 Al-based alloys, phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC phases in the Fe-Al-Cr-Ti-C quinary system and the formation of TiC were determined. A pseudo-eutectic trough (L α + L + TiC) exists at 1470 deg C at around Fe-26Al-5Cr-2Ti-1.7C on the vertical section between Fe-26Al-5Cr (α) and Ti-46C (TiC) in at.%. Large faceted TiC precipitates form from the melt after the formation of primary α phase even in hypoeutectic alloys. The TiC formation is thought to be due to the composition change of the liquid towards the hypereutectic compositions by solidification of the primary α. In order to remove the faceted TiC, which are unfavourable for strengthening the material, two different processing routes have been successfully tested: (i) solidification with an increased rate to reduce the composition variation of the liquid during solidification, and (ii) unidirectional solidification to separate the light TiC precipitates from the melt

  12. Hardening of Fe-Cr-Mn steels cold plastic working

    International Nuclear Information System (INIS)

    Malinov, L.S.; Konop-Lyashko, V.I.; Nikoporets, N.M.

    1983-01-01

    The dependence is established between the level of proper-- ties obtained after cold plastic working and development of martensite transformations when loading in Fe-Cr-Mn steels containing 0.1-0.5% C, 13% Cr, 8-12% Mn, as well as in a number of complex alloyed steels. It is shown that the highest level of mechanical properties can be obtained after cold plastic working only in steels with definite austenite stability. Cold plastic working can both activize and stabilize austenite relatively to martensite formation during loading. The first thing is found when under the effect of preliminary cold working dislocation splitting takes place, as well as the formation of a small amount of E-phase and martensite. The second thing manifests itself when under the effect of cold working performed above Md (Md<20 deg C) cell dislocation structure is formed and dislocation pinning takes place

  13. Effect of different factors on phase transformations in Fe-Mn alloys

    International Nuclear Information System (INIS)

    Balychev, Yu.M.; Tkachenko, F.K.

    1983-01-01

    Phase transformations proceeding under Fe-Mn alloy heating are studied and the effect of previous working conditions, particularly, cooling rate on these transformations is investigated. Investigations have been conducted on pure Fe-Mn alloys with 2-15% Mn. Phase transformations are shown to proceed according to α → #betta# and epsilon → #betta# reaction in Fe-Mn alloys containing 2-15% Mn under heating. Cooling rate in the range of approximately 5-1000 deg/min in preliminary working essentially affects phase transformations under subsequent heating

  14. Magnetic properties and thermal stability of MnBi/NdFeB hybrid bonded magnets

    International Nuclear Information System (INIS)

    Cao, S.; Yue, M.; Yang, Y. X.; Zhang, D. T.; Liu, W. Q.; Zhang, J. X.; Guo, Z. H.; Li, W.

    2011-01-01

    Magnetic properties and thermal stability were investigated for the MnBi/NdFeB (MnBi = 0, 20, 40, 60, 80, and 100 wt.%) bonded hybrid magnets prepared by spark plasma sintering (SPS) technique. Effect of MnBi content on the magnetic properties of the hybrid magnets was studied. With increasing MnBi content, the coercivity of the MnBi/NdFeB hybrid magnets increases rapidly, while the remanence and maximum energy product drops simultaneously. Thermal stability measurement on MnBi magnet, NdFeB magnet, and the hybrid magnet with 20 wt.% MnBi indicates that both the NdFeB magnet and the MnBi/NdFeB hybrid magnet have a negative temperature coefficient of coercivity, while the MnBi magnet has a positive one. The (BH) max of the MnBi/NdFeB magnet (MnBi = 20 wt.%) is 5.71 MGOe at 423 K, which is much higher than 3.67 MGOe of the NdFeB magnet, indicating a remarkable improvement of thermal stability.

  15. Hydrogenation Properties of TiFe Doped with Zirconium

    Directory of Open Access Journals (Sweden)

    Catherine Gosselin

    2015-11-01

    Full Text Available The goal of this study was to optimize the activation behaviour of hydrogen storage alloy TiFe. We found that the addition of a small amount of Zr in TiFe alloy greatly reduces the hydrogenation activation time. Two different procedural synthesis methods were applied: co-melt, where the TiFe was melted and afterward re-melted with the addition of Zr, and single-melt, where Ti, Fe and Zr were melted together in one single operation. The co-melted sample absorbed hydrogen at its maximum capacity in less than three hours without any pre-treatment. The single-melted alloy absorbed its maximum capacity in less than seven hours, also without pre-treatment. The reason for discrepancies between co-melt and single-melt alloys was found to be the different microstructure. The effect of air exposure was also investigated. We found that the air-exposed samples had the same maximum capacity as the argon protected samples but with a slightly longer incubation time, which is probably due to the presence of a dense surface oxide layer. Scanning electron microscopy revealed the presence of a rich Zr intergranular phase in the TiFe matrix, which is responsible for the enhanced hydrogenation properties of these Zr-doped TiFe alloys.

  16. Oxidation states of Fe and Ti in blue sapphire

    International Nuclear Information System (INIS)

    Wongrawang, P; Wongkokua, W; Monarumit, N; Thammajak, N; Wathanakul, P

    2016-01-01

    X-ray absorption near-edge spectroscopy (XANES) can be used to study the oxidation state of a dilute system such as transition metal defects in solid-state samples. In blue sapphire, Fe and Ti are defects that cause the blue color. Inter-valence charge transfer (IVCT) between Fe 2+ and Ti 4+ has been proposed to describe the optical color’s origin. However, the existence of divalent iron cations has not been thoroughly investigated. Fluorescent XANES is therefore employed to study K-edge absorptions of Fe and Ti cations in various blue sapphire samples including natural, synthetic, diffused and heat-treated sapphires. All the samples showed an Fe absorption edge at 7124 eV, corresponding to the Fe 3+ state; and Ti at 4984 eV, corresponding to Ti 4+ . From these results, we propose Fe 3+ -Ti 4+ mixed acceptor states located at 1.75 eV and 2.14 eV above the valence band of corundum, that correspond to 710 nm and 580 nm bands of UV–vis absorption spectra, to describe the cause of the color of blue sapphire. (paper)

  17. Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

    Energy Technology Data Exchange (ETDEWEB)

    Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

    2016-03-15

    Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

  18. Oxygen nonstoichiometry and defects in Mn-doped Gd2Ti2O7+x

    International Nuclear Information System (INIS)

    Porat, O.; Tuller, H.L.

    1996-01-01

    The oxygen nonstoichiometry in Mn-doped Gd 2 Ti 2 O 7 , Gd 2 (Ti 0.975 Mn 0.025 ) 2 O 7+x , was measured electrochemically, as a function of temperature and oxygen partial pressure, with the aid of an oxygen titration cell. The analysis of the data shows that the defect equilibrium can be described by considering the dominant point defects to be neutral oxygen interstitials, doubly charged oxygen vacancies, and trivalent and quadrivalent Mn ions substituted in the Ti sites. The enthalpies for the formation of neutral oxygen interstitials and trivalent Mn are determined

  19. Multiferroic BiFeO3-BiMnO3 Nanocheckerboard From First Principles

    OpenAIRE

    Palova, L.; Chandra, P.; Rabe, K. M.

    2010-01-01

    We present a first principles study of an unusual heterostructure, an atomic-scale checkerboard of BiFeO3-BiMnO3, and compare its properties to the two bulk constituent materials, BiFeO3 and BiMnO3. The "nanocheckerboard" is found to have a multiferroic ground state with the desired properties of each constituent: polar and ferrimagnetic due to BiFeO3 and BiMnO3, respectively. The effect of B-site cation ordering on magnetic ordering in the BiFeO3-BiMnO3 system is studied. The checkerboard ge...

  20. First-principles analysis of ferroelectric transition in MnSnO3 and MnTiO3 perovskites

    Science.gov (United States)

    Kang, Sung Gu

    2018-06-01

    The ferroelectric instabilities of an artificially adopted Pnma structure in low tolerance perovskites have been explored (Kang et al., 2017) [4], where an unstable A-site environment was reported to be the major driving source for the low tolerance perovskites to exhibit ferroelectric instability. This study examined the ferroelectric transition of two magnetic perovskite materials, MnSnO3 and MnTiO3, in Pnma phase. Phase transitions to the Pnma phase at elevated pressures were observed. MnSnO3, which has a lower (larger) tolerance factor (B-site cation radius), showed a higher ferroelectric mode amplitude than MnTiO3. The distribution of the bond length of Mn-O and the mean quadratic elongation (QE) of octahedra (SnO6 or TiO6) were investigated for structural analysis. However, MnTiO3 showed a larger spontaneous polarization than MnSnO3 due to high Born effective charges of titanium. This study is useful because it provides a valuable pathway to the design of promising multiferroic materials.

  1. Quantitative trait loci controlling Cu, Ca, Zn, Mn and Fe content in ...

    Indian Academy of Sciences (India)

    of essential minerals (such as Fe, Zn etc), breeding mineral- efficient crops that produce .... and seven digenic interactions were identified for Cu, Ca,. Zn, Mn and Fe, .... Eva P. 1993 Cadmium, copper and lead in wild rice from central. Canada.

  2. Enhanced exchange anisotropy in IrMn/CoFeB systems and its correlation with uncompensated interfacial spins

    DEFF Research Database (Denmark)

    Du, Yuqing; Pan, Genhua; Moate, Roy

    2010-01-01

    Bottom pinned exchange bias systems of IrMn/CoFe and IrMn/CoFeB on CoFe seed layers were studied. Enhanced exchange anisotropy has been observed for IrMn/CoFeB samples annealed at 350 °C. The ferromagnetic and antiferromagnetic layers of both samples are polycrystalline and textured {110} for the...

  3. A novel sandwich Fe-Mn damping alloy with ferrite shell prepared by vacuum annealing

    Science.gov (United States)

    Qian, Bingnan; Peng, Huabei; Wen, Yuhua

    2018-04-01

    To improve the corrosion resistance of high strength Fe-Mn damping alloys, we fabricated a novel sandwich Fe-17.5Mn damping alloy with Mn-depleted ferrite shell by vacuum annealing at 1100 °C. The formation behavior of the ferrite shell obeys the parabolic law for the vacuum annealed Fe-17.5Mn alloy at 1100 °C. The sandwich Fe-17.5Mn alloy with ferrite shell exhibits not only better corrosion resistance but also higher damping capacity than the conventional annealed Fe-17.5Mn alloy under argon atmosphere. The existence of only ferrite shell on the surface accounts for the better corrosion in the sandwich Fe-17.5Mn alloy. The better damping capacity in the sandwich Fe-17.5Mn alloy is owed to more stacking faults inside both ɛ martensite and γ austenite induced by the stress from ferrite shell. Vacuum annealing is a new way to improve the corrosion resistance and damping capacity of Fe-Mn damping alloys.

  4. Synchrotron diffraction studies of TiC/FeTi cermets obtained by SHS

    International Nuclear Information System (INIS)

    Contreras, L.; Turrillas, X.; Mas-Guindal, M.J.; Vaughan, G.B.M.; Kvick, A.; Rodriguez, M.A.

    2005-01-01

    TiC/FeTi composites have been obtained in situ by Self-propagating High-temperature Synthesis (SHS) of an intimate mixture of compacted powders of elemental carbon, titanium and iron. The reaction has been followed in real time by X-ray diffraction at the ESRF. The mechanism of the reaction is discussed in terms of the formation of a liquid phase corresponding to the eutectic of the Fe/Ti system prior to the TiC synthesis. Temperatures of reaction have been estimated by correlating thermal expansion coefficients with diffraction peaks shifts. The microstructures obtained by this method, suitable for cutting tools and wear resistant applications, are presented

  5. Tailoring luminescence properties of TiO2 nanoparticles by Mn doping

    International Nuclear Information System (INIS)

    Choudhury, B.; Choudhury, A.

    2013-01-01

    TiO 2 nanoparticles are doped with three different concentrations of Mn, 2%, 4% and 6% respectively. Absorption edge of TiO 2 is shifted from UV to visible region on amplification of Mn content. Room temperature photoluminescence spectra, excited at 320 nm, exhibit band edge and visible emission peaks associated with self trapped excitons, oxygen defects, etc. Doping of Mn increases the width and decreases the intensity of the UV emission peak. Potential fluctuations of impurities increase the width and auger type non-radiative recombination decreases the intensity of the UV emission peak. The intensity ratio of the UV to defect emission band decreases on doping, indicating degradation of structural quality. Excitation of pure and doped nanoparticles at 390 nm results in Mn 2+ emission peaks at 525 nm and 585 nm respectively. Photoluminescence excitation spectra also indicate the presence of Mn 2+ in the crystalline environment of TiO 2 . The oxygen defects and Mn related impurities act as efficient trap centers and increases the lifetime of the charge carriers. -- Highlights: ► Doping of Mn increases the d-spacing of TiO 2 nanoparticles. ► Characteristic d–d electronic transition of Mn 2+ is observed in the absorption spectra. ► Doping of Mn quenches the UV and visible emission peaks of TiO 2 . ► Photoexcitation at 390 nm generates emission peaks of Mn 2+

  6. Clarifying roughness and atomic diffusion contributions to the interface broadening in exchange-biased NiFe/FeMn/NiFe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, V.P., E-mail: valberpn@yahoo.com.br [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Merino, I.L.C.; Passamani, E.C. [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Alayo, W. [Departamento de Física, Universidade de Pelotas, 96010-610 Pelotas (Brazil); Tafur, M. [Instituto de Ciências Exatas, Universidade Federal de Itajubá, 37500-903 Itajubá (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, 74001-970 Goiânia (Brazil); Magalhães-Paniago, R. [Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Alvarenga, A.D. [Instituto Nacional de Metrologia, 25250-020 Xerém (Brazil); Saitovitch, E.B. [Coordenação de Física Experimental e Baixas Energias, Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro (Brazil)

    2013-09-02

    NiFe(30 nm)/FeMn(13 nm)/NiFe(10 nm) heterostructures prepared by magnetron sputtering at different argon working pressures (0.27, 0.67 and 1.33 Pa) were systematically investigated by using specular and off-specular diffuse X-ray scattering experiments, combined with ferromagnetic resonance technique, in order to distinguish the contribution from roughness and atomic diffusion to the total structural disorder at NiFe/FeMn interfaces. It was shown that an increase in the working gas pressure from 0.27 to 1.33 Pa causes an enhancement of the atomic diffusion at the NiFe/FeMn interfaces, an effect more pronounced at the top FeMn/NiFe interface. In particular, this atomic diffusion provokes a formation of non-uniform magnetic dead-layers at the NiFe/FeMn interfaces (NiFeMn regions with paramagnetic or weak antiferromagnetic properties); that are responsible for the substantial reduction of the exchange bias field in the NiFe/FeMn system. Thus, this work generically helps to understand the discrepancies found in the literature regarding the influence of the interface broadening on the exchange bias properties (e.g., exchange bias field) of the NiFe/FeMn system. - Highlights: • Roughness and atomic diffusion contributions to the interface broadening • Clarification of the exchange bias field dependence on the interface disorder • Ferromagnetic, paramagnetic and antiferromagnetic phases at the magnetic interface • Magnetic dead layers formed by increasing the argon work pressure • Atomic diffusion in heterostructures prepared at higher argon pressure.

  7. V-insertion in Li(Fe,Mn)FePO4

    Science.gov (United States)

    Wu, T.; Liu, J.; Sun, L.; Cong, L.; Xie, H.; Abdel-Ghany, A.; Mauger, A.; Julien, C. M.

    2018-04-01

    Insertion of 3% vanadium in LiMn1-yFeyPO4 has been investigated, with y = 0.2 corresponding to the highest manganese concentration before the stress/strain field degrades the electrochemical performance. V substitutes for Fe2+ in the trivalent state V3+. This substitution is accompanied with the formation of Fe vacancies while Mn remains in the Mn2+ valence state, leading to a composition LiMn0.8Fe0.2-0.045V0.03□0.015PO4 where □ is a Fe vacancy. The comparison between electrochemical properties of a pristine sample and a sample with 3 mol.% vanadium made of particles with the same morphology (spherical particles with the same dispersion 100-150 nm in size) and same carbon coating (same conductivity of the carbon layer) is reported. Although the vanadium is in the V3+ state at open circuit voltage (2.6 V) before cycling, a reversible V3+/V2+ is observed when the potential of the half-cell is lowered below the redox potential of 1.8 V vs Li+/Li, due to Li-vacancies. The V-insertion improves the electrochemical properties, due to a synergetic effect of an increase of the lithium diffusion coefficient by a factor two and an increase of the electric conductivity at any Li-concentration during the cycling process, in contradiction with prior claims that attributed the increase of conductivity to V-based impurities.

  8. Spin correlations in (Mn,Fe)2(P,Si) magnetocaloric compounds above Curie temperature

    NARCIS (Netherlands)

    Miao, X.F.; Caron, L.; Gubbens, P.C.M.; Yaouanc, A; Dalmas de Réotier, P; Luetkens, H.; Amato, A; van Dijk, N.H.; Brück, E.H.

    2016-01-01

    The longitudinal-field muon-spin relaxation (LF-μSR) technique was employed to study the spin correlations in (Mn,Fe)2(P,Si) compounds above the ferromagnetic transition temperature (TC). The (Mn,Fe)2(P,Si) compound under study is found to show itinerant magnetism. The standard deviation of the

  9. Magnetic structure and phase formation of magnetocaloric Mn-Fe-P-X compounds

    NARCIS (Netherlands)

    Ou, Z.Q.

    2013-01-01

    This thesis presents a study of the crystal and magnetic structure, the magnetocaloric effect and related physical properties in Mn-Fe-P-X compounds. The influences of boron addition in (Mn,Fe)2(P,As) compounds have been studied. It is found that boron atoms occupy interstitial sites within the

  10. Processing and characterization of AlCoFeNiXTi0,5 (X = Mn, V) high entropy alloys

    International Nuclear Information System (INIS)

    Triveno Rios, C.; Kiminami, C.S.

    2014-01-01

    The microstructure of high entropy alloys consists of solid solution phases with FC and BCC simple structures, contrary to classical metallurgy where they form complex structures of intermetallic compounds. Because of this they have several attractive properties for engineering applications. In this work the AlCoFeNiMnTi 0,5 and AlCoFeNiVTi 0,5 alloys were processed by melting arc. Since the main objective was the microstructural and mechanical characterization of ingots as-cast. The alloys were characterized by scanning electron microscopy, X-ray diffraction, microhardness and cold compression test. The results showed that the microstructure consists mainly of dendrites and interdendritic regions consisting of metastable crystalline phases. It was also observed that the AlCoFeNiVTi 0,5 alloy showed better mechanical properties than the AlCoFeNiMnTi 0,5 alloy. This may be associated with differences in the parameters of formation of simple solid solution phases between the two alloys. (author)

  11. Effect of Fe substitution at the Ni and Mn sites on the magnetic properties of Ni50Mn35In15 Heusler alloys

    International Nuclear Information System (INIS)

    Halder, Madhumita; Suresh, K.G.

    2015-01-01

    The structural and magnetic properties of Ni 48 Fe 2 Mn 35 In 15 and Ni 50 Mn 34 FeIn 15 Heusler alloys have been investigated. At room temperature, Ni 48 Fe 2 Mn 35 In 15 has L2 1 cubic structure, whereas Ni 50 Mn 34 FeIn 15 shows a two-phase structure due to the martensitic transition. In the case of Ni 48 Fe 2 Mn 35 In 15 , there is only one magnetic transition at 316 K with no martensitic transition. However, in Ni 50 Mn 34 FeIn 15 , we observe the martensitic transition at about 280 K. The Curie temperatures for austenite and martensite phases are 314 and 200 K, respectively. The maximum magnetic entropy changes are found to be 5.5 and 4.5 J kg −1 K −1 for Ni 48 Fe 2 Mn 35 In 15 and Ni 50 Mn 34 FeIn 15 , respectively, for 50 kOe. Ni 50 Mn 34 FeIn 15 exhibits exchange bias behavior, with a bias field of 130 Oe at 5 K. Both the alloys satisfy the empirical relation between the martensitic transition and the valence electron concentration (e/a) ratio. - Highlights: • Structural and magnetic properties of Ni 48 Fe 2 Mn 35 In 15 and Ni 50 Mn 34 FeIn 15 Heusler alloys have been investigated. • Ni 48 Fe 2 Mn 35 In 15 does not undergo a martensitic transition, whereas Ni 50 Mn 34 FeIn 15 shows martensitic transition. • Ni 50 Mn 34 FeIn 15 alloy exhibits exchange bias behavior. • Both alloys satisfy the empirical relation between martensitic transition and valence electron concentration (e/a)

  12. Application of damping mechanism model and stacking fault probability in Fe-Mn alloy

    International Nuclear Information System (INIS)

    Huang, S.K.; Wen, Y.H.; Li, N.; Teng, J.; Ding, S.; Xu, Y.G.

    2008-01-01

    In this paper, the damping mechanism model of Fe-Mn alloy was analyzed using dislocation theory. Moreover, as an important parameter in Fe-Mn based alloy, the effect of stacking fault probability on the damping capacity of Fe-19.35Mn alloy after deep-cooling or tensile deformation was also studied. The damping capacity was measured using reversal torsion pendulum. The stacking fault probability of γ-austenite and ε-martensite was determined by means of X-ray diffraction (XRD) profile analysis. The microstructure was observed using scanning electronic microscope (SEM). The results indicated that with the strain amplitude increasing above a critical value, the damping capacity of Fe-19.35Mn alloy increased rapidly which could be explained using the breakaway model of Shockley partial dislocations. Deep-cooling and suitable tensile deformation could improve the damping capacity owning to the increasing of stacking fault probability of Fe-19.35Mn alloy

  13. Precipitation processes in DC-cast AlMn(Fe,Si) alloys

    International Nuclear Information System (INIS)

    Voeroes, G.; Kovacs, I.

    1990-01-01

    The precipitation processes in DC cast Al-Mn alloys were investigated by electrical resistivity measurements. It was obtained that the addition of Fe or Fe and Si influences basically the precipitation of Mn. In pure Al-Mn alloys a phase transition like behaviour was observed at about 550 degC, which can be related to the formation of two different precipitate particles below and above this temperature

  14. Magnetic Fe2MO4 (M:Fe, Mn) activated carbons: Fabrication, characterization and heterogeneous Fenton oxidation of methyl orange

    International Nuclear Information System (INIS)

    Nguyen, Thi Dung; Phan, Ngoc Hoa; Do, Manh Huy; Ngo, Kim Tham

    2011-01-01

    We present a simple and efficient method for the fabrication of magnetic Fe 2 MO 4 (M:Fe and Mn) activated carbons (Fe 2 MO 4 /AC-H, M:Fe and Mn) by impregnating the activated carbon with simultaneous magnetic precursor and carbon modifying agent followed by calcination. The obtained samples were characterized by nitrogen adsorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), and the catalytic activity in heterogeneous Fenton oxidation of methyl orange (MO) was evaluated. The resulting Fe 2 MnO 4 /AC-H showed higher catalytic activity in the methyl orange oxidation than Fe 3 O 4 /AC-H. The effect of operational parameters (pH, catalyst loading H 2 O 2 dosage and initial MO concentration) on degradation performance of the oxidation process was investigated. Stability and reusability of selected catalyst were also tested.

  15. Magnetic studies of spin wave excitations in Fe/Mn multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Salhi, H. [LPMMAT, Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P. 5366 Mâarif, Casablanca (Morocco); LMPG, Ecole supérieure de technologie, Université Hassan de Casablanca, Casablanca (Morocco); Moubah, R.; El Bahoui, A.; Lassri, H. [LPMMAT, Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P. 5366 Mâarif, Casablanca (Morocco)

    2017-04-15

    The structural and magnetic properties of Fe/Mn multilayers grown by thermal evaporation technique were investigated by transmission electron microscopy, vibrating sample magnetometer and spin wave theory. Transmission electron microscopy shows that the Fe and Mn layers are continuous with a significant interfacial roughness. The magnetic properties of Fe/Mn multilayers were studied for various Fe thicknesses (t{sub Fe}). The change of magnetization as a function of temperature is well depicted by a T{sup 3/2} law. The Fe spin-wave constant was extracted and found to be larger than that reported for bulk Fe, which we attribute to the fluctuation of magnetic moments at the interface, due to the interfacial roughness. The experimental M (T) data were satisfactory fitted for multilayers with different Fe thicknesses; and several exchange interactions were extracted. - Highlights: • The structural and magnetic properties of Fe/Mn multilayers were studied. • Fe and Mn layers are continuous with an important interfacial roughness. • The Fe spin-wave constant is larger than that reported for bulk Fe due to the fluctuation of the interfacial magnetic moments.

  16. Magnetic studies of spin wave excitations in Fe/Mn multilayers

    International Nuclear Information System (INIS)

    Salhi, H.; Moubah, R.; El Bahoui, A.; Lassri, H.

    2017-01-01

    The structural and magnetic properties of Fe/Mn multilayers grown by thermal evaporation technique were investigated by transmission electron microscopy, vibrating sample magnetometer and spin wave theory. Transmission electron microscopy shows that the Fe and Mn layers are continuous with a significant interfacial roughness. The magnetic properties of Fe/Mn multilayers were studied for various Fe thicknesses (t Fe ). The change of magnetization as a function of temperature is well depicted by a T 3/2 law. The Fe spin-wave constant was extracted and found to be larger than that reported for bulk Fe, which we attribute to the fluctuation of magnetic moments at the interface, due to the interfacial roughness. The experimental M (T) data were satisfactory fitted for multilayers with different Fe thicknesses; and several exchange interactions were extracted. - Highlights: • The structural and magnetic properties of Fe/Mn multilayers were studied. • Fe and Mn layers are continuous with an important interfacial roughness. • The Fe spin-wave constant is larger than that reported for bulk Fe due to the fluctuation of the interfacial magnetic moments.

  17. Metastable bcc Fe-Mn alloys produced by rf sputtering

    International Nuclear Information System (INIS)

    Sumiyama, Kenji; Kadono, Masaru; Nakamura, Yoji

    1981-01-01

    Fe sub(1-x)Mn sub(x) alloy films obtained by rf sputtering technique have been investigated by X-ray diffraction, magnetization and Moessbauer effect measurements. The single bcc phase extends up to about x = 0.2, while a bcc-fcc mixed phase appears for x = 0.2 - 0.26. The lattice constants of the bcc phase are about 0.5% larger than those of the bulk specimens. The magnetization decreases monotonically with increasing x in the bcc phase, while it decreases sharply in the bcc-fcc mixed phase. These results are consistent with the Moessbauer spectra of these alloy films. The volume fraction of bcc and fcc phases has been estimated from Moessbauer analyses as well as magnetization measurements. (author)

  18. Structure and grindability of cast Ti-5Cr-xFe alloys

    International Nuclear Information System (INIS)

    Hsu, H.-C.; Pan, C.-H.; Wu, S.-C.; Ho, W.-F.

    2009-01-01

    The purpose of this study was to investigate the structure, microhardness and grindability of Ti-5Cr and a series of ternary Ti-5Cr-xFe alloys with 0.1, 0.5, 1, 3 and 5 wt.% Fe, respectively. This study evaluated the phase and structure of Ti-5Cr and Ti-5Cr-xFe alloys, using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. In addition, grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min), with the goal of developing a titanium alloy with better machinability than commercially pure titanium (c.p. Ti). The results showed that the structure of Ti-5Cr-xFe alloys is sensitive to the Fe content. With Fe contents higher than 0.5 wt.%, the equi-axed β phase is entirely retained, while ω phase was found in the Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The largest quantity of ω phase and highest microhardness were found in Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The grinding rates of the Ti-5Cr and Ti-5Cr-xFe alloys showed a similar tendency to the microhardness. The Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys exhibited the best grindability, especially at 500, 750 and 1000 m/min. Furthermore, the grindability of the tested metals increased in proportion to grinding speed up to 1000 m/min, with a decrease after 1200 m/min. This study concluded that Fe may be used to harden titanium and improve the grindability

  19. Synthesis and characterization of FeTiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Anil B. Gambhire

    2016-09-01

    Full Text Available Nanocrystalline FeTiO3 ceramic powders were prepared by the sol–gel process combined with a surfactant-assisted template method. The resulting powders were calcined at different temperatures ranging from 150 °C to 600 °C for 2 h in air. The results revealed that a pure hexagonal phase of FeTiO3 could be obtained at a low temperature, 600 °C. The phase evolution of FeTiO3 was investigated by X-ray diffraction patterns (XRD, Fourier-transform infrared spectroscopy (FT-IR, and X-ray photoelectron spectroscopy (XPS. Particle size and morphology were studied by transmission electron microscopy (TEM.

  20. Crystal structure of Fe2TiO5

    International Nuclear Information System (INIS)

    Shiojiri, M.; Sekimoto, S.; Maeda, T.; Ikeda, Y.; Iwauchi, K.

    1984-01-01

    The crystal structure of metal pseudobrookite, Fe 2 TiO 5 , is determined from high-resolution electron microscopy images observed and their computer simulated images, with the aid of electron diffraction and X-ray powder diffraction. The new structure has a monoclinic unit, containing eight molecules, with a = 2.223, b = 0.373, c = 0.980 nm, and β = 116.2 0 . The Fe, Ti, and O atoms occupy the positions (4c), +-(u, 0, w; 1/2 + u, 1/2, w), of C 2 3 (C2). The most probable parameters u and w, of Fe(1 to 4), Ti(1, 2), and O(1 to 10) are given. (author)

  1. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    International Nuclear Information System (INIS)

    Ma, Y.L.; Liu, X.B.; Nguyen, V.V.; Poudyal, N.; Yue, M.; Liu, J.P.

    2016-01-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd 2 Fe 14 B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH) max of 10 MGOe was obtained at NdFeB content of 50 wt%.

  2. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y.L. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); College of Metallurgical and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Liu, X.B.; Nguyen, V.V.; Poudyal, N. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Yue, M. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Liu, J.P., E-mail: pliu@uta.edu [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2016-08-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd{sub 2}Fe{sub 14}B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH){sub max} of 10 MGOe was obtained at NdFeB content of 50 wt%.

  3. Microstructure and mechanical properties of ion-beam-produced Fe-Ti-(N), Fe-Ti-(C), and Fe-Ti-(C,N) surface films

    Science.gov (United States)

    Hirvonen, J.-P.; Nastasi, M.; Zocco, T. G.; Jervis, T. R.

    1990-06-01

    Ion-mixed films of Fe53 Ti47 were produced by ion irradiating a Fe-Ti multilayer structure on AISI 304 stainless steel. The ion-mixed films were subsequently implanted with nitrogen, carbon, or both carbon and nitrogen. The microstructure following nitrogen implantation consisted of a bcc solid solution of iron and titanium and finely dispersed TiN precipitates. In the cases of carbon or carbon and nitrogen implantation, a two-phase structure consisting of an amorphous matrix with TiC or Ti(C,N) precipitates was found. All these films initially possessed improved tribological properties as revealed by lowered friction and increased wear resistance. However, after an extended test of 1000 wear cycles, a reduced friction was only observed for the carbon or carbon and nitrogen implanted samples. The wear track on the dual implanted surface was extremely smooth, while the surface of the nitrogen-implanted sample was partly worn through, causing the friction to increase to the level of the untreated sample. The improved tribological properties of the implanted films are attributed to an increase in surface hardness. However, the surface hardness is unable to explain differences between different implantations. In the case of the dual carbon and nitrogen implantation, improvements appear to be in part the result from an increased capability to accommodate plastic deformation. These conclusions are supported by transmission electron microscope studies of the wear tracks as well as by nanoindentation measurements.

  4. In-plain electric properties of [CaMnO3/REMO3] (RE=Bi, La M=Fe, Fe0.8Mn0.2) superlattices grown by pulsed laser deposition method

    NARCIS (Netherlands)

    Iwata, N.; Watabe, Y.; Oikawa, T.; Takase, K.; Huijben, Mark; Inaba, T.; Oshima, K.; Rijnders, Augustinus J.H.M.; Yamamoto, H.

    2014-01-01

    The [CaMnO3 (CMO)/REMO3] (RE = Bi, La M = Fe, Fe0.8Mn0.2) superlattices show semiconducting behavior with transition temperatures (TEg) of 71, 127, and 151 K in the [CMO/BiFe0.8Mn0.2O3], [CMO/BiFeO3], and [CMO/LaFeO3] superlattices. The formation of a magnetic polaron is expected in the CMO layer of

  5. Silicon induced Fe deficiency affects Fe, Mn, Cu and Zn distribution in rice (Oryza sativa L.) growth in calcareous conditions.

    Science.gov (United States)

    Carrasco-Gil, Sandra; Rodríguez-Menéndez, Sara; Fernández, Beatriz; Pereiro, Rosario; de la Fuente, Vicenta; Hernandez-Apaolaza, Lourdes

    2018-04-01

    A protective effect by silicon in the amelioration of iron chlorosis has recently been proved for Strategy 1 species, at acidic pH. However in calcareous conditions, the Si effect on Fe acquisition and distribution is still unknown. In this work, the effect of Si on Fe, Mn, Cu and Zn distribution was studied in rice (Strategy 2 species) under Fe sufficiency and deficiency. Plants (+Si or-Si) were grown initially with Fe, and then Fe was removed from the nutrient solution. The plants were then analysed using a combined approach including LA-ICP-MS images for each element of interest, the analysis of the Fe and Si concentration at different cell layers of root and leaf cross sections by SEM-EDX, and determining the apoplastic Fe, total micronutrient concentration and oxidative stress indexes. A different Si effect was observed depending on plant Fe status. Under Fe sufficiency, Si supply increased Fe root plaque formation, decreasing Fe concentration inside the root and increasing the oxidative stress in the plants. Therefore, Fe acquisition strategies were activated, and Fe translocation rate to the aerial parts was increased, even under an optimal Fe supply. Under Fe deficiency, +Si plants absorbed Fe from the plaque more rapidly than -Si plants, due to the previous activation of Fe deficiency strategies during the growing period (+Fe + Si). Higher Fe plaque formation due to Si supply during the growing period reduced Fe uptake and could activate Fe deficiency strategies in rice, making it more efficient against Fe chlorosis alterations. Silicon influenced Mn and Cu distribution in root. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Influence of substrate rocks on Fe-Mn crust composition

    Science.gov (United States)

    Hein, J.R.; Morgan, C.L.

    1999-01-01

    Principal Component and other statistical analyses of chemical and mineralogical data of Fe-Mn oxyhydroxide crusts and their underlying rock substrates in the central Pacific indicate that substrate rocks do not influence crust composition. Two ridges near Johnston Atoll were dredged repetitively and up to seven substrate rock types were recovered from small areas of similar water depths. Crusts were analyzed mineralogically and chemically for 24 elements, and substrates were analyzed mineralogically and chemically for the 10 major oxides. Compositions of crusts on phosphatized substrates are distinctly different from crusts on substrates containing no phosphorite. However, that relationship only indicates that the episodes of phosphatization that mineralized the substrate rocks also mineralized the crusts that grew on them. A two-fold increase in copper contents in crusts that grew on phosphatized clastic substrate rocks, relative to crusts on other substrate rock types, is also associated with phosphatization and must have resulted from chemical reorganization during diagenesis. Phosphatized crusts show increases in Sr, Zn, Ca, Ba, Cu, Ce, V, and Mo contents and decreases in Fe, Si, and As contents relative to non-phosphatized crusts. Our statistical results support previous studies which show that crust compositions reflect predominantly direct precipitation from seawater (hydrogenetic), and to lesser extents reflect detrital input and diagenetic replacement of parts of the older crust generation by carbonate fluorapatite.

  7. Electrochemical Corrosion Behavior of Oxidation Layer on Fe30Mn5Al Alloy

    Directory of Open Access Journals (Sweden)

    ZHU Xue-mei

    2017-08-01

    Full Text Available The Fe30Mn5Al alloy was oxidized at 800℃ in air for 160h, the oxidation-induced layer about 15μm thick near the scale-metal interface was induced to transform to ferrite and become enriched in Fe and depletion in Mn. The effect of the oxidation-induced Mn depletion layer on the electrochemical corrosion behavior of Fe30Mn5Al alloy was evaluated. The results show that in 1mol·L-1 Na2SO4 solution, the anodic polarization curve of the Mn depletion layer exhibits self-passivation, compared with Fe30Mn5Al austenitic alloy, and the corrosion potential Evs SCE is increased to -130mV from -750mV and the passive current density ip is decreased to 29μA/cm2 from 310μA/cm2. The electrochemical impedance spectroscopy(EIS of the Mn depletion layer has the larger diameter of capacitive arc, the higher impedance modulus|Z|, and the wider phase degree range, and the fitted polarization resistant Rt is increased to 9.9kΩ·cm2 from 2.7kΩ·cm2 by using an equivalent electric circuit of Rs-(Rt//CPE. The high insulation of the Mn depletion layer leads to an improved corrosion resistance of Fe30Mn5Al austenitic alloy.

  8. Enhancement of exchange coupling interaction of NdFeB/MnBi hybrid magnets

    Science.gov (United States)

    Nguyen, Truong Xuan; Nguyen, Khanh Van; Nguyen, Vuong Van

    2018-03-01

    MnBi ribbons were fabricated by melt - spinning with subsequent annealing. The MnBi ribbons were ground and mixed with NdFeB commercial Magnequench powders (MQA). The hybrid powder mixtures were subjected thrice to the annealing and ball-milling route. The hybrid magnets (100 - x)NdFeB/xMnBi, x=0, 30, 40, 50 and 100 wt% were in-mold aligned in an 18 kOe magnetic field and warm compacted at 290 °C by 2000 psi uniaxial pressure for 10 min. An enhancement of the exchange coupling of NdFeB/MnBi hybrid magnets was obtained by optimizing the magnets' microstructures via annealing and ball-milling processes. The magnetic properties of prepared NdFeB/MnBi hybrid magnets were studied and discussed in details.

  9. Tuning of the magneto-caloric effects in MnFe(P,As) by substitution of elements

    International Nuclear Information System (INIS)

    Tegus, O.; Brueck, E.; Li, X.W.; Zhang, L.; Dagula, W.; Boer, F.R. de; Buschow, K.H.J.

    2004-01-01

    MnFe(P,As) displays a large magnetocaloric effect around room temperature. Substitution of Cr for Fe results in a reduction of both the ordering temperature and the magnetocaloric effect. Substitution of Co for Fe leads to a decrease of the ordering temperature, whereas 10% extra Fe substituted for Mn leads to an increase of the ordering temperature. Finally, 10% extra Mn substituted for Fe results in an enhanced magnetocaloric effect with hardly any change of ordering temperature

  10. Nano-ilmenite FeTiO3 : synthesis and characterization

    OpenAIRE

    Raghavender, A. T.; Hoa Hong, Nguyen; Lee, Kyu Joon; Jung, Myung-Hwa; Skoko, Z.; Vasilevskiy, Mikhail; Cerqueira, M. F.; Samantilleke, A. P.

    2013-01-01

    In general, ilmenite FeTiO3 is synthesized by solid-state reaction at very high pressure and high temperature. Synthesis of FeTiO3 is not an easy task as the Fe2+ ions are not stable. Therefore, it is really challenging to prepare this material. In this work nano-ilmenite FeTiO3 was synthesized by the sol-gel method. Structural, optical and magnetic characterizations were performed. The bandgap of FeTiO3 was determined to be 2.8 eV showing FeTiO3 as suitable wide bandgap material for technolo...

  11. MWCNT-MnFe2O4 nanocomposite for efficient hyperthermia applications

    Science.gov (United States)

    Seal, Papori; Hazarika, Monalisa; Paul, Nibedita; Borah, J. P.

    2018-04-01

    In this work we present synthesis of multi-walled carbon nanotube (MWCNT)-Manganese ferrite (MnFe2O4) nanocomposite and its probable application in hyperthermia. MnFe2O4 nanoparticles were synthesized by co-precipitation method. X ray diffractogram (XRD) confirms the formation of cubic phase of MnFe2O4 with preferred crystallographic orientation along (311) plane. High resolution electron microscope (HRTEM) image of the composites confirms the presence of MnFe2O4 spherical nanoparticles on the surface of CNT which are bound strongly to the surface. MWCNT-MnFe2O4 nanocomposite were prepared after acid functionalization of MWCNT. Vibrational features of the synthesized samples were confirmed through Fourier transformed infra-red spectroscopy (FTIR). FTIR spectra of acid functionalized MWCNT shows a peak positioned at ˜1620cm-1 which corresponds to C=O functional group of carboxylic acid. Prepared MnFe2O4 nanoparticles and MWCNT-MnFe2O4 nanocomposites were subjected to hyperthermia studies.

  12. Magnetic properties in (Mn,Fe)-codoped ZnO nanowire

    International Nuclear Information System (INIS)

    Cao, Huawei; Lu, Pengfei; Cong, Zixiang; Yu, Zhongyuan; Cai, Ningning; Zhang, Xianlong; Gao, Tao; Wang, Shumin

    2013-01-01

    Using the first-principles density functional theory, we have studied the electronic structures and magnetic properties of Mn/Fe codoped ZnO nanowires systematically. The calculated results of formation energy indicate that the configuration of the lowest energy where Mn and Fe atoms form nearest neighbors on the outer cylindrical surface layer along the [0001] direction, will be determined. The magnetic coupling of 8 types of Mn/Fe codoped ZnO nanowires was investigated and ferromagnetic state was found in certain configurations. The mechanism is from the fierce hybridization between 3d of Mn and Fe with O 2p near the Fermi level. The relative energy difference for configuration VIII is 0.221 eV, which indicates that room temperature ferromagnetism could be obtained in such a system and Mn/Fe codoped ZnO nanowires are a promising nanoscale spintronic material. - Highlights: • The stable structure prefers that Mn/Fe form nearest neighbors on the outer surface. • The fierce p–d hybridization is responsible for ferromagnetic (FM) coupling. • Mn/Fe codoped ZnO nanowire is a promising FM semiconductor material

  13. Magnetic properties in (Mn,Fe)-codoped ZnO nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Huawei [Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), Ministry of Education, Beijing 100876 (China); Lu, Pengfei, E-mail: photon.bupt@gmail.com [Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), Ministry of Education, Beijing 100876 (China); Cong, Zixiang [School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100976 (China); Yu, Zhongyuan; Cai, Ningning; Zhang, Xianlong [Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), Ministry of Education, Beijing 100876 (China); Gao, Tao [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Wang, Shumin [Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden); State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2013-12-02

    Using the first-principles density functional theory, we have studied the electronic structures and magnetic properties of Mn/Fe codoped ZnO nanowires systematically. The calculated results of formation energy indicate that the configuration of the lowest energy where Mn and Fe atoms form nearest neighbors on the outer cylindrical surface layer along the [0001] direction, will be determined. The magnetic coupling of 8 types of Mn/Fe codoped ZnO nanowires was investigated and ferromagnetic state was found in certain configurations. The mechanism is from the fierce hybridization between 3d of Mn and Fe with O 2p near the Fermi level. The relative energy difference for configuration VIII is 0.221 eV, which indicates that room temperature ferromagnetism could be obtained in such a system and Mn/Fe codoped ZnO nanowires are a promising nanoscale spintronic material. - Highlights: • The stable structure prefers that Mn/Fe form nearest neighbors on the outer surface. • The fierce p–d hybridization is responsible for ferromagnetic (FM) coupling. • Mn/Fe codoped ZnO nanowire is a promising FM semiconductor material.

  14. Microstructures, mechanical properties and cytotoxicity of low cost beta Ti-Mn alloys for biomedical applications.

    Science.gov (United States)

    Santos, Pedro Fernandes; Niinomi, Mitsuo; Cho, Ken; Nakai, Masaaki; Liu, Huihong; Ohtsu, Naofumi; Hirano, Mitsuhiro; Ikeda, Masahiko; Narushima, Takayuki

    2015-10-01

    The microstructures, mechanical properties and biocompatibility of low cost β-type Ti-(6-18)Mn alloys were investigated after solution treatment. Ti-9 Mn exhibits the best combination of tensile strength and elongation among the fabricated alloys, and its performance is comparable to or superior to those of Ti-6Al-4V ELI (Ti-64 ELI) in terms of every parameter evaluated. A hardness of 338 HV, a Young's modulus of 94 GPa, a 0.2% proof stress of 1023 MPa, an ultimate tensile strength of 1048 MPa and elongation of 19% were obtained for Ti-9 Mn. Furthermore, the cell viability and metallic ion release ratios are comparable to those of commercially pure titanium, making this alloy promising for biomedical applications. The Young's modulus is also lower than that of Ti-64 ELI (110 GPa), which can possibly reduce the stress shielding effect in implanted patients. This study evaluates mechanical and biological performance of low cost solution treated β-type Ti-(6, 9, 13 and 18 mass%)Mn alloys. It includes alloys containing a Mn content range higher than most previously published works (which is around or lower than 8 mass%). Furthermore, the effects of the ω phase and the β phase stability of the alloys over some mechanical properties and microstructures are discussed. Ion release behavior under simulated body fluids and cell viability are also evaluated. For the case of the Ti-9 Mn, a mechanical and biological performance that is comparable to or superior than that of the widely used Ti-6Al-4V ELI and commercially pure Ti was observed. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Deep Drawing Behavior of CoCrFeMnNi High-Entropy Alloys

    Science.gov (United States)

    Bae, Jae Wung; Moon, Jongun; Jang, Min Ji; Ahn, Dong-Hyun; Joo, Soo-Hyun; Jung, Jaimyun; Yim, Dami; Kim, Hyoung Seop

    2017-09-01

    Herein, the deep drawability and deep drawing behavior of an equiatomic CoCrFeMnNi HEA and its microstructure and texture evolution are first studied for future applications. The CoCrFeMnNi HEA is successfully drawn to a limit drawing ratio (LDR) of 2.14, while the planar anisotropy of the drawn cup specimen is negligible. The moderate combination of strain hardening exponent and strain rate sensitivity and the formation of deformation twins in the edge region play important roles in successful deep drawing. In the meanwhile, the texture evolution of CoCrFeMnNi HEA has similarities with conventional fcc metals.

  16. HIGH TEMPERATURE TENSILE PROPERTIES OF NEW FE-CR-MN DEVELOPED STEEL

    OpenAIRE

    M. Mahmoudiniya; Sh. Kheirandish; M. Asadi Asadabad

    2017-01-01

    Nowadays, Ni-free austenitic stainless steels are being developed rapidly and high price of nickel is one of the most important motivations for this development. At present research a new FeCrMn steel was designed and produced based on Fe-Cr-Mn-C system. Comparative studies on microstructure and high temperature mechanical properties of  new steel and AISI 316 steel were done. The results showed that new FeCrMn developed steel has single austenite phase microstructure, and its tensile st...

  17. First-principles study of Mn-S codoped anatase TiO2

    Science.gov (United States)

    Li, Senlin; Huang, Jinliang; Ning, Xiangmei; Chen, Yongcha; Shi, Qingkui

    2018-04-01

    In this work, the CASTEP program in Materials Studio 2017 software package was applied to calculate the electronic structures and optical properties of pure anatase TiO2, S-doped, Mn-doped and Mn-S co-doped anatase TiO2 by GGA + U methods based on the density function theory (DFT). The results indicate that the lattice is distorted and the lattice constant is reduce due to doping. The doping also introduces impurity energy levels into the forbidden band. After substitution of Mn for Ti atom, band gap narrowing of anatase TiO2 is caused by the impurity energy levels appearance in the near Fermi surface, which are contributed by Mn-3d orbital, Ti-3d orbital and O-2p orbital hybridization. After substitution of S for O atom, band gap narrowing is creited with the shallow accepter level under the conduction hand of S-3p orbital. The Mn-S co-doped anatase TiO2 could be a potential candidate for a photocatalyst because of tis enhanced absorption ability of visible light. The results can well explain the immanent cause of a band gap narrowing as well as a red shift in the spectrum for doped anatase TiO2.

  18. Magnetic properties and structure of FePt/FeMn multilayers

    International Nuclear Information System (INIS)

    Phuoc, Nguyen N.; Suzuki, Takao

    2007-01-01

    A systematic study of the magnetic properties by ion beam sputter-deposition system, was conducted in conjunction with the structure of FePt/FeMn multilayers fabricated onto MgO(0 0 1) substrates. Both parallel and perpendicular exchange biases were observed in the multilayers and were found to decrease drastically, as the deposition temperature is higher than 350 deg. C, which is evidently due to the interdiffusion at the interface. The thickness dependence study shows that the perpendicular magnetic anisotropy observed in the multilayers originates from surface anisotropy, being consistent with the decrease of perpendicular magnetic anisotropy as the deposition temperature is increased. The difference between parallel and perpendicular blocking temperatures that was clearly observed, is possibly due to the spin canting out of plane at the interface

  19. Asymmetrically shaped hysteresis loop in exchange-biased FeNi/FeMn film

    International Nuclear Information System (INIS)

    Gnatchenko, S.L.; Merenkov, D.N.; Bludov, A.N.; Pishko, V.V.; Shakhayeva, Yu.A.; Baran, M.; Szymczak, R.; Novosad, V.A.

    2006-01-01

    The magnetization reversal of the bilayer polycrystalline FeNi(50 A)/FeMn(50 A) film sputtered in a magnetic field has been studied by magnetic and magneto-optical techniques. The external magnetic fields were applied along the easy or hard magnetization axis of the ferromagnetic permalloy layer. The asymmetry of hysteresis loop has been found. Appreciable asymmetry and the exchange bias were observed only in the field applied along the easy axis. The specific features of magnetization reversal were explained within the phenomenological model that involves high-order exchange anisotropy and misalignment of the easy axes of the antiferromagnetic and ferromagnetic layers. It has been shown that the film can exist in one of three equilibrium magnetic states in the field applied along the easy axis. The transitions between these states occur as first-order phase transitions. The observed hysteresis loop asymmetry is related to the existence of the metastable state

  20. Synthesis of Fe2O3/TiO2 nanorod-nanotube arrays by filling TiO2 nanotubes with Fe

    International Nuclear Information System (INIS)

    Mohapatra, Susanta K; Banerjee, Subarna; Misra, Mano

    2008-01-01

    Synthesis of hematite (α-Fe 2 O 3 ) nanostructures on a titania (TiO 2 ) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO 2 nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe/TiO 2 composite is then annealed in an O 2 atmosphere to convert it to Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The length of the Fe 2 O 3 inside the TiO 2 nanotubes can be tuned from 50 to 550 nm by changing the deposition time. The composite material is characterized by scanning electron microscopy, transmission electron microscopy and diffuse reflectance ultraviolet-visible studies to confirm the formation of one-dimensional Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The present approach can be used for designing variable one-dimensional metal oxide heterostructures

  1. Gibbs energy modelling of the driving forces and calculation of the fcc/hcp martensitic transformation temperatures in Fe-Mn and Fe-Mn-Si alloys

    International Nuclear Information System (INIS)

    Cotes, S.; Fernandez Guillermet, A.; Sade, M.

    1999-01-01

    Very recent, accurate dilatometric measurements of the fcc hcp martensitic transformation (MT) temperatures are used to develop a new thermodynamic description of the fcc and hcp phases in the Fe-Mn-Si system, based on phenomenological models for the Gibbs energy function. The composition dependence of the driving forces for the fcc→hcp and the hcp→fcc MTs is established. Detailed calculations of the MT temperatures are reported, which are used to investigate the systematic effects of Si additions upon the MT temperatures of Fe-Mn alloys. A critical comparison with one of the most recent thermodynamic analyses of the Fe-Mn-Si system, which is due to Forsberg and Agren, is also presented. (orig.)

  2. PHASE CONSTITUENTS AND MICROSTRUCTURE OF Ti3Al/Fe3Al + TiN/TiB2 COMPOSITE COATING ON TITANIUM ALLOY

    OpenAIRE

    JIANING LI; CHUANZHONG CHEN; CUIFANG ZHANG

    2011-01-01

    Laser cladding of the Fe3Al + B4C/TiN + Al2O3 pre-placed powders on the Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiN/TiB2 composite coating, which improved the wear resistance of the Ti-6Al-4V alloy surface. In this study, the Ti3Al/Fe3Al + TiN/TiB2 composite coating has been researched by means of X-ray diffraction and scanning electron microscope. It was found that during the laser cladding process, Al2O3 can react with TiB2, leading to the formations of Ti3Al and B. This principle can be...

  3. Fusion of 48Ti+58Fe and 58Ni+54Fe below the Coulomb barrier

    Science.gov (United States)

    Stefanini, A. M.; Montagnoli, G.; Corradi, L.; Courtin, S.; Bourgin, D.; Fioretto, E.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Mijatović, T.; Montanari, D.; Pagliaroli, M.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Toniolo, N.; Torresi, D.

    2015-12-01

    Background: No data on the fusion excitation function of 48Ti+58Fe in the energy region near the Coulomb barrier existed prior to the present work, while fusion of 58Ni+54Fe was investigated in detail some years ago, down to very low energies, and clear evidence of fusion hindrance was noticed at relatively high cross sections. 48Ti and 58Fe are soft and have a low-lying quadrupole excitation lying at ≈800 -900 keV only. Instead, 58Ni and 54Fe have a closed shell (protons and neutrons, respectively) and are rather rigid. Purpose: We aim to investigate (1) the possible influence of the different structures of the involved nuclei on the fusion excitation functions far below the barrier and, in particular, (2) whether hindrance is observed in 48Ti+58Fe , and to compare the results with current coupled-channels models. Methods: 48Ti beams from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro were used. The experimental setup was based on an electrostatic beam separator, and fusion-evaporation residues (ERs) were detected at very forward angles. Angular distributions of ERs were measured. Results: Fusion cross sections of 48Ti+58Fe have been obtained in a range of nearly six orders of magnitude around the Coulomb barrier, down to σ ≃2 μ b . The sub-barrier cross sections of 48Ti+58Fe are much larger than those of 58Ni+54Fe . Significant differences are also observed in the logarithmic derivatives and astrophysical S factors. No evidence of hindrance is observed, because coupled-channels calculations using a standard Woods-Saxon potential are able to reproduce the data in the whole measured energy range. Analogous calculations for 58Ni+54Fe predict clearly too large cross sections at low energies. The two fusion barrier distributions are wide and display a complex structure that is only qualitatively fit by calculations. Conclusions: It is pointed out that all these different trends originate from the dissimilar low-energy nuclear structures of

  4. Preparation of nanocrystalline Ce1-xSmx(Fe,Co)11Ti by melt spinning and mechanical alloying

    Science.gov (United States)

    Wuest, H.; Bommer, L.; Huber, A. M.; Goll, D.; Weissgaerber, T.; Kieback, B.

    2017-04-01

    Permanent magnetic materials based on Ce(Fe, Co)12-xTix with the ThMn12 structure are promising candidates for replacing NdFeB magnets. Its intrinsic magnetic properties are not far below the values of Nd2Fe14B, and the high amount of Fe and the fact that Ce is much more abundant and less expensive than Nd encourages the reasonable interest in these compounds. Nanocrystalline magnetic material of the composition Ce1-xSmxFe11-yCoyTi (x=0-1 and y=0; 1.95) has been produced by both melt spinning and mechanical alloying. Alloys containing only Ce as rare earth element (x=0) show coercivities below 77 kA/m, while for x=1 Hc,J values up to 392 kA/m are reached. Coercivity shows rather an exponential than a linear dependence on the gradual substitution of Ce by Sm.

  5. Martensitic Transformations and Mechanical and Corrosion Properties of Fe-Mn-Si Alloys for Biodegradable Medical Implants

    Science.gov (United States)

    Drevet, Richard; Zhukova, Yulia; Malikova, Polina; Dubinskiy, Sergey; Korotitskiy, Andrey; Pustov, Yury; Prokoshkin, Sergey

    2018-03-01

    The Fe-Mn-Si alloys are promising materials for biodegradable metallic implants for temporary healing process in the human body. In this study, three different compositions are considered (Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si, all in wt pct). The phase composition analysis by XRD reveals ɛ-martensite, α-martensite, and γ-austenite in various proportions depending on the manganese amount. The DSC study shows that the starting temperature of the martensitic transformation ( M s) of the alloys decreases when the manganese content increases (416 K, 401 K, and 323 K (143 °C, 128 °C, and 50 °C) for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). Moreover, mechanical compression tests indicate that these alloys have a much lower Young's modulus ( E) than pure iron (220 GPa), i.e., 145, 133, and 118 GPa for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively. The corrosion behavior of the alloys is studied in Hank's solution at 310 K (37 °C) using electrochemical experiments and weight loss measurements. The corrosion kinetics of the Fe-Mn-Si increases with the manganese content (0.48, 0.59, and 0.80 mm/year for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). The alloy with the highest manganese content shows the most promising properties for biomedical applications as a biodegradable and biomechanically compatible implant material.

  6. Multiple collinear magnetic arrangements in thin Mn films supported on Fe(001). Antiferromagnetic versus ferromagnetic behavior

    International Nuclear Information System (INIS)

    Martinez, E.; Vega, A.; Robles, R.; Vazquez de Parga, A.L.

    2005-01-01

    We present a theoretical study of the magnetic properties of thin Mn films of 6 and 7 monolayers supported on Fe(001). The ab-initio tight binding linear muffin tin orbital (TB-LMTO) method was used to investigate the competition between ferromagnetic (F) and antiferromagnetic (AF) couplings within the system. We found several collinear magnetic solutions that may coexist at room temperature. The most stable configurations are characterized by AF coupling between the surface and subsurface Mn layers together with F coupling between Mn and Fe at the interface. The ground state arrangements for the 6 and 7 Mn films display opposite sign of the surface magnetic moment relative to the Fe substrate. The implications of these results in the possible onset of non-collinear magnetism when a step is present at the interface are discussed in comparison with Cr/Fe systems where non-collinear magnetism has been recently reported

  7. Thermodynamic properties of alloys and fusibility diagram of Fe-Ni-Mn system

    International Nuclear Information System (INIS)

    Danilenko, V.M.; Turkevich, V.Z.

    1987-01-01

    Thermodynamic calculation of the fusibility diagram of Fe-Ni-Mn system in the subregular solution approximation is performed. The calculated fusibility diagram fits the experimental one in kind and degree

  8. Internal friction and longitudinal modulus behaviour of multiferroic PbZr0.52Ti0.48O3+Ni0.93Co0.02Mn0.05Fe1.95O4-δ particulate composites

    International Nuclear Information System (INIS)

    Ramana, M Venkata; Sreenivasulu, G; Reddy, N Ramamanohar; Kumar, K V Siva; Murty, B S; Murthy, V R K

    2007-01-01

    Multiferroic particulate composites with composition xNi 0.93 Co 0.02 Mn 0.5 Fe 1.95 O 4-δ + (1 - x)PbZr 0.52 Ti 0.48 O 3 where the molar fraction x varies as 0, 0.1, 0.2, 0.3, 0.4 and 0.5 were prepared by the conventional ceramic method. The presence of two phases was confirmed by x-ray diffraction and scanning electron microscopy. The temperature variation of the longitudinal modulus (L) and the internal friction (Q -1 ) of these particulate composites at 104.387 kHz was studied in the wide temperature range 30-420 deg. C. The temperature variation of the longitudinal modulus (L) in each composition of these particulate composites showed two abrupt minima. One minimum coincided with the ferroelectric-paraelectric Curie transition temperature (θ E ) and the other with the ferrimagnetic-paramagnetic Curie transition (θ M ) temperature. The internal friction (Q -1 ) measurements also showed two sharp peaks in each composition corresponding to those temperatures where the minima were noticed in the temperature variation of the longitudinal modulus behaviour. The Curie transition temperature of pure ferrite was found to be 560 deg. C. Addition of 10% of ferrite to ferroelectric in a magnetoelectric (ME) composite resulted in a 360 deg. C fall in θ M and with a further increase in ferrite content the θ M variation was found to be very nominal. However, no significant ferroelectric Curie transition temperature shift could be noticed. This behaviour is explained in the light of structural phase transitions in these multiferroic particulate composites. These ME composites were prepared with a view to using them as ME sensors and transducers

  9. Evaluation of mechanical properties of nanocrystalline Ti-Mo-Fe-Sn alloys system; Avaliacao de propriedades mecanicas de ligas nanocristalinas do sistema Ti-Mo-Fe-Sn

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, M.O.A; Vidilli, A.L.; Afonso, C.R.M., E-mail: andre.vidilli@gmail.com [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

    2014-07-01

    The Ti-6Al-4V, widely used in biomaterials, exhibits elastic modulus (E) of approximately 110GPa, which is significantly higher than the one of human bone (E = 10 to 30 GPa). In this project, a process of rapid solidification was utilized in 4 different alloys of Ti-Mo-Fe-Sn, in order to produce ultrafine nanocrystalline eutectic alloys, which present high strength (1800-2500 MPa), low elastic modulus (50-110 GPa) and good corrosion resistance. The alloys Ti{sub 62}Fe{sub 30}Mo{sub 8}, Ti{sub 56}Fe{sub 30}Mo{sub 8}Sn{sub 6}, Ti{sub 63}Fe{sub 23}Mo{sub 8}Sn{sub 6}, Ti{sub 60}Fe{sub 23}Mo{sub 8}Sn{sub 9} show Vickers microhardness de, respectively, 745 (1mm), 733 (1mm), 609 (1mm) e 651(1mm) HV. The characterization was performed using scanning electron microscopy (SEM) and X- ray diffraction (XRD). The results indicated the presence of a β-Ti (bcc) matrix and the intermetallic TiFe and Ti{sub 3}Sn phases, and the microstructure were formed by dendrites, and eutectic constituents, which were present in the compositions Ti{sub 62}Fe{sub 30}Mo{sub 8}, Ti{sub 56}Fe{sub 30}Mo{sub 8}Sn{sub 6}, Ti{sub 63}Fe{sub 23}Mo{sub 8}Sn{sub 6}, Ti{sub 60}Fe{sub 23}Mo{sub 8}Sn{sub 9}. (author)

  10. Wear resistance of TiB/sub 2/-Fe cermets

    International Nuclear Information System (INIS)

    Champagne, B.; Dallaire, S.

    1985-01-01

    A material which consists of TiB/sub 2/ dispersed in an iron matrix was synthesized by the exothermic reaction of ferrotitanium and boron. The as-reacted products were hot isostatically pressed to produce TiB/sub 2/-Fe cermets. The influence of HIP variables on the density and total fractional porosity of specimens is presented. Density above 95% is obtained by HIPping at temperatures below 1300 0 C. Increasing the temperature and the time of HIPping enhance the mechanical properties and wear resistance of TiB/sub 2/-Fe cermets by reducing their residual porosity. Relations obtained by regression analysis showed that the porosity strongly affects the properties of parts. Regression analysis point out that the wear loss of a 5% porosity TiB/sub 2/-Fe cermet is 270% higher than a dense HIPped cermet. Low stress and high stress abrasion resistance tests utilizing various abrasive media were carried out on dense HIPped cermets and results were compared with those obtained from WC-Co cermets and 1020 steel

  11. Characterization of TiO2–MnO2 composite electrodes synthesized using spark plasma sintering technique

    CSIR Research Space (South Africa)

    Tshephe, TS

    2015-03-01

    Full Text Available and electrochemical stability of the resulting materials were investigated. Relative densities of 99.33% and 98.49% were obtained for 90TiO2–10MnO2 and 80TiO2–10MnO2 when ball was incorporated. The 90TiO2–10MnO2 powder mixed with balls had its Vickers hardness value...

  12. Magnetic properties and loss separation in FeSi/MnZnFe2O4 soft magnetic composites

    International Nuclear Information System (INIS)

    Lauda, M.; Füzer, J.; Kollár, P.; Strečková, M.; Bureš, R.; Kováč, J.; Baťková, M.; Baťko, I.

    2016-01-01

    We investigated composites that have been prepared from FeSi powders covered with MnZnFe 2 O 4 (MnZn ferrite), which was prepared by sol–gel synthesis accompanied with the auto-combustion process. The aim of this paper is to analyze the complex permeability and core losses of prepared samples with different amount of MnZn ferrite. The microstructure and the powder morphology were examined by scanning electron microscopy. Magnetic measurements on bulk samples were carried out using a vibrating sample magnetometer, an impedance analyzer and hysteresisgraphs. The results indicate that the composites with 2.6 wt% MnZn ferrite show better soft magnetic properties than the composites with about 6 wt% MnZn ferrite. - Highlights: • Successful preparation of soft magnetic composite FeSi/MnZnFe 2 O 4 . • Study of the complex magnetic permeability. • Comparison of different compositions of prepared SMC's. • Determination of parts of magnetic losses.

  13. Solid solution inhomogeneity in DC-cast AlMn(Fe,Si) ingots

    International Nuclear Information System (INIS)

    Lakner, J.; Kovacs-Csetenyi, E.; Lal, K.

    1990-01-01

    The aim of this work was to characterize the structure in cast state of the AlMn1 alloy containing different Fe and Si concentration. The casting parameters were intended to keep constant and the effect of impurities was studied. The inhomogeneity along the diameter of cast billet was characterized by the dendrite arm spacing and by the solid solution content. To explain the results the model developed for binary AlFe and AlMn alloys was applied

  14. Exchange anisotropy and micromagnetic properties of PtMn/NiFe bilayers

    International Nuclear Information System (INIS)

    Pokhil, Taras; Linville, Eric; Mao, Sining

    2001-01-01

    Magnetic microstructure, exchange induced uniaxial and unidirectional anisotropy and structural transformation have been studied in PtMn/NiFe bilayer films and small elements as a function of annealing time. The relationship between the fcc-fct ordering phase transformation in PtMn and the development of exchange induced magnetic properties in PtMn/NiFe bilayers is complicated by the fact that the transformation occurs throughout the entire volume of the PtMn film, while the exchange between the layers is predominantly an interface effect. Consequently, the development of the exchange anisotropy should depend primarily on the character of the structural transformation at the interface between PtMn and NiFe. The purpose of this article is to correlate the volume phase transformation in PtMn to the development of exchange anisotropy and micromagnetic behavior in PtMn/NiFe bilayers. The interface structure can be inferred from the anisotropy and micromagnetic measurements, leading to a model that explains the relationship between the volume and interface transformation structures in PtMn, and magnetic properties of the bilayers. The structure and magnetic properties were characterized by x-ray diffraction, vibrating sample magnetometry, and magnetic force microscopy. [copyright] 2001 American Institute of Physics

  15. Induced Ti magnetization at La0.7Sr0.3MnO3 and BaTiO3 interfaces

    Directory of Open Access Journals (Sweden)

    Yaohua Liu

    2016-04-01

    Full Text Available In artificial multiferroics hybrids consisting of ferromagnetic La0.7Sr0.3MnO3 (LSMO and ferroelectric BaTiO3 epitaxial layers, net Ti moments are found from polarized resonant soft x-ray reflectivity and absorption. The Ti dichroic reflectivity follows the Mn signal during the magnetization reversal, indicating exchange coupling between the Ti and Mn ions. However, the Ti dichroic reflectivity shows stronger temperature dependence than the Mn dichroic signal. Besides a reduced ferromagnetic exchange coupling in the interfacial LSMO layer, this may also be attributed to a weak Ti-Mn exchange coupling that is insufficient to overcome the thermal energy at elevated temperatures.

  16. Initial stages of solid solution decomposition in Fe-Ti and Fe-Nb alloys

    International Nuclear Information System (INIS)

    Ustinovshchikov, Yu.I.; Chen Shiren; Shirobokova, M.S.

    1993-01-01

    Structural analysis of Fe-Ti and Fe-Nb systems is performed. Formation of Laves phases proceed through the stage of the formation of a structure representing a periodic sequence of the regions enriched and depleted in alloying element. Abnormal changes in the properties of alloys of the given systems are noted; there changes reside in a decrease of alloy hardness during the formation of the above structure

  17. Magnetism of DyMn2 and HoMn2 - 57Fe and 119Sn Moessbauer studies

    International Nuclear Information System (INIS)

    Krop, K.; Haeufler, T.; Hilscher, G.; Steiner, W.

    1995-01-01

    Moessbauer spectra were measured for two Laves phase compounds DyMn 2 and HoMn 2 in which manganese was substituted to 0.5% with 57 Fe and to 0.2% with 119 Sn. At 4.2 K the 57 Fe and 119 Sn spectra of the Dy compound were unambiguously fitted each with two Zeeman patterns (with relative contributions to the spectra 3:1) corresponding to two different Mn sites - magnetic and nonmagnetic. Transferred hyperfine fields at 119 Sn were found to be proportional to the magnetic moment of Dy and its ferromagnetic component, corroborating the magnetic structure found in neutron diffraction (ND) experiment. The same procedure was carried on with the spectra measured for the Ho compound, but the above mentioned proportionality was not found. ((orig.))

  18. Phenomenological approach to the spin glass state of (Cu-Mn, Ag-Mn, Au-Mn and Au-Fe) alloys at low temperatures

    International Nuclear Information System (INIS)

    Al-Jalali, Muhammad A.; Kayali, Fawaz A.

    2000-01-01

    Full text.The spin glass of: (Cu-Mn, Ag-Mn, Au-Mn, Au-Fe) alloys has been extensively studied. The availability of published and assured experimental data on the susceptibility x(T) of this alloys has enabled the design and application of phenomenological approach to the spin glass state of these interesting alloys. The use of and advanced (S.P.S.S) computer software has resulted revealing some important features of the spin glass in these alloys, the most important of which is that the spin glass state do not represent as phase change

  19. Geochemical Constraints on Core-Mantle Interaction from Fe/Mn Ratios

    Science.gov (United States)

    Humayun, M.; Qin, L.

    2003-12-01

    The greater density of liquid iron alloy, and its immiscibility with silicate, maintains the physical separation of the core from the mantle. There are no a priori reasons, however, why the Earth's mantle should be chemically isolated from the core. Osmium isotopic variations in mantle plumes have been interpreted in terms of interaction between outer core and the source regions of deep mantle plumes. If chemical transport occurs across the core-mantle boundary its mechanism remains to be established. The Os isotope evidence has also been interpreted as the signatures of subducted Mn-sediments, which are known to have relatively high Pt/Os. In the mantle, Fe occurs mainly as the divalent ferrous ion, and Mn occurs solely as a divalent ion, and both behave in a geochemically coherent manner because of similarity in ionic charge and radius. Thus, the Fe/Mn ratio is a planetary constant insensitive to processes of mantle differentiation by partial melting. Two processes may perturb the ambient mantle Fe/Mn of 60: a) the subduction of Mn-sediments should decrease the Fe/Mn ratio in plume sources, while b) chemical transport from the outer core may increase the Fe/Mn ratio. The differentiation of the liquid outer core to form the solid inner core may increase abundances of the light element constituents (FeS, FeO, etc.) to the point of exsolution from the core at the CMB. The exact rate of this process is determined by the rate of inner core growth. Two end-member models include 1) inner core formation mainly prior to 3.5 Ga with heat release dominated by radioactive sources, or 2) inner core formation occurring mainly in the last 1.5 Ga with heat release dominated by latent heat. This latter model would imply large fluxes of Fe into the sources of modern mantle plumes. Existing Fe/Mn data for Gorgona and Hawaiian samples place limits on both these processes. We describe a new procedure for the precise determination of the Fe/Mn ratio in magmatic rocks by ICP-MS. This

  20. Production and characterization of stainless steel based Fe-Cr-Ni-Mn-Si(-Co) shape memory alloys

    International Nuclear Information System (INIS)

    Otubo, J.

    1995-01-01

    It is well known that the Fe based alloys can exhibit shape memory effect due to the γ to ε martensitic transformation. The effect may not be as striking as observed in the NiTi alloy but it might become attractive from the practical point of view. In this work, two compositions of Fe-Cr-Ni-Mn-Si(-Co) stainless steel based shape memory alloy, prepared by the VIM technique, will be presented. The results are good with shape recovery of 95% for a pre-strain of 4% after some training cycles. In terms of workability the alloys produced are worse than the usual AISI304. However, adjusting the thermo-mechanical processing, it is perfectly possible to produce wire as thin as 1,20mm in dia. or down. (orig.)

  1. Mechanical alloying of TiFe intermetallic for hydrogen storage

    International Nuclear Information System (INIS)

    Vega, L.E.R.; Leiva, D.R.; Silva, W.B.; Ishikawa, T.T.; Botta, W.J.; Leal Neto, R.M.

    2016-01-01

    Elementary powders of Ti and Fe in the stoichiometric ratio 50:50 were submitted to mechanical alloying for 2, 6, 10 and 20 h in a planetary ball mill. The synthesis of TiFe intermetallic with high yield was achieved for all milling times. The structural characterization of the samples revealed the trend of the particles to form agglomerates and the formation of cracks. H-absorption capacities of 0,74; 0,90; 0,97 and 0,95 wt. % (at room temperature and 20 bar of H2) were obtained for processing times of 2, 6, 10 and 20 h, respectively, without using a thermal activation process after milling. (author)

  2. Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

    Directory of Open Access Journals (Sweden)

    Olejnik E.

    2016-06-01

    Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

  3. Charge transfers in complex transition metal alloys (Ti2Fe)

    International Nuclear Information System (INIS)

    Abramovici, G.

    1998-01-01

    We introduce a new non-orthogonal tight-binding model, for complex alloys, in which electronic structure is characterized by charge transfers. We give the analytic calculation of a charge transfer, in which overlapping two-center terms are rigorously taken into account. Then, we apply numerically this result to an approximant phase of a quasicrystal of Ti 2 Fe alloy. This model is more particularly adapted to transition metals, and gives realistic densities of states. (orig.)

  4. Preferential growth in FeCoV/Ti:N multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, D.; Senthil Kumar, M.; Boeni, P.; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The preferential growth in Fe{sub 0.50}Co{sub 0.48}V{sub 0.02}/Ti:N multilayers was studied by X-ray diffraction. X-ray specular reflectometry and subsequent simulation of the spectra was used to extract information about the thickness and interface roughness of individual layers. The investigation gives structural information about the material combination and its potential for the use of neutron polarizers. (author) 2 figs., 1 tab., 2 refs.

  5. Drastic effect of the Mn-substitution in the strongly correlated semiconductor FeSb2.

    Science.gov (United States)

    Kassem, Mohamed A.; Tabata, Yoshikazu; Waki, Takeshi; Nakamura, Hiroyuki

    2017-06-01

    We report the effects of Mn substitution, corresponding to hole doping, on the electronic properties of the narrow gap semiconductor, FeSb2, using single crystals of Fe1- x Mn x Sb2 grown by the Sb flux method. The orthorhombic Pnnm structure was confirmed by powder X-ray diffraction (XRD) for the pure and Mn-substituted samples. Their crystal structure parameters were refined using the Rietveld method. The chemical composition was investigated by wavelength-dispersive X-ray spectroscopy (WDX). The solubility limit of Mn in FeSb2 is x max ˜ 0.05 and the lattice constants change monotonically with increasing the actual Mn concentration. A drastic change from semiconducting to metallic electronic transports was found at very low Mn concentration at x ˜ 0.01. Our experimental results and analysis indicate that the substitution of a small amount of Mn changes drastically the electronic state in FeSb2 as well as the Co-substitution does: closing of the narrow gap and emergence of the density of states (DOS) at the Fermi level.

  6. Change of structure and some mechanical properties during processing of AlMn(Fe,Si) alloys

    International Nuclear Information System (INIS)

    Kovacs-Csetenyi, E.; Griger, A.; Turmezey, T.; Suchanek, V.

    1990-01-01

    The aim of this work was to study the change of structure and some mechanical properties during processing of AlMn(Fe,Si) alloys. An emphasis was given to the effect of Fe and Si on the properties measured in deformed and annealed states, because of its technological importance

  7. Phase Constituents and Microstructure of Ti3Al/Fe3Al + TiN/TiB2 Composite Coating on Titanium Alloy

    Science.gov (United States)

    Li, Jianing; Chen, Chuanzhong; Zhang, Cuifang

    Laser cladding of the Fe3Al + B4C/TiN + Al2O3 pre-placed powders on the Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiN/TiB2 composite coating, which improved the wear resistance of the Ti-6Al-4V alloy surface. In this study, the Ti3Al/Fe3Al + TiN/TiB2 composite coating has been researched by means of X-ray diffraction and scanning electron microscope. It was found that during the laser cladding process, Al2O3 can react with TiB2, leading to the formations of Ti3Al and B. This principle can be used to improve the Fe3Al + B4C/TiN laser-cladded coating on the Ti-6Al-4V alloy. Furthermore, during the cladding process, C consumed the oxygen in Fe3Al + B4C /TiN + Al2O3 molten pool, which retarded the productions of the redundant metal oxides.

  8. Fe and Mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kangjoo [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of)], E-mail: kangjoo@kunsan.ac.kr; Kim, Hyun-Jung; Choi, Byoung-Young; Kim, Seok-Hwi; Park, Ki-hoon [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of); Park, Eungyu [Department of Geology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Koh, Dong-Chan [Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Yun, Seong-Taek [Department of Earth and Environmental Sciences, Korea University, Seoul 136-701 (Korea, Republic of)

    2008-01-15

    Iron and Mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low SO{sub 4} concentrations. The mass balance and isotopic approaches of this study demonstrate that reduction of SO{sub 4}, supplied from agricultural activities such as fertilization and irrigation, is important in lowering Fe and Mn levels in alluvial groundwaters underneath a paddy field. This study was performed to investigate the processes regulating Fe and Mn levels in groundwaters of a point bar area, which has been intensively used for flood cultivation. Four multilevel-groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry. The results show that Fe and Mn levels are regulated by the presence of NO{sub 3} at shallow depths and by SO{sub 4} reduction at the greater depths. Isotopic and mass balance analyses revealed that NO{sub 3} and SO{sub 4} in groundwater are mostly supplied from the paddy field, suggesting that the Fe-and Mn-rich zone of the study area is confined by the agricultural activities. For this reason, the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of Fe/Mn-rich groundwaters in the paddy field area.

  9. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    Science.gov (United States)

    Ma, Y. L.; Liu, X. B.; Nguyen, V. V.; Poudyal, N.; Yue, M.; Liu, J. P.

    2016-08-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd2Fe14B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%.

  10. Fe and Mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field

    International Nuclear Information System (INIS)

    Kim, Kangjoo; Kim, Hyun-Jung; Choi, Byoung-Young; Kim, Seok-Hwi; Park, Ki-hoon; Park, Eungyu; Koh, Dong-Chan; Yun, Seong-Taek

    2008-01-01

    Iron and Mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low SO 4 concentrations. The mass balance and isotopic approaches of this study demonstrate that reduction of SO 4 , supplied from agricultural activities such as fertilization and irrigation, is important in lowering Fe and Mn levels in alluvial groundwaters underneath a paddy field. This study was performed to investigate the processes regulating Fe and Mn levels in groundwaters of a point bar area, which has been intensively used for flood cultivation. Four multilevel-groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry. The results show that Fe and Mn levels are regulated by the presence of NO 3 at shallow depths and by SO 4 reduction at the greater depths. Isotopic and mass balance analyses revealed that NO 3 and SO 4 in groundwater are mostly supplied from the paddy field, suggesting that the Fe-and Mn-rich zone of the study area is confined by the agricultural activities. For this reason, the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of Fe/Mn-rich groundwaters in the paddy field area

  11. The effect of magnetic ordering on the giant magnetoresistance of Cr-Fe-V and Cr-Fe-Mn

    International Nuclear Information System (INIS)

    Somsen, Ch.; Acet, M.; Nepecks, G.; Wassermann, E.F.

    2000-01-01

    Cr-rich Cr 1-x Fe x alloys with compositions in the vicinity of mixed ferromagnetic and antiferromagnetic exchange (x=0.18) exhibit giant magnetoresistance. In order to understand the influence of the antiferromagnetism of Cr on the giant magnetoresistance one can manipulate the antiferromagnetic exchange either by adding vanadium, which destroys the antiferromagnetism of Cr, or by adding manganese, which enhances it. Cr-Fe-V and Cr-Fe-Mn alloys also have Curie temperatures that lie between low temperatures and room temperature in the concentration region where giant magnetoresistance is observed. Therefore, they are also used as samples to study the magnetoresistance as a function of the strength of FM exchange. We discuss these points in the light of temperature and concentration-dependent magnetoresistance experiments on Cr 0.99-x Fe x V 0.01 , Cr 0.96-x Fe x V 0.04 , Cr 0.90-x Fe x Mn 0.10 and Cr 0.55 Fe x Mn 0.45-x alloys. Results indicate that the most favorable condition for a large magnetoresistance in these alloys occurs at temperatures near the Curie temperature

  12. Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio

    International Nuclear Information System (INIS)

    Zhang, Weiwen; Lin, Bo; Fan, Jianlei; Zhang, Datong; Li, Yuanyuan

    2013-01-01

    The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al 7 Cu 2 Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese script Al m Fe, α-Fe or Al 6 (FeMn) partially transform to a new Chinese script Cu-rich α(CuFe) (Al 7 Cu 2 Fe or Al 7 Cu 2 (FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al 20 Cu 2 Mn 3 ), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively

  13. Damage annealing in low temperature Fe/Mn implanted ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Gunnlaugsson, H. P. [University of Aarhus, Department of Physics and Astronomy (Denmark); Bharuth-Ram, K., E-mail: kbr@tlabs.ac.za [Durban University of Technology, Physics Department (South Africa); Johnston, K. [PH Department, ISOLDE/CERN (Switzerland); Langouche, G. [University of Leuven, Instituut voor Kern-en Stralings fysika (Belgium); Mantovan, R. [Laboratorio MDM, IMM-CNR (Italy); Mølholt, T. E. [University of Iceland, Science Institute (Iceland); Naidoo, D. [University of the Witwatersrand, School of Physics (South Africa); Ólafsson, O. [University of Iceland, Science Institute (Iceland); Weyer, G. [University of Aarhus, Department of Physics and Astronomy (Denmark)

    2015-04-15

    {sup 57}Fe Emission Mössbauer spectra obtained after low fluence (<10{sup 12} cm {sup −2}) implantation of {sup 57}Mn (T{sub 1/2}= 1.5 min.) into ZnO single crystal held at temperatures below room temperature (RT) are presented. The spectra can be analysed in terms of four components due to Fe {sup 2+} and Fe {sup 3+} on Zn sites, interstitial Fe and Fe in damage regions (Fe {sub D}). The Fe {sub D} component is found to be indistinguishable from similar component observed in emission Mössbauer spectra of higher fluence (∼10{sup 15} cm {sup −2}){sup 57}Fe/ {sup 57}Co implanted ZnO and {sup 57}Fe implanted ZnO, demonstrating that the nature of the damage regions in the two types of experiments is similar. The defect component observed in the low temperature regime was found to anneal below RT.

  14. Damage annealing in low temperature Fe/Mn implanted ZnO

    International Nuclear Information System (INIS)

    Gunnlaugsson, H. P.; Bharuth-Ram, K.; Johnston, K.; Langouche, G.; Mantovan, R.; Mølholt, T. E.; Naidoo, D.; Ólafsson, O.; Weyer, G.

    2015-01-01

    57 Fe Emission Mössbauer spectra obtained after low fluence (<10 12 cm −2 ) implantation of 57 Mn (T 1/2 = 1.5 min.) into ZnO single crystal held at temperatures below room temperature (RT) are presented. The spectra can be analysed in terms of four components due to Fe 2+ and Fe 3+ on Zn sites, interstitial Fe and Fe in damage regions (Fe D ). The Fe D component is found to be indistinguishable from similar component observed in emission Mössbauer spectra of higher fluence (∼10 15 cm −2 ) 57 Fe/ 57 Co implanted ZnO and 57 Fe implanted ZnO, demonstrating that the nature of the damage regions in the two types of experiments is similar. The defect component observed in the low temperature regime was found to anneal below RT

  15. Preparation and Characterization of Mn/N Co-Doped TiO2 Loaded on Wood-Based Activated Carbon Fiber and Its Visible Light Photodegradation

    Directory of Open Access Journals (Sweden)

    Xiaojun Ma

    2015-09-01

    Full Text Available Using MnSO4·H2O as manganese source and urea as nitrogen source, Mn/N co-doped TiO2 loaded on wood-based activated carbon fiber (Mn/Ti-N-WACF was prepared by sol–gel method. Mn/Ti-N-WACF with different Mn doping contents was characterized by scanning electron microscopy, X-ray diffraction (XRD and X-ray photoelectron spectroscopies (XPS, and ultraviolet-visible spectrophotometer. Results showed that the loading rate of TiO2 in Mn/Ti-N-WACF was improved by Mn/N co-doping. After calcination at 450 °C, the degree of crystallinity of TiO2 was reduced due to Mn/N co-doption in the resulting Mn/Ti-N-WACF samples, but the TiO2 crystal phase was not changed. XPS spectra revealed that some Ti4+ ions from the TiO2 lattice of Mn/Ti-N-WACF system were substituted by doped Mn. Moreover, new bonds formed within N–Ti–N and Ti–N–O because of the doped N that substituted some oxygen atoms in the TiO2 lattice. Notably, the degradation rate of methylene blue for Mn/Ti-N-WACF was improved because of the co-doped Mn/N under visible-light irradiation.

  16. Magnetic properties of Sc{sub x}Ti{sub 1-x}Fe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, M. [Lab. de Cristallographie, CNRS, 38 - Grenoble (France); Deportes, J. [Lab. Louis Neel, CNRS, 38 - Grenoble (France); Ouladdiaf, B. [Institut Laue-Langevin, 38 - Grenoble (France); Sayetat, F. [Lab. de Cristallographie, CNRS, 38 - Grenoble (France)

    1995-02-09

    The magnetic properties and their thermal dependences of Sc{sub 0.1}Ti{sub 0.9}Fe{sub 1.96}, Sc{sub 0.1}Ti{sub 0.9}Fe{sub 2} and Sc{sub 0.1}Ti{sub 0.9}Fe{sub 2.04} are compared with those of TiFe{sub 2}. The substitution changes the iron-iron distances. Consequently, the Fe atoms on the 6h site show in addition to the antiferromagnetic component a small ferromagnetic one, and a weak magnetic moment appears on the 2a site. ((orig.)).

  17. Shape memory and associated properties in Fe-Mn-Si-based ribbons produced by melt-spinning

    International Nuclear Information System (INIS)

    Valeanu, Mihaela; Filoti, G.; Kuncser, V.; Tolea, Felicia; Popescu, B.; Galatanu, A.; Schinteie, G.; Jianu, A.D.; Mitelea, I.; Schinle, D.; Craciunescu, C.M.

    2008-01-01

    Four Fe-Mn-Si alloys, Fe 62 Mn 32 Si 6 , Fe 62 Mn 20 Si 5 Cr 8 Ni 5 , Fe 62 Mn 16 Si 5 Cr 12 Ni 5 and Fe 65 Mn 9 Si 7 Cr 10 Ni 9 , were obtained by the melt-spinning method. The samples were structurally, magnetic and shape memory effect (SME) investigated, both 'as quenched' and thermally treated. The Mn-rich compositions show different phase, magnetic behavior and SME in comparison with Mn-poor compositions. The thermal treatments generate transformation between the two existing majority phases (α and γ), related magnetization and SME behavior. The features are derived from the corroboration of structural, magnetic interaction and magnitude of SME data

  18. An ab initio study on the structural, electronic and mechanical properties of quaternary full-Heusler alloys FeMnCrSn and FeMnCrSb

    Science.gov (United States)

    Erkişi, Aytaç

    2018-06-01

    The quaternary full Heusler alloys FeMnCrSn and FeMnCrSb, which have face-centred cubic (FCC) crystal structure and conform to ? space group with 216 space number, have been investigated using Generalised Gradient Approximation (GGA) in the Density Functional Theory (DFT) as implemented in VASP (Vienna Ab initio Simulation Package) software. These alloys are considered in ferromagnetic (FM) order. After the investigation of structural stability of these alloys, their mechanical and thermal properties and also electronic band structures have been examined. The calculated spin-polarised electronic band structures and total electronic density of states (DOS) within GGA approximation show that these alloys can exhibit both metallic and half-metallic characters in different structural phases. The calculated formation enthalpies and the plotted energy-volume graphs show that Type-III phase is most stable structural phase for these materials. Also, FeMnCrSb alloy in Type-I/Type-III phases and FeMnCrSn alloy in Type-III phase show half-metallic behaviour with integer total magnetic moments almost 2 and 1 μB per formula unit, respectively, since there are band gaps observed in spin-down states, whereas they have metallic behaviour in majority bands. Other structural phases of both systems are also metallic. Moreover, the calculated elastic constants and the estimated anisotropy shear factors indicate that these materials are stable mechanically in all of three phases except FeMnCrSn in Type-I phase that does not satisfy Born stability criteria in this phase and have high anisotropic behaviour.

  19. Hydrogenation properties and microstructure of Ti-Mn-based alloys for hybrid hydrogen storage vessel

    International Nuclear Information System (INIS)

    Shibuya, Masachika; Nakamura, Jin; Akiba, Etsuo

    2008-01-01

    Ti-Mn-based AB 2 -type alloys which are suitable for a hybrid hydrogen storage vessel have been synthesized and evaluated hydrogenation properties. As the third element V was added to Ti-Mn binary alloys. All the alloys synthesized in this work mainly consist of the C14 Laves and BCC phase. In the case of Ti0.5V0.5Mn alloy, the amounts of hydrogen absorption was 1.8 wt.% at 243 K under the atmosphere of 7 MPa H 2 , and the hydrogen desorption pressure was in the range of 0.2-0.4 MPa at 243 K. The hydrogen capacity of this alloy did not saturate under 7 MPa H 2 and seems to increase with hydrogen pressure up to 35 MPa that is estimated working pressure of the hybrid hydrogen storage vessel

  20. Nano-impact testing of TiFeN and TiFeMoN films for dynamic toughness evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Beake, B D [Micro Materials Ltd, Willow House, Ellice Way, Yale Business Village, Wrexham LL13 7YL (United Kingdom); Vishnyakov, V M; Colligon, J S, E-mail: ben@micromaterials.co.uk [Dalton Research Institute, Manchester Metropolitan University, Manchester M1 5GD (United Kingdom)

    2011-03-02

    TiFeN and TiFeMoN films were deposited on silicon wafers by ion-beam-assisted deposition. Their mechanical properties were measured by nanoindentation (quasi-static) and nano-impact (dynamic) techniques. Nano-impact testing enabled assessment of their toughness and resistance to fatigue fracture under repetitive loading. At low impact forces, films with a higher resistance to plastic deformation (H{sup 3}/E{sup 2}) were much more resistant to the formation of cracks throughout the test. At higher impact forces, these films initially show impact resistance but with continued impacts they are unable to protect the Si substrate, performing as poorly as films with lower H{sup 3}/E{sup 2} and suffer delamination from the Si substrate over a large area.

  1. Magnetic properties of M0.3Fe2.7O4 (M = Fe, Zn and Mn) ferrites nanoparticles

    Science.gov (United States)

    Modaresi, Nahid; Afzalzadeh, Reza; Aslibeiki, Bagher; Kameli, Parviz

    2018-06-01

    In the present article a comparative study on the structural and magnetic properties of nano-sized M0.3Fe0.7Fe2O4 (M = Fe, Zn and Mn) ferrites have been reported. The X-ray diffraction (XRD) patterns show that the crystallite size depends on the cation distribution. The Rietveld refinement of XRD patterns using MAUD software determines the distribution of cations and unit cell dimensions. The magnetic measurements show that the maximum and minimum value of saturation magnetization is obtained for Zn and Mn doped samples, respectively. The peak temperature of AC magnetic susceptibility of Zn and Fe doped samples below 300 K shows the superparamagnetic behavior in these samples at room temperature. the AC susceptibility results confirm the presence of strong interactions between the nanoparticles which leads to a superspin glass state in the samples at low temperatures.

  2. Preparation of nanocrystalline Ce{sub 1−x}Sm{sub x}(Fe,Co){sub 11}Ti by melt spinning and mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, H., E-mail: holger.wuest@de.bosch.com [Robert Bosch GmbH, Postfach 10 60 50, 70049 Stuttgart (Germany); Bommer, L., E-mail: lars.bommer@de.bosch.com [Robert Bosch GmbH, Postfach 10 60 50, 70049 Stuttgart (Germany); Huber, A.M., E-mail: arne.huber@de.bosch.com [Robert Bosch GmbH, Postfach 10 60 50, 70049 Stuttgart (Germany); Goll, D., E-mail: dagmar.goll@htw-aalen.de [Aalen University, Materials Research Institute, Beethovenstr. 1, 73430 Aalen (Germany); Weissgaerber, T., E-mail: thomas.weissgaerber@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Branch Lab Dresden, Winterbergstraße 28, 01277 Dresden (Germany); Kieback, B., E-mail: bernd.kieback@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Branch Lab Dresden, Winterbergstraße 28, 01277 Dresden (Germany); Technische Universität Dresden, Institute for Materials Science, Helmholtzstraße 7, 01069 Dresden (Germany)

    2017-04-15

    Permanent magnetic materials based on Ce(Fe, Co){sub 12−x}Ti{sub x} with the ThMn{sub 12} structure are promising candidates for replacing NdFeB magnets. Its intrinsic magnetic properties are not far below the values of Nd{sub 2}Fe{sub 14}B, and the high amount of Fe and the fact that Ce is much more abundant and less expensive than Nd encourages the reasonable interest in these compounds. Nanocrystalline magnetic material of the composition Ce{sub 1−x}Sm{sub x}Fe{sub 11−y}Co{sub y}Ti (x=0−1 and y=0; 1.95) has been produced by both melt spinning and mechanical alloying. Alloys containing only Ce as rare earth element (x=0) show coercivities below 77 kA/m, while for x=1 H{sub c,J} values up to 392 kA/m are reached. Coercivity shows rather an exponential than a linear dependence on the gradual substitution of Ce by Sm. - Highlights: • CeFe{sub 11}Ti nanocrystalline samples demonstrate values of H{sub c,J} up to 77 kA/m. • SmFe{sub 11}Ti nanocrystalline samples demonstrate values of H{sub c,J} up to 392 kA/m. • Dependence of H{sub c,J} on x in Ce{sub 1−x}Sm{sub x(}Fe, Co){sub 11}Ti obeys non-linear dependence. • Optimum annealing shifts to from 800 °C for CeFe{sub 11}Ti to 900 °C for SmFe{sub 11}Ti.

  3. Martensitic transformation, fcc and hcp relative phase stability, and thermal cycling effects in Fe-Mn and Fe-Mn-X Alloys (X = Si, Co)

    International Nuclear Information System (INIS)

    Baruj, Alberto

    1999-01-01

    In this Thesis we present a study of the fcc and hcp relative phase stability in the Fe-Mn and Fe-Mn-Co systems. In particular, we have investigated the effect of two main factors affecting the relative phase stability: changes in the chemical composition of the alloys and changes in the density of crystalline defects in the microstructure.In order to analyse the effect of chemical composition, we have performed an experimental study of the fcc/hcp martensitic transformation temperatures in Fe-Mn-Co alloys in the composition range lying between 15% and 34% Mn, and between 1% and 16% Co.We have measured the martensitic transformation temperatures by means of dilatometry and electrical resistivity.We have combined this information with measurements of the fcc/hcp martensitic transformation temperatures in Co-rich alloys to perform a modelling of the Gibbs energy function for the hcp phase in the Fe-Mn-Co and Fe-Co systems.We found that, for alloys in the Mn range between 17% and 25%, Co additions tend to stabilise slightly the fcc phase.In the alloys with Mn contents below that range, increasing the amount of Co stabilise the bcc phase. In alloys with Mn contents above 25% the Neel temperature is depressed by the addition of Co, which stabilise the hcp phase.In order to investigate the effect of changes in the density of crystalline defects, we have performed thermal cycling experiments through the fcc/hcp martensitic transformation in Fe-Mn, Fe-Mn-Co and Fe-Mn-Si alloys.We have applied the thermodynamic description obtained before in order to analyse these experiments.We found in the thermal cycling experiments a first stage where the martensitic transformation is promoted.This stage occurs in all the studied alloys during the first cycle or the two first cycles.Increasing the number of thermal cycles, the promotion stage is replaced by an inhibition of the transformation stage.We propose a possible microstructural interpretation of these phenomena where the plastic

  4. Fe-Ti/Fe (II)-loading on ceramic filter materials for residual chlorine removal from drinking water.

    Science.gov (United States)

    Man, Kexin; Zhu, Qi; Guo, Zheng; Xing, Zipeng

    2018-06-01

    Ceramic filter material was prepared with silicon dioxide (SiO 2 ), which was recovered from red mud and then modified with Fe (II) and Fe-Ti bimetal oxide. Ceramic filter material can be used to reduce the content of residual chlorine from drinking water. The results showed that after a two-step leaching process with 3 M hydrochloric acid (HCl) and 90% sulfuric acid (H 2 SO 4 ), the recovery of SiO 2 exceeded 80%. Fe (II)/Fe-Ti bimetal oxide, with a high adsorption capacity of residual chlorine, was prepared using a 3:1 M ratio of Fe/Ti and a concentration of 0.4 mol/L Fe 2+ . According to the zeta-potential, scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, Fe (II) and Fe-Ti bimetal oxide altered the zeta potential and structural properties of the ceramic filter material. There was a synergistic interaction between Fe and Ti in which FeOTi bonds on the material surface and hydroxyl groups provided the active sites for adsorption. Through a redox reaction, Fe (II) transfers hypochlorite to chloride, and FeOTiCl bonds were formed after adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Initial oxidation of TiFe1−xMnx (x = 0–0.3) by low dose exposures to H2O and O2

    International Nuclear Information System (INIS)

    Shwartz, A.; Shamir, N.; Froumin, N.; Zalkind, S.; Edry, I.; Haim, A.; Mintz, M.H.

    2014-01-01

    Highlights: • Thermodynamics of adsorption and initial oxidation of TiFe 1−x Mn x by H 2 O versus O 2 . • Explanation of different oxide formations. • Explanation of the role of the different constituents of the alloys in the processes. - Abstract: The very initial room-temperature oxidation processes of the ternary pseudo-binary TiFe 1−x Mn x (x = 0–0.3) intermetallics by trace amounts of H 2 O vapor and O 2 were studied utilizing XPS and AES techniques. Different reactivities of the two gases were obtained, with a lower oxidation ability of H 2 O, relative to O 2 , as anticipated from thermodynamic considerations. The exposure to O 2 results in a two stage oxidation of the Ti ingredient, which first converts into a divalent TiO (up to exposures of about 2 L), then proceeds into a tetravalent TiO 2 form. Unlike oxygen, water exposure produces only the divalent oxide through the whole exposure range studied (11 L). The Mn component in these compounds is oxidized only by O 2 and not by H 2 O. The Fe ingredient is not oxidized at all and remains in its metallic form up to exposures of 30 L

  6. Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films

    DEFF Research Database (Denmark)

    Szymczewska, Dagmara; Molin, Sebastian; Hendriksen, Peter Vang

    2017-01-01

    In this work, thin films (~1000 nm) of a pure MnCo2O4 spinel together with its partially substituted derivatives (MnCo1.6Cu0.2Fe0.2O4, MnCo1.6Cu0.4O4, MnCo1.6Fe0.4O4) were prepared by spray pyrolysis and were evaluated for electrical conductivity. Doping by Cu increases the electrical conductivit...

  7. Synthesis and Dielectric Properties of Mn-Doped BaTi2O5 Ceramics

    Science.gov (United States)

    Akishige, Yukikuni; Honda, Kazuo; Tsukada, Shinya

    2011-09-01

    High-density ceramics of BaTi2O5 have been fabricated by a conventional sintering method using both sol-gel-derived BaTi2O5 powders and MnO2 additives of 0.2-0.8 wt %. The effects of sintering conditions on the densification, microstructural evolution and dielectric properties are investigated. As the effect of Mn addition, the BaTi2O5 phase becomes stable at least up to 1250 °C, and a significant densification is achieved at temperatures as low as 1200-1250 °C. The dielectric constant ɛ' vs temperature T curve of the MnO2-added ceramics exhibits a broad maximum ɛ'max at the ferroelectric phase transition temperature TC, which is 140 °C lower than that of the nondoped ceramics. Among the ceramics with different Mn contents, the 0.2 wt % MnO2-added ceramics have the largest ɛ'max of 470 at 328 °C and the smallest tan δ of <0.05 at a high temperature of around 520 °C at 1 MHz. We observed a ferroelectric D-E hysteresis loop for the first time in the polycrystalline form of BaTi2O5.

  8. Experimental investigation and thermodynamic calculation of the Fe-Mg-Mn and Fe-Mg-Ni systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peisheng; Zhao, Jingrui; Xu, Honghui; Liu, Shuhong; Ouyang, Hongwu [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Du, Yong [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Harbin Institute of Technology (China). State Key Lab. of Advanced Welding Production Technology; Gang, Tie; Fen, Jicai [Harbin Institute of Technology (China). State Key Lab. of Advanced Welding Production Technology; Zhang, Lijun [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Bochum Univ. (Germany). ICAMS Inst.; He, Cuiyun [Guangxi Univ. (China). College of Physical Science and Technology

    2011-01-15

    Based on the thermodynamic calculations extrapolated from the corresponding binary sub-systems, four decisive alloys in the Fe-Mg-Mn system and three in the Fe-Mg-Ni system were selected and prepared using a powder metallurgy method to measure the isothermal sections at 500 C in both systems. The prepared samples were annealed at 500 C, and then subjected to X-ray diffraction, optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectrometry as well as electron probe microanalysis. Taking into account the presently obtained experimental data and the experimental data available in the literature, thermodynamic modeling was performed for the above systems. It was found that a direct extrapolation from the corresponding three binary systems can well reproduce all the experimental data in the Fe-Mg-Mn system, while two thermodynamic parameters are needed in the Fe-Mg-Ni system to fit all the experimental data. The liquidus projections and reaction schemes for the Fe-Mg-Mn and Fe-Mg-Ni systems are also presented. (orig.)

  9. FeRu/TiO2 and Fe/TiO2 catalysts after reduction and Fischer-Tropsch synthesis studied by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Kraan, A.M. van der; Nonnekens, R.C.H.; Niemantsverdriet, J.W.

    1986-01-01

    A series of TiO 2 -supported bimetallic FeRu catalysts with different Fe:Ru ratios (infinity; 10:1; 3:1; 1:1; 1:3) has been studied by means of in situ Moessbauer spectroscopy. The influence of reduction and Fischer-Tropsch synthesis on the state of iron in the FeRu/TiO 2 catalysts is derived. (Auth.)

  10. Recent advances on Fe- and Mn-based cathode materials for lithium and sodium ion batteries

    Science.gov (United States)

    Zhu, Xiaobo; Lin, Tongen; Manning, Eric; Zhang, Yuancheng; Yu, Mengmeng; Zuo, Bin; Wang, Lianzhou

    2018-06-01

    The ever-growing market of electrochemical energy storage impels the advances on cost-effective and environmentally friendly battery chemistries. Lithium-ion batteries (LIBs) are currently the most critical energy storage devices for a variety of applications, while sodium-ion batteries (SIBs) are expected to complement LIBs in large-scale applications. In respect to their constituent components, the cathode part is the most significant sector regarding weight fraction and cost. Therefore, the development of cathode materials based on Earth's abundant elements (Fe and Mn) largely determines the prospects of the batteries. Herein, we offer a comprehensive review of the up-to-date advances on Fe- and Mn-based cathode materials for LIBs and SIBs, highlighting some promising candidates, such as Li- and Mn-rich layered oxides, LiNi0.5Mn1.5O4, LiFe1-xMnxPO4, NaxFeyMn1-yO2, Na4MnFe2(PO4)(P2O7), and Prussian blue analogs. Also, challenges and prospects are discussed to direct the possible development of cost-effective and high-performance cathode materials for future rechargeable batteries.

  11. XRD analysis of undoped and Fe doped TiO2 nanoparticles by Williamson Hall method

    International Nuclear Information System (INIS)

    Bharti, Bandna; Barman, P. B.; Kumar, Rajesh

    2015-01-01

    Undoped and Fe doped titanium dioxide (TiO 2 ) nanoparticles were synthesized by sol-gel method at room temperature. The synthesized samples were annealed at 500°C. For structural analysis, the prepared samples were characterized by X-ray diffraction (XRD). The crystallite size of TiO 2 and Fe doped TiO 2 nanoparticles were calculated by Scherer’s formula, and was found to be 15 nm and 11 nm, respectively. Reduction in crystallite size of TiO 2 with Fe doping was observed. The anatase phase of Fe-doped TiO 2 nanoparticles was also confirmed by X-ray diffraction. By using Williamson-Hall method, lattice strain and crystallite size were also calculated. Williamson–Hall plot indicates the presence of compressive strain for TiO 2 and tensile strain for Fe-TiO 2 nanoparticles annealed at 500°C

  12. Immobilization of TiO2 nanoparticles on Fe-filled carbon nanocapsules for photocatalytic applications

    International Nuclear Information System (INIS)

    Huang, H.-C.; Huang, G.-L.; Chen, H.-L.; Lee, Y.-D.

    2006-01-01

    Using a simple sol-gel method, a novel magnetic photocatalyst was produced by immobilization of TiO 2 nano-crystal on Fe-filled carbon nanocapsules (Fe-CNC). High resolution TEM images indicated that the immobilization of TiO 2 on Fe-CNC was driven primarily by heterogeneous coagulation, whereas surface nucleation and growth was the dominant mechanism for immobilizing TiO 2 on acid-functionalized hollow CNC. The TiO 2 immobilized on Fe-CNC exhibited the anatase phase as revealed by the X-ray diffraction (XRD) patterns. In comparison with free TiO 2 and TiO 2 -coated CNC, TiO 2 -coated Fe-CNC displayed good performance in the removal of NO gas under UV exposure. Due to the advantages of easy recycling and good photocatalytic efficiency, the novel magnetic photocatalyst developed here has potential use in photocatalytic applications for pollution prevention

  13. Concentrations of Mn and Fe in the Sediment Cores of Sarawak and Sabah Coastal Waters

    International Nuclear Information System (INIS)

    Zal Uyun Wan Mahmood; Zaharudin Ahmad; Che Abdul Rahim Mohamed

    2010-01-01

    Sediment cores were taken at eight stations along Sarawak and Sabah coastal waters using a gravity box corer on July 2004. The sediment cores were cut into 2 cm interval for measurement of Mn and Fe concentration using the Inductive Couple Plasma-Mass Spectrometer (ICP-MS). Overall, the sediment cores contained much mud which include a mixture of silt (46 - 67 %) and clay (18 - 53 %) compared to sand (0.4 - 16 %). The concentrations of Mn and Fe were in the range of 154 - 366 μg/ g and 0.9 - 3.4 %, respectively. The variation was studied by ANOVA, which showed a significant difference (p = 0.000) for both of Mn and Fe concentrations at all sampling stations. In those ranges, Fe concentration was higher compared to Mn. It is believed that dissolving and diluting process influenced the concentration of Mn in the water column and sediment. Fe showed a significant correlation (r > 0.5, p geo < 1 and classification 0 - 1. (author)

  14. Electrochemical characterization of FeMnO3 microspheres as potential material for energy storage applications

    Science.gov (United States)

    Saravanakumar, B.; Ramachandran, S. P.; Ravi, G.; Ganesh, V.; Guduru, Ramesh K.; Yuvakkumar, R.

    2018-01-01

    In this study, uniform iron manganese trioxide (FeMnO3) microspheres were characterized as electrode for supercapacitor applications. The microspheres were synthesized by hydrothermal method in the presence of different molar ratios of sucrose. X-ray diffraction pattern confirmed that the obtained microsphere has body-centered lattice structure of space group 1213(199). The Raman peak observed at 640 cm-1 might be attributed to the stretching mode of vibration of Mn-O bonds perpendicular to the direction of MnO6 octahedral double chains. The photoluminescence peak at the 536 nm corresponded to Fe2+ ions in FeMnO3 lattice point of body-centered cubic structure. The characteristic strong infrared (IR) bands observed at 669 cm-1 corresponded to Fe-O stretching. The electrochemical characterization of the obtained FeMnO3 products could be understood by carrying out cyclic voltammeter, electroimpedance spectra, and galvanostatic charging and discharge studies in a three-cell setup that demonstrates the exceptional specific capacitance of 773.5 F g-1 at a scan rate of 10 mV s-1 and 763.4 F g-1 at a current density of 1 A g-1.

  15. Porous Fe-Mn-O nanocomposites: Synthesis and supercapacitor electrode application

    Directory of Open Access Journals (Sweden)

    Guoxing Zhu

    2016-06-01

    Full Text Available Transition metal oxide micro-/nanostructures demonstrate high potential applications in energy storage devices. Here, we report a facile synthesis of highly homogeneous oxide composites with porous structure via a coordination polymer precursor, which was prepared with the assistance of tartaric acid. The typical product, Fe-Mn-O composite was demonstrated here. The obtained Fe-Mn-O product was systemically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, elemental mapping analysis, and X-ray photoelectron spectroscopy. It was demonstrated that the Fe-Mn-O nanocomposite shows interconnected porous structure, in which iron, manganese, and oxygen are uniformly distributed. In addition, the Fe-Mn-O nanocomposite was then fabricated as capacitor electrodes. Operating in an aqueous neutral solution, the Fe-Mn-O composite electrodes showed an wide working potential window from −0.2 to 1.0 V (vs. SCE, and a specific capacitance of 86.7 Fg−1 or 0.4 Fcm−2 at a constant current density of 1 Ag−1 with good cycle life. This study offers a new precursor approach to prepare porous metal oxide composites, which would be applied in energy-storage/conversion devices, catalysts, sensors, and so on.

  16. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, S.; Shimakura, H. [Niigata University of Pharmacy and Applied Life Sciences, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Tahara, S. [Faculty of Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213 (Japan); Okada, T. [Niigata College of Technology, Kamishin’eicho, Nishi-ku, Niigata 950-2076 (Japan)

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  17. Effect of foliar applied (Zn, Fe, Cu and Mn) in citrus production

    International Nuclear Information System (INIS)

    Khurshid, F.; Sarwar, S.; Khattak, R.A.

    2008-01-01

    A study was conducted to evaluate the impact of micronutrients (Zn, Fe, Cu and Mn) on sweet orange (Citrus Sinensis L.), blood red var., on farmer's orchard at Khanpur, district Haripur, NWFP, during 2002-03. Micronutrients were applied in foliar sprays over the canopy of each tree. The main effects and interactions of Zinc sulphate (Zn), iron sulphate (Fe), Copper Sulphate (Cu) and Manganese Sulphate (Mn) were studied in factorial combinations. A basal dose of nitrogen, phosphorus and potassium was applied at the rate 1.5, 1 and 1 kg tree/sup -1/. Zn, Fe, Cu and Mn were applied alone and in various combinations at the rate 0.115, 0.057, 0.05 and 0.13 kg in 100 liters of water. Application of micronutrients significantly increased Zn, Fe, Cu and Mn concentrations in leaves, compared with control. Zn treatments significantly increased the yield, number of fruit and total sugar. Manganese treatments significantly increased the total soluble solids and reduced the acidity of fruit juice. Other quality parameters, including fruit size, percent peel, percent pulp, sugar as well as total soluble solids, were improved with the application of Zn, Fe, Cu and Mn. (author)

  18. Microstructure and thermal stability of Fe, Ti and Ag implanted Yttria-stabilized zirconia

    NARCIS (Netherlands)

    van Hassel, B.A.; van Hassel, B.A.; Burggraaf, Anthonie; Burggraaf, A.J.

    1991-01-01

    Yttria-stabilized zirconia (YSZ) was implanted with 15 keV Fe or Ti ions up to a dose of 8×1016 at cm−2. The resulting “dopant” concentrations exceeded the concentrations corresponding to the equilibrium solid solubility of Fe2O3 or TiO2 in YSZ. During oxidation in air at 400° C, the Fe and Ti

  19. Electronic structure of FeTiSb using relativistic and scalar-relativistic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sahariya, Jagrati [Department of Physics, Manipal University Jaipur, Jaipur-303007, Rajasthan (India); Mund, H. S., E-mail: hmoond@gmail.com [Department of Physics, M. L. Sukhadia University, Udaipur-313001, Rajasthan (India)

    2016-05-06

    Electronic and magnetic properties of FeTiSb have been reported. The calculations are performed using spin polarized relativistic Korringa-Kohn-Rostoker scheme based on Green’s function method. Within SPR-KKR a fully relativistic and scalar-relativistic approaches have been used to investigate electronic structure of FeTiSb. Energy bands, total and partial density of states, atom specific magnetic moment along with total moment of FeTiSb alloys are presented.

  20. Visible light photocatalysts (Fe, N):TiO{sub 2} from ammonothermally processed, solvothermal self-assembly derived Fe-TiO{sub 2} mesoporous microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Mingming; Xiong, Fengqiang; Ganeshraja, Ayyakannu Sundaram [Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023 (China); Feng, Xiaohua; Wang, Chuanxi [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Thomas, Tiju, E-mail: tijuthomas@iitm.ac.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu (India); Yang, Minghui, E-mail: myang@dicp.ac.cn [Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023 (China)

    2017-07-01

    Iron (III) and nitrogen co-doped mesoporous TiO{sub 2} microspheres (Fe-N-TiO{sub 2}) are prepared using a self-assembly based solvothermal process followed by an ammonothermal method. Among all samples, 1 mol.% of Fe dopants and 500 °C nitridation (for 2 h) gives the highest visible light photoactivity. Results imply that the Fe{sup 3+}/Fe{sup 2+} dopant trap energy level introduced within the band gap in mildly Fe (∼1 at%) doped TiO{sub 2} and the mesoporous nature of the material, both aid in the observed catalytic performance. Subjecting Fe-TiO{sub 2} samples to ammonothermal process induces oxygen vancancies, and substitutional and interstitial N. This reduces optical band gap, and introduces local states. The lower band gap and local states together aid in the absorption of visible light and separation of charge carriers. Co-dopants are distributed uniformly in the best photocatalysts. The active species generated in the photocatalytic system is shown to be singlet molecular oxygen ({sup 1}O{sub 2}) using selective radical quenchers. - Highlights: • Iron (III) and nitrogen co-doped mesoporous TiO{sub 2} microspheres (Fe-N-TiO{sub 2}) are prepared. • Fe{sup 3+}/Fe{sup 2+} dopant trap energy level introduced within the band gap in Fe (∼1 at%) doped TiO{sub 2}. • Subjecting Fe-TiO{sub 2} samples to ammonothermal process induces oxygen vancancies, and causes substitutional and interstitial N. • Co-dopants are distributed uniformly in the best photocatalysts. • Active species generated is shown to be singlet molecular oxygen ({sup 1}O{sub 2}).

  1. Diffusion of Nb in Fe and in some Fe alloys

    International Nuclear Information System (INIS)

    Kurokawa, S.; Ruzzante, J.E.; Hey, A.M.; Dyment, F.

    1981-01-01

    Diffusion data of microalloying elements such as Nb, V, Ti, are required when analysing the transformation and recrystallization behaviour of HSLA steels in order to optimize grain refinement and precipitation hardening. The diffusion behaviour of Nb in pure Fe, Fe 1.5 Mn, Fe 0.6 Si and Fe 1.5 Mn 0.6 Si has been measured between 1080 and 1200 0 C. Results indicate that Si increases Nb diffusivity while Mn decreases it. The sequence of diffusion coeficients values is: D sup(Nb) sub(Fe 1.5 Mn) [pt

  2. Microstructure of two phases alloy Al3Ti/Al3Ti0.75Fe0.25

    International Nuclear Information System (INIS)

    Angeles, C.; Rosas, G.; Perez, R.

    1998-01-01

    The titanium-aluminium system presents three intermetallic compounds from those Al 3 Ti is what less attention has received. The objective of this work is to generate and characterize the microstructure of multiphase alloys nearby to Al 3 Ti compound through Fe addition as alloying. This is because it has been seen that little precipitates of Al 2 Ti phase over Al 3 Ti intermetallic compound increases its ductility. (Author)

  3. Thermal decomposition study of Mn doped Fe3O4 nanoparticles

    Science.gov (United States)

    Malek, Tasmira J.; Chaki, S. H.; Tailor, J. P.; Deshpande, M. P.

    2016-05-01

    Fe3O4 is an excellent magnetic material among iron oxides. It has a cubic inverse spinel structure exhibiting distinguished electric and magnetic properties. In this paper the authors report the synthesis of Mn doped Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its thermal characterization. Ferric chloride hexa-hydrate (FeCl3•6H2O), manganese chloride tetra-hydrate (MnCl2•4H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the as-synthesized Mn doped Fe3O4 nanoparticles were determined by energy dispersive analysis of X-rays (EDAX) technique. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out on the Mn doped Fe3O4 nanoparticles in the temperature range of ambient to 1124 K. The thermo-curves revealed that the particles decompose by four steps. The kinetic parameters were evaluated using non-mechanistic equations for the thermal decomposition.

  4. Mn and Fe Impurities in Si$_{1-x}$ Ge$_{x}$ alloys

    CERN Multimedia

    2002-01-01

    Following our investigations of Mn and Fe impurities in elemental semiconductors and in silicon in particular by means of on-line $^{57}$Fe Mössbauer spectroscopy, utilizing radioactive $^{57}$Mn$^{+}$ ion beams at ISOLDE, we propose to extend these studies to bulk and epitaxially-grown Si$_{1-x}$Ge$_{x}$ alloys. In these materials, although already successfully employed in electronic devices, little is known about point defects and important harmful 3d impurities. The experiments aim to determine a variety of fundamental properties: The lattice location of ion-implanted Mn/Fe, the electronic and vibrational properties of dilute Fe impurities in different lattice sites, the charge-state and composition dependence of the diffusivity of interstitial Fe on an atomic scale, the reactions and formation of complexes with lattice defects created by the $^{57}$Mn implantation or by the recoil effect in the nuclear decay to the Mössbauer state of $^{57m}$Fe. Feasibility studies in 2003 indicate that these aims can b...

  5. Kineococcus radiotolerans Dps forms a heteronuclear Mn-Fe ferroxidase center that may explain the Mn-dependent protection against oxidative stress.

    Science.gov (United States)

    Ardini, Matteo; Fiorillo, Annarita; Fittipaldi, Maria; Stefanini, Simonetta; Gatteschi, Dante; Ilari, Andrea; Chiancone, Emilia

    2013-06-01

    The ferroxidase center of DNA-binding protein from starved cells (Dps) is a major player in the iron oxidation/detoxification process that leads to a decreased reactive oxygen species production. The possible Mn(II) participation in this process has been studied in Dps from Kineococcus radiotolerans, a radiation-resistant bacterium with a high cytosolic Mn/Fe ratio and a high capacity to survive ionizing and stress conditions. The X-ray structure of recombinant K. radiotolerans Dps loaded with Mn(II) has been solved at 2.0Å resolution. Mn(II) binding to K. radiotolerans Dps and its effect on Fe(II) oxidation have been characterized in spectroscopic measurements. In K. radiotolerans Dps, the Fe-Fe ferroxidase center can have a Mn-Fe composition. Mn(II) binds only at the high affinity, so-called A site, whereas Fe(II) binds also at the low affinity, so-called B site. The Mn-Fe and Fe-Fe centers behave distinctly upon iron oxidation by O2. A site-bound Mn(II) or Fe(II) plays a catalytic role, while B site-bound Fe(II) behaves like a substrate and can be replaced by another Fe(II) after oxidation. When H2O2 is the Fe(II) oxidant, single electrons are transferred to aromatic residues near the ferroxidase center and give rise to intra-protein radicals thereby limiting OH release in solution. The presence of the Mn-Fe center results in significant differences in the development of such intra-protein radicals. Mn(II) bound at the Dps ferroxidase center A site undergoes redox cycling provided the B site contains Fe. The results provide a likely molecular mechanism for the protective role of Mn(II) under oxidative stress conditions as it participates in redox cycling in the hetero-binuclear ferroxidase center. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Anomalous magnetic aftereffect in Nd3(Fe,T)29 (T = Ti or Re) intermetallic compounds

    International Nuclear Information System (INIS)

    Collocott, S.J.; Dunlop, J.B.; Gwan, P.B.

    1999-01-01

    Full text: The intermetallic compounds Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 order ferromagnetically with Curie Temperatures, T c , of 430 and 370 K respectively. They have a monoclinic crystal structure, space group A2/m (Nd 3 (Fe,Ti) 29 type) with two rare earth sites and eleven Fe(T) sites, which is an intermediate structure between the rhombohedral Th 2 Zn 17 and tetragonal ThMn 12 structures, and is closely related to hexagonal CaCu 5 . Ferromagnetic materials, depending on their magnetic prehistory, may exhibit a time dependent magnetisation. The term 'magnetic aftereffect' is used to describe this behaviour, which may fall into three categories: 1. Reversible or diffusion aftereffect which is associated with the diffusion of impurity atoms or holes within the ferromagnetic lattice. 2. The irreversible or fluctuation aftereffect, which results in a logarithmic time dependence of magnetisation, J(t)=J(0)+Sln(t+t 0 ), where S is the magnetic viscosity and t 0 a parameter to establish the origin of the time scale measurements. 3. Quantum tunnelling of magnetisation which is observed at very low temperatures. A range of magnetic aftereffects have been observed in both Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 . Of particular interest is the case where the material is fully saturated by application of a field in the positive direction, the applied field is then reversed to trace out part of the major demagnetisation curve into the third quadrant, and thence along a recoil curve, such that in zero applied field the magnetisation is zero (H=0, J=0). (This corresponds to dc field magnetisation.) This magnetic prehistory results in two interesting effects; spontaneous remagnetisation e.g. remagnetisation without application of an external field, and thermal remagnetisation e.g. an increase in magnetisation as the temperature is increased. Additionally, the behaviour of the magnetic viscosity has been explored on the major demagnetisation curve as a function of temperature

  7. Investigation of CoFeV/TiZr multilayer by polarized neutron reflectometry

    International Nuclear Information System (INIS)

    Chen Bo; Li Xinxi; Huang Chaoqiang

    2007-06-01

    The interracial structures of CoFeV/TiZr multilayer play an important role in performance of polarizing supermirrors. Aiming to requirement, CoFeV/ TiZr layered samples with different structures were prepared. Specular reflection of polarized neutrons was employed to study the depth profile of scattering length, density, thickness and roughness of CoFeV/TiZr multilayer and magnetically dead layers. The result shows that the roughness in CoFeV/ TiZr multilayer can be described with roughness increase law and the thickness of magnetically dead layers is about 0.5 nm. The producing technology of the multilayer reaches the requirements. (authors)

  8. Decay of neutron-rich Mn nuclides and deformation of heavy Fe isotopes

    CERN Document Server

    Hannawald, M; Wöhr, A; Walters, W B; Kratz, K L; Fedosseev, V; Mishin, V I; Böhmer, W; Pfeiffer, B; Sebastian, V; Jading, Y; Köster, U; Lettry, Jacques; Ravn, H L

    1999-01-01

    The use of chemically selective laser ionization combined with beta-delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms Mn-61 up through 14-ms Mn-69. The measured half-lives are found to be significantly longer near N=40 than the values calculated with a QRPA shell model using ground-state deformations from the FRDM and ETFSI models. Gamma-ray singles and coincidence spectroscopy has been performed for Mn-64 and Mn-66 decays to levels of Fe-64 and Fe-66, revealing a significant drop in the energy of the first 2+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40.

  9. Band structure of the quaternary Heusler alloys ScMnFeSn and ScFeCoAl

    Science.gov (United States)

    Shanthi, N.; Teja, Y. N.; Shaji, Shephine M.; Hosamani, Shashikala; Divya, H. S.

    2018-04-01

    In our quest for materials with specific applications, a theoretical study plays an important role in predicting the properties of compounds. Heusler alloys or compounds are the most studied in this context. More recently, a lot of quaternary Heusler compounds are investigated for potential applications in fields like Spintronics. We report here our preliminary study of the alloys ScMnFeSn and ScFeCoAl, using the ab-initio linear muffin-tin orbital method within the atomic sphere approximation (LMTO-ASA). The alloy ScMnFeSn shows perfect half-metallicity, namely, one of the spins shows a metallic behaviour and the other spin shows semi-conducting behaviour. Such materials find application in devices such as the spin-transfer torque random access memory (STT-MRAM). In addition, the alloy ScMnFeSn is found to have an integral magnetic moment of 4 µB, as predicted by the Slater-Pauling rule. The alloy ScFeCoAl does not show half-metallicity.

  10. Anisotropies in sputtered FeCoV films and FeCoV/Ti:N multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, D.; Vananti, A.; Terrier, C.; Boeni, P.; Schnyder, B.; Tixier, S.; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    SQUID and MOKE magnetometry as well as mechanical and X-ray stress analysis have been used in order to prove the magnetostrictive nature of the anisotropy in Fe{sub 0.50}Co{sub 0.48}V{sub 0.02} films and Fe{sub 0.50}Co{sub 0.48}V{sub 0.02} /Ti:N multilayers. The investigation stresses on the dependence on the sputter gas pressure and on the thickness of the deposited layer. (author) 1 fig., 6 refs.

  11. Microstructure and corrosion resistance of Sm-containing Al-Mn-Si-Fe-Cu alloy

    Directory of Open Access Journals (Sweden)

    Han Yuyin

    2017-12-01

    Full Text Available Optimizing alloy composition is an effective way to improve physical and chemical properties of automobile heat exchanger materials.A Sm-containing Al-Mn-Si-Fe-Cu alloy was investigated through transmission electron microscopy,scanning electron microscopy,and electrochemical measurement.Experimental results indicated that main phases distributed in the alloy wereα-Al(Mn,FeSi,Al2Sm and Al10Cu7Sm2.Alloying with Sm element could refine the precipitated α-Al(Mn,FeSi phase.Polarization testing results indicated that the corrosion surfacewas mainly composed of pitting pits and corrosion products.Sea water acetic acid test(SWAAT showed that corrosion loss increased first and then slowed downwith increase of the corrosion time.

  12. Interdiffusion coefficients and atomic mobilities in fcc Cu-Fe-Mn alloys

    Directory of Open Access Journals (Sweden)

    Li J.

    2014-01-01

    Full Text Available In the present work, the interdiffusion coefficients in fcc Cu-Fe-Mn alloys were experimentally determined via a combination of solid/solid diffusion couples, electron probe microanalysis (EPMA technique and Matano-Kirkaldy method. Based on the reliable thermodynamic description of fcc phase in the Cu-Fe-Mn system available in the literature as well as the ternary diffusion coefficients measured in the present work, the atomic mobilities in fcc Cu-Fe-Mn alloys were assessed by utilizing the DICTRA (Diffusion Controlled TRAnsformation software package. The calculated interdiffusion coefficients based on the assessed atomic mobilities agree well with most of the experimental data. The comprehensive comparison between various model-predicted diffusion properties and the measured data, including the concentration penetration profiles, interdiffusion flux profile, and diffusion paths, further verify the reliability of the presently obtained atomic mobilities.

  13. Nanostructured Mn-Fe Binary Mixed Oxide: Synthesis, Characterization and Evaluation for Arsenic Removal.

    Science.gov (United States)

    Pillewan, Pradnya; Mukherjee, Shrabanti; Bansiwal, Amit; Rayalu, Sadhana

    2014-07-01

    Adsorption of arsenic on bimetallic Mn and Fe mixed oxide was carried out using both field as well as simulated water. The material was synthesized using hydrothermal method and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Langmuir and Freundlich adsorption isotherms were computed using batch adsorption studies to determine the adsorption capacity of Mn-Fe binary mixed oxide for arsenic. Adsorption capacity for MFBMO obtained from Freundlich model was found to be 2.048 mg/g for simulated water and 1.084 mg/g for field water. Mn-Fe binary mixed oxide was found to be effective adsorbent for removal of arsenic from water.

  14. MnFe(PGe) compounds: Preparation, structural evolution, and magnetocaloric effects

    International Nuclear Information System (INIS)

    Yue Ming; Zhang Hong-Guo; Zhang Jiu-Xing; Liu Dan-Min

    2015-01-01

    The interdependences of preparation conditions, magnetic and crystal structures, and magnetocaloric effects (MCE) of the MnFePGe-based compounds are reviewed. Based upon those findings, a new method for the evaluation of the MCE in these compounds, based on differential scanning calorimetry (DSC), is proposed. The MnFePGe-based compounds are a group of magnetic refrigerants with giant magnetocaloric effect (GMCE), and as such, have drawn tremendous attention, especially due to their many advantages for practical applications. Structural evolution and phase transformation in the compounds as functions of temperature, pressure, and magnetic field are reported. Influences of preparation conditions upon the homogeneity of the compounds’ chemical composition and microstructure, both of which play a key role in the MCE and thermal hysteresis of the compounds, are introduced. Lastly, the origin of the “virgin effect” in the MnFePGe-based compounds is discussed. (paper)

  15. Magnetocaloric effects in MnFeP1-x As x -based compounds

    International Nuclear Information System (INIS)

    Brueck, E.; Ilyn, M.; Tishin, A.M.; Tegus, O.

    2005-01-01

    Here we present the results of an investigation of some magnetic and thermal properties of the compounds MnFeP 0.45 As 0.55 , MnFeP 0.47 As 0.53 , and Mn 1.1 Fe 0.9 P 0.47 As 0.53 which can be regarded as possible magnetic refrigerants for room temperature applications. Magnetization measurements are performed in the temperature range 250-330 K, in magnetic fields up to 5 T. The coexistence of the magnetic and structural first-order phase transitions is revealed in all three samples, suggesting its key role in the large values observed for the magnetocaloric effect. The adiabatic temperature change measured directly was up to 4.0, 3.4, and 4.2 K for a magnetic field change of 1.45 T

  16. Acoustic properties of TiNiMoFe base alloys

    International Nuclear Information System (INIS)

    Gyunter, V.Eh.; Chernyshev, V.I.; Chekalkin, T.L.

    2000-01-01

    The regularity of changing the acoustic properties of the TiNi base alloys in dependence on the alloy composition and impact temperature is studied. It is shown that the oscillations of the TiNiMoFe base alloys within the temperature range of the B2 phase existence and possible appearance of the martensite under the load differ from the traditional materials oscillations. After excitation of spontaneous oscillations within the range of M f ≤ T ≤ M d there exists the area of long-term and low-amplitude low-frequency acoustic oscillations. It is established that free low-frequency oscillations of the TH-10 alloy sample are characterized by the low damping level in the given temperature range [ru

  17. Hierarchical FeTiO3-TiO2 hollow spheres for efficient simulated sunlight-driven water oxidation.

    Science.gov (United States)

    Han, Taoran; Chen, Yajie; Tian, Guohui; Wang, Jian-Qiang; Ren, Zhiyu; Zhou, Wei; Fu, Honggang

    2015-10-14

    Oxygen generation is the key step for the photocatalytic overall water splitting and considered to be kinetically more challenging than hydrogen generation. Here, an effective water oxidation catalyst of hierarchical FeTiO3-TiO2 hollow spheres are prepared via a two-step sequential solvothermal processes and followed by thermal treatment. The existence of an effective heterointerface and built-in electric field in the surface space charge region in FeTiO3-TiO2 hollow spheres plays a positive role in promoting the separation of photoinduced electron-hole pairs. Surface photovoltage, transient-state photovoltage, fluorescence and electrochemical characterization are used to investigate the transfer process of photoinduced charge carriers. The photogenerated charge carriers in the hierarchical FeTiO3-TiO2 hollow spheres with a proper molar ratio display much higher separation efficiency and longer lifetime than those in the FeTiO3 alone. Moreover, it is suggested that the hierarchical porous hollow structure can contribute to the enhancement of light utilization, surface active sites and material transportation through the framework walls. This specific synergy significantly contributes to the remarkable improvement of the photocatalytic water oxidation activity of the hierarchical FeTiO3-TiO2 hollow spheres under simulated sunlight (AM1.5).

  18. Influence of elemental diffusion on low temperature formation of MgH2 in TiMn1.3T0.2-Mg (T = 3d-transition elements)

    International Nuclear Information System (INIS)

    Yamamoto, K.; Tanioka, S.; Tsushio, Y.; Shimizu, T.; Morishita, T.; Orimo, S.; Fujii, H.

    1996-01-01

    In order to examine the influence of the elemental diffusion from the host compound into the Mg region on low temperature formation of MgH 2 , we have investigated the hydriding properties and the microstructures of the composite materials TiMn 1.3 T 0.2 -Mg (T = V, Cr, Mn, Fe, Co, Ni and Cu). MgH 2 is formed at 353 K in all composite materials. Of all the substitutions, the amount of MgH 2 is the largest in the case of the Cu substitution, which originates from the existence of the Mg-Mg 2 Cu eutectic formed by Cu diffusion from the host compound TiMn 1.3 Cu 0.2 into the Mg region during the liquid phase sintering. In addition, the hydrogen capacity of TiMn 1.3 Cu 0.2 -Mg (that is TiMn 1.3 Cu 0.1 -(Mg+Mg 2 Cu) after the sintering) easily saturates in comparison with TiMn 1.5 -(Mg+Mg 2 Cu) without Cu diffusion. It is concluded that Cu diffusion promotes the mobility of hydrogen atoms at the complex interface between the host compound and the Mg region. (orig.)

  19. Influence of Mn-dopant on the properties of α-FeOOH particles precipitated in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2006-01-01

    The effects of Mn-dopant on the formation of solid solutions α-(Fe, Mn)OOH in dependence on the initial concentration ratio r = [Mn]/([Mn] + [Fe]), as well as on the size and morphology of the corresponding particles were investigated using Moessbauer and FT-IR spectroscopies, high-resolution scanning electron microscopy (FE SEM) and an energy dispersive X-ray analyser (EDS). The value of the hyperfine magnetic field of 34.9 T, as recorded for the reference α-FeOOH sample at RT, decreased linearly up to 21.4 T for sample with r = 0.1667. Only a paramagnetic doublet at RT was recorded for sample with r = 0.2308, a ferrite phase was additionally found for r = 0.3333. Fe-OH bending IR bands, δ OH and γ OH , were influenced by the Mn-substitution as manifested through their gradual shifts. FE SEM micrographs showed a great elongation of the starting acicular particles along the c-axis with an increase in Mn-doping. For r = 0.1667 and 0.2308 star-shaped and dendritic twin α-(Fe, Mn)OOH particles were observed. The length of these α-(Fe, Mn)OOH particles decreased, whereas their width increased. The α-Fe 2 O 3 phase was not detected in any of the samples prepared

  20. Fractionation and risk assessment of Fe and Mn in surface sediments from coastal sites of Sonora, Mexico (Gulf of California).

    Science.gov (United States)

    Jara-Marini, Martín E; García-Camarena, Raúl; Gómez-Álvarez, Agustín; García-Rico, Leticia

    2015-07-01

    The aim of this study was to evaluate Fe and Mn distribution in geochemical fractions of the surface sediment of four oyster culture sites in the Sonora coast, Mexico. A selective fractionation scheme to obtain five fractions was adapted for the microwave system. Surface sediments were analyzed for carbonates, organic matter contents, and Fe and Mn in geochemical fractions. The bulk concentrations of Fe ranged from 10,506 to 21,918 mg/kg (dry weight, dry wt), and the bulk concentrations of Mn ranged from 185.1 to 315.9 mg/kg (dry wt) in sediments, which was low and considered as non-polluted in all of the sites. The fractionation study indicated that the major geochemical phases for the metals were the residual, as well as the Fe and Mn oxide fractions. The concentrations of metals in the geochemical fractions had the following order: residual > Fe and Mn oxides > organic matter > carbonates > interchangeable. Most of the Fe and Mn were linked to the residual fraction. Among non-residual fractions, high percentages of Fe and Mn were linked to Fe and Mn oxides. The enrichment factors (EFs) for the two metals were similar in the four studied coasts, and the levels of Fe and Mn are interpreted as non-enrichment (EF < 1) because the metals concentrations were within the baseline concentrations. According to the environmental risk assessment codes, Fe and Mn posed no risk and low risk, respectively. Although the concentrations of Fe and Mn were linked to the residual fraction, the levels in non-residual fractions may significantly result in the transference of other metals, depending on several physico-chemical and biological factors.

  1. Effect of alloying elements on σ phase formation in Fe-Cr-Mn alloys

    International Nuclear Information System (INIS)

    Okazaki, Yoshimitsu; Miyahara, Kazuya; Hosoi, Yuzo; Tanino, Mitsuru; Komatsu, Hazime.

    1989-01-01

    Alloys of Fe-(8∼12%) Cr-(5∼30%) Mn were solution-treated at 1373 K for 3.6 ks, followed by cold-working of 50% reduction. Both solution-treated and 50% cold-worked materials were aged in the temperature range from 773 to 973 K for 3.6 x 10 3 ks. The identification of σ phase formation was made by using X-ray diffraction from the electrolytically extracted residues of the aged specimens. The region of σ phase formation determined by the present work is wider than that on the phase diagram already reported. It is to be noted that Mn promotes markedly the σ phase formation, and that three different types of σ phase formation are observed depending on Mn content: α→γ + α→γ + α + σ in 10% Mn, α→γ + σ in 15 to 20% Mn alloys, α→χ(Chi) →χ + σ + γ in 25 to 30% Mn alloys. An average electron concentration (e/a) in the σ phase was estimated by quantitative analysis of alloying elements using EPMA. The e/a value in the σ phase formed in Fe-(12∼16%) Cr-Mn alloys aged at 873 K for 3.6 x 10 3 ks is about 7.3, which is independent of Mn content. In order to prevent σ phase formation in Fe-12% Cr-15% Mn alloy, the value of Ni * eq of 11 (Ni * eq = Ni + 30(C) + 25(N)) is required. (author)

  2. Kα X-ray satellite spectra of Ti, V, Cr and Mn induced by photons

    Indian Academy of Sciences (India)

    K X-ray emission spectra of Ti, V, Cr and Mn generated by photon excitation have been studied with a crystal spectrometer. The measured energy shifts of K satellite relative to the diagram line are compared with values obtained by electron excitation and with different theoretical estimates. The present experimental ...

  3. Above room temperature ferromagnetism in Si:Mn and TiO(2-delta)Co.

    Science.gov (United States)

    Granovsky, A; Orlov, A; Perov, N; Gan'shina, E; Semisalova, A; Balagurov, L; Kulemanov, I; Sapelkin, A; Rogalev, A; Smekhova, A

    2012-09-01

    We present recent experimental results on the structural, electrical, magnetic, and magneto-optical properties of Mn-implanted Si and Co-doped TiO(2-delta) magnetic oxides. Si wafers, both n- and p-type, with high and low resistivity, were used as the starting materials for implantation with Mn ions at the fluencies up to 5 x 10(16) cm(-2). The saturation magnetization was found to show the lack of any regular dependence on the Si conductivity type, type of impurity and the short post-implantation annealing. According to XMCD Mn impurity in Si does not bear any appreciable magnetic moment at room temperature. The obtained results indicate that above room temperature ferromagnetism in Mn-implanted Si originates not from Mn impurity but rather from structural defects in Si. The TiO(2-delta):Co thin films were deposited on LaAlO3 (001) substrates by magnetron sputtering in the argon-oxygen atmosphere at oxygen partial pressure of 2 x 10(-6)-2 x 10(-4) Torr. The obtained transverse Kerr effect spectra at the visible and XMCD spectra indicate on intrinsic room temperature ferromagnetism in TiO(2-delta):Co thin films at low (< 1%) volume fraction of Co.

  4. Spectral evidence for inherent 'dead layer' formation at La1-ySryFeO3 /La1-xSrxMnO3 heterointerface

    International Nuclear Information System (INIS)

    Hashimoto, R.; Chikamatsu, A.; Kumigashira, H.; Oshima, M.; Nakagawa, N.; Ohnishi, T.; Lippmaa, M.; Wadati, H.; Fujimori, A.; Ono, K.; Kawasaki, M.; Koinuma, H.

    2004-01-01

    Full text: We have investigated the electronic structure of a La 0.6 Sr 0.4 FeO 3 (LSFO)/La 0.6 Sr 0.4 MnO 3 (LSMO) heterointerface using Mn 2p-3d resonant photoemission spectroscopy. The strong enhancement of Mn 3d partial density of states (PDOS) at Mn 2p-3d threshold enables us to extract true Mn 3d PDOS of LSMO layers in the vicinity of interface with the LSFO overlayer. The LSFO / LSMO multilayers have been successfully grown on single-crystal (001) SrTiO 3 substrates by laser molecular beam epitaxy. Figure 1 shows the Mn 2p-3d resonant spectra near the Fermi level (E F ) of LSMO layers. We clearly found that the spectral intensity of e g states near E F is gradually reduced with increasing the LSFO overlayer thickness and finally saturated at 5-7 ML. In the inset, we plotted the spectral intensity of e g states of Mn 3d as a function of the LSFO overlayer thickness. These results indicate the formation of the charge transfer layer with the decay length of about 2 ML at the heterointerface

  5. Synthesis of α-Fe2O3 and Fe-Mn Oxide Foams with Highly Tunable Magnetic Properties by the Replication Method from Polyurethane Templates

    Directory of Open Access Journals (Sweden)

    Yuping Feng

    2018-02-01

    Full Text Available Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N2 atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe2O3 foams are obtained from the metallic iron slurry independently of the N2 flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N2 flow. While the main phases for a N2 flow rate of 180 L/h are α-Fe2O3 and FeMnO3, the predominant phase for high N2 flow rates (e.g., 650 L/h is Fe2MnO4. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe2MnO4 foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N2 flow rate (i.e., the amount of Fe2MnO4 is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids.

  6. Synthesis of α-Fe2O3 and Fe-Mn Oxide Foams with Highly Tunable Magnetic Properties by the Replication Method from Polyurethane Templates

    Science.gov (United States)

    Feng, Yuping; Fornell, Jordina; Zhang, Huiyan; Solsona, Pau; Barό, Maria Dolors; Suriñach, Santiago; Sort, Jordi

    2018-01-01

    Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU) templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N2 atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe2O3) foams are obtained from the metallic iron slurry independently of the N2 flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N2 flow. While the main phases for a N2 flow rate of 180 L/h are α-Fe2O3 and FeMnO3, the predominant phase for high N2 flow rates (e.g., 650 L/h) is Fe2MnO4. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe2MnO4 foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N2 flow rate (i.e., the amount of Fe2MnO4) is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids. PMID:29439450

  7. Magnetic properties of melt-spun FeMnAlB alloys

    International Nuclear Information System (INIS)

    Betancourt, I.; Nava, F.

    2007-01-01

    Magnetic properties of melt spun Fe 89-x Mn 11 Al x (x=2,4,8,15) and Fe 87-y Mn 11 Al 2 By(y=6,8,10) alloy series were studied by vibrating sample magnetometry and complex permeability measurements. The saturation magnetization exhibited an initial high value of 210emu/g followed by a decreasing tendency with increasing Al and B additions (up to 139emu/g). On the other hand, the initial permeability showed variations within the range 1000-2000, whereas the relaxation frequency displayed a maximum of 2MHz for the 4at% Al alloy

  8. The crystallization of amorphous Fe2MnGe powder prepared by ball milling

    International Nuclear Information System (INIS)

    Zhang, L.; Brueck, E.; Tegus, O.; Buschow, K.H.J.; Boer, F.R. de

    2003-01-01

    We synthesized for the first time the intermetallic compound Fe 2 MnGe. To avoid preferential evaporation of volatile components we exploited mechanical alloying. Amorphous Fe 2 MnGe alloy powder was prepared by planetary ball milling elemental starting materials. The amorphous-to-crystalline transition was studied by means of differential scanning calorimetry (DSC) and X-ray diffraction (XRD). A cubic D0 3 phase is formed at low temperature and transforms to a high-temperature hexagonal D0 19 phase. The apparent activation energy was determined by means of the Kissinger method

  9. Polarized neutron reflectivity study of a thermally treated MnIr/CoFe exchange bias system.

    Science.gov (United States)

    Awaji, Naoki; Miyajima, Toyoo; Doi, Shuuichi; Nomura, Kenji

    2010-12-01

    It has recently been found that the exchange bias of a MnIr/CoFe system can be increased significantly by adding a thermal treatment to the bilayer. To reveal the origin of the higher exchange bias, we performed polarized neutron reflectivity measurements at the JRR-3 neutron source. The magnetization vector near the MnIr/CoFe interface for thermally treated samples differed from that for samples without the treatment. We propose a model in which the pinned spin area at the interface is extended due to the increased roughness and atomic interdiffusion that result from the thermal treatment.

  10. Effects of thermo-mechanical treatment and microalloying with Cr, Nb and Ti on phase transformation in C-Mn steel strips produced by compact strip production process

    International Nuclear Information System (INIS)

    Zhu, Y.Z.; Liang, D.M.; Li, J.C.; Xu, J.P.; Xue, Z.L.

    2011-01-01

    Highlights: → The order of solid solution of carbides influences phase transformation of C-Mn steel in cooling. → Evidences of early stage of solid solution of carbides were provides in the paper. → Transitional state evidences such as carbon enriched regions were observed in this study. - Abstract: The C-Mn steel strips microalloyed with Cr, Nb, Ti was produced by compact strip production process and then heat-treated under different conditions. Optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy were used to investigate phase transformations in the steel after different treatments. It was revealed that the phase transformations upon quenching were greatly affected by the austenization temperature and time. When the steel was annealed at 950 deg. C, carbides of Cr, Mn and Fe were dissolved dramatically, while carbides of Nb and Ti are relatively stable at this temperature. When the temperature increases to 1100 deg. C, the carbides of Nb were dissolved rapidly, while the carbides of Ti still show somewhat stable (partial dissolution). Annealing time influences both the amount and the shapes of carbides in the steel, which leads to different phase transformations in the following air cooling processes. Grain growth in the steel in annealing process strongly depends on the dissolution of carbides on grain boundaries. Additionally, a subsequent rolling after annealing treatment at 950 deg. C lead to obvious precipitation of carbides of Ti and Nb in the steel.

  11. Local and average structure of Mn- and La-substituted BiFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bo; Selbach, Sverre M., E-mail: selbach@ntnu.no

    2017-06-15

    The local and average structure of solid solutions of the multiferroic perovskite BiFeO{sub 3} is investigated by synchrotron X-ray diffraction (XRD) and electron density functional theory (DFT) calculations. The average experimental structure is determined by Rietveld refinement and the local structure by total scattering data analyzed in real space with the pair distribution function (PDF) method. With equal concentrations of La on the Bi site or Mn on the Fe site, La causes larger structural distortions than Mn. Structural models based on DFT relaxed geometry give an improved fit to experimental PDFs compared to models constrained by the space group symmetry. Berry phase calculations predict a higher ferroelectric polarization than the experimental literature values, reflecting that structural disorder is not captured in either average structure space group models or DFT calculations with artificial long range order imposed by periodic boundary conditions. Only by including point defects in a supercell, here Bi vacancies, can DFT calculations reproduce the literature results on the structure and ferroelectric polarization of Mn-substituted BiFeO{sub 3}. The combination of local and average structure sensitive experimental methods with DFT calculations is useful for illuminating the structure-property-composition relationships in complex functional oxides with local structural distortions. - Graphical abstract: The experimental and simulated partial pair distribution functions (PDF) for BiFeO{sub 3}, BiFe{sub 0.875}Mn{sub 0.125}O{sub 3}, BiFe{sub 0.75}Mn{sub 0.25}O{sub 3} and Bi{sub 0.9}La{sub 0.1}FeO{sub 3}.

  12. Self-ignition combustion synthesis of TiFe in hydrogen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wakabayashi, R. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)], E-mail: ryuta@eng.hokudai.ac.jp; Sasaki, S. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Saita, I. [National Institute of Advanced Industrial Science and Technology (AIST), AIST Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Sato, M. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Uesugi, H. [Bio Coke Lab., Ltd., 5-34-20 Hirato, Totsuka-ku, Yokohama, Kanagawa 244-0802 (Japan); Akiyama, T. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2009-07-08

    This paper describes the self-ignition combustion synthesis (SICS) of highly active titanium iron (TiFe) in a high-pressure hydrogen atmosphere without employing an activation process. In the experiments, well-mixed powders of Ti and Fe in the molar ratio of 1:1 were uniformly heated up to 1085 deg. C, the eutectic temperature of Ti-Fe binary system, in pressurized hydrogen at 0.9 MPa. The electric source was disconnected immediately after the ignition between Ti and Fe, and the mixture was cooled naturally. In this study, the exothermic reaction Ti + Fe = TiFe + 40 kJ occurred at around 1085 deg. C after the hydrogenation and decomposition of Ti. X-ray diffraction analysis showed that the final product had only one phase-TiFeH{sub 0.06}-which can store hydrogen of 1.55 mass% under hydrogen pressure of 4 MPa. The product obtained by SICS contained considerably more hydrogen quickly as compared to the commercially available product; this fact can be explained by the porous structure of the obtained product, which was observed using a scanning electron microscope. In conclusion, the SICS of TiFe saved time and energy, yields products with high porosity and small crystals, enabled easy hydrogenation, and did not require activation processes.

  13. Growth and characterizations of Ba2Ti2Fe2As4O single crystals

    Directory of Open Access Journals (Sweden)

    Yun-Lei Sun, Abduweli Ablimit, Jin-Ke Bao, Hao Jiang, Jie Zhou and Guang-Han Cao

    2013-01-01

    Full Text Available Single crystals of a new iron-based superconductor Ba2Ti2Fe2As4O have been grown successfully via a Ba2As3-flux method in a sealed evacuated quartz tube. Bulk superconductivity with Tc ~ 21.5 K was demonstrated in resistivity and magnetic susceptibility measurements after the as-grown crystals were annealed at 500 °C in vacuum for a week. X-ray diffraction patterns confirm that the annealed and the as-grown crystals possess the identical crystallographic structure of Ba2Ti2Fe2As4O. Energy-dispersive x-ray spectra indicate that partial Ti/Fe substitution exists in the [Fe2As2] layers and the annealing process redistributes the Ti within the Fe-plane. The ordered Fe-plane stabilized by annealing exhibits superconductivity with magnetic vortex pinned by Ti.

  14. Intermartensitic transitions in Ni-Mn-Fe-Cu-Ga Heusler alloys

    International Nuclear Information System (INIS)

    Khan, Mahmud; Gautam, Bhoj; Pathak, Arjun; Dubenko, Igor; Stadler, Shane; Ali, Naushad

    2008-01-01

    A series of Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga Heusler alloys have been investigated by means of x-ray diffraction, magnetizations, thermal expansion, and electrical resistivity measurements. In Ni 2 Mn 0.75 Cu 0.25 Ga, martensitic and ferromagnetic transitions occur at the same temperature. Partial substitution of Mn by Fe results in a decrease of the martensitic transition temperature, T M , and an increase of the ferromagnetic transition temperature, T C , resulting in separation of the two transitions. In addition to the martensitic transition, complete thermoelastic intermartensitic transformations have been observed in the Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga samples with x>0.04. An unusual transition is observed in the alloy with x = 0.04. The magnetization curve as a function of increasing temperature shows only one first-order transition in the temperature range 5-400 K, which is identified as a typical coupled magnetostructural martensitic transformation. The magnetization curve as a function of decreasing temperature shows three different transitions, which are characterized as the ferromagnetic transition, the martensitic transition and the intermartensitic transition.

  15. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  16. Serrated Flow and Dynamic Strain Aging in Fe-Mn-C TWIP Steel

    Science.gov (United States)

    Lan, Peng; Zhang, Jiaquan

    2018-01-01

    The tensile behavior, serrated flow, and dynamic strain aging of Fe-(20 to 24)Mn-(0.4 to 0.6)C twinning-induced plasticity (TWIP) steel have been investigated. A mathematical approach to analyze the DSA and PLC band parameters has been developed. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with a theoretical ordering index (TOI) between 0.1 and 0.3, DSA can occur at the very beginning of plastic deformation and provide serrations during work hardening, while for TOI less than 0.1 the occurrence of DSA is delayed and twinning-dominant work hardening remains relatively smooth. The critical strain for the onset of DSA and PLC bands in Fe-Mn-C TWIP steels decreases as C content increases, while the numbers of serrations and bands increase. As Mn content increases, the critical strain for DSA and PLC band varies irregularly, but the numbers of serrations and bands increase. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with grain size of about 10 to 20 μm, the twinning-induced work hardening rate is about 2.5 to 3.0 GPa, while the DSA-dominant hardening rate is about 2.0 GPa on average. With increasing engineering strain from 0.01 to 0.55 at an applied strain rate of 0.001s-1, the cycle time for PLC bands in Fe-Mn-C TWIP steel increases from 6.5 to 162 seconds, while the band velocity decreases from 4.5 to 0.5 mm s-1, and the band strain increases from 0.005 to 0.08. Increasing applied strain rate leads to a linear increase of band velocity despite composition differences. In addition, the influence of the Mn and C content on the tensile properties of Fe-Mn-C TWIP steel has been also studied. As C content increases, the yield strength and tensile strength of Fe-Mn-C TWIP steel increase, but the total elongation variation against C content is dependent on Mn content. As Mn content increases, the yield strength and tensile strength decrease, while the total elongation increases, despite C content. Taking both tensile properties and serrated flow behavior into

  17. Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

    International Nuclear Information System (INIS)

    Demchishin, A.V.; Gnilitskyi, I.; Orazi, L.; Ascari, A.

    2015-01-01

    Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics

  18. Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

    Energy Technology Data Exchange (ETDEWEB)

    Demchishin, A.V., E-mail: ademch@meta.ua [Institute of Problems in Material Science, NASU, Kiev (Ukraine); Gnilitskyi, I., E-mail: iaroslav.gnilitskyi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Orazi, L., E-mail: leonardo.orazi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Ascari, A., E-mail: a.ascari@unibo.it [DIN – Department of Industrial Engineering, University of Bologna, Bologna (Italy)

    2015-07-01

    Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics.

  19. Experimental and thermodynamic assessments of substitutions in the AlFeSi, FeMnSi, FeSiZr and AlCaFeSi systems (65 wt % Si) - solidification simulation

    International Nuclear Information System (INIS)

    Gueneau, C.; Ansara, I.

    1994-01-01

    The substitutions of Al Si, Fe Mn and Fe Zr in some intermetallic compounds of the Al-Fe-Si, Fe-Mn-Si and Fe-Si-Zr systems are modelled in the Si-rich corner using a two sublattice model. The solidification paths of the studied alloys are determined at equilibrium. The ascalculated phase volume fractions of the alloys are compared to the experimental ones. Finally, a solidification simulation using the Gulliver-Scheil's model is performed in order to explain the formation of some precipitates experimentally observed. (authors). 14 figs., 19 refs

  20. Effect of calcination temperature on structural properties and photocatalytic activity of Mn-C-codoped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jianbo; Xin, Wei; Liu, Guanglong; Lin, Die; Zhu, Duanwei, E-mail: liugl@mail.hzau.edu.cn [Laboratory of Eco-Environmental Engineering Research, College of Resources and Environment, Huazhong Agricultural University (HZAU), Wuhan (China)

    2016-03-15

    Mn-C-codoped TiO{sub 2} catalysts were synthesized by modified sol-gel method based on the self-assembly technique using polyoxyethylene sorbitan monooleate (Tween 80) as template and carbon precursor and the effect of calcination temperature on their structural properties and photocatalytic activity were investigated. The XRD results showed undoped and Mn-C-codoped TiO{sub 2} calcined at 400 deg C only include anatase phase and the rutile phase appears when the calcination temperature reached to 600 deg C. UV-vis absorption spectroscopy demonstrates that the absorption spectra are strongly modified by the calcination temperature. Moreover, the Mn-C-TiO{sub 2} calcined at 400 deg C showed the lowest PL intensity due to a decrease in the recombination rate of photogenerated electrons and holes under light irradiation. The photocatalytic activity of Mn-C-codoped TiO{sub 2} were evaluated by the degradation of methyl orange (MO) under the simulate daylight irradiation and all the prepared Mn-C-codoped TiO{sub 2} samples exhibited high photocatalytic activities for photocatalytic decolorisation of methyl orange aqueous solution. At 400 deg C, the Mn-C-codoped TiO{sub 2} samples showed the highest photocatalytic activity due to synergetic effects of good crystallize ation, appropriate phase composition and slower recombination rate of photogenerated charge carriers, which further confirms the calcination temperature could affect the properties of Mn-C-codoped TiO2 significantly. (author)

  1. Optimized thermoelectric performance of the n-type half-Heusler material TiNiSn by substitution and addition of Mn

    Directory of Open Access Journals (Sweden)

    Enkhtaivan Lkhagvasuren

    2017-04-01

    Full Text Available Alloys based on the half-Heusler compound TiNiSn with the addition of Mn or with a substitution of Ti by Mn are investigated as high-temperature thermoelectric materials. In both materials an intrinsic phase separation is observed, similar to TiNiSn where Ti has been partially substituted by Hf, with increasing Mn concentration the phase separation drastically reduces the lattice thermal conductivity while the power factor is increased. The thermoelectric performance of the n-type conducting alloy can be optimized both by substitution of Ti by Mn as well as the addition of Mn.

  2. Mixed phase in cubic and hexagonal HoMn2111Cd PAC and 119Sn, 57Fe Moessbauer studies

    International Nuclear Information System (INIS)

    Cottenier, S.; Meersschaut, J.; Demuynck, S.; Swinnen, B.; Rots, M.

    1998-01-01

    Hyperfine parameters on 57 Fe, 119 Sn and 111 Cd substituted into the Mn sublattice were measured by Moessbauer and PAC spectroscopies. From these results it is tentatively concluded that C15 and C14 HoMn 2 are mixed-phase compounds. In C14 HoMn 2 there is no (or small) moment on the 2a site. (orig.)

  3. The high temperature orthorhombic ⇄ hexagonal phase transformation of FeMnP

    Science.gov (United States)

    Chenevier, B.; Soubeyroux, J. L.; Bacmann, M.; Fruchart, D.; Fruchart, R.

    1987-10-01

    The compound FeMnP has the hexagonal Fe 2P structure above 1473K. The metal atoms are disordered. The disorder rate decreases with temperature and at 1413K a transition Hex → Orth. takes place. The low temperature phase is of Co 2P type. A simple transition model is proposed based on the displacement of phosphorus chains along the shortest axis of the structure. The thermal evolution of the orthorhombic cell parameters evidences the strong anisotropy of the bondings.

  4. Tetragonal Ce-based Ce-Sm(Fe, Co, Ti){sub 12} alloys for permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Cid, Andres; Salazar, Daniel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Gabay, Aleksandr M.; Hadjipanayis, George C. [Department of Physics and Astronomy, University of Delaware, Newark, DE, 19716 (United States); Barandiaran, Jose Manuel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Department of Electricity and Electronics, University Basque Country (UPV/EHU), 48080 Bilbao (Spain)

    2016-12-15

    Abundance and relatively low cost of Ce provide a great incentive for its use in rare-earth permanent magnets. It has been recently reported that the tetragonal Ce(Fe,Co,Ti)12 compounds may exhibit application-worthy intrinsic magnetic properties. In this work the effect of the α-Fe phase formation due to the evaporation of Sm during alloy fabrication has been studied, as a previous step in the attempt to convert the intrinsic magnetic properties into functional properties of a permanent magnet. Ce{sub 0.5}Sm{sub 0.5}Fe{sub 9}Co{sub 2}Ti alloys based on the ThMn12-type crystal structure have been synthesized via melt-spinning with different Sm content. Coercive fields between 2.8 and 1.4 kOe have been found for α-Fe phase contents between 8 and 46% in volume, showing the influence of the α-Fe phase on the coercivity and exchange coupling between the hard and soft phase. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Mn doping effect on structure and magnetism of epitaxial (FePt)1-xMnx films

    International Nuclear Information System (INIS)

    Huang, J.C.A.; Chang, Y.C.; Yu, C.C.; Yao, Y.D.; Hu, Y.M.; Fu, C.M.

    2003-01-01

    We study the structure and perpendicular magnetism of molecular beam epitaxy grown (FePt) 1-x Mn x films with doping concentration x=0, 1%, 2%, 3%, 4%, and 5%. The (FePt) 1-x Mn x films were made by multilayers growth of [Fe/Pt/Mn]xN at 100 deg. C and annealed at 600 deg. C. X-ray diffraction scans indicate that relatively better L1 0 ordered structure for low Mn doping (x 3%. The perpendicular magnetic anisotropy effect of the (FePt) 1-x Mn x films tends to decrease with the increase of Mn doping for x>1%. However, the x=1% doped films possess slightly better perpendicular magnetic anisotropy effect than the zero doped film. The perpendicular magnetic anisotropy constant are of about 1.3x10 7 and 1.6x10 7 erg/cm 3 for x=0% and x=1%, respectively

  6. Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

    International Nuclear Information System (INIS)

    Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching; Lee, Chih-Jhan; Ho, Wen-Fu

    2010-01-01

    In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable β phase began. However, when 4 mass% Fe or greater was added, the β phase was entirely retained with a bcc crystal structure. Moreover, the ω phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of ω phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9 o ) and Ti-5Nb-5Fe (29.5 o ) alloys were greater than that of c.p. Ti (2.7 o ) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

  7. Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taichung 40605, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Changhua 51591, Taiwan (China); Lee, Chih-Jhan [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China); Ho, Wen-Fu, E-mail: fujii@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China)

    2010-09-15

    In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable {beta} phase began. However, when 4 mass% Fe or greater was added, the {beta} phase was entirely retained with a bcc crystal structure. Moreover, the {omega} phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of {omega} phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9{sup o}) and Ti-5Nb-5Fe (29.5{sup o}) alloys were greater than that of c.p. Ti (2.7{sup o}) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

  8. Irreversible effects in the FeTi/H system

    International Nuclear Information System (INIS)

    Reilly, J.J.; Johnson, J.R.; Lynch, J.F.; Reidinger, F.

    1982-03-01

    The equilibrium hydrogen absorption isotherm using annealed, strain-free FeTi, exhibits only one plateau up to a composition of FeTiH/sub 1.95/. However, the desorption isotherm, determined immediately after the first hydriding step, exhibits the usual two plateaux. X-ray diffraction results of samples with compositions within the absorption plateau limits indicate the major phases present to be α and γ, although a small amount of β phase was always detected. Apparently the absorption isotherm represents the direct conversion of α → γ and β phase precipitation is almost completely suppressed. Thermodynamic quantities for this conversion are given. The results are attributed to the influence of lattice strain upon the behavior of the β1 and β2 phases. A practical consequence of the effect is the distortion of the pressure-composition isotherm in the β-γ region as a function of hydriding-dehydriding cycles. This is caused by an increase in H solubility of the β and γ phases and the widening of the phase composition limits as the strain increases with cycle number. However, after many hundreds of cycles there is no further significant increase in strain and the isotherm shape becomes essentially fixed and reproducible. The distortion is reversible by mild annealing

  9. Low-energy Coulomb excitation of $^{62}$Fe and $^{62}$Mn following in-beam decay of $^{62}$Mn

    CERN Document Server

    Gaffney, L P; Bastin, B; Bildstein, V; Blazhev, A; Bree, N; Darby, I; De Witte, H; DiJulio, D; Diriken, J; Fedosseev, V N; Fransen, Ch; Gernhäuser, R; Gustafsson, A; Hess, H; Huyse, M; Kesteloot, N; Kröll, Th; Lutter, R; Marsh, B A; Reiter, P; Seidlitz, M; Van Duppen, P; Voulot, D; Warr, N; Wenander, F; Wimmer, K; Wrzosek-Lipska, K

    2015-01-01

    Sub-barrier Coulomb-excitation was performed on a mixed beam of $^{62}$Mn and $^{62}$Fe, following in-trap $\\beta^{-}$ decay of $^{62}$Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418 keV, which has been tentatively associated to a $2^{(+)},3^{(+)}\\rightarrow1^{+}_{g.s.}$ transition. This fixes the relative positions of the $\\beta$-decaying $4^{(+)}$ and $1^{+}$ states in $^{62}$Mn for the first time. Population of the $2^{+}_{1}$ state was observed in $^{62}$Fe and the cross-section determined by normalisation to the $^{109}$Ag target excitation. Combining this Coulomb-excitation cross-section with previously measured lifetimes of the $2^{+}_{1}$ state, the spectroscopic quadrupole moment, $Q_{s}(2^{+}_{1})$, is extracted, albeit with a large uncertainty.

  10. Magnetoresistance in ferromagnetic shape memory alloy NiMnFeGa

    International Nuclear Information System (INIS)

    Liu, Z.H.; Ma, X.Q.; Zhu, Z.Y.; Luo, H.Z.; Liu, G.D.; Chen, J.L.; Wu, G.H.; Zhang Xiaokai; Xiao, John Q.

    2011-01-01

    The magnetoresistance (MR){=[R(H)-R(0)]/R(0)} properties in ferromagnetic shape memory alloy of NiMnFeGa ribbons and single crystals, and NiFeGa ribbons have been investigated. It is found that the NiMnFeGa melt-spun ribbon exhibited GMR effect, arising from the spin-dependent scattering from magnetic inhomogeneities consisting of antiferromagnetically coupled Mn atoms in B2 structure. In the absence of these magnetic inhomogeneities, Heusler alloys seem to show a common linear MR behavior at around 0.8T C , regardless of sample structures. This may be explained by the s-d model. At low temperatures, conventional AMR behaviors due to the spin-orbital coupling are observed. This is most likely due to the diminished MR from s-d model because of much less spin fluctuation, and is not associated with martensite phase. MR anomaly at intermediate field (ρ perpendicular >ρ || ) is also observed in single crystal samples, which may be related to unique features of Heusler alloys. - Highlights: → NiMnFeGa melt-spun ribbon exhibited GMR effect with a large negative MR up to -13%. → GMR behavior is arising from the spin-dependent scattering from magnetic inhomogeneities. → In the absence of these magnetic inhomogeneities, Heusler alloys seem to show a common linear MR behavior at around 0.8T C . → Conventional AMR behaviors due to the spin-orbital coupling are observed in NiMnFeGa single crystal and Ni 2 FeGa ribbon samples at low temperatures.

  11. Effect of Fe on the phases and microstructure of TiC-Fe cermets by combustion synthesis/quasi-isostatic pressing

    International Nuclear Information System (INIS)

    Zhang Weifang; Zhang Xinghong; Wang Jianli; Hong Changqing

    2004-01-01

    Fully dense TiC-Fe cermets (x = 10, 20, 30, and 40 wt.%) were produced from Ti-C-Fe powder mixtures by combustion synthesis with quasi-isostatic pressing. The effect of Fe content on combustion temperature, combustion wave velocity, and final product density was investigated. The final product was characterized by XRD, SEM, and TEM. The combustion temperature and wave velocity decreased with increasing Fe content. Product density increased with increasing Fe content (96% at 30 wt.%). X-ray diffraction and transmission electron microscopy (TEM) revealed the final product to contain TiC, Fe phases, lath martensite, and Fe 2 Ti. The TiC particle size decreased with increasing Fe content. In addition, a low density of dislocations was observed in both the TiC particles and Fe binder, indicative of annealing and recrystallization, respectively

  12. modified BiFeO3–BaTiO3

    Indian Academy of Sciences (India)

    based perovskite structures lead- free BiFeO3–BaTiO3 solid solutions are popularly studied due to the high Curie temperature (TC). It was reported that the BiFeO3–BaTiO3 system possessed high piezoelectric. ∗. Author for correspondence ...

  13. Experimental investigation of the phase equilibria in the Co-Fe-Ti ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chaohui; Chen, Chong; Peng, Yingbiao; Du, Yong; Li, Kun [Central South Univ., State Key of Powder Metallurgy, Changsha (China); Lu, Xingxu [Central South Univ., State Key of Powder Metallurgy, Changsha (China); Central South Univ., School of Materials Science and Engineering, Changsha (China)

    2015-08-15

    Phase equilibria in the Co-Fe-Ti ternary system were investigated by means of the equilibrated alloy method with X-ray powder diffraction and electron probe microanalysis. No ternary compounds were found. The experimental results indicated the existence of seven two-phase and one three-phase regions at 600 C, five two-phase and two three-phase regions at 800 C, and six two-phase and two three-phase regions at 950 C. The solubility of Co in TiFe{sub 2} was determined to be larger than 54 at.% at all investigated temperatures, and the solubilities of Fe in TiCo{sub 3} and Ti{sub 2}Co showed an appreciable increase with increasing temperature. The three-phase equilibrium in the Ti-rich corner at 800 C was revealed to be ((β-Ti) + Ti(Fe, Co) + Ti{sub 2}Co) rather than ((α-Ti) + Ti(Fe, Co) + Ti{sub 2}Co) reported in previous investigations. Based on the experimental data obtained in the present work, three isothermal sections at 600, 800 and 950 C were established.

  14. Trends in (LaMnO3)n/(SrTiO3)m superlattices with varying layer thicknesses

    KAUST Repository

    Jilili, J.

    2015-09-01

    We investigate the thickness dependence of the structural, electronic, and magnetic properties of (LaMnO3)n/(SrTiO3)m (n, m = 2, 4, 6, 8) superlattices using density functional theory. The electronic structure turns out to be highly sensitive to the onsite Coulomb interaction. In contrast to bulk SrTiO3, strongly distorted O octahedra are observed in the SrTiO3 layers with a systematic off centering of the Ti atoms. The systems favour ferromagnetic spin ordering rather than the antiferromagnetic spin ordering of bulk LaMnO3 and all show half-metallicity, while a systematic reduction of the minority spin band gaps as a function of the LaMnO3 and SrTiO3 layer thicknesses originates from modifications of the Ti dxy states.

  15. Toward an Active and Stable Catalyst for Oxygen Evolution in Acidic Media: Ti-Stabilized MnO2

    DEFF Research Database (Denmark)

    Frydendal, Rasmus; Paoli, Elisa Antares; Chorkendorff, Ib

    2015-01-01

    Catalysts are required for the oxygen evolution reaction, which are abundant, active, and stable in acid. MnO2 is a promising candidate material for this purpose. However, it dissolves at high overpotentials. Using first-principles calculations, a strategy to mitigate this problem by decorating...... undercoordinated surface sites of MnO2 with a stable oxide is developed here. TiO2 stands out as the most promising of the different oxides in the simulations. This prediction is experimentally verified by testing sputter-deposited thin films of MnO2 and Ti-MnO2. A combination of electrochemical measurements...

  16. Effect of Manganese on Microstructures and Solidification Modes of Cast Fe-Mn-Si-Cr-Ni Shape Memory Alloys

    Science.gov (United States)

    Peng, Huabei; Wen, Yuhua; Du, Yangyang; Yu, Qinxu; Yang, Qin

    2013-10-01

    We investigated microstructures and solidification modes of cast Fe-(13-27)Mn-5.5Si-8.5Cr-5Ni shape memory alloys to clarify whether Mn was an austenite former during solidification. Furthermore, we examined whether the Creq/Nieq equations (Delong, Hull, Hammer and WRC-1992 equations) and Thermo-Calc software® together with database TCFE6 were valid to predict the solidification modes of cast Fe-(13-27)Mn-5.5Si-8.5Cr-5Ni shape memory alloys. The results have shown that the solidification modes of Fe-(13-27)Mn-5.5Si-8.5Cr-5Ni alloys changed from the F mode to the FA mode with increasing the Mn concentration. Mn is an austenite former during the solidification for the cast Fe-Mn-Si-Cr-Ni shape memory alloys. The Delong, Hull, Hammer, and WRC-1992 equations as well as Thermo-Calc software® together with database TCFE6 are invalid to predict the solidification modes of cast Fe-(13-27)Mn-5.5Si-8.5Cr-5Ni SMAs. To predict the solidification modes of cast Fe-Mn-Si-Cr-Ni alloys, a new Creq/Nieq equation should be developed or the thermodynamic database of Thermo-Calc software® should be corrected.

  17. Erosion resistance of FeAl-TiB2 and FeAl-WC at room and elevated temperatures

    International Nuclear Information System (INIS)

    Alman, D.E.; Tylczak, J.H.; Hawk, J.A.

    2000-01-01

    The resistance of FeAl-40%TiB 2 and FeAl-80%WC cermets to solid particle erosion at 25, 180, 500 and 700 C was evaluated and compared to the behavior of WC-6%Co (Co-90%WC) cemented carbides. Even though the WC-Co contained a higher volume fraction of the hard phase, the erosion rates of the FeAl-cermets were similar in magnitude to the erosion rates of the WC-Co. However, the erosion rates of the FeAl-cermets either were constant (FeAl-TiB 2 ) or decreased (FeAl-WC) with increasing test temperature; whereas, the erosion rates of the WC-Co cemented carbides increased with increasing test temperature. This indicated that once the microstructures of the FeAl-cermets are optimized for wear resistance, these materials might make promising candidates for high-temperature wear applications

  18. Levels Of Mn, Fe, Ni, Cu, Zn And Cd, In Effluent From A Sewage ...

    African Journals Online (AJOL)

    This study reports the results of preliminary investigation of heavy metal levels-Ni, Cd, Fe, Zn, Cu and Mn; pH; temperature and electrical conductivity in effluents from a sewage treatment oxidation pond and its receiving stream. The heavy metal concentrations were determined with Inductively Coupled Plasma-Mass ...

  19. Assessment of the concentration of Cr, Mn and Fe in sediment using ...

    African Journals Online (AJOL)

    In the present study, laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of levels of Cr, Mn and Fe in sediment samples and the results have been compared with that of flame-atomic absorption spectroscopy (F-AAS). Fourteen sediment samples were collected from Tinishu Akaki River ...

  20. Synthesis and Characterization of Multimetallic Fe(II) and Mn(II ...

    African Journals Online (AJOL)

    Iron(II) and Manganese(II) complexes of the resulting ligand were obtained from its reactions with Fe(II) and Mn(II) salts in absolute methanol for the metal to ligand ratio 2:3. These complexes were characterized by Solubility, Conductivity, IR and UV-VIS spectrometry, elemental analysis and mass spectrometry. Keywords: ...

  1. Effect of Carbon Doping on the Structure and Magnetic Phase Transition in (Mn,Fe

    NARCIS (Netherlands)

    Nguyên, V.T.; Yibole, -.; Miao, X.F.; Goubitz, K.; van Eijck, L.; van Dijk, N.H.; Brück, E.H.

    2017-01-01

    Given the potential applications of (Mn,Fe2(P,Si))-based materials for room-temperature magnetic refrigeration, several research groups have carried out fundamental studies aimed at understanding the role of the magneto-elastic coupling in the first-order magnetic transition and

  2. Microstructural, mechanical, corrosion and cytotoxicity characterization of the hot forged FeMn30(wt.%) alloy

    Czech Academy of Sciences Publication Activity Database

    Čapek, Jaroslav; Kubásek, J.; Vojtěch, D.; Jablonská, E.; Lipov, J.; Ruml, T.

    2016-01-01

    Roč. 58, Jan (2016), s. 900-908 ISSN 0928-4931 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : FeMn alloys * biodegradability * cytotoxicity * microstructure * mechanical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.164, year: 2016

  3. Local structure of 57Mn/57Fe implanted into lithium hydride

    International Nuclear Information System (INIS)

    Miyazaki, Jun; Nagatomo, Takashi; Kobayashi, Yoshio

    2013-01-01

    We report the in-beam Moessbauer Spectra of 57 Mn implanted into polycrystalline LiH at under room temperature. As compared with the result of DFT calculations, 57 Fe atoms were implanted into Li or H substitutional site in LiH crystal. With an increase the sample temperature, we could observe the decrease of lattice defects. (author)

  4. Structural, optical, and magnetic properties of Mn and Fe-doped Co3O4 nanoparticles

    Directory of Open Access Journals (Sweden)

    C. Stella

    2015-08-01

    Full Text Available Mn and Fe-doped Co3O4 nanoparticles were prepared by a simple precipitation method. The synthesized particles were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, and vibrating sample magnetometer (VSM techniques. XRD analysis showed the cubic structure of Co3O4. SEM and TEM images confirmed the formation of interconnected nanoparticles. Mn and Fe-doped Co3O4 showed broad absorption in the visible region compared to undoped sample and the band gap values are red shifted. Five Raman active modes were observed from the Raman spectra. FTIR spectra confirmed the spinel structure of Co3O4 and the doping of Mn and Fe shifts the vibrational modes to lower wave number region. The magnetic measurements confirmed that Fe-doped Co3O4 shows a little ferromagnetic behavior compared to undoped and Mn-doped Co3O4, which could be related to the uncompensated surface spins and the finite size effects.

  5. The geochemical profile of Mn, Co, Cu and Fe in Kerteh Mangrove Forest, Terengganu

    International Nuclear Information System (INIS)

    Kamaruzzaman, B.Y.; Antotina, A.; Airiza, Z.; Syalindran, S.; Ong, M.C.

    2007-01-01

    The geochemical profile of Kerteh mangrove sediments was analyzed for the vertical and horizontal distribution. The 100 cm core sediment sample and 15 surface sediments samples were taken from the field. The geochemical elements of Mn, Co, Cu and Fe of the sediments were analyzed. Geochemical proxy of Mn, Co, Cu and Fe were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The mean concentrations of Mn, Co, Cu and Fe for the vertical distribution were 210.18 μg/ g, 15.55 μg/ g, 43.65 μg/ g and 1.88 μg/ g respectively. on the other hand, the mean concentrations of the geochemical elements for horizontal distributions were 230.50 μg/ g for Mn, 17.57 μg/ g for Co, 43.381 μg/ g for Cu and 2.93 μg/ g for Fe. Enrichment factor and normalization was used to point out the level of pollution. The EF and the normalization indicated that all the geochemical elements were from the natural sources. (author)

  6. Degradable and porous Fe-Mn-C alloy for biomaterials candidate

    Science.gov (United States)

    Pratesa, Yudha; Harjanto, Sri; Larasati, Almira; Suharno, Bambang; Ariati, Myrna

    2018-02-01

    Nowadays, degradable implants attract attention to be developed because it can improve the quality of life of patients. The degradable implant is expected to degrade easily in the body until the bone healing process already achieved. However, there is limited material that could be used as a degradable implant, polymer, magnesium, and iron. In the previous study, Fe-Mn-C alloys had succesfully produced austenitic phase. However, the weakness of the alloy is degradation rate of materials was considered below the expectation. This study aimed to produce porous Fe-Mn-C materials to improve degradation rate and reduce the density of alloy without losing it non-magnetic properties. Potassium carbonate (K2CO3) were chosen as filler material to produce foam structure by sintering and dissolution process. Multisteps sintering process under argon gas environment was performed to generate austenite phase. The product showed an increment of the degradation rate of the foamed Fe-Mn-C alloy compared with the solid Fe-Mn-C alloy without losing the Austenitic Structure

  7. Assessment of the concentration of Cr, Mn and Fe in sediment using ...

    African Journals Online (AJOL)

    Preferred Customer

    determination of levels of Cr, Mn and Fe in sediment samples and the results have ... produced within the plasma emit radiation over a broad spectral range, from UV ... intake [36] and their oxides play important role in the soil for fixing trace ...

  8. Jahn-teller domains and magnetic domains in Mn2FeO4

    NARCIS (Netherlands)

    Kub, J.; Brabers, V.A.M.; Novák, P.; Gemperle, R.; Simsova, J.

    2000-01-01

    Elastic (Jahn–Teller) domains and magnetic domains in the tetragonal spinel Mn2FeO4 were studied using X-ray double-crystal topography, X-ray diffractometry and the colloid-SEM method. The Jahn–Teller domains of the measured samples are tetragonal with the [0 0 1] c-axis alternating perpendicularly

  9. HIGH TEMPERATURE TENSILE PROPERTIES OF NEW FE-CR-MN DEVELOPED STEEL

    Directory of Open Access Journals (Sweden)

    M. Mahmoudiniya

    2017-03-01

    Full Text Available Nowadays, Ni-free austenitic stainless steels are being developed rapidly and high price of nickel is one of the most important motivations for this development. At present research a new FeCrMn steel was designed and produced based on Fe-Cr-Mn-C system. Comparative studies on microstructure and high temperature mechanical properties of  new steel and AISI 316 steel were done. The results showed that new FeCrMn developed steel has single austenite phase microstructure, and its tensile strength and toughness were higher than those of 316 steel at 25, 200,350 and 500°C. In contrast with 316 steel, the new FeCrMn steel did not show strain induced transformation and dynamic strain aging phenomena during tensile tests that represented higher austenite stability of new developed steel. Lower density and higher strength of the new steel caused higher specific strength in comparison with the 316 one that can be considered as an important advantage in structural applications but in less corrosive environment

  10. Magnetic properties of the CrMnFeCoNi high-entropy alloy

    International Nuclear Information System (INIS)

    Schneeweiss, Oldřich; Friák, Martin; Masaryk University, Brno; Dudová, Marie; Holec, David

    2017-01-01

    In this paper, we present experimental data showing that the equiatomic CrMnFeCoNi high-entropy alloy undergoes two magnetic transformations at temperatures below 100 K while maintaining its fcc structure down to 3 K. The first transition, paramagnetic to spin glass, was detected at 93 K and the second transition of the ferromagnetic type occurred at 38 K. Field-assisted cooling below 38 K resulted in a systematic vertical shift of the hysteresis curves. Strength and direction of the associated magnetization bias was proportional to the strength and direction of the cooling field and shows a linear dependence with a slope of 0.006 ± 0.001 emu T. The local magnetic moments of individual atoms in the CrMnFeCoNi quinary fcc random solid solution were investigated by ab initio (electronic density functional theory) calculations. Results of the numerical analysis suggest that, irrespective of the initial configuration of local magnetic moments, the magnetic moments associated with Cr atoms align antiferromagnetically with respect to a cumulative magnetic moment of their first coordination shell. The ab initio calculations further showed that the magnetic moments of Fe and Mn atoms remain strong (between 1.5 and 2 μ B ), while the local moments of Ni atoms effectively vanish. Finally, these results indicate that interactions of Mn- and/or Fe-located moments with the surrounding magnetic structure account for the observed macroscopic magnetization bias.

  11. Effects of phase transformation and interdiffusion on the exchange bias of NiFe/NiMn

    International Nuclear Information System (INIS)

    Lai, Chih-Huang; Lien, W. C.; Chen, F. R.; Kai, J. J.; Mao, S.

    2001-01-01

    The correlation between the exchange field of NiFe/NiMn and the phase transformation of NiMn was investigated. Transmission electron microscopy (TEM) dark-field images, contributed by the order phase of NiMn, were used to identify the location and volume fraction of the order phase. TEM selected area diffraction patterns showed the (110) superlattice diffraction rings of NiMn, verifying the existence of the order phase in the annealed samples. The order volume fraction can be calculated by the dark field image contributed by the (110) diffraction. The exchange field increased almost linearly with increasing order volume fraction. Energy dispersive x-ray spectroscopy attached to TEM indicated that Mn diffused into NiFe for annealing at 280 degreeC, leading to a larger coercivity and small coercivity squareness. Part of the NiMn still maintains the paramagnetic phase even after annealing at 280 degreeC. [copyright] 2001 American Institute of Physics

  12. Stress-induced phase transformation and room temperature aging in Ti-Nb-Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cai, S.; Schaffer, J.E. [Fort Wayne Metals Research Products Corp, 9609 Ardmore Ave., Fort Wayne, IN 46809 (United States); Ren, Y. [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

    2017-01-05

    Room temperature deformation behavior of Ti-17Nb-1Fe and Ti-17Nb-2Fe alloys was studied by synchrotron X-ray diffraction and tensile testing. It was found that, after proper heat treatment, both alloys were able to recover a deformation strain of above 3.5% due to the Stress-induced Martensite (SIM) phase transformation. Higher Fe content increased the beta phase stability and onset stress for SIM transformation. A strong {110}{sub β} texture was produced in Ti-17Nb-2Fe compared to the {210}{sub β} texture that was observed in Ti-17Nb-1Fe. Room temperature aging was observed in both alloys, where the formation of the omega phase increased the yield strength (also SIM onset stress), and decreased the ductility and strain recovery. Other metastable beta Ti alloys may show a similar aging response and this should draw the attention of materials design engineers.

  13. New understanding on separation of Mn and Fe from ferruginous manganese ores by the magnetic reduction roasting process

    Science.gov (United States)

    Liu, Bingbing; Zhang, Yuanbo; Wang, Juan; Wang, Jia; Su, Zijian; Li, Guanghui; Jiang, Tao

    2018-06-01

    Magnetic reduction roasting followed by magnetic separation process is reported as a simple route to realize separation of Mn and Fe from ferruginous manganese ores (Fe-Mn ores). However, the separation and recovery of Mn and Fe oxides are not very effective. This work clarified the underlying reason for the poor separation and also proposed some suggestions for the magnetic reduction process. In this work, the effect of temperature on the magnetic reduction roasting - magnetic separation of Fe-Mn ore was investigated firstly. Then the reduction behaviors of MnO2-Fe2O3 system and MnO2-Fe2O3-10 wt.%SiO2 system under 10 vol.% CO-90 vol.% CO2 at 600-1000 °C were investigated by XRD, XPS, SEM-EDS, VSM, DSC and thermodynamics analyses. Reduction and separation tests showed that higher reduction temperature was beneficial to the recovery of iron while it's not in favor of the recovery of manganese when the temperature was over 800 °C. The formation of composite oxide MnxFe3-xO4 with strong magnetism between the interface of the MnO2 and Fe2O3 particles leaded to the poor separation of iron and manganese. In addition, the formation mechanism of MnxFe3-xO4 from MnO2 and Fe2O3 as well as the interface reaction reduced under 10 vol.% CO was discussed in this study. Finally, some suggestions were recommended for the magnetic reduction roasting for utilizing the Fe-Mn ores effectively.

  14. Photocatalytic and microwave absorbing properties of polypyrrole/Fe-doped TiO2 composite by in situ polymerization method

    International Nuclear Information System (INIS)

    Li Qiaoling; Zhang Cunrui; Li Jianqiang

    2011-01-01

    Research highlights: → Polypyrrole/Fe-doped TiO 2 composite is prepared by in situ polymerization of pyrrole on the Fe-doped TiO 2 template. → The Fe-doped TiO 2 microbelts are prepared by sol-gel method using the absorbent cotton template for the first time. → Then the Fe-doped TiO 2 microbelts are used as template for the preparation of polypyrrole/Fe-doped TiO 2 composites. → The structure, morphology and properties of the composites are characterized with scanning electron microscope (SEM), IR, Net-work Analyzer. → A possible formation mechanism of Fe-doped TiO 2 microbelts and polypyrrole/Fe-doped TiO 2 composites has been proposed. → The effect of the mol ratio of pyrrole/Fe-doped TiO 2 on the photocatalysis properties and microwave loss properties of the composites is investigated. - Abstract: The Fe-doped TiO 2 microbelts were prepared by sol-gel method using the absorbent cotton template for the first time. Then the Fe-doped TiO 2 microbelts were used as templates for the preparation of polypyrrole/Fe-doped TiO 2 composites. Polypyrrole/Fe-doped TiO 2 composites were prepared by in situ polymerization of pyrrole on the Fe-doped TiO 2 template. The structure, morphology and properties of the composites were characterized with scanning electron microscope (SEM), FTIR, Net-work Analyzer. The possible formation mechanisms of Fe-doped TiO 2 microbelts and polypyrrole/Fe-doped TiO 2 composites have been proposed. The effect of the molar ratio of pyrrole/Fe-doped TiO 2 on the photocatalytic properties and microwave loss properties of the composites was investigated.

  15. TiO2 Surface Coating of Mn-Zn Dopped Ferrites Study

    DEFF Research Database (Denmark)

    Solný, Tomáš; Ptacek, Petr; Másilko, Jiří

    2016-01-01

    This study deals with TiO2 coating of powder Mn-Zn ferrite in order to recieve photocatalytic layer on the top of these particles, forming core-shell catalyst. Powder catalysts are of great advance over the world due to the high surface area, considering the kinetics proceeds through heterogenous...... phase boundary catalysis. However their withdrawal from cleaning systems often requires energetically and economically demanding processes such as filtration and ultrafiltration. Since the ferrite is magnetic, the advantage of such formed core-shell photocatalyst is easibility of removing from...... photocatalytic decomposition system using external magnetic field. In this study the surface coating is performed, using Ti alkoxides mixtures with nanosized TiO2 particles and C and Au coating to form film layer of TiO2 on the surface of ferrite. XRD, SEM – EDS analyses are employed to study surface coating....

  16. TiC/Fe-Al复合陶瓷材料量子化学计算研究%Quantum Chemistry Calculation on Composite Ceramics of TiC/Fe-Al

    Institute of Scientific and Technical Information of China (English)

    闵新民; 许德华; 叶春勇

    2006-01-01

    用离散变分密度泛函方法研究了TiC、FeAl、Fe3Al和TiC/Fe-Al复合陶瓷材料,讨论了材料组成、结构、化学键与性能等之间的关系.在TiC/FeAl和TiC/Fe3Al复合体系中,界面上两相之间的离子和共价相互作用都较强.从TiC、FeAl和Fe3Al单相,到TiC/FeAl和TiC/Fe3Al复合体系,离子键强度逐渐减弱,而共价键强度逐渐增强.TiC/Fe3Al复合体系中轨道相互作用和共价键比TiC/FeAl的强.这与TiC/Fe-Al系列样品中,随铝含量逐渐减少,即FeAl含量逐渐减少,Fe3Al逐渐增多,抗弯强度等增加的实验结果一致.

  17. Magnetic, electrical transport and electron spin resonance studies of Fe-doped manganite LaMn0.7Fe0.3O3+δ

    International Nuclear Information System (INIS)

    Liu, X.J.; Li, Z.Q.; Yu, A.; Liu, M.L.; Li, W.R.; Li, B.L.; Wu, P.; Bai, H.L.; Jiang, E.Y.

    2007-01-01

    We have investigated the magnetic, electrical transport and electron spin resonance (ESR) properties of polycrystalline Fe-doped manganite LaMn 0.7 Fe 0.3 O 3+ δ prepared by sol-gel method. A typical cluster-glass feature is presented by DC magnetization and AC susceptibility measurements and a sharp but shallow memory effect was observed. Symmetrical Lorentzian lines of the Mn/Fe spectra were detected above 120 K, where the sample is a paramagnetic (PM) insulator. When the temperature decreases from 120 K, magnetic clusters contributed from ferromagnetic (FM) interaction between Mn 3+ and Mn 3+ /Fe 3+ ions develop and coexist with PM phase. At lower temperature, these FM clusters compete with antiferromagnetic (AFM) ones between Fe 3+ ions, which are associated with a distinct field-cooled (FC) effect in characteristic of cluster-glass state

  18. First-principle study on magnetic properties of Mn/Fe codoped ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Chen Hongxia, E-mail: chenhongxia1@sina.com [College of Physical Science and Electronic Techniques, Yancheng Teachers University, Yancheng 224002 (China); Department of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2012-07-15

    We studied the magnetic properties of Mn/Fe codoped ZnS comparatively with and without defects using first-principle calculation. The calculated results indicate that the Mn/Fe codoped ZnS system tends to stabilize in a ferrimagnetic (FiM) configuration. To obtain a ferromagnetic (FM) configuration, we consider the doped system with defects, such as S or Zn vacancy. The calculated results indicate that the doped system with Zn vacancy favors FiM states. Although the FM states of the doped system with S vacancy are more stable than the FiM states in negative charge states, the FM states are not stable enough to exist. Finally, we replaced an S atom by a C atom in the doped system. The C atom prefers to substitute the S atom connecting Mn and Fe atoms. The formation energy of this defect is -0.40 eV, showing that Mn/Fe/C codoped ZnS can be fabricated easily by experiments. Furthermore, the FM state was lower in energy than the FiM state by 114 meV. Such a large energy difference between the FM and FiM states implies that room temperature ferromagnetism could be expected in such a system. - Highlights: Black-Right-Pointing-Pointer Mn/Fe codoped ZnS system tends to stabilize in a ferrimagnetic configuration with or without defects. Black-Right-Pointing-Pointer By additional C codoping, the doped system tends to stabilize in a ferromagnetic configuration. Black-Right-Pointing-Pointer Energy difference between ferrimagnetic and ferromagnetic states is 114 meV. Black-Right-Pointing-Pointer This indicates room temperature ferromagnetism can be likely in such a system.

  19. Enhanced exchange bias in MnN/CoFe bilayers after high-temperature annealing

    Science.gov (United States)

    Dunz, M.; Schmalhorst, J.; Meinert, M.

    2018-05-01

    We report an exchange bias of more than 2700 Oe at room temperature in MnN/CoFe bilayers after high-temperature annealing. We studied the dependence of exchange bias on the annealing temperature for different MnN thicknesses in detail and found that samples with tMnN > 32nm show an increase of exchange bias for annealing temperatures higher than TA = 400 °C. Maximum exchange bias values exceeding 2000 Oe with reasonably small coercive fields around 600 Oe are achieved for tMnN = 42, 48 nm. The median blocking temperature of those systems is determined to be 180 °C after initial annealing at TA = 525 °C. X-ray diffraction measurements and Auger depth profiling show that the large increase of exchange bias after high-temperature annealing is accompanied by strong nitrogen diffusion into the Ta buffer layer of the stacks.

  20. Aleaciones cuasicristalinas Al93Fe3Cr2Ti2

    Directory of Open Access Journals (Sweden)

    García-Escorial, Asunción

    2015-12-01

    Full Text Available Aluminium alloy powder having a nominal composition of Al93Fe3Cr2Ti2 (at% has been prepared using gas atomisation. The atomised powder present a microstructure of an aluminium matrix reinforced with a spherical quasicrystalline icosahedral phase, in the range of nanometre in size. The powder was consolidated into bars using warm extrusion. The microstructure of the extruded bars retains the quasicrystalline microstructure and the bars present outstanding mechanical properties, i.e. proof stress of 280 MPa at 300 °C. Upon heating the microstructure evolves towards the equilibrium. The thermal evolution was investigated by means of x-ray diffraction, differential scanning calorimeter, scanning electron microscopy and transmission electron microscopy. According to these observations a transformation in two steps is proposed. A first step consists in the decomposition of the supersaturated solid solution of the matrix and the quasicrystals, and a second step in the transformation of the quasicrystals into the equilibrium phases.Se ha obtenido por atomización por gas polvo de la aleación Al93Fe3Cr2Ti2 (at%. Este polvo presenta una microestructura de una matriz de aluminio reforzada por precipitados icosaédricos de tamaño nanométrico. El polvo fue consolidado por extrusión en forma de barras cilíndricas. La microestructura de las barras retiene la microestructura cuasicristalina de las partículas de polvo. El material consolidado presenta propiedades mecánicas prometedoras, como un límite elástico de 280 MPA a 300 °C. Con los tratamientos térmicos, la microestructura evoluciona hacia el equilibrio. Esta evolución se estudia por difracción de rayos x, calorimetría diferencial de barrido, microscopías electrónicas de barrido y de transmisión. A la luz de los resultados obtenidos se propone que la transformación de las fases con el tiempo de tratamiento térmico ocurre en dos pasos. Primeramente, tiene lugar la descomposición de la

  1. New Insights into Mn1−xZnxFe2O4 via Fabricating Magnetic Photocatalyst Material BiVO4/Mn1−xZnxFe2O4

    Directory of Open Access Journals (Sweden)

    Taiping Xie

    2018-02-01

    Full Text Available BiVO4/Mn1−xZnxFe2O4 was prepared by the impregnation roasting method. XRD (X-ray Diffractometer tests showed that the prepared BiVO4 is monoclinic crystal, and the introduction of Mn1−xZnxFe2O4 does not change the crystal structure of BiVO4. The introduction of a soft-magnetic material, Mn1−xZnxFe2O4, was beneficial to the composite photocatalyst’s separation from the liquid solution using an extra magnet after use. UV-vis spectra analysis indicated that Mn1−xZnxFe2O4 enhanced the absorption intensity of visible light for BiVO4. EIS (electrochemical impedance spectroscopy investigation revealed that the introduction of Mn1−xZnxFe2O4 enhanced the conductivity of BiVO4, further decreasing its electron transfer impedance. The photocatalytic efficiency of BiVO4/Mn1−xZnxFe2O4 was higher than that of pure BiVO4. In other words, Mn1−xZnxFe2O4 could enhance the photocatalytic reaction rate.

  2. Microstructural Influence on Dynamic Properties of Age Hardenable FeMnAl Alloys

    Science.gov (United States)

    2011-04-01

    strain amplitude on a wrought Fe-28Mn-9Al-0.86C-0.7W-0.43Mo-0.49Nb alloy and on a martensitic stainless steel of composition Fe-12Cr-1.25Ni-0.2V-1.8W...the martensite and loss of strength was used to explain the lower cyclic life of the stainless steel at elevated temperatures. Within the Fe-Mn-Al-C...through F in Table 2), 1010 carbon steel and 304 stainless steel as functions of exposure time in 1 atm flowing oxygen at 700°C (a) and 500°C (b).56

  3. Effect of Ti seed and spacer layers on structure and magnetic properties of FeNi thin films and FeNi-based multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Svalov, A.V., E-mail: andrey.svalov@ehu.es [Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48080 Bilbao (Spain); Department of Magnetism and Magnetic Nanomaterials, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Larrañaga, A. [SGIker, Servicios Generales de Investigación, Universidad del País Vasco (UPV/EHU), 48080 Bilbao (Spain); Kurlyandskaya, G.V. [Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48080 Bilbao (Spain); Department of Magnetism and Magnetic Nanomaterials, Ural Federal University, 620002 Ekaterinburg (Russian Federation)

    2014-10-15

    Highlights: • Fe{sub 19}Ni{sub 81} films and FeNi-based multilayers were prepared by magnetron sputtering. • The samples were deposited onto glass substrates at room temperature. • Ti/FeNi films exhibit good (1 1 1) texture and crystallinity. • The thick Cu seed increases the coercive force of the magnetic layer. • The thin Ti spacer restores the magnetic softness of the Cu/Ti/FeNi multilayers. - Abstract: The microstructure and magnetic properties of sputtered permalloy films and FeNi-based multilayers prepared by magnetron sputtering have been studied. X-ray diffraction measurements indicate that Ti/FeNi films exhibit good (1 1 1) texture and crystallinity. Ti/FeNi bilayers with high crystallographic quality have relatively low resistivity. The Ti seed layer does not influence the magnetic properties of FeNi film in Ti/FeNi bilayers, but the thick Cu seed layer leads to an increase of the coercive force of the magnetic layer. For the FeNi films deposited on thick Cu seed layer, the (0 1 0) and (0 0 2) diffraction peaks of hcp nickel were clearly observed. The thin Ti spacer between Cu and FeNi layers prevents the formation of the nickel phase and restores the magnetic softness of the FeNi layer in the Cu/Ti/FeNi sample. Obtained results can be important for the development of multilayer sensitive elements for giant magnetoimpedance or magnetoresistance detectors.

  4. Mn-coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetron sputtering for dental applications

    Science.gov (United States)

    Park, Seon-Yeong; Choe, Han-Cheol

    2018-02-01

    In this study, Mn-coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetrons sputtering for dental applications were studied using different experimental techniques. Mn coating films were formed on Ti-29Nb-xHf alloys by a radio frequency magnetron sputtering technique for 0, 1, 3, and 5 min at 45 W. The microstructure, composition, and phase structure of the coated alloys were examined by optical microscopy, field emission scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The microstructure of Ti-29Nb alloy showed α" phase in the needle-like structure and Ti-29Nb-15Hf alloy showed β phase in the equiaxed structure. As the sputtering time increased, the circular particles of Mn coatings on the Ti-29Nb alloy increased at inside and outside surfaces. As the sputtering time increased, [Mn + Ca/P] ratio of the plasma electrolytic oxidized films in Ti- 29Nb-xHf alloys increased. The corrosion potential (Ecorr) of Mn coatings on the Ti-29Nb alloy showed higher than that of Mn coatings on the Ti-29Nb-15Hf alloy. The passive current density (Ipass) of the Mn coating on the Ti-29Nb alloy and Mn coatings on the Ti-29Nb-15Hf alloy was less noble than the non-Mn coated Ti-29Nb and Ti-29Nb-15Hf alloys surface.

  5. Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

    2016-03-01

    Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.

  6. Effect of chitosan coating on the structural and magnetic properties of MnFe2O4 and Mn0.5Co0.5Fe2O4 nanoparticles

    Science.gov (United States)

    Mdlalose, W. B.; Mokhosi, S. R.; Dlamini, S.; Moyo, T.; Singh, M.

    2018-05-01

    We report the influence of polymer coatings on structural and magnetic properties of MnFe2O4 and Mn0.5Co0.5Fe2O4 nanoferrites synthesized by glycol thermal technique and then coated with chitosan viz. CHI-MnFe2O4 and CHI-Mn0.5Co0.5Fe2O4. The compounds were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), high-resolution scanning electron microscopy (HRSEM), Mössbauer spectroscopy and magnetization measurements. The powder XRD patterns of naked nanoferrites confirmed single-phase spinel cubic structure with an average crystallite size of 13 nm, while the coated samples exhibited an average particle size of 15 nm. We observed a reduction in lattice parameters with coating. HRTEM results correlated well with XRD results. 57Fe Mössbauer spectra showed ordered magnetic spin states in both nanoferrites. This study shows that coatings have significant effects on the structural and magnetic properties of Mn-nanoferrites. Magnetization studies performed at room temperature in fields up to 14 kOe revealed the superparamagnetic nature of both naked and coated nanoparticles with spontaneous magnetizations at room temperature of 49.2 emu/g for MnFe2O4, 23.6 emu/g for coated CHI-MnFe2O4 nanoparticles, 63.2 emu/g for Mn0.5Co0.5Fe2O4 and 33.2 emu/g for coated CHI-Mn0.5Co0.5Fe2O4 nanoparticles. We observed reduction in coercive fields due to coating. Overall, chitosan-coated manganese and manganese-cobalt nanoferrites present as suitable candidates for biomedical applications owing to physicochemical, and magnetic properties exhibited.

  7. The electrochemical properties of Zr-Ti-V-Ni-Mn hydrogen storage alloys with various compositions for an electrode of Ni-MH secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Jun; Jung, So Yi; Park, Choong Nyeon [Dept. of Metallurgical Engineering, Chonnam National University, Kwangju (Korea)

    1999-12-01

    Effects of alloy modification for the Zr{sub 0.7}Ti{sub 0.3}V{sub 0.4}Ni{sub 1.2}Mn{sub 0.4} alloy as an electrode materials have been investigated. When Ti in the alloy was partially substituted by Zr, the hydrogen storage capacity and subsequently the discharge capacity increased significantly, however, the activation characteristic and rate capability decreased. By substituting Mn with other elements (Cr, Co and Fe) in the alloy, discharge capacity decreased but the cycle life and rate capability were improved. Considering both the discharge capacity, the high rate discharge property and cycle life, the Zaire.{sub 7}Ti{sub 0.3}V{sub 0.4}Ni{sub 1.2}Mn{sub 0.3}Cr{sub 0.1} alloy among the alloys subjected to the test was found to be a prominent alloy for a practical usage. 11 refs., 5 figs., 2 tabs.

  8. Local moments, exchange interactions, and magnetic order in Mn-doped LaFe2Si2 alloys

    International Nuclear Information System (INIS)

    Turek, I.; Divis, M.; Niznansky, D.; Vejpravova, J.

    2007-01-01

    Formation of local magnetic moments in the intermetallic compound LaFe 2 Si 2 due to doping by a few at% of Mn has been investigated by theoretical and experimental tools. While a number of low-temperature experiments prove appearance of non-zero magnetic moments due to the Mn doping, the measured 57 Fe Moessbauer spectra rule out sizable local moments of Fe atoms. This conclusion is in agreement with results of first-principles electronic structure calculations that yield non-vanishing moments only on Mn atoms. The calculated Mn-Mn exchange interactions are of both signs which indicate a magnetically frustrated ground state, probably with a spin-glass-like arrangement of the Mn moments

  9. Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weiwen, E-mail: mewzhang@scut.edu.cn; Lin, Bo; Fan, Jianlei; Zhang, Datong; Li, Yuanyuan

    2013-12-20

    The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al{sub 7}Cu{sub 2}Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese script Al{sub m}Fe, α-Fe or Al{sub 6}(FeMn) partially transform to a new Chinese script Cu-rich α(CuFe) (Al{sub 7}Cu{sub 2}Fe or Al{sub 7}Cu{sub 2}(FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al{sub 20}Cu{sub 2}Mn{sub 3}), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively.

  10. Structural and dielectric characteristics of double perovskite La2(NiFe)1/2MnO6

    Science.gov (United States)

    Nasir, Mohd.; Kandasami, Asokan; Sen, Somaditya

    2018-05-01

    Recently, La2NiMnO6 has drawn significant interest because large magnetic field induced changes in dielectric properties makes this compound a promising material for potential spintronic device applications. In the present study, the structural and dielectric characteristics of sol-gel prepared La2(Ni1/2Fe1/2)MnO6 double perovskite ceramics were evaluated. La2(Ni1/2Fe1/2)MnO6 was crystallized in the monoclinic P21/n structure with ordered Ni2+/Fe2+ and Mn4+ cations. A giant dielectric constant with relaxor-like behavior was observed, which was attributed to the dipolar effects arising from hopping between Ni2+/Fe2+ and Mn4+ ions.

  11. Effect of Chlorine precursor in surface and cataytic properties of Fe/TiO2 Catalysts

    OpenAIRE

    López, Tessi; Pecchi, Gina; Moreno, Abel; García Fierro, José Luis; Gómez, R.; Reyes, P.

    2002-01-01

    Titania-supported iron (1wt%) catalysts were prepared by the sol-gel method using different gelation pH (3 and 9), metal precursors (FeCl2 and FeCl3) and calcination temperatures (873 and 1073K). Characterization data of calcined catalysts revealed that in all samples the dominant iron species is Fe3+ and the crystalline phase of the TiO2 substrate depends on the gelation pH and the metal precursor used. It was found that in the Fe/TiO2 ex-FeCl3 samples an important part of the iron ions beca...

  12. Synthesis and enhanced electrochemical performance of the honeycomb TiO2/LiMn2O4 cathode materials

    DEFF Research Database (Denmark)

    Zhang, J.Y.; Shen, J.X.; Wei, C.B.

    2016-01-01

    angle compare to LiMn2O4, implying that TiO2 doping induced a change of crystal structure. By performing electrochemical measurements, we observed an enhancement of specific capacity (127.28 mAhg−1) and an improvement of cycling stability in the TiO2/LiMn2O4 hybrid materials. After 100 cycles of charge...

  13. Fe-Mn bi-metallic oxides loaded on granular activated carbon to enhance dye removal by catalytic ozonation.

    Science.gov (United States)

    Tang, Shoufeng; Yuan, Deling; Zhang, Qi; Liu, Yameng; Zhang, Qi; Liu, Zhengquan; Huang, Haiming

    2016-09-01

    A Fe-Mn bi-metallic oxide supported on granular activated carbon (Fe-Mn GAC) has been fabricated by an impregnation-desiccation method and tested in the catalytic ozonation of methyl orange (MO) degradation and mineralization. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy characterizations revealed that Fe-Mn oxides were successfully loaded and uniformly distributed on the GAC, and nitrogen adsorption isotherms showed that the supported GAC retained a large surface area and a high pore volume compared with the pristine GAC. The catalytic activity was systematically assessed by monitoring the MO removal efficiencies at different operational parameters, such as catalyst dosage, initial solution pH, and ozone flow rate. The Fe-Mn GAC exhibited better catalytic activity relative to ozone alone and GAC alone, improving the TOC removal by 24.5 and 11.5 % and COD removal by 13.6 and 7.3 %, respectively. The reusability of the hybrid was examined over five consecutive cyclic treatments. The Fe-Mn GAC catalytic activity was only a slight loss in the cycles, showing good stability. The addition of Na2CO3 as hydroxyl radicals (•OH) scavengers proved that the catalytic ozonation mechanism was the enhanced generation of •OH by the Fe-Mn GAC. The above results render the Fe-Mn GAC an industrially promising candidate for catalytic ozonation of dye contaminant removal.

  14. Sulphur mustard degradation on zirconium doped Ti-Fe oxides

    Energy Technology Data Exchange (ETDEWEB)

    Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Grygar, Tomas Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno Veslarska 230, 628 00 Brno (Czech Republic)

    2011-09-15

    Highlights: {yields} New stechiometric materials for sulphur mustard degradation. {yields} High degree of degradation, more then 95% h{sup -1}. {yields} One-pot synthesis procedure. - Abstract: Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr{sup 4+} dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr{sup 4+} to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr{sup 4+} doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.

  15. FeOOH-loaded MnO2 nano-composite: An efficient emergency material for thallium pollution incident.

    Science.gov (United States)

    Chen, Meiqing; Wu, Pingxiao; Yu, Langfeng; Liu, Shuai; Ruan, Bo; Hu, Haihui; Zhu, Nengwu; Lin, Zhang

    2017-05-01

    A FeOOH-loaded MnO 2 nano-composite was developed as an emergency material for Tl(I) pollution incident. Structural characterizations showed that FeOOH successfully loaded onto MnO 2 , the nanosheet-flower structure and high surface area (191 m 2  g -1 ) of material contributed to the excellent performance for Tl(I) removal. FeOOH-loaded MnO 2 with a Fe/Mn molar ratio of 1:2 exhibited a noticeable enhanced capacity for Tl(I) removal compared to that of pure MnO 2 . The outstanding performance for Tl(I) removal involves in extremely high efficiency (achieved equilibrium and drinking water standard within 4 min) and the large maximum adsorption capacity (450 mg g -1 ). Both the control-experiment and XPS characterization proved that the removal mechanism of Tl(I) on FeOOH-loaded MnO 2 included adsorption and oxidation: the oxidation of MnO 2 played an important role for Tl(I) removal, and the adsorption of FeOOH loaded on MnO 2 enhanced Tl(I) purification at the same time. In-depth purification of Tl(I) had reach drinking water standards (0.1 μg L -1 ) at pH above 7, and there wasn't security risk produced from the dissolution of Mn 2+ and Fe 2+ . Moreover, the as-prepared material could be utilized as a recyclable adsorbent regenerated by using NaOH-NaClO binary solution. Therefore, the synthesized FeOOH-loaded MnO 2 in this study has the potential to be applied as an emergency material for thallium pollution incident. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Reduced-activation austenitic stainless steels: The Fe--Mn--Cr--C system

    International Nuclear Information System (INIS)

    Klueh, R.L.; Maziasz, P.J.

    1988-01-01

    Nickel-free manganese-stabilized steels are being developed for fusion-reactor applications. As the first part of this effort, the austenite-stable region in the Fe--Mn--Cr--C system was determined. Results indicated that the Schaeffler diagram developed for Fe--Ni--Cr--C alloys cannot be used to predict the constituents expected for high-manganese steels. This is true because manganese is not as strong an austenite stabilizer relative to δ-ferrite formation as predicted by the diagram, but it is a stronger austenite stabilizer relative to martensite than predicted. Therefore, the austenite-stable region for Ne--Mn--Cr--C alloys occurs at lower chromium and hugher combinations of manganese and carbon than predicted by the Schaeffler diagram. Development of a manganese-stabilized stainless steel should be possible in the composition range of 20 to 25% Mn, 10 to 15% Cr, and 0.01 to 0.25%C. Tensile behavior of an Fe--20%Mn--12%Cr--0.25%C alloy was determined. The strength and ductility of this possible base composition was comparable to type 316 stainless steel in both the solution-annealed and cold-worked condition

  17. Dielectric properties of Mn doped SrTiO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Savinov, Maxim; Trepakov, Vladimír; Syrnikov, P. P.; Železný, Vladimír; Pokorný, Jan; Deyneka, Alexander; Jastrabík, Lubomír; Galinetto, P.

    2008-01-01

    Roč. 20, - (2008), 095221/1-095221/6 ISSN 0953-8984 R&D Projects: GA AV ČR KAN301370701; GA AV ČR 1QS100100563; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z10100521 Keywords : dielectric permittivity * IR reflectivity * SrTiO3:Mn Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.900, year: 2008

  18. Phase transformation, magnetic property and microstructure of Ni-Mn-Fe-Co-Ga ferromagnetic shape memory alloys

    International Nuclear Information System (INIS)

    Tsuchiya, K.; Sho, Y.; Kushima, T.; Todaka, Y.; Umemoto, M.

    2007-01-01

    Effects of addition of Fe and Co on the phase stability, magnetic property and microstructures were investigated for Ni-Mn-Ga. In Ni-Mn 21- x -Fe x -Ga 27 alloys, martensitic transformation temperatures decreased with increasing amount of Fe (x) up to 15 mol%, then slightly increased by the further addition. The crystal structure of martensite phase was 10 M for x 15 mol%. Relatively high martensite stability was obtained for Ni 52 -Mn 16- x -Fe x -Co 5 -Ga 27 alloys. The highest stability of the ferromagnetic martensite phase was achieved in Ni 52 -Mn 6 -Fe 10 -Co 5 -Ga 27 after aging at 773 K for 3.6 ks. Martensite structure was non-modulated 2 M in this series of alloys

  19. Body retention and tissue distribution of 59Fe and 54Mn in newborn rats fed iron-supplemented cow's milk

    International Nuclear Information System (INIS)

    Gruden, Nevenka

    1980-01-01

    The effect of iron-fortified cow's milk on body 59 Fe and 54 Mn retention and selective tissue distribution has been studied in newborn rats. Six-day old rats, divided into three groups were artificially fed for 7 hrs 0,45 ml of cow's milk or cow's milk enriched with either 52 or 103 μg of Fe /ml and marked with 59 Fe and 54 Mn. After 4 days there was no significant difference in whole body or carcass activity between the groups. Iron added to milk in large amounts did not influence body 59 Fe or 54 Mn retention in newborn rats, whereas it enhanced 59 Fe deposition in the liver and the intestinal wall and, to a lesser extent, 54 Mn deposition in the liver

  20. One-pot hydrothermal synthesis, characterization, and electrochemical properties of rGO/MnFe2O4 nanocomposites

    Science.gov (United States)

    Kotutha, Isara; Swatsitang, Ekaphan; Meewassana, Worawat; Maensiri, Santi

    2015-06-01

    In this work, a simple facile route for preparing an rGO/MnFe2O4 nanocomposite through a one-pot hydrothermal approach was demonstrated. Graphite oxide (GO) was prepared from graphite powder by a modified Hummers method. Fe(NO3)2 • 9H2O and Mn(NO3)2 • H2O were used as the precursors for the preparation of the rGO/MnFe2O4 nanocomposite. The formation of the rGO/MnFe2O4 nanocomposite was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Rama spectroscopy (Raman). The specific surface area of the prepared composite obtained by Brunauer-Emmett-Teller (BET) analysis was lower than that of pure rGO but higher than that of pure MnFe2O4. Consequently, the electrochemical performance was investigated by using a three-electrode cell system in 6.0 M KOH. The results show that the specific capacitance was determined to be 190.3, 276.9, and 144.5 F/g at a scan rate of 10 mV/s, and 194.9, 274.6, and 134.4 F/g at a current density of 5.0 A/g for rGO, rGO/(5 mmol) MnFe2O4, and rGO/(10 mmol) MnFe2O4, respectively. These results suggest that the composite of MnFe2O4 nanoparticles on an rGO nanosheet can improve the capacitive behavior of the fabricated electrode, but the electrochemical properties are reduced when the MnFe2O4 concentration ratio is high.

  1. The investigation of Fe-Mn-based alloys with shape memory effect by small-angle scattering of polarized neutrons

    International Nuclear Information System (INIS)

    Kopitsa, G.P.; Runov, V.V.; Grigoriev, S.V.; Bliznuk, V.V.; Gavriljuk, V.G.; Glavatska, N.I.

    2003-01-01

    The small-angle polarized neutron scattering (SAPNS) technique has been used to study a nuclear and magnetic homogeneity in the distribution of both substituent (Si, Cr, Ni) and interstitial (C, N) alloying elements on the mesoscopic range in Fe-Mn-based alloys with shape memory effect (SME). The four groups of alloys with various basic compositions: FeMn 18 (wt%), FeMn 20 Si 6 , FeMn 20 Cr 9 N 0.2 and FeMn 17 Cr 9 Ni 4 Si 6 were investigated. It was found that the small-angle scattering of neutrons and depolarization on these alloys are very small altogether. The scattering did not exceed 1.5% from the incident beam and depolarization ∼2% for all samples. It means that these alloys are well nuclear and magnetically homogeneous on the scale of 10-1000 A. However, the difference in the homogeneity depending on the compositions still takes place. Thus, the adding of Si in FeMn 18 and FeMn 20 Cr 9 N 0.2 alloys improves the homogeneity pronouncedly. At once, the effect of the doping by C or N atoms on the homogeneity in FeMn 20 Si 6 and FeMn 17 Cr 9 Ni 4 Si 6 alloys is multivalued and depend on the presence of substitutional atoms (Ni and Cr). The capability of SAPNS as a method for the study of mesoscopic homogeneity in materials with SME and testing of the quality of their preparation is discussed

  2. Qualitative analysis of As, Ba, Cd, Cr, Zn, Fe, Mn, K, Hg, Pb y Cu, as constituents of Amatitlan Lake sediment by XRF

    International Nuclear Information System (INIS)

    Beltran, P.A.E.; Morales, E.A.

    1987-10-01

    Samples of fifteen sampling points were analyzed. Molybdenum X-ray tube with secondary excitation assembly, SiLi detector and deconvolution software AXIL were employed; self-standardization method based upon incoherent ratio was used for quantitative analysis of some elements. Ca, P, S, Ti, Mn, Fe, Cr, Zn, Cu, Ni, Ga, As, Pb, Ge, Sr and Pb, were found. As, Pb and Cu concentrations lower than 109 mg/lt, 119 mg/lt, and 500mg/lt, respectively, were measured. Hg was not detected. (author)

  3. Magnetron Sputtering as a Fabrication Method for a Biodegradable Fe32Mn Alloy

    Directory of Open Access Journals (Sweden)

    Till Jurgeleit

    2017-10-01

    Full Text Available Biodegradable metals are a topic of great interest and Fe-based materials are prominent examples. The research task is to find a suitable compromise between mechanical, corrosion, and magnetic properties. For this purpose, investigations regarding alternative fabrication processes are important. In the present study, magnetron sputtering technology in combination with UV-lithography was used in order to fabricate freestanding, microstructured Fe32Mn films. To adjust the microstructure and crystalline phase composition with respect to the requirements, the foils were post-deposition annealed under a reducing atmosphere. The microstructure and crystalline phase composition were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. Furthermore, for mechanical characterization, uniaxial tensile tests were performed. The in vitro corrosion rates were determined by electrochemical polarization measurements in pseudo-physiological solution. Additionally, the magnetic properties were measured via vibrating sample magnetometry. The foils showed a fine-grained structure and a tensile strength of 712 MPa, which is approximately a factor of two higher compared to the sputtered pure Fe reference material. The yield strength was observed to be even higher than values reported in literature for alloys with similar composition. Against expectations, the corrosion rates were found to be lower in comparison to pure Fe. Since the annealed foils exist in the austenitic, and antiferromagnetic γ-phase, an additional advantage of the FeMn foils is the low magnetic saturation polarization of 0.003 T, compared to Fe with 1.978 T. This value is even lower compared to the SS 316L steel acting as a gold standard for implants, and thus enhances the MRI compatibility of the material. The study demonstrates that magnetron sputtering in combination with UV-lithography is a new concept for the fabrication of already in situ

  4. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xinyi Zhang

    2015-11-01

    Full Text Available Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4 cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g−1 increases from 112.2 mAh g−1 of Li2.0MnTiO4 to 187.5 mAh g−1 of Li2.4Mn0.8TiO4. In addition, the ex situ XRD experiments indicate that the monoclinic Li2MnTiO4 tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li2MnTiO4 phase shows better structural reversibility and stability.

  5. Study of the Thermodynamics of Chromium(III) and Chromium(VI) Binding to Fe3O4 and MnFe2O4 nanoparticles

    Science.gov (United States)

    Luther, Steven; Brogfeld, Nathan; Kim, Jisoo; Parsons, J.G.

    2013-01-01

    Removal of chromium(III) or (VI) from aqueous solution was achieved using Fe3O4, and MnFe2O4 nanomaterials. The nanomaterials were synthesized using a precipitation method and characterized using XRD. The size of the nanomaterials was determined to be 22.4 ± 0.9 nm (Fe3O4) and 15.5 ± 0.5 nm (MnFe2O4). The optimal binding pH for chromium(III) and chromium(VI) were pH 6 and pH 3. Isotherm studies were performed, under light and dark conditions, to determine the capacity of the nanomaterials. The capacities for the light studies with MnFe2O4 and Fe3O4 were determined to be 7.189 and 10.63 mg/g, respectively, for chromium(III). The capacities for the light studies with MnFe2O4 and Fe3O4 were 3.21 and 3.46 mg/g, respectively, for chromium(VI). Under dark reaction conditions the binding of chromium(III) to the MnFe2O4 and Fe3O4 nanomaterials were 5.74 and 15.9 mg/g, respectively. The binding capacity for the binding of chromium(VI) to MnFe2O4 and Fe3O4 under dark reaction conditions were 3.87 and 8.54 mg/g, respectively. The thermodynamics for the reactions showed negative ΔG values, and positive ΔH values. The ΔS values were positive for the binding of chromium(III) and for chromium(VI) binding under dark reaction conditions. The ΔS values for chromium(VI) binding under the light reaction conditions were determined to be negative. PMID:23558081

  6. Photocatalytic degradation of Rhodamine B dye using Fe doped TiO2 nanocomposites

    Science.gov (United States)

    Barkhade, Tejal; Banerjee, Indrani

    2018-05-01

    The unique properties of titanium dioxide (TiO2) such as high photo catalytic activity, high chemical stability and low toxicity have made it a suitable photocatalyst in recent decades. The effect of modification of TiO2 with doping of iron on its characteristics and photo catalytic efficiency was studied. The change in band gap energy of TiO2 nanoparticles after doping with Fe has been studied. Significant enhancement in photo catalytic property of TiO2 after Fe doping under light exposure conditions has been investigated. Acute exposure to non-biodegradable Rhodamine B resulted in many health problems like burning of eyes, skin irritation, nasal burning, and chest pain etc. Therefore, degradation of this dye is needed to save environment and animals. Considering the similar radius of Fe3+ and Ti4+ ions (respectively 0.64 Å and 0.68 Å), titanium position in the lattice of TiO2 can be replaced by iron cations easily. The undoped and Fe doped TiO2 nano composites were synthesized by sol-gel method, in which 1.0M% of Fe was doped with TiO2 and then the samples were characterized by using FE-SEM, UV-Visible diffuse spectroscopy, Raman Spectroscopy, and FTIR. Photo catalytic degradation of Rhodamine B dye experiment was carried out in visible light range. After 90 min time duration pink colour of dye turned colourless, indicating significant degradation rate with time.

  7. Precipitatation Behavior of FeTiP Phase in High Strength IF Steel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of chemical composition and annealing parameters on the behavior of FeTiP precipitation has been investigated. With increasing Ti content the yield strength and tensile strength were reduced, and the tendency of FeTiP precipitation became more remarkable. No FeTiP precipitate was observed and the best mechanical properties have been obtained in the steel sheet, of which the atom ratio of Ti to N is approximately equal to 1. In the temperature range of 700 to 800€℃ the FeTiP precipitation could appear easily. The precipitation process was suppressed when the annealing temperature was below 600€℃, and the FeTiP phase was dissolved above 900€℃. The FeTiP precipitates would inhibit the migration of grain boundaries during the recrystallization in certain extent, and weaken the density of {111} fiber texture, which resulted in the reduction of r value. The relationship between composition and processing parameters, as well as their influence on the mechanical properties is discussed.

  8. Fabrication of band gap engineered nanostructured tri-metallic (Mn-Co-Ti) oxide thin films

    Science.gov (United States)

    Mansoor, Muhammad Adil; Yusof, Farazila Binti; Nay-Ming, Huang

    2018-04-01

    In continuation of our previous studies on photoelectrochemical (PEC) properties of titanium based composite oxide thin films, an effort is made to develop thin films of 1:1:2 manganese-cobalt-titanium oxide composite, Mn2O3-Co2O3-4TiO2 (MCT), using Co(OAc)2 and a bimetallic manganese-titanium complex, [Mn2Ti4(TFA)8(THF)6(OH)4(O)2].0.4THF (1), where OAc = acetato, TFA = trifluoroacetato and THF = tetrahydrofuran, via aerosol-assisted chemical vapour deposition (AACVD) technique. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopic analyses confirmed formation of thin film of Mn2O3-Co2O3-4TiO2 composite material with uniformly distributed agglomerated particles. The average size of 39.5 nm, of the particles embedded inside agglomerates, was estimated by Scherer's equation. Further, UV-Vis spectroscopy was used to estimate the band gap of 2.62 eV for MCT composite thin film.

  9. Investigation of Ti-Fe-Co bulk alloys with high strength and enhanced ductility

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Kato, Hidemi; Inoue, Akihisa

    2005-01-01

    High-strength Ti-Fe-Co alloys were produced in the shape of arc-melted ingots with the dimensions of about 20-25mm in diameter and 7-10mm in height. The structure of the Ti-Fe-Co alloys (at Fe/Co ratio >1) studied by X-ray diffractometry and scanning electron microscopy consisted of an ordered Pm3-bar m Ti(FeCo) compound and a disordered body-centered cubic Im3-bar m β-Ti solid solution. The optimization of the Ti-Fe-Co alloy composition is performed from the viewpoint of both high strength and ductility. The strongest Ti-Fe-Co alloys have a hypereutectic structure and exhibit a high strength of about 2000MPa and a plastic deformation of 15%. The high strength and ductility values can be achieved without using the injection mould casting or rapid solidification procedure. The deformation behavior and the fractography of Ti-Fe-Co alloys are studied in detail

  10. Synthesis of nano-TiO2 photocatalysts with tunable Fe doping concentration from Ti-bearing tailings

    Science.gov (United States)

    Sui, Yulei; Liu, Qingxia; Jiang, Tao; Guo, Yufeng

    2018-01-01

    In this work, highly pure nano-TiO2 photocatalysts with varying Fe doping concentration were successfully synthesized from low-cost Ti-bearing tailings by an acidolysis-hydrothermal route. The effects of H2SO4 concentration, leaching temperature, acid/tailings ratio and leaching time on the recovery of TiO2 from the tailings were investigated. Synthesized samples were characterized by XRD, TEM, EDS, XPS, and UV-vis spectroscopy. The results showed that the material prepared is characteristic anatase with the average size of 20 nm and the Fe doping concentration in the synthesized nano-TiO2 is tunable. The photocatalytic activity of synthesized nano-TiO2 photocatalyst was also evaluated by the photodegradation of Rhodamine B under visible light and UV light irradiation. Our study demonstrates a low-cost approach to synthesize highly efficient and visible light responsive catalysts.

  11. Magnetic properties of PrMn2-xFexGe2-57Fe Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Wang, J L; Campbell, S J; Cadogan, J M; Tegus, O; Studer, A J; Hofmann, M

    2006-01-01

    We have investigated the magnetic behaviour of PrMn 2-x Fe x Ge 2 compounds with x = 0.4, 0.6 and 0.8 over the temperature range 4.2-350 K using ac magnetic susceptibility, dc magnetization and 57 Fe Moessbauer effect spectroscopy, as well as neutron diffraction for the PrMn 1.2 Fe 0.8 Ge 2 compound. Replacement of Mn with Fe leads to contraction of the unit cell and a shortening of the Mn-Mn spacing, resulting in modification of the magnetic structure. PrMn 1.6 Fe 0.4 Ge 2 is an intralayer antiferromagnet at room temperature and ferromagnetic below T C inter ∼230 K with additional ferromagnetic ordering of the Pr sublattice detected below T C Pr ∼30 K. Re-entrant ferromagnetism has been observed in PrMn 1.4 Fe 0.6 Ge 2 with four magnetic transitions (T N intra ∼333 K, T C inter ∼168 K, T N inter ∼152 K and T C Pr ∼40 K). Moreover, it was found that T C inter and T C Pr increase with applied field while T N inter decreases. PrMn 1.2 Fe 0.8 Ge 2 is antiferromagnetic with T N intra ∼242 K and T N inter ∼154 K. The magnetic transition temperatures for all compounds are also marked by changes in the 57 Fe magnetic hyperfine field and the electric quadrupole interaction parameters. The 57 Fe transferred hyperfine field at 4.5 K in PrMn 1.6 Fe 0.4 Ge 2 and PrMn 1.4 Fe 0.6 Ge 2 is reduced (below the ordering temperature of the Pr sublattice) compared with that at 80 K (above T C Pr ), indicating that the transferred hyperfine field from Pr acts in the opposite direction to that from the Mn atoms. The neutron data for PrMn 1.2 Fe 0.8 Ge 2 demonstrate that an anisotropic thermal expansion occurs within the interplanar antiferromagnetic range

  12. Coercivity and nanostructure of melt-spun Ti-Fe-Co-B-based alloys

    Directory of Open Access Journals (Sweden)

    W. Y. Zhang

    2016-05-01

    Full Text Available Nanocrystalline Ti-Fe-Co-B-based alloys, prepared by melt spinning and subsequent annealing, have been characterized structurally and magnetically. X-ray diffraction and thermomagnetic measurements show that the ribbons consist of tetragonal Ti3(Fe,Co5B2, FeCo-rich bcc, and NiAl-rich L21 phases; Ti3(Fe,Co5B2, is a new substitutional alloy series whose end members Ti3Co5B2 and Ti3Fe5B2 have never been investigated magnetically and may not even exist, respectively. Two compositions are considered, namely Ti11+xFe37.5-0.5xCo37.5−0.5xB14 (x = 0, 4 and alnico-like Ti11Fe26Co26Ni10Al11Cu2B14, the latter also containing an L21-type alloy. The volume fraction of the Ti3(Fe,Co5B2 phase increases with x, which leads to a coercivity increase from 221 Oe for x = 0 to 452 Oe for x = 4. Since the grains are nearly equiaxed, there is little or no shape anisotropy, and the coercivity is largely due to the magnetocrystalline anisotropy of the tetragonal Ti3(Fe,Co5B2 phase. The alloy containing Ni, Al, and Cu exhibits a magnetization of 10.6 kG and a remanence ratio of 0.59. Our results indicate that magnetocrystalline anisotropy can be introduced in alnico-like magnets, adding to shape anisotropy that may be induced by field annealing.

  13. Oxidation Resistance of Fe3Al/TiC Composite at High Temperature%Fe3Al/TiC复合材料的高温抗氧化性能

    Institute of Scientific and Technical Information of China (English)

    范敏; 鲍剑斌

    2003-01-01

    研究了Fe3Al/TiC复合材料的高温抗氧化性能.结果表明:Fe3Al/TiC复合材料在950℃的氧化动力学特征均近似服从抛物线规律,并且随TiC含量增加,Fe3Al/TiC复合材料的高温抗氧化性能降低.

  14. Tunneling magnetoresistance and electroresistance in Fe/PbTiO3/Fe multiferroic tunnel junctions

    International Nuclear Information System (INIS)

    Dai, Jian-Qing

    2016-01-01

    We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO 3 /Fe multiferroic tunnel junction with asymmetric TiO 2 - and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p z orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

  15. Tunneling magnetoresistance and electroresistance in Fe/PbTiO{sub 3}/Fe multiferroic tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jian-Qing, E-mail: djqkust@sina.com [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2016-08-21

    We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction with asymmetric TiO{sub 2}- and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p{sub z} orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

  16. Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Jingjing; Xu, Bajin; Ling, Guoping, E-mail: linggp@zju.edu.cn

    2014-06-01

    Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl{sub 2}–AlCl{sub 3}–1-ethyl-3-methylim-idazolium chloride (MnCl{sub 2}–AlCl{sub 3}–EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm{sup 2}, while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L{sub c} > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

  17. Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

    International Nuclear Information System (INIS)

    Ding, Jingjing; Xu, Bajin; Ling, Guoping

    2014-01-01

    Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl 2 –AlCl 3 –1-ethyl-3-methylim-idazolium chloride (MnCl 2 –AlCl 3 –EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm 2 , while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L c > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

  18. Crystal structure and magnetic properties of the Cr-doped spiral antiferromagnet BiMnFe2O6

    International Nuclear Information System (INIS)

    Batuk, Dmitry; De Dobbelaere, Christopher; Tsirlin, Alexander A.; Abakumov, Artem M.; Hardy, An; Van Bael, Marlies K.; Greenblatt, Martha; Hadermann, Joke

    2013-01-01

    Graphical abstract: - Highlights: • The substitution of Cr for Mn in BiMnFe 2 O 6 is possible by the solution–gel method. • The BiCr x Mn 1−x Fe 2 O 6 solid solution is obtained for the x values up to 0.3. • Increasing Cr content lowers the temperature of the antiferromagnetic ordering. - Abstract: We report the Cr 3+ for Mn 3+ substitution in the BiMnFe 2 O 6 structure. The BiCr x Mn 1−x Fe 2 O 6 solid solution is obtained by the solution–gel synthesis technique for the x values up to 0.3. The crystal structure investigation using a combination of X-ray powder diffraction and transmission electron microscopy demonstrates that the compounds retain the parent BiMnFe 2 O 6 structure (for x = 0.3, a = 5.02010(6)Å, b = 7.06594(7)Å, c = 12.6174(1)Å, S.G. Pbcm, R I = 0.036, R P = 0.011) with only a slight decrease in the cell parameters associated with the Cr 3+ for Mn 3+ substitution. Magnetic susceptibility measurements suggest strong similarities in the magnetic behavior of BiCr x Mn 1−x Fe 2 O 6 (x = 0.2; 0.3) and parent BiMnFe 2 O 6 . Only T N slightly decreases upon Cr doping that indicates a very subtle influence of Cr 3+ cations on the magnetic properties at the available substitution rates

  19. The Effect of Nano-TiC Addition on Sintered Nd-Fe-B Permanent Magnets

    DEFF Research Database (Denmark)

    Mural, Zorjana; Kollo, Lauri; Xia, Manlong

    2017-01-01

    This paper addresses the effect of nano-TiC addition on sintered Nd-Fe-B permanent magnets. TiC nanoparticles were added to sintered Nd-Fe-B magnets with a specific aim to improve the Curie temperature and thermal stability. A standard powder metallurgy route was adopted to prepare the magnets....... It was found that introducing nano-TiC prior to jet milling was effective as the nanoparticles dispersed in the final alloy, concentcalcrating in the neodymium-rich phase of the magnets. Magnets with optimal properties were obtained with the addition of 1 wt% TiC nanoparticles. The hysteresis loop...

  20. Charge ordering and multiferroicity in Fe{sub 3}BO{sub 5} and Fe{sub 2}MnBO{sub 5} oxyborates

    Energy Technology Data Exchange (ETDEWEB)

    Maignan, A., E-mail: antoine.maignan@ensicaen.fr [Laboratoire CRISMAT, UMR 6508 CNRS/ENSICAEN/UNICAEN, 6 bd du Maréchal Juin, 14050 CAEN Cedex 4 (France); Lainé, F.; Guesdon, A.; Malo, S. [Laboratoire CRISMAT, UMR 6508 CNRS/ENSICAEN/UNICAEN, 6 bd du Maréchal Juin, 14050 CAEN Cedex 4 (France); Damay, F. [Laboratoire Léon Brillouin, UMR 12, LLB-Saclay, 91191 GIF-SUR-YVETTE Cedex (France); Martin, C. [Laboratoire CRISMAT, UMR 6508 CNRS/ENSICAEN/UNICAEN, 6 bd du Maréchal Juin, 14050 CAEN Cedex 4 (France)

    2017-02-15

    The comparison of Fe{sub 3}BO{sub 5} and Fe{sub 2}MnBO{sub 5} reveals that the 2Fe{sup 2+}: Fe{sup 3+} charge ordering of the former is suppressed in the latter. Spin dynamics probed by ac susceptibility are strongly affected by the substitution, inducing superparamagnetism at low temperature in Fe{sub 2}MnBO{sub 5}. Interestingly, for both oxyborates, glassiness is observed in the dielectric properties at low temperature, but only Fe{sub 3}BO{sub 5} shows a magnetodielectric effect close to its lower magnetic transition. A change in the electrical polarization, measured by pyroelectric current integration, is observed in Fe{sub 3}BO{sub 5} and is even more pronounced in Fe{sub 2}MnBO{sub 5}. Such results suggest that these oxyborates behave like antiferromagnetic relaxor ferroelectrics. These features are proposed to be related to the distribution of the species (Fe{sup 3+}, Fe{sup 2+} and Mn{sup 2+}) over the four transition metal sites forming the ludwigite structure. - Graphical abstract: 90 K [010] electron diffraction patterns of Fe{sub 3}BO{sub 5}. The yellow arrows in the pattern indicate the extra-spots corresponding to the superstructure induced by the charge ordering. - Highlights: • The TEM (ED) study of the Fe{sub 3}BO{sub 5} oxyborate at 90 K reveals a superstructure related to a Fe{sup 2+}/Fe{sup 3+} ordering. • The Fe{sub 2}MnBO{sub 5}, Mn-substituted counterpart, does not show such ordering. • Our magnetic and electric measurements demonstrate that these magnetic ferrites exhibit glassiness in their charges (relaxor-type) with additional superparamagnetism at low T for Fe{sub 2}MnBO{sub 5} and magnetodielectric coupling near T{sub N2}=72 K in Fe{sub 3}BO{sub 5}. • The pyroelectric measurements confirm the existence of a ferroelectric behavior in these antiferromagnets. Accordingly, our results open the route to the study of other large class of the M{sub 2}{sup 2+}M’{sup 3+}BO{sub 5} ludwigites and to their complex magnetism and its

  1. Gamma→alpha transformation during cooling of Fe-Mn alloys

    International Nuclear Information System (INIS)

    Shtejnberg, M.M.; Mirzaev, D.A.; Ponomareva, T.N.

    1977-01-01

    Consideration is given to the effect of the cooling rate on the temperatures of γ→α transformation initiation, the structure and microhardness of Fe-Mn alloys. The general principles governing phase transformations in these alloys are similar to those which have been the subject of earlier investigations for Fe-Ni, Fe-Cr, Fe-Mo systems. It has been found that the higher manganese content results in a more intensive temperature drop for all the stages and elimination of stage 111 at a relatively low manganese content. Support is provided for the existence of the four stages of γ→α transformation in the iron alloys. The yield point, ultimate strength and microhardness of each alloy are related by Petch's relations to the size of the martensite packet which at the given grain size of the γsup(')-phase is defined by a transformation stage and a cooling rate at the given stage

  2. Molybdenum isotopes in modern marine hydrothermal Fe/Mn deposits: Implications for Archean and Paleoproterozoic Mo cycles

    Science.gov (United States)

    Goto, K. T.; Hein, J. R.; Shimoda, G.; Aoki, S.; Ishikawa, A.; Suzuki, K.; Gordon, G. W.; Anbar, A. D.

    2016-12-01

    Molybdenum isotope (δ98/95Mo) variations recorded in Archean and Paleoproterozoic Fe/Mn-rich sediments have been used to constrain ocean redox conditions at the time of deposition (Canfield et al., 2013 PNAS; Planavsky et al., 2014 Nat. Geo.; Kurzweil et al., 2015 GCA). However, except for hydrogenous Fe-Mn crusts (Siebert et al., 2003), δ98/95Mo variation of modern Fe and Mn oxide deposits has been poorly investigated. Marine hydrothermal systems are thought to be the major source of Fe and Mn in Archean and Paleoproterozoic Fe- and Mn-rich sediments. Hence, to accurately interpret Mo isotope data of those ancient sedimentary rocks, it is important to evaluate the possible influence of hydrothermally derived Mo on δ98/95Mo of modern Fe- and Mn-rich sediments. In this study, we analyzed Mo isotopic compositions of one hydrothermal Fe oxide and 15 Mn oxides from five different hydrothermal systems in the modern ocean. The Fe oxide is composed mainly of goethite, and has a δ98/95Mo of 0.7‰, which is 1.4‰ lighter than that of present-day seawater. The observed offset is similar to isotope fractionation observed during adsorption experiments of Mo on goethite (Δ98/95Mogoethite-solution = -1.4 ± 0.5%; Goldberg et al., 2009 GCA). The 15 hydrothermal Mn oxides show large variations in δ98/95Mo ranging from -1.7 to 0.5‰. However, most of the values are similar to those of modern hydrogenous Fe-Mn crusts (Siebert et al., 2003 EPSL), and fall within the range of estimated δ98/95Mo of Mn oxides precipitated from present-day seawater using the isotope offset reported from adsorption experiments (Δ98/95Mo = -2.7 ± 0.3‰; Wasylenki et al., 2008 GCA). These findings indicate that seawater is the dominant source of Mo for modern hydrothermal Fe and Mn deposits. However, the observed large variation indicates that the contribution Mo from local hydrothermal systems is not negligible. The oceanic Mo inventory during the Archean and Paleoproterozoic is thought to be

  3. Microstructure and magnetic properties of Nd-Fe-B-(Re, Ti alloys

    Directory of Open Access Journals (Sweden)

    Hasiak Mariusz

    2015-03-01

    Full Text Available The microstructure and magnetic properties of nanocomposite hard magnetic Nd-Fe-B-(Re, Ti materials with different Nd and Fe contents are studied. The role of Re and Ti addition in phase composition and volume fraction of the Nd-Fe-B phase is determined. All samples are annealed at the same temperature of 993 K for 10 min. Mössbauer spectroscopy shows that the addition of 4 at.% of Re to the Nd8Fe78B14 alloy leads to creation of an ineligible amount of the magnetically hard Nd2Fe14B phase. Moreover, the microstructure and magnetic characteristics recorded in a wide range of temperatures for the Nd8Fe79−xB13Mx (x = 4; M = Re or Ti alloys are also analyzed.

  4. Solubility and precipitation of Fe on reduced TiO{sub 2}(001)

    Energy Technology Data Exchange (ETDEWEB)

    Busiakiewicz, Adam, E-mail: adambus@uni.lodz.pl

    2014-01-01

    The solubility of Fe in reduced rutile TiO{sub 2} crystals and the followed precipitation on the (001) surface have been studied using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) in ultra-high vacuum. The first step includes dissolving Fe in reduced TiO{sub 2} at 1073 K by the means of thermal diffusion and as a result the saturated solid solution is formed. Then, it undergoes fast cooling which leads to obtaining a supersaturated solid solution. When this supersaturated crystal is annealed at low temperatures of about 500 K, Fe starts to precipitate on the (001) surface forming spherical Fe-containing nanoparticles. The fast migration of Fe cations to the surface and their precipitation at relatively low temperatures are caused by high diffusion anisotropy and the reduction of the TiO{sub 2}. At about 900 K, the size of nanoparticles increases and they are transformed into nanocrystals with clearly visible facets. Simultaneously, the number of the nanocrystals substantially decreases. The partial oxidation of Fe is also observed around 900 K, which is related to strong metal support interaction between Fe and reduced TiO{sub 2}(001). The XPS and STM results suggest that the nanocrystals are mostly composed of mixed Fe/Ti oxides like FeTiO{sub 3} of ilmenite structure. Above 973 K, the nanocrystals disappear which is explained by the restored solubility of Fe cations in the reduced TiO{sub 2}. The process of the nanoparticle precipitation at lower temperatures is repeatable and the precipitation and disappearance of Fe-containing nanocrystals on TiO{sub 2}(001) are also a fully reversible phenomenon easily controlled by annealing temperature. - Highlights: • The supersaturated solid solution of Fe in TiO{sub 2}(001) is obtained at 1073 K. • Fe precipitates forming nanoparticles above 500 K and nanocrystals above 900 K. • Nanocrystals are ascribed to formation of FeTiO{sub 3} compound.

  5. Effect of Fe Content on the Microstructure and Mechanical Properties of Ti-Al-Mo-V-Cr-Fe Alloys

    Directory of Open Access Journals (Sweden)

    Bae K.C.

    2017-06-01

    Full Text Available To investigate the effect of Fe content on the correlation between the microstructure and mechanical properties in near-b titanium alloys, the Ti-5Al-5Mo-5V-1Cr-xFe alloy system has been characterized in this study. As the Fe content increased, the number of nucleation sites and the volume fraction of the α phase decreased. We observed a significant difference in the shape and size of the α phase in the matrix before and after Fe addition. In addition, these morphological deformations were accompanied by a change in the shape of the α phase, which became increasingly discontinuous, and changed into globular-type α phase in the matrix. These phenomena affected the microstructure and mechanical properties of Ti alloys. Specimen #2 exhibited a high ultimate tensile strength (1071 MPa, which decreased with further addition of Fe.

  6. Role of the antiferromagnetic pinning layer on spin wave properties in IrMn/NiFe based spin-valves

    Energy Technology Data Exchange (ETDEWEB)

    Gubbiotti, G., E-mail: gubbiotti@fisica.unipg.it; Tacchi, S. [Istituto Officina dei Materiali del CNR (IOM-CNR), Unità di Perugia, I-06123 Perugia (Italy); Del Bianco, L. [Department of Physics and Astronomy, University of Bologna, I-40127 Bologna (Italy); Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Bonfiglioli, E.; Giovannini, L.; Spizzo, F.; Zivieri, R. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia (Italy)

    2015-05-07

    Brillouin light scattering (BLS) was exploited to study the spin wave properties of spin-valve (SV) type samples basically consisting of two 5 nm-thick NiFe layers (separated by a Cu spacer of 5 nm), differently biased through the interface exchange coupling with an antiferromagnetic IrMn layer. Three samples were investigated: a reference SV sample, without IrMn (reference); one sample with an IrMn underlayer (10 nm thick) coupled to the bottom NiFe film; one sample with IrMn underlayer and overlayer of different thickness (10 nm and 6 nm), coupled to the bottom and top NiFe film, respectively. The exchange coupling with the IrMn, causing the insurgence of the exchange bias effect, allowed the relative orientation of the NiFe magnetization vectors to be controlled by an external magnetic field, as assessed through hysteresis loop measurements by magneto-optic magnetometry. Thus, BLS spectra were acquired by sweeping the magnetic field so as to encompass both the parallel and antiparallel alignment of the NiFe layers. The BLS results, well reproduced by the presented theoretical model, clearly revealed the combined effects on the spin dynamic properties of the dipolar interaction between the two NiFe films and of the interface IrMn/NiFe exchange coupling.

  7. Calculation of exchange constants in manganese ferrite (MnFe2O4)

    International Nuclear Information System (INIS)

    Zuo Xu; Barbiellini, Bernardo; Vittoria, Carmine

    2004-01-01

    The exchange constants and electronic structure of manganese ferrite (MnFe 2 O 4 ) were calculated using Becke's density functional. The total exchange energy consists of Hartree-Fock (HF) and Becke's density functional terms. We introduced one parameter w as the weight of HF's contribution. We also introduced a parameter α to scale the radial part of the 3d wave functions of Fe 3+ ions. By varying w and α the calculated exchange constants were quantitatively fitted to the experimental values of a spinel ferrite for the first time. Direct (d-d) and indirect (d-p-d) hopping are controlled by the parameters w and α

  8. Characterization of High Dose Mn, Fe, and Ni implantation into p-GaN

    CERN Document Server

    Pearton, S J; Thaler, G; Abernathy, C R; Theodoropoulou, N; Hebard, A F; Chu, S N G; Wilson, R G; Zavada, J M; Polyakov, A Y; Osinsky, A V; Norris, P E; Chow, P P; Wowchack, A M; Hove, J M V; Park, Y D

    2002-01-01

    The magnetization of p-GaN or p-AlGaN/GaN superlattices was measured after implantation with high doses (3-5x10 sup 1 sup 6 cm sup - sup 2) of Mn, Fe, or Ni and subsequent annealing at 700-1000 deg. C. The samples showed ferromagnetic contributions below temperatures ranging from 190-250 K for Mn to 45-185 K for Ni and 80-250 K for Fe. The use of superlattices to enhance the hole concentration did not produce any change in ferromagnetic ordering temperature. No secondary phase formation was observed by x-ray diffraction, transmission electron microscopy, or selected area diffraction pattern analysis for the doses we employed.

  9. Strength of "Light" Ferritic and Austenitic Steels Based on the Fe - Mn - Al - C System

    Science.gov (United States)

    Kaputkina, L. M.; Svyazhin, A. G.; Smarygina, I. V.; Kindop, V. E.

    2017-01-01

    The phase composition, the hardness, the mechanical properties at room temperature, and the resistance to hot (950 - 1000°C) and warm (550°C) deformation are studied for cast deformable "light" ferritic and austenitic steels of the Fe - (12 - 25)% Mn - (0 - 15)% Al - (0 - 2)% C system alloyed additionally with about 5% Ni. The high-aluminum high-manganese low-carbon and carbonless ferritic steels at a temperature of about 0.5 T melt have a specific strength close to that of the austenitic steels and may be used as weldable scale-resistant and wear-resistant materials. The high-carbon Fe - (20 - 24)% Mn - (5 - 9)% Al - 5% Ni - 1.5% C austenitic steels may be applied as light high-strength materials operating at cryogenic temperatures after a solution treatment and as scale- and heat-resistant materials in an aged condition.

  10. STUDY OF COATINGS OBTAINED FROM ALLOY Fe-Mn-C-B-Si-Ni-Cr

    Directory of Open Access Journals (Sweden)

    Mychajło Paszeczko

    2016-09-01

    Full Text Available Tribological behaviour of coatings obtained from eutectic alloy Fe-Mn-C-B-Si-Ni-Cr was studied. The coatings were obtained by the method of gas metal arc welding (GMA with use of powder wire. GMA welding method is widely used for the regeneration of machine parts. Eutectic Fe-Mn-C-B-Si-Ni-Cr alloys can be used to obtain high quality coatings resistant to wear and corrosion. Pin-on-disk dry sliding wear tests at sliding speeds 0.4 m/s and under load 10 MPa were conducted for pin specimens. During friction a typical tribological behavior was observed. The mechanism of wear was mechanical-chemical.

  11. Martensitic Transformation and Superelasticity in Fe-Mn-Al-Based Shape Memory Alloys

    Science.gov (United States)

    Omori, Toshihiro; Kainuma, Ryosuke

    2017-12-01

    Ferrous shape memory alloys showing superelasticity have recently been obtained in two alloy systems in the 2010s. One is Fe-Mn-Al-Ni, which undergoes martensitic transformation (MT) between the α (bcc) parent and γ' (fcc) martensite phases. This MT can be thermodynamically understood by considering the magnetic contribution to the Gibbs energy, and the β-NiAl (B2) nanoprecipitates play an important role in the thermoelastic MT. The temperature dependence of critical stress for the MT is very small (about 0.5 MPa/°C) due to the small entropy difference between the parent and martensite phases in the Fe-Mn-Al-Ni alloy, and consequently, superelasticity can be obtained in a wide temperature range from cryogenic temperature to about 200 °C. Microstructural control is of great importance for obtaining superelasticity, and the relative grain size is among the most crucial factors.

  12. The La(Fe,Mn,Si)13Hz magnetic phase transition under pressure

    DEFF Research Database (Denmark)

    Lovell, Edmund; Bez, Henrique N.; Boldrin, David C.

    2017-01-01

    We study the magnetocaloric metamagnetic transition in LaFe11.74Mn0.06Si1.20 and LaFe11.76Mn0.06Si1.18H1.65 under hydrostatic pressure up to 1.2 GPa. For both compounds, hydrostatic pressure depresses the zero field critical temperature. However, in detail, pressure influences the magnetic...... and extrinsic hysteresis loss brought about by the use of hydrostatic pressure. We explore the multicaloric field-pressure cycle, demonstrating that although the gain introduced by overcoming the magnetic hysteresis loss is closely countered by the loss introduced in the pressure cycle, there are significant...... properties in different ways in the two compounds. In the dehydrogenated case the transition broadens under pressure whereas in the hydrogenated case the transition sharpens. In both cases thermal hysteresis increases under pressure, although with different trends. These observations suggest both intrinsic...

  13. Effects of compositional modifications on the sensitization behavior of Fe-Cr-Mn steels

    International Nuclear Information System (INIS)

    Edgemon, G.L.; Tortorelli, P.F.; Bell, G.E.C.

    1992-01-01

    Fe-Cr-Mn steels may possibly be used in conjuction with aqueous blankets or coolants in a fusion device. Therefore, standard chemical immersion (modified Strauss) tests were conducted to characterize the effects of compositional modifications on the thermal sensitization behavior of these steels. A good correlation among weight losses, intergranular corrosion, and cracking was found. The most effective means of decreasing their susceptibility was through reduction of the carbon concentration of these steels to 0.1%, but the sensitization resistance of Fe-Cr-Mn-0.1 C compositions was still inferior to type 304L and other similar stainless steels. Alloying additions that form stable carbides did not have a very significant influence on the sensitization behavior. (orig.)

  14. Characteristics of Fe-28Mn-6Si-5Cr shape memory alloy produced by centrifugal casting

    International Nuclear Information System (INIS)

    Otsuka, H.; Maruyama, T.; Kubo, H.

    2000-01-01

    Recent application of ferrous shape memory alloys, particularly Fe-Mn-Si alloys as pipe joints used for a tunnel driving technique in the field of civil engineering, requires efficient production of alloy pipes. Centrifugal casting is one of the efficient manufacturing techniques which can produce suitable sizes of pipes of approximately 4 to 14 inches in outside diameter. The mechanical properties of the centrifugally cast Fe-Mn-Si shape memory alloy were investigated to have 700 MPa in tensile strength and shape recovery of ∝3% of the initial deformation. The shape recovery achieved by the centrifugally cast materials proved to be comparable to that of the rolled materials. The TEM microstructure of the centrifugally cast materials deformed necessarily in the process of shape recovery reveals random distribution of ε (hcp) bands containing many dislocations inside, whereas the structure of the rolled materials shows ε phases containing fewer dislocations. (orig.)

  15. Interface electron structure of Fe3Al/TiC composites

    Institute of Scientific and Technical Information of China (English)

    PANG Lai-xue; SUN Kang-ning; SUN Jia-tao; FAN Run-hua; REN Shuai

    2006-01-01

    Based on YU's solids and molecules emperical electron theory(EET), interface valence electron structure of TiC-Fe3Al composites was set up, and the valence electron density of different atomic states TiC and Fe3Al composites in various planes was determined. The results indicate that the electron density of (100)Fe3Al is consistent with that of (110)TiC in the first-class approximation, the absolute value of minimum electron density difference along the interface is 0.007 37 nm-2, and the relative value is 0.759%. (110)TiC//(100)Fe3Al preferred orientation is believed to benefit the formation of the cuboidal shape TiC. In the other hand, it shows that the particle growth is accompanied by the transport of electron, the deviation continuity of electron density intrinsically hinders the grain growth. The electron density of (100)TiC is not consistent with Fe3Al arbitrary crystallographic plane,thus it well explains that the increased titanium and carbon contents do not increase the size of large particles. The crystallographic orientation of (110)TiC//(100)FeAl will improve the mechanical properties. Therefore interface electron theory is an effective theoretical implement for designing excellent property of composites.

  16. Ti2FeZ (Z=Al, Ga, Ge) alloys: Structural, electronic, and magnetic properties

    International Nuclear Information System (INIS)

    Liping, Mao; Yongfan, Shi; Yu, Han

    2014-01-01

    Using the first-principle projector augmented wave potential within the generalized gradient approximation taking into account the on-site Coulomb repulsive, we investigate the structural, electronic and magnetic properties of Ti 2 FeZ (Z=Al, Ga, Ge) alloys with Hg 2 CuTi-type structure. These alloys are found to be half-metallic ferrimagnets. The total magnetic moments of the Heusler alloys Ti 2 FeZ follow the µ t =Z t −18 rule and agree with the Slater–Pauling curve quite well. The band gaps are mainly determined by the bonding and antibonding states created from the hybridizations of the d states between the Ti(A)–Ti(B) coupling and Fe atom. - Highlights: • Ti 2 FeZ (Z=Al, Ga, Ge) are found to be half-metallic ferrimagnets. • The band gaps are mainly determined by the hybridizations of the d states between the Ti(A)–Ti(B) coupling and Fe atom. • The s–p elements play an important role in the half-metallicity of these Heusler alloys

  17. Influence of Ti in the β-Zr(Fe) phase stability at ambient temperature

    International Nuclear Information System (INIS)

    Coelho, J.S.

    1980-12-01

    Investigations of the Fe-Ti-Zr alloy system with concentrations ranging from 1 at.% Ti to 20 at.% Ti and with a fixed concentration of 4 at.% Fe were performed using X-Ray diffraction, Mossbauer Spectroscopy and Optical and Electronic Metallographies. The alloys were melted in arc furnace in argon atmosphere and after being homogenized, they were quenched from the beta field into cold water in order to retain the high temperature β-Zr(Fe)-Ti phase. The obtained results show that the beta phase was partially retained until the concentration of 7 at.% Ti and was completely retained at the concentration equal to or higher than 8 at.% Ti. It is assumed in Moessbauer Spectroscopy a doublet for the beta phase and a singlet for the supersatured α'-Zr(Fe)-Ti phase resulting from the martensitic transformation. The relative amount of each phase detected by Moessbauer Spectroscopy was measured by the relative area of the each spectral line. The stability of the beta phase at room temperature was discussed in terms of short-range ordering caused by the Fe-Ti bonds. Some related properties were discussed through the changing of the lattice parameter, isomer shift and quadrupole splitting. (Author) [pt

  18. Interface adjustment and exchange coupling in the IrMn/NiFe system

    Energy Technology Data Exchange (ETDEWEB)

    Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Del Bianco, L., E-mail: lucia.delbianco@unife.it

    2017-01-01

    The exchange bias effect was investigated, in the 5–300 K temperature range, in samples of IrMn [100 Å]/NiFe [50 Å] (set A) and in samples with inverted layer-stacking sequence (set B), produced at room temperature by DC magnetron sputtering in a static magnetic field of 400 Oe. The samples of each set differ for the nominal thickness (t{sub Cu}) of a Cu spacer, grown at the interface between the antiferromagnetic and ferromagnetic layers, which was varied between 0 and 2 Å. It has been found out that the Cu insertion reduces the values of the exchange field and of the coercivity and can also affect their thermal evolution, depending on the stack configuration. Indeed, the latter also determines a peculiar variation of the exchange bias properties with time, shown and discussed with reference to the samples without Cu of the two sets. The results have been explained considering that, in this system, the exchange coupling mechanism is ruled by the glassy magnetic behavior of the IrMn spins located at the interface with the NiFe layer. Varying the stack configuration and t{sub Cu} results in a modulation of the structural and magnetic features of the interface, which ultimately affects the spins dynamics of the glassy IrMn interfacial component. - Highlights: • Exchange bias effect in IrMn/NiFe samples with interfacial Cu spacer. • A variation of exchange bias with time is observed in as-deposited samples. • Magnetic modification of the interface by varying the stack sequence and Cu thickness. • Interface adjustment affects the dynamics of interfacial IrMn spins. • The exchange bias properties can be tuned by interface adjustment.

  19. Mechanical properties of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials

    OpenAIRE

    Umezawa, Osamu

    2005-01-01

    Tensile and high-cycle fatigue behavior of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials were studied. Through the repeated thermomechanical treatment (RTMT) which is a repeat of the multi steps cold-working followed by heat treatment, Si crystals and/or intermetallic compounds were broken into some fragments and dispersed in the aluminum matrix. Fine dispersion of the second phase particles exhibited good ductility, since early fracture was overcome. A few large Si cry...

  20. Mechanical Stabilisation for Bainitic Reaction in a Fe-Mn-Si-C Bainitic Steel

    OpenAIRE

    Yang , J.; Huang , C.; Hsieh , W.; Chiou , C.

    1995-01-01

    In this work, the effects of different amounts (5, 10, 20, 40%) of compressive deformation of austenite on the isothermal transformation of bainite in a Fe-Mn-Si-C alloy steel have been investigated. It is found that the prior deformation of austenite retards significantly the bainitic transformation. At the same isothermal transformation temperature, as the amount of prior deformation is higher, the quantity of bainite (which can be obtained after the isothermal transformation is completed) ...

  1. About the mechanical stability of MnFe(P,Si,B) giant-magnetocaloric materials

    Energy Technology Data Exchange (ETDEWEB)

    Guillou, F., E-mail: f.guillou@tudelft.nl [FAME, Faculty of Applied Sciences, TU Delft, Mekelweg 15, 2629 JB Delft (Netherlands); Yibole, H.; Dijk, N.H. van [FAME, Faculty of Applied Sciences, TU Delft, Mekelweg 15, 2629 JB Delft (Netherlands); Zhang, L. [BASF Netherlands B.V., Strijkviertel 67, 3454 PK De Meern (Netherlands); Hardy, V. [CRISMAT, Ensicaen, UMR 6508 CNRS, 6 B" d Maréchal Juin, 14050 Caen Cedex (France); Brück, E. [FAME, Faculty of Applied Sciences, TU Delft, Mekelweg 15, 2629 JB Delft (Netherlands)

    2014-12-25

    Highlights: • Electrical resistivity and hardness show an evolution at T{sub C} with thermal cycling. • Degradation depends on the (c/a) lattice discontinuity at the transition. • Boron substituted materials present an improved mechanical stability. - Abstract: Due to its ability to control the latent heat and the hysteresis (thermal or magnetic) at the first-order transition (FOT) without deteriorating the saturation magnetisation, boron substitution in MnFe(P,Si) materials has recently been reported to be an ideal parameter to reach promising magnetocaloric performances: ΔS ≈ 10 Jkg{sup −1} K{sup −1} and cyclic ΔT of 2.6 K (and more) at a moderate magnetic field of ΔB = 1 T. Additionally, an interesting aspect for applications is the improvement of the mechanical stability in B doped materials compared to the pristine MnFe(P,Si) compounds. These improved mechanical properties were initially supported by naked-eye inspection and the observation of a constant ΔT during a few thousands of magnetic cycles. (Guillou et al., 2014) Here, the evolution upon cycling of MnFe(P,Si,B) materials is studied in a more quantitative and systematic manner. For that purpose transformation temperatures, electrical resistivity, micro-hardness and the microstructure are tracked as a function of the thermal cycling across the FOT for three prototypical compositions in the MnFe(P,Si,B) system. It turns out this set of data confirms the initial finding that B substitution has a positive effect on the mechanical stability. The origin of this improvement is discussed, in particular in respect to the lattice parameter discontinuities at the phase transition.

  2. A review on the martensitic transformation and shape memory effect in Fe-Mn-Si alloys

    International Nuclear Information System (INIS)

    Gu, Q.; Humbeeck, J. van; Delaey, L.

    1994-01-01

    The martensitic transformation and the shape memory effect in Fe-Mn-Si alloys received great attention recently due to its potential commercial value. In this paper, the mechanisms for the martensitic transformation and various parameters influencing the shape memory effect like alloy composition, applied stress, prestrain, crystal orientation, temperature, grain size, pre-existing martensite, thermal cycling and training etc. are reviewed and discussed. (orig.)

  3. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-04-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaz, tourmaline and spodumene by measuring the first order K sub(α) fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  4. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-01-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaze, tourmaline and spodumene by measuring the first order Kα fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  5. MnFe 2 O 4 /bentonite nano composite as a novel magnetic material ...

    African Journals Online (AJOL)

    It is also found that the presence of bentonite in the magnetic composite has not made any changes in the spinel structure of MnFe2O4. SEM images of the sorbent shows nanocomposite with a uniform structure and nanochannels from 0.3 to 0.8 mμ in diameter having a surface area of 130 m2 g-1. The results also revealed ...

  6. Mechanism and kinetics of Fe, Cr, Mo and Mn atom interaction with molecular oxygen

    International Nuclear Information System (INIS)

    Akhmadov, U.S.; Zaslonko, I.S.; Smirnov, V.N.

    1988-01-01

    Rate constants of atomic interaction of some transition metals (Fe, Cr, Mo, Mn) with molecular oxygen are measured in shock waves using the resonance atomic-absorption method. A new method for determination of the parameter γ in the modified Lambert-Beer law D=ε(lN)γ is suggested and applied. Bond strength in CrO and MoO molecules is estimated

  7. Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Möncke, Doris; Wondraczek, Lothar, E-mail: lothar.wondraczek@uni-jena.de [Otto-Schott-Institute of Materials Research, Friedrich-Schiller-University Jena, Fraunhoferstr. 6, 07743 Jena (Germany); Sirotkin, Sergey [Institut des Sciences Moléculaires - CNRS UMR 5255, Université de Bordeaux, 33405 Talence (France); Stavrou, Elissaios; Kamitsos, Efstratios I. [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constaniou Ave., 116 35 Athens (Greece)

    2014-12-14

    Ionic sulfophosphate liquids of the type ZnO-Na{sub 2}O-Na{sub 2}SO{sub 4}-P{sub 2}O{sub 5} exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T{sub g} and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn{sup 2+} to six-fold around Mn{sup 2+} ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T{sub g}. Raman and infrared spectroscopy show that the structure of these glasses involves only SO{sub 4}{sup 2−} and PO{sub 4}{sup 3−} monomers as well as P{sub 2}O{sub 7}{sup 4-} dimers. Replacement of ZnO by MnO is found to favour PO{sub 4}{sup 3−} over P{sub 2}O{sub 7}{sup 4-} species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn{sup 2+}, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn{sup 2+} ions are present primarily in MnO{sub 6}-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.

  8. Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

    International Nuclear Information System (INIS)

    Möncke, Doris; Wondraczek, Lothar; Sirotkin, Sergey; Stavrou, Elissaios; Kamitsos, Efstratios I.

    2014-01-01

    Ionic sulfophosphate liquids of the type ZnO-Na 2 O-Na 2 SO 4 -P 2 O 5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T g and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn 2+ to six-fold around Mn 2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T g . Raman and infrared spectroscopy show that the structure of these glasses involves only SO 4 2− and PO 4 3− monomers as well as P 2 O 7 4- dimers. Replacement of ZnO by MnO is found to favour PO 4 3− over P 2 O 7 4- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn 2+ , a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn 2+ ions are present primarily in MnO 6 -clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities

  9. Synthesis and Deposition of TiC-Fe Coatings by Oxygen-acetylene Flame Spraying

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A simpler and more convenient method for producing wear-resistant, TiC-reinforced coatings were investigated in this study. It consists of the simultaneous synthesis and deposition of TiC-Fe materials by oxyacetylene flame spraying.Solid reagents bound together to form a single particle are injected into the flame stream where an in-situ reaction occurs. The reaction products are propelled onto a substrate to form a coating. Microstructural analyses reveal that TiC and Fe are the dominant phases in the coatings. The reaction between Ti and C happens step by step along with the reactive spray powder flight, and TiC-Fe materials were mainly synthesized where the spray distance is 125~170 mm. The TiC-Fe coatings are composed of alternate TiC-rich and TiC-poor lamellae with different microhardness of 11.9~13.7 and 3.0~6.0 Gpa, respectively. Submicron and round TiC particles are dispersed within a ductile metal matrix. The peculiar microstructure is thought to be responsible for its good wear resistance, which is better nearly five times than WC-reinforced cermet coatings obtained by traditional oxyacetylene flame spray.

  10. Ab initio lattice stability of fcc and hcp Fe-Mn random alloys

    International Nuclear Information System (INIS)

    Gebhardt, T; Music, D; Hallstedt, B; Schneider, J M; Ekholm, M; Abrikosov, I A; Vitos, L

    2010-01-01

    We have studied the lattice stability of face centred cubic (fcc) versus hexagonal close packed (hcp) Fe-Mn random alloys using ab initio calculations. In the calculations we considered the antiferromagnetic order of local moments, which for fcc alloys models the magnetic configuration of this phase at room temperature (below its Neel temperature) as well as their complete disorder, corresponding to paramagnetic fcc and hcp alloys. For both cases, the results are consistent with our thermodynamic calculations, obtained within the Calphad approach. For the room temperature magnetic configuration, the cross-over of the total energies of the hcp phase and the fcc phase of Fe-Mn alloys is at the expected Mn content, whereas for the magnetic configuration above the fcc Neel temperature, the hcp lattice is more stable within the whole composition range studied. The increase of the total energy difference between hcp and antiferromagnetic fcc due to additions of Mn as well as the stabilizing effect of antiferromagnetic ordering on the fcc phase are well displayed. These results are of relevance for understanding the deformation mechanisms of these random alloys.

  11. Ab initio lattice stability of fcc and hcp Fe-Mn random alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gebhardt, T; Music, D; Hallstedt, B; Schneider, J M [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Ekholm, M; Abrikosov, I A [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden); Vitos, L, E-mail: gebhardt@mch.rwth-aachen.d [Department of Materials Science and Engineering, Applied Materials Physics, oyal Institute of Technology, SE-10044 Stockholm (Sweden)

    2010-07-28

    We have studied the lattice stability of face centred cubic (fcc) versus hexagonal close packed (hcp) Fe-Mn random alloys using ab initio calculations. In the calculations we considered the antiferromagnetic order of local moments, which for fcc alloys models the magnetic configuration of this phase at room temperature (below its Neel temperature) as well as their complete disorder, corresponding to paramagnetic fcc and hcp alloys. For both cases, the results are consistent with our thermodynamic calculations, obtained within the Calphad approach. For the room temperature magnetic configuration, the cross-over of the total energies of the hcp phase and the fcc phase of Fe-Mn alloys is at the expected Mn content, whereas for the magnetic configuration above the fcc Neel temperature, the hcp lattice is more stable within the whole composition range studied. The increase of the total energy difference between hcp and antiferromagnetic fcc due to additions of Mn as well as the stabilizing effect of antiferromagnetic ordering on the fcc phase are well displayed. These results are of relevance for understanding the deformation mechanisms of these random alloys.

  12. Crystal structure and thermal expansion of Mn(1-x)Fe(x)Ge.

    Science.gov (United States)

    Dyadkin, Vadim; Grigoriev, Sergey; Ovsyannikov, Sergey V; Bykova, Elena; Dubrovinsky, Leonid; Tsvyashchenko, Anatoly; Fomicheva, L N; Chernyshov, Dmitry

    2014-08-01

    A series of temperature-dependent single-crystal and powder diffraction experiments has been carried out using synchrotron radiation in order to characterize the monogermanides of Mn, Fe and their solid solutions. The MnGe single crystal is found to be enantiopure and we report the absolute structure determination. The thermal expansion, parametrized with the Debye model, is discussed from the temperature-dependent powder diffraction measurements for Mn(1-x)Fe(x)Ge (x = 0, 0.1, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 0.9). Whereas the unit-cell dimension and the Debye temperature follow a linear trend as a function of composition, the thermal expansion coefficient deviates from linear dependence with increasing Mn content. No structural phase transformations have been observed for any composition in the temperature range 80-500 K for both single-crystal and powder diffraction, indicating that the phase transition previously observed with neutron powder diffraction most probably has a magnetic origin.

  13. Effect of addition of V and C on strain recovery characteristics in Fe-Mn-Si alloy

    International Nuclear Information System (INIS)

    Lin Chengxin; Wang Guixin; Wu Yandong; Liu Qingsuo; Zhang Jianjun

    2006-01-01

    Shape recoverable strain, recovery stress and low-temperature stress relaxation characteristics in an Fe-17Mn-5Si-10Cr-4Ni (0.08C) alloy and an Fe-17Mn-2Cr-5Si-2Ni-1V (0.23C) alloy have been studied by means of X-ray diffraction, transmission electron microscopy and measurement of recoverable strain and recovery stress. The amount of stress-induced ε martensite under tensile deformation at room temperature, recoverable strain and recovery stress are increased obviously with addition V and C in Fe-Mn-Si alloy, which is owing to the influence of addition V and C on strengthening austenitic matrix. Addition of V and C in Fe-Mn-Si alloy is evidently effective to reduce the degree of low-temperature stress relaxation, for the dispersed VC particles 50-180 nm in size precipitated during annealing restrain the stress induced martensitic transformation

  14. Structural, magnetic and thermal properties of CaMn0.9957Fe0.01O3-δ

    International Nuclear Information System (INIS)

    Przewoznik, J.; Chmist, J.; Kolwicz-Chodak, L.; Tarnawski, Z.; Kapusta, Cz.; Kolodziejczyk, A.

    2007-01-01

    The polycrystalline CaMn 0.99 57 Fe 0.01 O 3-δ compound was studied using powder X-ray diffraction, 57 Fe Moessbauer spectroscopy, ac susceptometry, dc magnetometry, specific heat and electrical resistivity measurements. X-ray diffraction measurements performed between 70 and 300 K show a thermal expansion anomaly at the Neel temperature. A weak ferromagnetic component and a spin-glass behaviour below Neel temperature are found in magnetic measurements. The Moessbauer spectroscopy measurements performed between 30 and 300 K provided the Neel temperature value of 118 K, the same as obtained from dc magnetisation and close to that derived from the specific heat (119 K). The temperature evolution of the Fe hyperfine field was analysed within a molecular field model and revealed equal strengths of the Fe-Mn and Mn-Mn exchange interactions in this compound

  15. Lithium-Excess Research of Cathode Material Li₂MnTiO₄ for Lithium-Ion Batteries.

    Science.gov (United States)

    Zhang, Xinyi; Yang, Le; Hao, Feng; Chen, Haosen; Yang, Meng; Fang, Daining

    2015-11-20

    Lithium-excess and nano-sized Li 2+x Mn₁ - x /2 TiO₄ ( x = 0, 0.2, 0.4) cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD) experiments indicate that the obtained main phases of Li 2.0 MnTiO₄ and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM) images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20-30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g -1 increases from 112.2 mAh g -1 of Li 2.0 MnTiO₄ to 187.5 mAh g -1 of Li 2.4 Mn 0.8 TiO₄. In addition, the ex situ XRD experiments indicate that the monoclinic Li₂MnTiO₄ tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li₂MnTiO₄ phase shows better structural reversibility and stability.

  16. Fe and Mn Transport and Settling Modelling in the Upper Course of the Lerma River

    Directory of Open Access Journals (Sweden)

    García-Aragón Juan Antonio

    2013-06-01

    Full Text Available A metal transport and deposition model together with concentration measurements of Fe and Mn was developed in the Upper Course of the Lerma River, Mexico State. The hydraulic sections of 27.9 km of the Lerma River were measured in the field in order to supply the numerical model. A general mass balance equation considering full mixing in selected reaches of the Lerma River was developed and solved using the finite-difference method. At the same time a sampling campaign of water and sediment allowed us to obtain Fe and Mn concentrations in each phase. Metal concentrations were obtained by Energy Dispersive X-Ray Fluorescence Method (EDXRF. Partition coefficients for water and suspended sediment and for water and deposited sediment were calculated. Well defined periods and areas of deposition of Fe and Mn were obtained by the transport model and the spatial variation of the partition coefficients agree with the pattern obtained in the simulation. It is concluded that the current practice of constant values of the partition coefficients could not be used in modelling transport and deposition of metals if we are dealing with hydrologic extreme events and river sediment deposition areas.

  17. TRACE METAL CONTENT (Cu, Zn, Mn AND Fe) IN URTICA DIOICA L. AND PLANTAGO MAJOR L.

    Science.gov (United States)

    Krolak, Elzbieta; Raczuk, Jolanta; Borkowska, Lidia

    2016-11-01

    The aim of the study was to compare the contents of Cu, Zn, Mn and Fe in the washed and unwashed leaves and roots of two plant species: Urica dioica L. and Plantago major L., used in herbal medicine. These two herb species occur in the same environmental habitats, yet their morphological structure is different. The soil and plant samples for analyses were collected from an uncontaminated area in Eastern Poland. In each habitat location, the samples were taken from sandy soils with slightly acidic and neutral pH values. The obtained results showed that U. dioica and P. major accumulated similar amounts of trace metals, such as: Cu, Zn and Fe, in leaves, despite the differences in the morphological structure of their overground parts. The content of Mn in leaves U. dioica was about twice as much as in P. major. Also, no differences in the metal content were observed between washed and unwashed leaves of both species. However, in the same habitat conditions, a significantly higher content of Cu, Zn and Mn was found in the roots of P. major than U. dioica. The content of Fe in the roots was similar in both species. P. major and U. dioica may be a valuable source of microelements, if they are obtained from unpolluted habitats.

  18. Shape-Memory Effect and Pseudoelasticity in Fe-Mn-Based Alloys

    Science.gov (United States)

    La Roca, P.; Baruj, A.; Sade, M.

    2017-03-01

    Several Fe-based alloys are being considered as potential candidates for applications which require shape-memory behavior or superelastic properties. The possibility of using fabrication methods which are well known in the steel industry is very attractive and encourages a large amount of research in the field. In the present article, Fe-Mn-based alloys are mainly addressed. On the one hand, attention is paid to the shape-memory effect where the alloys contain (a) a maximum amount of Mn up to around 30 wt%, (b) several possible substitutional elements like Si, Cr, Ni, Co, and Nb and (c) some possible interstitial elements like C. On the other hand, superelastic alloys are analyzed, mainly the Fe-Mn-Al-Ni system discovered a few years ago. The most noticeable properties resulting from the martensitic transformations which are responsible for the mentioned properties, i.e., the fcc-hcp in the first case and the bcc-fcc in the latter are discussed. Selected potential applications are also analyzed.

  19. Local and average structure of Mn- and La-substituted BiFeO3

    Science.gov (United States)

    Jiang, Bo; Selbach, Sverre M.

    2017-06-01

    The local and average structure of solid solutions of the multiferroic perovskite BiFeO3 is investigated by synchrotron X-ray diffraction (XRD) and electron density functional theory (DFT) calculations. The average experimental structure is determined by Rietveld refinement and the local structure by total scattering data analyzed in real space with the pair distribution function (PDF) method. With equal concentrations of La on the Bi site or Mn on the Fe site, La causes larger structural distortions than Mn. Structural models based on DFT relaxed geometry give an improved fit to experimental PDFs compared to models constrained by the space group symmetry. Berry phase calculations predict a higher ferroelectric polarization than the experimental literature values, reflecting that structural disorder is not captured in either average structure space group models or DFT calculations with artificial long range order imposed by periodic boundary conditions. Only by including point defects in a supercell, here Bi vacancies, can DFT calculations reproduce the literature results on the structure and ferroelectric polarization of Mn-substituted BiFeO3. The combination of local and average structure sensitive experimental methods with DFT calculations is useful for illuminating the structure-property-composition relationships in complex functional oxides with local structural distortions.

  20. X-ray diffraction and high resolution transmission electron microscopy characterization of intermetallics formed in Fe/Ti nanometer-scale multilayers during thermal annealing

    International Nuclear Information System (INIS)

    Wu, Z.L.; Peng, T.X.; Cao, B.S.; Lei, M.K.

    2009-01-01

    Intermetallics formation in the Fe/Ti nanometer-scale multilayers magnetron-sputtering deposited on Si(100) substrate during thermal annealing at 623-873 K was investigated by using small and wide angle X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The Fe/Ti nanometer-scale multilayers were constructed with bilayer thickness of 16.2 nm and the sublayer thickness ratio of 1:1. At the annealing temperature of 623 K, intermetallics FeTi were formed by nucleation at the triple joins of α-Fe(Ti)/α-Ti interface and α-Ti grain boundary with an orientational correlation of FeTi(110)//α-Ti(100) and FeTi[001]//α-Ti[001] to adjacent α-Ti grains. The lateral growth of intermetallics FeTi which is dependent on the diffusion path of Ti led to a coalescence into an intermetallic layer. With an increase in the annealing temperature, intermetallics Fe 2 Ti were formed between the intermetallics FeTi and the excess Fe due to the limitation of Fe and Ti atomic concentrations, resulting in the coexistence of intermetallics FeTi and Fe 2 Ti. It was found that the low energy interface as well as the dominant diffusion path constrained the nucleation and growth of intermetallics during interfacial reaction in the nanometer-scale metallic multilayers.

  1. Fe-ion implantation in pulse laser deposited La0⋅75Ca0⋅25MnO3 ...

    Indian Academy of Sciences (India)

    Unknown

    effect of Al substitution (Martin et al 1996) on Pr based compounds have been reported. Fe doping (Ahn et al. 1996) have consistently suppressed conduction and ferro- magnetism. The physics governing the observed proper- ties has still not been fully understood and Mn3+–O–Mn4+ chains are believed to be responsible ...

  2. Influence of manganese, carbon and nitrogen on high-temperature strength of Fe-Cr-Mn austenitic alloys

    International Nuclear Information System (INIS)

    Hosoi, Y.; Okazaki, Y.; Wade, N.; Miyahara, K.

    1990-01-01

    High Mn-Cr-Fe base alloys are candidates for the first wall material of fusion reactors because of rapid decay of radioactivity of the alloys after neutron irradiation compared with that of Ni-Cr-Fe base alloys. Their high temperature properties, however, are not clearly understood at present. In this paper, a study has been made of the effects of Mn, C and N content on the high-temperature tensile strength and creep properties of a 12% CR-Fe base alloy. Mn tends to decrease tensile strength and proof stress at intermediate temperatures. At higher temperatures in the austenite range, however, tensile properties scarcely depend on Mn content. C and N additions improve the tensile properties markedly. The combined addition of 0.2%C and 0.2%N to a 12%Cr-15%Mn-Fe base alloy makes the strength at 873K as high as that of a modified type 316 stainless steel. Combined alloying with C and N also improves the creep strength. Cold working is very useful in increasing the creep strength because of the finely dispersed precipitates in the matrix during creep. From these results, Fe-12%Cr-15%Mn-15%Mn-0.2%c-0.2%N is recommended as one of the most suitable alloys in this system for high temperature usage. (author)

  3. Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

    International Nuclear Information System (INIS)

    Du, Jiandi; Ding, Dongyan; Xu, Zhou; Zhang, Junchao; Zhang, Wenlong; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

    2017-01-01

    Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al 8 Cu 4 Ce phase, Al 6 Cu 6 La phase and Al 6 (Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

  4. The Formation of Lithiated Ti-Doped {alpha}-Fe{sub 2}O{sub 3} Nanocrystalline Particles by Mechanical Milling of Ti-Doped Lithium Spinel Ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Widatallah, H. M., E-mail: hisham@ictp.trieste.it [Khartoum University, Department of Physics (Sudan); Gismelseed, A. M.; Bouziane, K. [Sultan Qaboos University, Department of Physics (Oman); Berry, F. J. [Open University, Department of Chemistry (United Kingdom); Al Rawas, A. D.; Al-Omari, I. A.; Yousif, A. A.; Elzain, M. E. [Sultan Qaboos University, Department of Physics (Oman)

    2004-12-15

    The milling of spinel-related Ti-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} for different times is studied with XRD, Moessbauer spectroscopy and magnetic measurements. Milling converts the material to Li-Ti-doped {alpha}-Fe{sub 2}O{sub 3} nanocrystalline particles via an intermediate {gamma}-LiFeO{sub 2}-related phase. The role played by the dopant Ti-ion in the process is emphasized.

  5. The Formation of Lithiated Ti-Doped α-Fe2O3 Nanocrystalline Particles by Mechanical Milling of Ti-Doped Lithium Spinel Ferrite

    International Nuclear Information System (INIS)

    Widatallah, H. M.; Gismelseed, A. M.; Bouziane, K.; Berry, F. J.; Al Rawas, A. D.; Al-Omari, I. A.; Yousif, A. A.; Elzain, M. E.

    2004-01-01

    The milling of spinel-related Ti-doped Li 0.5 Fe 2.5 O 4 for different times is studied with XRD, Moessbauer spectroscopy and magnetic measurements. Milling converts the material to Li-Ti-doped α-Fe 2 O 3 nanocrystalline particles via an intermediate γ-LiFeO 2 -related phase. The role played by the dopant Ti-ion in the process is emphasized.

  6. Synergistic effects of F and Fe in co-doped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yufei, E-mail: zhang.yu.fei@stu.xjtu.edu.cn; Shen, Huiyuan; Liu, Yanhua, E-mail: yhliu@mail.xjtu.edu.cn [Xi’an Jiaotong University, Department of Building Environment and Services Engineering, School of Human Settlements and Civil Engineering (China)

    2016-03-15

    TiO{sub 2} photocatalysts co-doped with F and Fe were synthesized by a sol–gel method. Synergistic effects of F and Fe in the co-doped TiO{sub 2} were verified by NH{sub 3} decomposition, X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet–visible (UV–Vis) absorption spectroscopy, and was analyzed by the simulation based on the density functional theory (DFT). The results from NH{sub 3} decomposition confirmed that the cooperation of F and Fe broadened the optical response of TiO{sub 2} to visible light region and also enhanced the photocatalytic activity of TiO{sub 2} under ultraviolet light. XRD patterns, SEM and HRTEM images showed that the co-doped samples were nanometric anatase with an average particle size of 25 nm. Co-doping with F and Fe inhibited the grain growth of TiO{sub 2} from anatase to rutile and resulted in a larger lattice defect. XPS analysis exhibited that the doped F and Fe atoms were into the TiO{sub 2} lattice. UV–Vis absorption spectra showed that its optical absorption edge was moved up to approximately 617 nm and its ultraviolet absorption was also enhanced. The DFT results indicated that the cooperation of Fe 3d and O 2p orbits narrowed the band gap of TiO{sub 2} and F 2p orbit widened the upper valence bands. The synergistic electron density around F and Fe in co-doped TiO{sub 2} was capable to enhance the photo-chemical stability of TiO{sub 2}.

  7. Ab Initio Guided Low Temperature Synthesis Strategy for Smooth Face–Centred Cubic FeMn Thin Films

    Directory of Open Access Journals (Sweden)

    Friederike Herrig

    2018-05-01

    Full Text Available The sputter deposition of FeMn thin films with thicknesses in the range of hundred nanometres and beyond requires relatively high growth temperatures for the formation of the face-centred cubic (fcc phase, which results in high thin film roughness. A low temperature synthesis strategy, based on local epitaxial growth of a 100 nm thick fcc FeMn film as well as a Cu nucleation layer on an α-Al2O3 substrate at 160 °C, enables roughness values (Ra as low as ~0.6 nm, which is in the same order of magnitude as the pristine substrate (~0.1 nm. The synthesis strategy is guided by ab initio calculations, indicating very strong interfacial bonding of the Cu nucleation layer to an α-Al2O3 substrate (work of separation 5.48 J/m²—which can be understood based on the high Cu coordination at the interface—and between fcc FeMn and Cu (3.45 J/m². Accompanied by small lattice misfits between these structures, the strong interfacial bonding is proposed to enable the local epitaxial growth of a smooth fcc FeMn thin film. Based on the here introduced synthesis strategy, the implementation of fcc FeMn based thin film model systems for materials with interface dominated properties such as FeMn steels containing κ-carbide precipitates or secondary phases appears meaningful.

  8. Nano-MnO2@TiO2 microspheres: A novel structure and excellent performance as anode of lithium-ion batteries

    Science.gov (United States)

    Cao, Zhiguang; Chen, Xiaoqiao; Xing, Lidang; Liao, Youhao; Xu, Mengqing; Li, Xiaoping; Liu, Xiang; Li, Weishan

    2018-03-01

    A structurally hierarchical MnO2/TiO2 composite (Nano-MnO2@TiO2) is fabricated by calcining MnCO3 microspheres and coating a thin layer of TiO2 through the heat decomposition of tetrabutyl titanate, and evaluated as anode of gravimetrically and volumetrically high energy density lithium ion battery. The characterizations from FESEM, TEM, HRTEM and XRD, indicate that the resulting Nano-MnO2@TiO2 takes a spherical morphology with a core of about 2 μm in diameter, consisting of compact MnO2 nanoparticles, and a shell of 60 nm thick, consisting of smaller TiO2 nanoparticles. The charge/discharge tests demonstrate that Nano-MnO2@TiO2 exhibits excellent performance as anode of lithium ion battery, delivering a capacity of 938 mAh g-1 at 300 mA g-1 after 200 cycles, compared to the 103 mAh g-1 of the uncoated sample. The microsphere consisting of compact nanoparticles provides Nano-MnO2@TiO2 with high specific gravity. The dimensionally and structurally stable TiO2 maintains the integrity of MnO2 microspheres and facilitates lithium insertion/extraction. This unique structure yields the excellent cyclic stability and rate capability of Nano-MnO2@TiO2.

  9. Large positive spin polarization and giant inverse tunneling magnetoresistance in Fe/PbTiO3/Fe multiferroic tunnel junction

    International Nuclear Information System (INIS)

    Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min

    2014-01-01

    We perform first-principles electronic structure and spin-dependent transport calculations of a multiferroic tunnel junction (MFTJ) with an epitaxial Fe/PbTiO 3 /Fe heterostructure. We predict a large positive spin-polarization (SP) and an intriguing giant inverse tunneling magnetoresistance (TMR) ratio in this tunnel junction. We demonstrate that the tunneling properties are determined by ferroelectric (FE) polarization screening and electronic reconstruction at the interface with lower electrostatic potential. The intricate complex band structure of PbTiO 3 , in particular the lowest decay rates concerning Pb 6p z and Ti 3d z2 states near the Γ ¯ point, gives rise to the large positive SP of the tunneling current in the parallel magnetic configuration. However, the giant inverse TMR ratio is attributed to the minority-spin electrons of the interfacial Ti 3d xz +3d yz orbitals which have considerably weight in the extended area around the Γ ¯ point at the Fermi energy and causes remarkable contributions to the conductance in the antiparallel magnetic configuration. - Highlights: • We study spin-dependent tunneling in Fe/PbTiO 3 /Fe multiferroic tunnel junction. • We find a large positive spin polarization in the parallel magnetic configuration. • An intriguing giant inverse TMR ratio (about −2000%) is predicted. • Complex band structure of PbTiO 3 causes the large positive spin polarization. • Negative TMR is due to minority-spin electrons of interfacial Ti d xz +d yz orbitals

  10. TiFeCoNi oxide thin film - A new composition with extremely low electrical resistivity at room temperature

    International Nuclear Information System (INIS)

    Yang, Ya-Chu; Tsau, Chun-Huei; Yeh, Jien-Wei

    2011-01-01

    We show the electrical resistivity of a TiFeCoNi oxide thin film. The electrical resistivity of the TiFeCoNi thin film decreased sharply after a suitable period of oxidation at high temperature. The lowest resistivity of the TiFeCoNi oxide film was 35 ± 3 μΩ-cm. The low electrical resistivity of the TiFeCoNi oxide thin film was attributed to Ti, which is more reactive than the other elements, reacting with oxygen at the initial stage of annealing. The low resistivity is caused by the remaining electrons.

  11. Effect of Mechanical Activation on the In Situ Formation of TiB2 Particulates in the Powder Mixture of TiH2 and FeB

    Directory of Open Access Journals (Sweden)

    Huynh X.-K.

    2017-06-01

    Full Text Available The in situ formation of TiB2 particulates via an interface reaction between Ti and FeB powders was studied. The effects of mechanical activation by high-energy milling on the decomposition of TiH2 and the interface reactions between Ti and FeB powders to form TiB2 were investigated. Powder mixtures were fabricated using planetary ball-milling under various milling conditions. The specific ball-milling energy was calculated from the measured electrical power consumption during milling process. High specific milling energy (152.6 kJ/g resulted in a size reduction and homogeneous dispersion of constituent powders. This resulted in a decrease in the decomposition temperature of TiH2 and an increase in the formation reaction of TiB2 particulates in the Fe matrix, resulting in a homogeneous microstructure of nanoscale TiB2 evenly distributed within the Fe matrix. In contrast, the powder mixture milled with low specific milling energy (36.5 kJ/g showed an inhomogeneous microstructure composed of relatively large Fe-Fe2B particles surrounded by a thin layer of Fe-TiB2 within a finely dispersed Fe-TiB2 matrix region.

  12. Microstructure and corrosion properties of CrMnFeCoNi high entropy alloy coating

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Qingfeng [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Lu, Fenggui [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Li, Ruifeng [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, 212003 (China); Huang, Jian; Wu, Yixiong [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China)

    2017-02-28

    Highlights: • Equimolar CrMnFeCoNi high entropy alloy coating are prepared by laser cladding. • The cladding layer forms a simple FCC phase solid solution with identical dendritic structure. • The cladding layer exhibits a noble corrosion resistance in both 3.5 wt.% NaCl and 0.5 M sulfuric acid. • Element segregation makes Cr-depleted interdendrites the starting point of corrosion reaction. - Abstract: Equimolar CrMnFeCoNi high entropy alloy (HEA) is one of the most notable single phase multi-component alloys up-to-date with promising mechanical properties at cryogenic temperatures. However, the study on the corrosion behavior of CrMnFeCoNi HEA coating has still been lacking. In this paper, HEA coating with a nominal composition of CrMnFeCoNi is fabricated by laser surface alloying and studied in detail. Microstructure and chemical composition are determined by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used to investigate the corrosion behavior. The coating forms a simple FCC phase with an identical dendritic structure composed of Fe/Co/Ni-rich dendrites and Mn/Ni-rich interdendrites. Both in 3.5 wt.% NaCl solution and 0.5 M sulfuric acid the coating exhibits nobler corrosion resistance than A36 steel substrate and even lower i{sub corr} than 304 stainless steel (304SS). EIS plots coupled with fitted parameters reveal that a spontaneous protective film is formed and developed during immersion in 0.5 M sulfuric acid. The fitted R{sub t} value reaches its maximum at 24 h during a 48 h’ immersion test, indicating the passive film starts to break down after that. EDS analysis conducted on a corroded surface immersed in 0.5 M H{sub 2}SO{sub 4} reveals that corrosion starts from Cr-depleted interdendrites.

  13. [Experimental study and correction of the absorption and enhancement effect between Ti, V and Fe].

    Science.gov (United States)

    Tuo, Xian-Guo; Mu, Ke-Liang; Li, Zhe; Wang, Hong-Hui; Luo, Hui; Yang, Jian-Bo

    2009-11-01

    The absorption and enhancement effects in X-ray fluorescence analysis for Ti, V and Fe elements were studied in the present paper. Three bogus duality systems of Ti-V/Ti-Fe/V-Fe samples were confected and measured by X-ray fluorescence analysis technique using HPGe semiconductor detector, and the relation curve between unitary coefficient (R(K)) of element count rate and element content (W(K)) were obtained after the experiment. Having analyzed the degree of absorption and enhancement effect between every two elements, the authors get the result, and that is the absorption and enhancement effect between Ti and V is relatively distinctness, while it's not so distinctness in Ti-Fe and V-Fe. After that, a mathematics correction method of exponential fitting was used to fit the R(K)-W(K) curve and get a function equation of X-ray fluorescence count rate and content. Three groups of Ti-V duality samples were used to test the fitting method and the relative errors of Ti and V were less than 0.2% as compared to the actual results.

  14. Magnetoelectric effect in lead free piezoelectric Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}–modified CFO based magnetostrictive (Co{sub 0.6}Zn{sub 0.4}Fe{sub 1.7} Mn{sub 0.3}O{sub 4}) particulate nanocomposite prepared by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Megha [Nanotechnology Research Laboratory, Desh Bhagat University, Mandi Govindgarh 147330, Punjab (India); Sharma, Puneet [School of Physics & Materials Science, Thapar University, Patiala 147004, Punjab (India); Kumari, Mukesh; Singh, Anoop Pratap [Magnetics & Advanced ceramics laboratory, Department of Physics, Indian Institute of Technology, Delhi 110016 (India); Tyagi, Mintu, E-mail: mintutyagi@deshbhagatuniversity.in [Nanotechnology Research Laboratory, Desh Bhagat University, Mandi Govindgarh 147330, Punjab (India)

    2017-03-15

    Lead free magnetoelectric composites that comprise Co{sub 0.6}Zn{sub 0.4}Fe{sub 1.7}Mn{sub 0.3}O{sub 4} (CZFMO) and Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} (BNT) were synthesized using sol-gel method and it's structural, dielectric, magnetic, ferroelectric and magnetoelectric (ME) properties were studied. The X-ray diffraction displayed the single phase formation of parent phases and the presence of two phases in the composites. The temperature dependent dielectric spectra of samples indicates two anomalies at ~220 °C and ~320 °C were ascribed to ferroelectric to antiferroelectric, and anti-ferroelectric to paraelectric phase transitions respectively. Room temperature (RT) magnetic measurements show that composites are soft magnetic. The composite with x=0.2, showed the large value of ME voltage coefficient (α{sub E})~58 mV/cmOe. Moreover, these ME composites provide a great opportunity as potential lead free systems for multifunctional devices. - Highlights: • In this work, Modified CFO based lead free particulate nanocomposites with significantly high value of ME coupling coefficient α{sub E} ~52 mV/cmOe have been prepared. • This sufficient high value of α{sub E} in such composites is obtained by manipulating/improving the piezomagnetic component. • The studies on BNT based particulate ME composites are very scarce in literature. However, no report is available in on the modified CFO based lead free particulate composites.

  15. Mechanical Properties of Nano structured TiC-FeAl Hard Materials

    International Nuclear Information System (INIS)

    Shon, In-Jin; Jo, Hyoung-Gon; Kim, Byung-Su; Yoon, Jin-Kook; Hong Kyung-Tae

    2015-01-01

    For the formation of cemented Tic composite, Co or Ni is added as a binder. However, the high cost and low hardness of Co or Ni as binder and the low corrosion resistance of Tic-Co and Tic-Ni composite have generated interest to find alternative binder materials. It has been reported that FeAl show higher oxidation resistance and hardness as well as low cost compared to Co or Ni. Highly dense nanocrystalline Tic and Tic-FelAl with a relative density of up to 100% were obtained within 2 min by PCAS(pulsed current activated sintering) under the condition of 80MPa and up to 1300. The effect of FeAl addition of FeAl on the consolidation, the microstructure and the mechanical properties (hardness and fracture toughness) of TiC were investigated. The fracture toughness of TiC greatly increases without great decrease of the hardness by addition of FeAl. Not only fracture toughness but also hardness values of TiC-10vol.%FeAl were higher than those of TiC-10vol.%Fe, TiC-10vol.%Ni and TiC-10vol.%Co.

  16. Hydrogen kinetics studies of MgH2-FeTi composites

    Science.gov (United States)

    Meena, Priyanka; Jangir, Mukesh; Singh, Ramvir; Sharma, V. K.; Jain, I. P.

    2018-05-01

    MgH2 + x wt% FeTi (x=10, 25, 50) nano composites were ball milled to get nano structured material and characterized for structural, morphological and thermal properties. XRD of the milled samples revealed the formation of MgH2, FeTi, Fe2Ti and H0.06FeTi phases. Morphological studies by SEM were undertaken to investigate the effect of hydrogenation of nanostructure alloy. EDX confirmed elemental composition of the as-prepared alloy. TGA studies showed higher desorption temperature for milled MgH2 compared to x wt% FeTi added MgH2. Activation energy for hydrogen desorption was found to be -177.90, -215.69, -162.46 and -87.93 kJ/mol for milled MgH2 and Mg2+x wt% FeTi (10, 25, 50), showing 89.97 kJ/ mol reduction in activation energy for 50 wt% alloy additives resulting in improved hydrogen storage capacity. DSC investigations were carried out to investigate the effect of alloy on hydrogen absorption behavior of MgH2.

  17. Effect of Fe2+ and Fe3+ substitution on the crystal structure, optical and magnetic properties of anatase Ti1-δ (δ %Fe2+)O2 nanoparticles

    International Nuclear Information System (INIS)

    Wisnu Ari Adi; Adel Fisli

    2018-01-01

    Recently electromagnetic wave absorber materials are becoming a very interesting study to be studied more deeply because it is unique in terms of its interaction with electromagnetic waves itself. The main requirement to be met as an electromagnetic wave absorber material is that the material must have the characteristics of dielectric loss and magnetic loss are high. Anatase TiO 2 is a good dielectric material but these material is diamagnetic. Fe substitution was expected to manipulate the magnetic properties of this material. Modification of anatase TiO 2 was prepared by the precipitation method through the procedure as follows: 25 ml of iron salt solution containing 0.3 M Fe 2+ and 0.3 M Fe 3+ (mol ratio of 2 : 1) respectively mixed into 50 ml of 3 M TiCl 4 . The mixture solution of titanium and iron was added to a 150 ml solution of 2.5 M ammonia with drop wise rate 3 ml/min. After that the precipitate was washed then heated in an oven and calcined at 500 °C for 3 hours. There are two types of samples obtained namely anatase Ti 1-δ (δ %Fe 3+ ) Ti 1-δ (δ %Fe 2+ ) where (δ =0, 0.5, 1, and 5 wt %). Phase identification was measured by X-ray diffraction and crystal structure was analyzed by using the Rietveld method. Refinement result indicates that the sample has tetragonal crystal structure a single phase of anatase TiO 2 . Fe atoms have been successfully substituted into Ti without changing the crystal structure of this material. While based on the results of the analysis of optical and magnetic properties showed that the substitution effect of both Fe 2+ and Fe 3+ has managed to reduce energy of band gap and can transform this magnetic phase of this material from diamagnetic becomes paramagnetic at room temperature. It was concluded that it has successfully carried out material engineering of anatase TiO 2 with a substitution of up to 5 wt % of either Fe 2+ or Fe 3+ into ion Ti 4+ by the precipitation method. (author)

  18. Synthesis of MnFe2O4@Mn-Co oxide core-shell nanoparticles and their excellent performance for heavy metal removal.

    Science.gov (United States)

    Ma, Zichuan; Zhao, Dongyuan; Chang, Yongfang; Xing, Shengtao; Wu, Yinsu; Gao, Yuanzhe

    2013-10-21

    Magnetic nanomaterials that can be easily separated and recycled due to their magnetic properties have received considerable attention in the field of water treatment. However, these nanomaterials usually tend to aggregate and alter their properties. Herein, we report an economical and environmentally friendly method for the synthesis of magnetic nanoparticles with core-shell structure. MnFe2O4 nanoparticles have been successfully coated with amorphous Mn-Co oxide shells. The synthesized MnFe2O4@Mn-Co oxide nanoparticles have highly negatively charged surface in aqueous solution over a wide pH range, thus preventing their aggregation and enhancing their performance for heavy metal cation removal. The adsorption isotherms are well fitted to a Langmuir adsorption model, and the maximal adsorption capacities of Pb(II), Cu(II) and Cd(II) on MnFe2O4@Mn-Co oxide are 481.2, 386.2 and 345.5 mg g(-1), respectively. All the metal ions can be completely removed from the mixed metal ion solutions in a short time. Desorption studies confirm that the adsorbent can be effectively regenerated and reused.

  19. Tuning glass formation and brittle behaviors by similar solvent element substitution in (Mn,Fe)-based bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tao [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Ran, E-mail: liran@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Xiao, Ruijuan [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Gang [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, Jianfeng [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhang, Tao, E-mail: zhangtao@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2015-02-25

    A family of Mn-rich bulk metallic glasses (BMGs) was developed through the similar solvent elements (SSE) substitution of Mn for Fe in (Mn{sub x}Fe{sub 80−x})P{sub 10}B{sub 7}C{sub 3} alloys. The effect of the SSE substitution on glass formation, thermal stability, elastic constants, mechanical properties, fracture morphologies, Weibull modulus and indentation fracture toughness was discussed. A thermodynamics analysis provided by Battezzati et al. (L. Battezzati, E. Garrone, Z. Metallkd. 75 (1984) 305–310) was adopted to explain the compositional dependence of the glass-forming ability (GFA). The elastic moduli follow roughly linear correlations with the substitution concentration of Mn in (Mn{sub x}Fe{sub 80−x})P{sub 10}B{sub 7}C{sub 3} BMGs. The introduction of Mn to replace Fe significantly decreases the plasticity of the resulting BMGs and the Weibull modulus of the fracture strength. A super-brittle Mn-based BMGs of (Mn{sub 55}Fe{sub 25})P{sub 10}B{sub 7}C{sub 3} BMGs were found with the indentation fracture toughness (K{sub c}) of 1.91±0.04 MPa m{sup 1/2}, the lowest value among all kinds of BMGs so far. The atomic and electronic structure of the selected BMGs were simulated by the first principles molecular dynamics calculations based on density functional theory, which provided a possible understanding of the brittleness caused by the similar chemical element replacement of Mn for Fe.

  20. Phase transitions and magnetocaloric effects in intermetallic compounds MnFeX (X=P, As, Si, Ge)

    International Nuclear Information System (INIS)

    Tegus, O.; Bao Li-Hong; Song Lin

    2013-01-01

    Since the discovery of giant magnetocaloric effect in MnFeP 1−x As x compounds, much valuable work has been performed to develop and improve Fe 2 P-type transition-metal-based magnetic refrigerants. In this article, the recent progress of our studies on fundamental aspects of theoretical considerations and experimental techniques, effects of atomic substitution on the magnetism and magnetocalorics of Fe 2 P-type intermetallic compounds MnFeX (X=P, As, Ge, Si) is reviewed. Substituting Si (or Ge) for As leads to an As-free new magnetic material MnFeP 1−x Si(Ge) x . These new materials show large magnetocaloric effects resembling MnFe(P, As) near room temperature. Some new physical phenomena, such as huge thermal hysteresis and ‘virgin’ effect, were found in new materials. On the basis of Landau theory, a theoretical model was developed for studying the mechanism of phase transition in these materials. Our studies reveal that MnFe(P, Si) compound is a very promising material for room-temperature magnetic refrigeration and thermo-magnetic power generation. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  1. Effect of Mn addition on the structural and magnetic properties of Fe-Pd ferromagnetic shape memory alloys

    International Nuclear Information System (INIS)

    Sanchez-Alarcos, V.; Recarte, V.; Perez-Landazabal, J.I.; Gonzalez, M.A.; Rodriguez-Velamazan, J.A.

    2009-01-01

    The effect of Mn addition on the structural and magnetic properties of Fe-Pd ferromagnetic shape memory alloys is investigated. In particular, a complete characterization of the influence of the partial substitution of Fe by Mn has been performed on Fe 69.4-x Pd 30.6 Mn x (x = 0, 1, 2.5 and 5) alloys. The substitution of 1% Fe by Mn fully inhibits the undesirable irreversible face-centered tetragonal to body-centered tetragonal transformation without decreasing the face-centered cubic to face-centered tetragonal temperature. In addition, the substitution of 2.5% Fe by Mn gives rise to the highest thermoelastic transformation temperature observed to date in the Fe-Pd system, probably due to an increase in the valence electron concentration. The magnetocaloric effect has been evaluated in this alloy system for the first time. Nevertheless, the low values obtained suggest that the Fe-Pd alloys are not good candidates for magnetic refrigeration applications.

  2. A structural phase transition coupled to the Fe{sup 3+} spin-state crossover in anhydrous RbMn[Fe(CN){sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Rykov, A. I., E-mail: rykov3@yahoo.com; Wang, J., E-mail: wangjh@dicp.ac.cn; Zhang, T. [Chinese Academy of Sciences, Moessbauer Effect Data Center, Dalian Institute of Chemical Physics (China); Nomura, K. [University of Tokyo, Graduate School of Engineering (Japan)

    2013-04-15

    Linkage isomerism is the coexistence of iso-compositional molecules or solids differing by connectivity of the metal to a ligand. In a crystalline solid state, the rotation is possible for asymmetric ligands, e.g., for cyanide ligand. Here we report on our observation of a phase transition in anhydrous RbMn[Fe(CN){sub 6}] (nearly stoichiometric) and on the effect of linkage isomerism ensuing our interpretation of the results of Moessbauer study in which we observe the iron spin state crossover among two phases involved into this transition. The anhydrous RbMn[Fe(CN){sub 6}] can be prepared via prolonged thermal treatment (1 week at at 80 Degree-Sign C) of the as-synthesized hydrated RbMn[Fe(CN){sub 6}]{center_dot}H{sub 2}O. The latter compound famous for its charge-transfer phase transition is a precursor in our case. As the temperature is raising above 80 Degree-Sign C (remaining below 100 Degree-Sign C) we observe RbMn[Fe(CN){sub 6}] that inherited its F-43 m symmetry from RbMn[Fe(CN){sub 6}]{center_dot}H{sub 2}O transforming to a phase of the Fm-3 m symmetry. In the latter, more than half of Fe{sup 3 + } ions are in high-spin state. We suggest a plausible way to explain the spin-crossover that is to allow the linkage isomerism by rotation of the cyanide ligands.

  3. Properties of Mn0.4Zn0.6Fe2O4 and Mn0.6Zn0.4Fe2O4 as Nanocatalyst for Ammonia Production

    Directory of Open Access Journals (Sweden)

    Puspitasari Poppy

    2017-01-01

    Full Text Available Ammonia synthesis requires high pressure and high temperature process. Unfortunately, the capital intensive cost resulting low yield of ammonia by using recent catalyst which is iron oxide. Therefore, manganese zinc ferrite as a soft ferrite material will be introduced as a new nanocatalyst to enhance the ammonia yield. As a new nanocatalyst for ammonia production, study of comparasion two different concentration of MnZn Ferrite is very important. This paper will compare the yield of ammonia by using two different nanocatalyst which are Mn0.4Zn0.6Fe2O4 and Mn0.6Zn0.4Fe2O4. Both were synthesized by sol-gel method and has been characterize by using FESEM (morphology, XRD (phase identification, EDX (elemental analysis and TPR (oxide reduction. The ammonia was produce with and without magnetic field applied. The result shows that the ammonia yield is higher for Mn0.4Zn0.6Fe2O4 nanocatalyst than Mn0.6Zn0.4Fe2O4 by using magnetic field applied. 67.2% of yield has been achieved by using new nanocatalyst Mn0.6Zn0.4Fe2O4 and magnetic field applied at ambient environment.

  4. Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, Murat, E-mail: murat.ozmen@inonu.edu.tr [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Güngördü, Abbas [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Erdemoglu, Sema [Inonu University, Faculty of Science, Department of Chemistry, Malatya (Turkey); Ozmen, Nesrin [Inonu University, Faculty of Education, Department of Science Teaching Program, Malatya (Turkey); Asilturk, Meltem [Akdeniz University, Department of Materials Science and Engineering, Antalya (Turkey)

    2015-08-15

    Highlights: • Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized and characterized. • The photocatalytic efficiency of the photocatalysts was evaluated for BPA and ATZ. • Toxicity of photocatalysts and photocatalytic by-products were determined. • Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality on X. laevis. • Degradation of BPA caused a significant reduction of lethal effects. - Abstract: The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO{sub 2}. Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV–vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO{sub 2} was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO{sub 2} increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2–4 h of degradation. However, biochemical assays showed that both Mn-doped TiO{sub 2} and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn

  5. Fe-induced enhancement of antiferromagnetic spin correlations in Mn2-xFexBO4

    Science.gov (United States)

    Kazak, N. V.; Platunov, M. S.; Knyazev, Yu. V.; Moshkina, E. M.; Gavrilkin, S. Yu.; Bayukov, O. A.; Gorev, M. V.; Pogoreltsev, E. I.; Zeer, G. M.; Zharkov, S. M.; Ovchinnikov, S. G.

    2018-04-01

    Fe substitution effect on the magnetic behavior of Mn2-xFexBO4 (x = 0.3, 0.5, 0.7) warwickites has been investigated combining Mössbauer spectroscopy, dc magnetization, ac magnetic susceptibility, and heat capacity measurements. The Fe3+ ions distribution over two crystallographic nonequivalent sites is studied. The Fe introduction breaks a long-range antiferromagnetic order and leads to onset of spin-glass ground state. The antiferromagnetic short-range-order spin correlations persist up to temperatures well above TSG reflecting in increasing deviations from the Curie-Weiss law, the reduced effective magnetic moment and "missing" entropy. The results are interpreted in the terms of the progressive increase of the frustration effect and the formation of spin-correlated regions.

  6. Cyanide-bridged Fe(III)-Mn(III) bimetallic complexes with dimeric and chain structures constructed from a newly made mer-Fe tricyanide: structures and magnetic properties.

    Science.gov (United States)

    Kim, Jae Il; Kwak, Hyun Young; Yoon, Jung Hee; Ryu, Dae Won; Yoo, In Young; Yang, Namgeun; Cho, Beong Ki; Park, Je-Geun; Lee, Hyosug; Hong, Chang Seop

    2009-04-06

    Four cyanide-linked Fe(III)-Mn(III) complexes were prepared by reacting Mn Schiff bases with a new molecular precursor (PPh(4))[Fe(qcq)(CN)(3)] [1; qcq = 8-(2-quinolinecarboxamido)quinoline anion]. They include a dimeric molecule, [Fe(qcq)(CN)(3)][Mn(3-MeOsalen)(H(2)O)] x 2 H(2)O [2 x 2 H(2)O; 3-MeOsalen = N,N'-ethylenebis(3-methoxysalicylideneiminato) dianion], and three 1D zigzag chains, [Fe(qcq)(CN)(3)][Mn(5-Clsalen)] x 3 H(2)O [3 x 2 MeOH; 5-Clsalen = N,N'-ethylenebis(5-chlorosalicylideneiminato) dianion], [Fe(qcq)(CN)(3)][Mn(5-Brsalen)] x 2 MeOH [4 x 2 MeOH; 5-Brsalen = N,N'-ethylenebis(5-bromosalicylideneiminato) dianion], and Fe(qcq)(CN)(3)][Mn(salen)].MeCN x H(2)O [5 x MeCN; salen = N,N'-ethylenebis(salicylideneiminato) dianion]. The complexes consist of extensive hydrogen bonding and pi-pi stacking interactions, generating multidimensional structures. Magnetic studies demonstrate that antiferromagnetic couplings are operative between Fe(III) and Mn(III) centers bridged by cyanide ligands. On the basis of an infinite chain model, magnetic coupling parameters of 2-5 range from -9.3 to -14.1 cm(-1). A long-range order is observed at 2.3 K for 3 and 2.2 K for 4, while compound 5 shows spin glass behavior possibly coupled with magnetic ordering.

  7. Polarized neutron reflectivity studies on epitaxial BiFeO3/La0.7Sr0.3MnO3 heterostructure integrated with Si (100

    Directory of Open Access Journals (Sweden)

    S. R. Singamaneni

    2018-05-01

    Full Text Available This work reports polarized neutron reflectivity (PNR measurements performed using the Magnetism Reflectometer at Oak Ridge National Laboratory on epitaxial BiFeO3(BFO/La0.7Sr0.3MnO3(LSMO/SrTiO3(STO/MgO/TiN heterostructure deposited on Si (100 substrates. By measuring the angular dependence of neutrons reflected from the sample, PNR can provide insights on interface magnetic spin structure, chemical composition and magnetic depth profiles with a nanometer resolution. Our first analysis of nuclear scattering length density (NSLD and magnetic scattering length density (MSLD depth profiles measured at 4 K have successfully reproduced most of the expected features of this heterostructure, such as the NSLD for the Si, TiN, MgO, STO, LSMO layers and remanent magnetization (2.28μB/Mn of bulk LSMO. However, the SLD of the BFO is decreased by about 30% from the expected value. When 5 V was applied across the BFO/LSMO interface, we found that the magnetic moment of the LSMO layer could be varied by about 15-20% at 6 K. Several mechanisms such as redistribution of oxygen vacancies, interface strain, charge screening and valence state change at the interface could be at play. Work is in progress to gain an improved in-depth understanding of these effects using MOKE and STEM-Z interface specific measurements.

  8. Polarized neutron reflectivity studies on epitaxial BiFeO3/La0.7Sr0.3MnO3 heterostructure integrated with Si (100)

    Science.gov (United States)

    Singamaneni, S. R.; Prater, J. T.; Glavic, A.; Lauter, V.; Narayan, J.

    2018-05-01

    This work reports polarized neutron reflectivity (PNR) measurements performed using the Magnetism Reflectometer at Oak Ridge National Laboratory on epitaxial BiFeO3(BFO)/La0.7Sr0.3MnO3(LSMO)/SrTiO3(STO)/MgO/TiN heterostructure deposited on Si (100) substrates. By measuring the angular dependence of neutrons reflected from the sample, PNR can provide insights on interface magnetic spin structure, chemical composition and magnetic depth profiles with a nanometer resolution. Our first analysis of nuclear scattering length density (NSLD) and magnetic scattering length density (MSLD) depth profiles measured at 4 K have successfully reproduced most of the expected features of this heterostructure, such as the NSLD for the Si, TiN, MgO, STO, LSMO layers and remanent magnetization (2.28μB/Mn) of bulk LSMO. However, the SLD of the BFO is decreased by about 30% from the expected value. When 5 V was applied across the BFO/LSMO interface, we found that the magnetic moment of the LSMO layer could be varied by about 15-20% at 6 K. Several mechanisms such as redistribution of oxygen vacancies, interface strain, charge screening and valence state change at the interface could be at play. Work is in progress to gain an improved in-depth understanding of these effects using MOKE and STEM-Z interface specific measurements.

  9. Fe-Ca-phosphate, Fe-silicate, and Mn-oxide minerals in concretions from the Monterey Formation

    Science.gov (United States)

    Medrano, M.D.; Piper, D.Z.

    1997-01-01

    Concentrically zoned phosphatic-enriched concretions were collected at three sites from the Monterey Formation. The following minerals were identified: vivianite, lipscombite, rockbridgeite, leucophosphite, mitridatite, carbonate fluorapatite, nontronite, todorokite, and barite. The mineralogy of the concretions was slightly different at each of the three collection sites. None of the concretions contains all of the minerals, but the spatial distribution of minerals in individual concretions, overlapping mineralogies between different concretions, and the geochemical properties of the separate minerals suggest a paragenesis represented by the above order. Eh increased from the precipitation of vivianite to that of rockbridgeite/lipscombite. The precipitation of leucophosphite, then mitridatite, carbonate fluorapatite and todorokite/Fe-oxide indicates increasing pH. Concretion growth culminated with the precipitation of todorokite, a Mn oxide, and minor amounts of barite along microfractures. Conspicuously absent are Fe-sulfide and Mn-phosphate minerals. The concretions are hosted by finely laminated diatomite. The laminations exhibit little to no deformation around the concretions, requiring that the concretions formed after compaction. We interpret this sediment feature and the paragenesis as recording the evolving pore-water chemistry as the formation was uplifted into the fresh-ground-water zone.

  10. In situ Fabrication of Fe-TiB{sub 2} Nanocomposite Powder by Planetary Ball Milling and Subsequent Heat-treatment of FeB and TiH{sub 2} Powder Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Xuan-Khoa [Hanoi Uneversity of Science and Technology, Hanoi (Viet Nam); Bae, Sun-Woo; Kim, Ji Soon [University of Ulsan, Ulsan (Korea, Republic of)

    2017-01-15

    Fe-TiB{sub 2} powder was synthesized in-situ by the planetary ball milling and subsequent heat-treatment of an iron boride (FeB) and titanium hydride (TiH{sub 2}) powder mixture. Mechanical activation of the (FeB+TiH{sub 2}) powder mixtures was observed after a milling time of 3 hours at 700 rpm of rotation speed, but activation was not the same after 1 hour milling time. The particle size of the (FeB+ TiH{sub 2}) powder mixture was reduced to the nanometer scale, and each constituent was homogeneously distributed. A sharp exothermic peak was observed at a lower temperature (749 ℃) on the DSC curves for the (FeB+TiH{sub 2}) powder mixture milled for 3 hours, compared to the one milled for 1 hour (774 ℃). These peaks were confirmed to have resulted from the formation reaction of the TiB{sub 2} phase, from Ti and B elements in the FeB. The Fe-TiB{sub 2} composite powder fabricated in situ exhibited only two phases of Fe and TiB{sub 2} with homogeneous distribution. The size of the TiB{sub 2} particulates in the Fe matrix was less than 5 nm.

  11. Thermodynamic calculation on the stability of (Fe,Mn){sub 3}AlC carbide in high aluminum steels

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Kwang-Geun [Automotive Steel Products Research Group, POSCO Technical Research Laboratories, POSCO, Jeonnam 545-090 (Korea, Republic of); School of Materials Science and Engineering, Pusan National University, Pusan, 609-735 (Korea, Republic of); Lee, Hyuk-Joong [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Kwak, Jai-Hyun [Automotive Steel Products Research Group, POSCO Technical Research Laboratories, POSCO, Jeonnam 545-090 (Korea, Republic of); Kang, Jung-Yoon [School of Materials Science and Engineering, Pusan National University, Pusan, 609-735 (Korea, Republic of); Lee, Byeong-Joo, E-mail: calphad@postech.ac.k [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)

    2010-08-27

    A CALPHAD type thermodynamic description for the Fe-Mn-Al-C quaternary system has been constructed by combining a newly assessed Mn-Al-C ternary description and a partly modified Fe-Al-C description to an existing thermodynamic database for steels. A special attention was paid to reproduce experimentally reported phase stability of {kappa} carbide in high Al and high Mn steels. This paper demonstrates that the proposed thermodynamic description makes it possible to predict phase equilibria in corresponding alloys with a practically acceptable accuracy. The applicability of the thermodynamic calculation is also demonstrated for the interpretation of microstructural and constitutional evolution during industrial processes for high Al steels.

  12. Thermodynamic calculation on the stability of (Fe,Mn)3AlC carbide in high aluminum steels

    International Nuclear Information System (INIS)

    Chin, Kwang-Geun; Lee, Hyuk-Joong; Kwak, Jai-Hyun; Kang, Jung-Yoon; Lee, Byeong-Joo

    2010-01-01

    A CALPHAD type thermodynamic description for the Fe-Mn-Al-C quaternary system has been constructed by combining a newly assessed Mn-Al-C ternary description and a partly modified Fe-Al-C description to an existing thermodynamic database for steels. A special attention was paid to reproduce experimentally reported phase stability of κ carbide in high Al and high Mn steels. This paper demonstrates that the proposed thermodynamic description makes it possible to predict phase equilibria in corresponding alloys with a practically acceptable accuracy. The applicability of the thermodynamic calculation is also demonstrated for the interpretation of microstructural and constitutional evolution during industrial processes for high Al steels.

  13. Structural, Raman, and dielectric studies on multiferroic Mn-doped Bi 1-xLax FeO 3 ceramics

    KAUST Repository

    Xing, Zhibiao

    2014-04-03

    Multiferroic Bi1-xLaxFeO3 [BLFO (x)] ceramics with x = 0.10-0.50 and Mn-doped BLFO (x = 0.30) ceramics with different doping contents (0.1-1.0 mol%) were prepared by solid-state reaction method. They were crystallized in a perovskite phase with rhombohedral symmetry. In the BLFO (x) system, a composition (x)-driven structural transformation (R3c→C222) was observed at x = 0.30. The formation of Bi2Fe 4O9 impure phase was effectively suppressed with increasing the x value, and the rhombohedral distortion in the BLFO ceramics was decreased, leading to some Raman active modes disappeared. A significant red frequency shift (~13 cm-1) of the Raman mode of 232 cm-1 in the BLFO ceramics was observed, which strongly perceived a significant destabilization in the octahedral oxygen chains, and in turn affected the local FeO6 octahedral environment. In the Mn-doped BLFO (x = 0.30) ceramics, the intensity of the Raman mode near 628 cm-1 was increased with increasing the Mn-doping content, which was resulted from an enhanced local Jahn-Teller distortions of the (Mn,Fe)O6 octahedra. Electron microscopy images revealed some changes in the ceramic grain sizes and their morphologies in the Mn-doped samples at different contents. Wedge-shaped 71° ferroelectric domains with domain walls lying on the {110} planes were observed in the BLFO (x = 0.30) ceramics, whereas in the 1.0 mol% Mn-doped BLFO (x = 0.30) samples, 71° ferroelectric domains exhibited a parallel band-shaped morphology with average domain width of 95 nm. Dielectric studies revealed that high dielectric loss of the BLFO (x = 0.30) ceramics was drastically reduced from 0.8 to 0.01 (measured @ 104 Hz) via 1.0 mol% Mn-doping. The underlying mechanisms can be understood by a charge disproportion between the Mn4+ and Fe2+ in the Mn-doped samples, where a reaction of Mn4+ + Fe2+→Mn3+ + Fe3+ is taken place, resulting in the reduction in the oxygen vacancies and a suppression of the electron hopping from Fe3+ to Fe2+ ions

  14. Structural, Raman, and dielectric studies on multiferroic Mn-doped Bi 1-xLax FeO 3 ceramics

    KAUST Repository

    Xing, Zhibiao; Zhu, Xinhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

    2014-01-01

    Multiferroic Bi1-xLaxFeO3 [BLFO (x)] ceramics with x = 0.10-0.50 and Mn-doped BLFO (x = 0.30) ceramics with different doping contents (0.1-1.0 mol%) were prepared by solid-state reaction method. They were crystallized in a perovskite phase with rhombohedral symmetry. In the BLFO (x) system, a composition (x)-driven structural transformation (R3c→C222) was observed at x = 0.30. The formation of Bi2Fe 4O9 impure phase was effectively suppressed with increasing the x value, and the rhombohedral distortion in the BLFO ceramics was decreased, leading to some Raman active modes disappeared. A significant red frequency shift (~13 cm-1) of the Raman mode of 232 cm-1 in the BLFO ceramics was observed, which strongly perceived a significant destabilization in the octahedral oxygen chains, and in turn affected the local FeO6 octahedral environment. In the Mn-doped BLFO (x = 0.30) ceramics, the intensity of the Raman mode near 628 cm-1 was increased with increasing the Mn-doping content, which was resulted from an enhanced local Jahn-Teller distortions of the (Mn,Fe)O6 octahedra. Electron microscopy images revealed some changes in the ceramic grain sizes and their morphologies in the Mn-doped samples at different contents. Wedge-shaped 71° ferroelectric domains with domain walls lying on the {110} planes were observed in the BLFO (x = 0.30) ceramics, whereas in the 1.0 mol% Mn-doped BLFO (x = 0.30) samples, 71° ferroelectric domains exhibited a parallel band-shaped morphology with average domain width of 95 nm. Dielectric studies revealed that high dielectric loss of the BLFO (x = 0.30) ceramics was drastically reduced from 0.8 to 0.01 (measured @ 104 Hz) via 1.0 mol% Mn-doping. The underlying mechanisms can be understood by a charge disproportion between the Mn4+ and Fe2+ in the Mn-doped samples, where a reaction of Mn4+ + Fe2+→Mn3+ + Fe3+ is taken place, resulting in the reduction in the oxygen vacancies and a suppression of the electron hopping from Fe3+ to Fe2+ ions

  15. Magnetic hybride layers. Magnetic properties of locally exchange-coupled NiFe/IrMn layers; Magnetische Hybridschichten. Magnetische Eigenschaften lokal austauschgekoppelter NiFe/IrMn-Schichten

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Christine

    2010-10-06

    By the lateral modification of the magnetic properties of exchange-coupled NiFe/IrMn layers soft-magnetic layers were produced, which show both new static and dynamic properties. As lateral structuration methods hereby the localoxidation as well as ion implantation were applied. By means of thes procedures it has been succeeded to mould specific magnetic domain configurations with strp structure into the layers. In dependence of the structure orientation as well as strip period the remagnetization behavior as well as the magnetic-resonance frequency and damping of the layers could directly be modified. The new dynamical properties are hereby discussed in the framework of the coupling via dynamical charges and the direct affection of the effective field of the artificially inserted domain state. The presented results prove by this the large potential of the lateral magneto-structuration for the tuning of specifical static as well as dynamic properties of magnetically thin layers.

  16. Semiconductor Ceramic Mn0.5Fe1.5O3-Fe2O3 from Natural Minerals as Ethanol Gas Sensors

    Science.gov (United States)

    Aliah, H.; Syarif, D. G.; Iman, R. N.; Sawitri, A.; Sanjaya WS, M.; Nurul Subkhi, M.; Pitriana, P.

    2018-05-01

    In this research, Mn and Fe-based ceramic gas sensing were fabricated and characterized. This research used natural mineral which is widely available in Indonesia and intended to observe the characteristics of Mn and Fe-based semiconducting material. Fabricating process of the thick films started by synthesizing the ceramic powder of Fe(OH)3 and Mn oxide material using the precipitation method. The deposition from precipitation method previously was calcined at a temperature of 800 °C to produce nanoparticle powder. Nanoparticle powder that contains Mn and Fe oxide was mixed with an organic vehicle (OV) to produce a paste. Then, the paste was layered on the alumina substrate by using the screen printing method. XRD method was utilized to characterize the thick film crystal structure that has been produced. XRD spectra showed that the ceramic layer was formed from the solid Mn0.5Fe1.5O3 (bixbyite) and Fe2O3. In addition, the electrical properties (resistance) examination was held in the room that contains air and ethanol to determine the sensor sensitivity of ethanol gas. The sensor resistance decreases as the ethanol gas was added, showing that the sensor was sensitive to ethanol gas and an n-type semiconductor. Gas sensor exhibit sensitive characterization of ethanol gas on the concentration of (100 to 300) ppm at a temperature of (150 to 200) °C. This showed that the Mn0.5Fe1.5O3-Fe2O3 ceramic semiconductor could be utilized as the ethanol gas detector.

  17. Coupling catalytic hydrolysis and oxidation on Mn/TiO2-Al2O3 for HCN removal

    Science.gov (United States)

    Wang, Langlang; Wang, Xueqian; Cheng, Jinhuan; Ning, Ping; Lin, Yilong

    2018-05-01

    The manganese-modified titania-alumina (Mn/TiO2-Al2O3) catalyst synthesized by sol-gol method was used to remove hydrogen cyanide (HCN) from simulated flue gas. Further, effects of the mass ratios of Ti/Al, Mn loading, calcination temperature, and relative humidity on HCN conversion efficiency and catalytic activity were systematically investigated. The results indicated that the Mn/TiO2-Al2O3 catalyst exhibited significantly enhanced HCN removal efficiency, and the maximum yield of N2 increased to 68.02% without the participation of water vapor. When water vapor was added into the flue gas, the yield of N2 decreased and the formation of NOx was also inhibited. The XRD and XPS results indicated that Mn was mainly present in the form of Mn2+, Mn3+, and Mn4+ on the surface of catalyst and chemisorbed oxygen played a major role in the HCN catalytic oxidation process. The results of DSC-TGA analysis and H2-TPR indicated that the catalyst also exhibited a good thermal and chemical stability. NH3-TPD and CO2-TPD indicated that the surface of the catalyst mainly contained acidic sites. During the reaction, part of NH3 was adsorbed by Brönsted and Lewis acid sites. NH3 adsorbed on Lewis acid sites participated in NH3-SCR, which reduced the amount of NOx produced and resulted in a high N2 yield.

  18. Synthesis and magnetic properties of the thin film exchange spring system of MnBi/FeCo

    Science.gov (United States)

    Sabet, S.; Hildebrandt, E.; Alff, L.

    2017-10-01

    Manganese bismuth thin films with a nominal thickness of ∼40 nm were grown at room temperature onto quartz glass substrate in a DC magnetron sputtering unit. In contrast to the usual multilayer approach, the MnBi films were deposited using a single sputtering target with a stoichiometry of Mn55Bi45 (at. %). A subsequent in-situ annealing step was performed in vacuum in order to form the ferromagnetic LTP of MnBi. X-ray diffraction confirmed the formation of a textured LTP MnBi hard phase after annealing at 330 °C. This film shows a maximum saturation magnetization of 530 emu/cm3, high out-of-plane coercivity of 15 kOe induced by unreacted bismuth. The exchange coupling effect was investigated by deposition of a second layer of FeCo with 1 nm and 2 nm thickness onto the LTP MnBi films. The MnBi/FeCo double layer showed as expected higher saturation magnetization with increasing thickness of the FeCo layer while the coercive field remained constant. The fabrication of the MnBi/FeCo double layer for an exchange spring magnet was facilitated by deposition from a single stoichiometric target.

  19. Ordered Fe(II)Ti(IV)O3 Mixed Monolayer Oxide on Rutile TiO2(011).

    Science.gov (United States)

    Halpegamage, Sandamali; Ding, Pan; Gong, Xue-Qing; Batzill, Matthias

    2015-08-25

    Oxide monolayers supported or intermixed with an oxide support are potential nanocatalysts whose properties are determined by the interplay with the support. For fundamental studies of monolayer oxides on metal oxide supports, well-defined systems are needed, but so far, the synthesis of monolayer oxides with long-range order on single-crystal oxide surfaces is rare. Here, we show by a combination of scanning tunneling microscopy, photoemission spectroscopy, and density functional theory (DFT)-based computational analysis that the rutile TiO2(011) surface supports the formation of an ordered mixed FeTiO3 monolayer. Deposition of iron in a slightly oxidizing atmosphere (10(-8) Torr O2) and annealing to 300 °C results in a well-ordered surface structure with Fe in a 2+ charge state and Ti in a 4+ charge states. Low-energy ion scattering suggests that the cation surface composition is close to half Fe and half Ti. This surface is stable in ultrahigh vacuum to annealing temperatures of 300 °C before the iron is reduced. DFT simulations confirm that a surface structure with coverage of 50% FeO units is stable and forms an ordered structure. Although distinct from known bulk phases of the iron-titanium oxide systems, the FeTiO3 monolayer exhibits some resemblance to the ilmenite structure, which may suggest that a variety of different mixed oxide phases (of systems that exist in a bulk ilmenite phase) may be synthesized in this way on the rutile TiO2(011) substrate.

  20. Arsenic removal in aqueous solution by a novel Fe-Mn modified biochar composite: Characterization and mechanism.

    Science.gov (United States)

    Lin, Lina; Qiu, Weiwen; Wang, Di; Huang, Qing; Song, Zhengguo; Chau, Henry Wai

    2017-10-01

    The aim of this study was to develop a cost-effective method for As removal from aqueous systems. To this end, pristine biochar (BC) was impregnated with Fe-Mn oxides and a comparative analysis was conducted on the adsorption capacities of BC, Fe-Mn binary oxide (FMO), and Fe/Mn modified biochar (FMBC). The ferromanganese oxides increased the specific surface areas of BC. FMBC presented greater adsorption of As (Q max = 8.25mgg -1 ) than FMO and BC. Energy dispersive spectrometer analysis and electron microscope scanning revealed numerous pores of FMBC with the existence of Fe-Mn oxide using. Distinguished binding energy shifting of the As3d, Fe2p, O1s, and Mn2p3/2 regions after As sorption were found, indicating that Mn(III) oxidation and interaction of oxygen-containing function groups in the FMBC promoted the conversion of As(III) to As(V). Furthermore, chemisorption was found to be the main mechanism for As sorption on FMBC. Thus, the results suggest that FMBC could be used as an inexpensive and highly efficient adsorbent for As removal from water environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Synthesis and characterization of La(Cr,Fe,Mn)O{sub 3} nanoparticles obtained by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, F.A., E-mail: fernandafabianro@gmail.com [Universidade Federal de Sergipe, Campus Prof. Aluísio Campos, Departamento de Física, 49100-000 São Cristóvão, SE (Brazil); Pedra, P.P.; Filho, J.L.S. [Universidade Federal de Sergipe, Campus Prof. Aluísio Campos, Departamento de Física, 49100-000 São Cristóvão, SE (Brazil); Duque, J.G.S.; Meneses, C.T. [Universidade Federal de Sergipe, Campus Prof. Alberto Carvalho, Departamento de Física, 49500-000 Itabaiana, SE (Brazil)

    2015-04-01

    Magnetic and structural properties have been investigated in La(Cr,Fe,Mn)O{sub 3} nanoparticles obtained by co-precipitation method. The X-ray diffraction measurements allied to Rietveld method confirm the formation of LaCrO{sub 3}, LaFeO{sub 3} and LaMnO{sub 3} nanoparticles with crystal structure orthorhombic (Pbnm), orthorhombic (Pnma) and rhombohedral (R-3c), respectively. We also verified an decreasing in the average crystallite size from 73 to 26 nm, depending of the transition metal. The magnetic measurements reveal an antiferromagnetic behavior for the LaCrO{sub 3} sample with T{sub N}~289 K, and a weak ferromagnetic ordering for the LaMnO{sub 3} sample with T{sub c}~200 K. - Highlights: • La(Cr,Fe,Mn)O{sub 3} nanoparticles were synthesized by coprecipitation method. • XRD results confirm the formation single phase in the compounds studied. • Magnetic property in the La(Fe,Cr,Mn)O{sub 3} nanoparticles dependent on the TM. • La(Cr,Fe)O{sub 3} nanoparticles presented behavior antiferromagnetic and LaMnO{sub 3} ferromagnetic.

  2. Corrosion behaviour of Fe-Mn-Si based shape memory steels trained by cold rolling

    International Nuclear Information System (INIS)

    Soederberg, O.; Liu, X.W.; Ullakko, K.; Lindroos, V.K.

    1999-01-01

    Fe-Mn-Si based high nitrogen steels have been studied in recent years for potential industrial applications. These steels show good shape memory properties, high strength and excellent ductility. In the present study, the effects of training history on the corrosion properties of Fe-Mn-Si-Cr-Ni based high nitrogen steels were investigated. The corrosion behaviour of shape memory alloys was analyzed by implementing anodic polarisation measurements and immersion tests. The shape memory steels in annealed, deformed and recovered conditions were studied to examine the training effect on their corrosion behaviour. The features of the anodic polarisation curves indicated a general corrosion type of these steels. The experimental results showed that Cr and Mn had a marked influence on the corrosion behaviour of the steels, followed by Ni, N and V. It was also apparent that the deformation during the shape memory training by cold rolling decreased the corrosion stability, and the recovery heating reduced further their corrosion resistance. However, further studies are needed in order to better understand the corrosion behaviour of the investigated alloys. (orig.)

  3. A FeNiMnC alloy with strain glass transition

    Directory of Open Access Journals (Sweden)

    Hui Ma

    2018-02-01

    Full Text Available Recent experimental and theoretical investigations suggested that doping sufficient point defects into a normal ferroelastic/martensitic alloy systems could lead to a frozen disordered state of local lattice strains (nanomartensite domains, thereby suppressing the long-range strain-ordering martensitic transition. In this study, we attempt to explore the possibility of developing novel ferrous Elinvar alloys by replacing nickel with carbon and manganese as dopant species. A nominal Fe89Ni5Mn4.6C1.4 alloy was prepared by argon arc melting, and XRD, DSC, DMA and TEM techniques were employed to characterize the strain glass transition signatures, such as invariance in average structure, frequency dispersion in dynamic mechanical properties (storage modulus and internal friction and the formation of nanosized strain domains. It is indicated that doping of Ni, Mn and C suppresses γ→α long-range strain-ordering martensitic transformation in Fe89Ni5Mn4.6C1.4 alloy, generating randomly distributed nanosized domains by strain glass transition. Keywords: Strain glass transition, Elinvar alloys, Point defects, Nanosized domains

  4. Building Composite Fe-Mn Oxide Flower-Like Nanostructures: A Detailed Magnetic Study

    KAUST Repository

    Zuddas, Efisio; Lentijo Mozo, Sergio; Casu, Alberto; Deiana, Davide; Falqui, Andrea

    2017-01-01

    Here we show that it’s possible to produce different magnetic core-multiple shells heterostructures from monodispersed iron oxide spherical magnetic seeds by finely controlling the amount of a manganese precursor and using in a smart and simple way a cation exchange synthetic approach. In particular, by increasing the amount of precursor we were able to produce nanostructures ranging from Fe3O4/Mn-ferrite core/single shell nanospheres to larger, flower-like Fe3O4/Mn-ferrite/Mn3O4 core-double shell nanoparticles. We first demonstrate how the formation of the initial thin manganese-ferrite shell determines a dramatic reduction of the superficial disorder in the starting iron oxide, bringing to nanomagnets with lower hardness. Then, the growth of the second and most external manganese oxide shell causes the magnetical hardening of the heterostructures, while its magnetic exchange coupling with the rest of the heterostructure can be antiferromagentic or ferromagnetic, depending on the strength of the applied external magnetic field. This response is similar to that of an iron oxide-manganese oxide core-shell system but differs from what observed in multiple-shell heterostructures. Finally, we report as the most external shell becomes magnetically irrelevant above the ferrimagnetic-paramagnetic transition of the manganese oxide and the resulting magnetic behavior of the flower-like structures is then studied in-depth.

  5. Evaluation of erosion-corrosion resistance in Fe-Mn-Al austenitic steels

    Directory of Open Access Journals (Sweden)

    William Arnulfo Aperador

    2013-04-01

    Full Text Available In this paper, the effects of Mn and Al against corrosion/errosion resistance of three samples of the Fe-Mn-Al austenitic alloys are evaluated. The samples have composition Fe-(4,9 ~ 11,0 wt. (% Al-(17,49 ~ 34,3 wt. (% Mn-(0,43 ~ 1,25 wt. (%C, those were prepared in an induction furnace from high purity materials. The alloys were evaluated in a composed solution of NaCl 0,5 M and Silica in a special chamber and AISI 316 stainless steel as reference material. The electrochemical characterization was performed by Tafel curve polarizations technique. This microstructural characterization was by Scanning Electron Microscopy (SEM. It was observed the significant decrease in the corrosion rate for steels Fermanal with a lower percentage of aluminum and manganese under conditions of dynamic corrosion and erosion-corrosion. SEM allows assessment of the dominant damage mechanisms and corroborated the results obtained by electrochemical measurements.

  6. Building Composite Fe-Mn Oxide Flower-Like Nanostructures: A Detailed Magnetic Study

    KAUST Repository

    Zuddas, Efisio

    2017-07-21

    Here we show that it’s possible to produce different magnetic core-multiple shells heterostructures from monodispersed iron oxide spherical magnetic seeds by finely controlling the amount of a manganese precursor and using in a smart and simple way a cation exchange synthetic approach. In particular, by increasing the amount of precursor we were able to produce nanostructures ranging from Fe3O4/Mn-ferrite core/single shell nanospheres to larger, flower-like Fe3O4/Mn-ferrite/Mn3O4 core-double shell nanoparticles. We first demonstrate how the formation of the initial thin manganese-ferrite shell determines a dramatic reduction of the superficial disorder in the starting iron oxide, bringing to nanomagnets with lower hardness. Then, the growth of the second and most external manganese oxide shell causes the magnetical hardening of the heterostructures, while its magnetic exchange coupling with the rest of the heterostructure can be antiferromagentic or ferromagnetic, depending on the strength of the applied external magnetic field. This response is similar to that of an iron oxide-manganese oxide core-shell system but differs from what observed in multiple-shell heterostructures. Finally, we report as the most external shell becomes magnetically irrelevant above the ferrimagnetic-paramagnetic transition of the manganese oxide and the resulting magnetic behavior of the flower-like structures is then studied in-depth.

  7. Facile fabrication of composited Mn_3O_4/Fe_3O_4 nanoflowers with high electrochemical performance as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhao, Dianyun; Hao, Qin; Xu, Caixia

    2015-01-01

    Graphical abstract: Mn_3O_4/Fe_3O_4 nanoflowers are successfully prepared through one step dealloying of Mn_5Fe_5Al_9_0 alloy at room temperature. This hierarchical flower-like structure with consists of a packed array of uniform regular hexagon-like nanoslices. Combined with the specific hierarchical flower-like architecture and the synergistic effect exerted by Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits enhanced performance as anode material for lithium ion batteries than pure Mn_3O_4 and Fe_3O_4 anode. - Highlights: • Mn_3O_4/Fe_3O_4 nanoflowers are easily prepared by one step dealloying method. • The nanoflowers consist of packed regular nanoslices with interconnected voids. • Mn_3O_4/Fe_3O_4 nanoflowers deliver higher discharge capacity than Mn_3O_4 and Fe_3O_4. • Mn_3O_4/Fe_3O_4 nanoflowers show lower initial irreversible loss than Mn_3O_4 anode. - Abstract: Mn_3O_4/Fe_3O_4 nanoflowers with controllable components are simply fabricated through one step etching of the Mn_5Fe_5Al_9_0 ternary alloy. The as-made hierarchical flower-like structure with interconnected voids consists of a packed array of uniform regular hexagon-like nanoslices. Based on the simple dealloying strategy the target metals are directly converted to uniform nanocomposite composed of Mn_3O_4 and Fe_3O_4 species. With the unique hierarchical flower-like structure and the synergistic effects between Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits higher performance as anode material for lithium ion batteries than that of pure Mn_3O_4 and Fe_3O_4 anodes. The Mn_3O_4/Fe_3O_4 nanocomposite deliver much higher discharge capacity and lower initial irreversible loss than Mn_3O_4 anode. The Mn_3O_4/Fe_3O_4 anode material also shows an excellent cycling stability at the high rate of 1500 mA g"−"1 with outstanding rate capability. With the advantages of simple preparation and excellent electrochemical performance, Mn_3O_4/Fe_3O_4 nanoflowers manifest great application potential as

  8. Magnetic properties and loss separation in FeSi/MnZnFe{sub 2}O{sub 4} soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Lauda, M. [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Füzer, J., E-mail: jan.fuzer@upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Kollár, P. [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Strečková, M.; Bureš, R. [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia); Kováč, J.; Baťková, M.; Baťko, I. [Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia)

    2016-08-01

    We investigated composites that have been prepared from FeSi powders covered with MnZnFe{sub 2}O{sub 4} (MnZn ferrite), which was prepared by sol–gel synthesis accompanied with the auto-combustion process. The aim of this paper is to analyze the complex permeability and core losses of prepared samples with different amount of MnZn ferrite. The microstructure and the powder morphology were examined by scanning electron microscopy. Magnetic measurements on bulk samples were carried out using a vibrating sample magnetometer, an impedance analyzer and hysteresisgraphs. The results indicate that the composites with 2.6 wt% MnZn ferrite show better soft magnetic properties than the composites with about 6 wt% MnZn ferrite. - Highlights: • Successful preparation of soft magnetic composite FeSi/MnZnFe{sub 2}O{sub 4}. • Study of the complex magnetic permeability. • Comparison of different compositions of prepared SMC's. • Determination of parts of magnetic losses.

  9. Fe/Ti co-pillared clay for enhanced arsenite removal and photo oxidation under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuan [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guang Dong Electric Power Design Institute, China Energy Engineering Group Co. Ltd., Guangzhou 510663 (China); Cai, Xiaojiao [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jingwei [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); The 718th Research Institute of CSIC, Handan 056027 (China); Zhou, Shimin [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Na, Ping, E-mail: naping@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2015-01-01

    Graphical abstract: - Highlights: • An iron and titanium co-pillared montmorillonite (Fe-Ti/MMT) was synthesized for arsenite removal. • Variety of characterization results indicated that Fe and Ti species were pillared in MMT. • A possible mechanism of arsenite adsorption/oxidation with UV light was established. • The participation of Fe component can promote the process of photocatalytic oxidation in Fe-Ti/MMT + As(III) system. • Fe-Ti/MMT can function as both photocatalyst and adsorbent for arsenite removal. - Abstract: A series of iron and titanium co-pillared montmorillonites (Fe-Ti/MMT) were prepared using hydrolysis of inserted titanium and different iron content in montmorillonite (MMT). The Fe-Ti/MMT were characterized by X-ray fluorescence, N{sub 2} adsorption and desorption, X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirming the effective insertion of Fe species and TiO{sub 2} in the MMT. The Fe-Ti/MMT was used to remove arsenite (As(III)) from aqueous solutions under different conditions. The result of As(III) adsorption under UV irradiation showed that the photo activity can be enhanced by incorporating Fe and Ti in MMT. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicated that the hydroxyl groups bonded to metal oxide (M–OH) played an important role in the adsorption of As(III)

  10. Large recoverable electrostrain in Mn-doped (Ba,Sr) TiO3 ceramics

    International Nuclear Information System (INIS)

    Zhang, L.X.; Chen, W.; Ren, X.

    2004-01-01

    In this letter we demonstrate that with a different principle, BaTiO 3 ceramics, so far considered as inferior piezoelectrics compared with Pb(Zr,Ti)O 3 (PZT), can show a large recoverable electrostrain. This principle utilizes a point-defect-mediated reversible domain switching mechanism, which can in theory generate 0.368% strain for BaTiO 3 ceramics at the best condition. Experimental results showed that, after aging at room temperature, 1.0 mol % Mn-doped (Ba 0.95 Sr 0.05 )TiO 3 ceramics generate a large recoverable nonlinear strain of about 0.12%-0.15% at a field of 3 kV/mm. This value exceeds that of conventional hard PZT piezoelectric ceramics. A microscopic model for the domain-related electrostrain effect in ceramics is proposed. It is also found that the large electrostrain effect is quite stable with respect to both changing frequency and fatigue cycles. Large electrostrain remains recoverable down to 0.05 Hz and after 10 000 cycles. These results demonstrate the potential of our approach in achieving large recoverable electrostrain in environmental-friendly (Pb-free) ceramics

  11. Photocatalytic activity of Fe-doped CaTiO₃ under UV-visible light.

    Science.gov (United States)

    Yang, He; Han, Chong; Xue, Xiangxin

    2014-07-01

    The photocatalytic degradation of methylene blue (MB) over Fe-doped CaTiO₃ under UV-visible light was investigated. The as-prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) system, Fourier transform infrared spectra (FT-IR), and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the doping with Fe significantly promoted the light absorption ability of CaTiO₃ in the visible light region. The Fe-doped CaTiO₃ exhibited higher photocatalytic activity than CaTiO₃ for the degradation of MB. However, the photocatalytic activity of the Fe-doped CaTiO₃ was greatly influenced by the calcination temperature during the preparation process. The Fe-doped CaTiO₃ prepared at 500°C exhibited the best photocatalytic activity, with degradation of almost 100% MB (10ppm) under UV-visible light for 180 min. Copyright © 2014. Published by Elsevier B.V.

  12. A study for preparation of Ti-Fe coating by high temperature sintering method

    International Nuclear Information System (INIS)

    Hu Yonghai

    1995-03-01

    A new technology for preparation of Ti-Fe alloy coating on the steel substrate was investigated by high temperature sintering method. The pulp of titanium hydride powder was coated on the cleaned steel substrate, then heated in vacuum for desorption of hydrogen and sintered at high temperature in argon atmosphere for forming Ti-Fe alloy coating. The electron probe analysis shows a strong coherent diffusion layer formed between the elements of titanium and iron. X-ray diffraction analysis indicates that the coating consists of α-Ti, TiFe and TiFe 2 three phases. The wear resistance of the coating is twice as large as that of grey cast iron and the hardness determined can reach 7300∼7800 N/mm 2 . The coating is almost porous free. The corrosion potential increases with the time and the corrosion resistance is near to that of pure titanium. The working life of ridge-type diaphragm valve coated by Ti-Fe alloy for carbonization tower of alkali factories is five times higher than that of valve made of grey cast iron. Therefore, this new technology can be widely used in metallurgical, chemical and nuclear industries. (9 figs., 10 tabs.)

  13. Band structure analysis on olivine LiMPO4 and delithiated MPO4 (M = Fe, Mn) cathode materials

    International Nuclear Information System (INIS)

    Yi, Ting-Feng; Fang, Zi-Kui; Xie, Ying; Zhu, Yan-Rong; Dai, Changsong

    2014-01-01

    Highlights: • The conductivity of Li x MPO 4 were discussed relying on first principles technique. • Relationship between structure properties and microscopic bonding was addressed. • A mechanism responsible for the structural instability of MnPO 4 was proposed. - Abstract: Olivine compounds, i.e. Li x MPO 4 (M = Fe, Mn), are now regarded as the most competitive positive-electrode materials for future applications of large-scale rechargeable lithium batteries. There are significant interests in their electronic structures, because the microscopic information is very important for elucidating the structural stability, electrochemical performance, and electronic conductivity issues of batteries for high-rate applications. The structure stabilities of LiMPO 4 and MPO 4 (M = Fe, Mn) cathode materials are analyzed according to first principles calculations. The result shows that LiMPO 4 (M = Fe, Mn) materials exhibit good structure stability, which is mainly contributed to the extremely strong P-O covalent bonds. Furthermore, the introduction of P ions is also helpful for the chemical potential decrease of the materials. The band structure analysis reveals that the electronic conductance of LiFePO 4 , LiMnPO 4 , and FePO 4 is poor, while MnPO 4 possesses half metallic property. According to the electron distribution, it can be confirmed that Mn-O(II) bonds are weakened after Li + extractions, which is different from the variation trend of Fe-O(II) bonds. The decrease of Mn-O(II) bond strength is thus favorable for the phase transformation observed in experiments

  14. Magnetic properties of the Ce2Fe17-x Mn x helical magnets up to high magnetic fields

    International Nuclear Information System (INIS)

    Kuchin, A.G.; Mushnikov, N.V.; Bartashevich, M.I.; Prokhnenko, O.; Khrabrov, V.I.; Lapina, T.P.

    2007-01-01

    Magnetic properties of the Ce 2 Fe 17- x Mn x , x=0-2, alloys in magnetic fields up to 40 T are reported. The compounds with x=0.5-1 are helical antiferromagnets and those with 1 B that couple antiparallelly to the Fe moments. Easy-plane magnetic anisotropy in the Ce 2 Fe 17- x Mn x compounds weakens upon substitution of Mn for Fe. The absolute value of the first anisotropy constant in the Ce 2 Fe 17- x Mn x helical ferromagnets decreases slower with increasing temperature than that calculated from the third power of the spontaneous magnetization. Noticeable magnetic hysteresis in the Ce 2 Fe 17- x Mn x , x=0.5-2, helical magnets over the whole range of magnetic fields reflects mainly irreversible deformation of the helical magnetic structure during the magnetization of the compounds. A contribution from short-range order (SRO) magnetic clusters to the magnetic hysteresis of the helical magnets has been also estimated

  15. Plasma preparation and low-temperature sintering of spherical TiC-Fe composite powder

    Institute of Scientific and Technical Information of China (English)

    Jian-jun Wang; Jun-jie Hao; Zhi-meng Guo; Song Wang

    2015-01-01

    A spherical Fe matrix composite powder containing a high volume fraction (82vol%) of fine TiC reinforcement was produced us-ing a novel process combining in situ synthesis and plasma techniques. The composite powder exhibited good sphericity and a dense struc-ture, and the fine sub-micron TiC particles were homogeneously distributed in theα-Fe matrix. A TiC–Fe cermet was prepared from the as-prepared spherical composite powder using powder metallurgy at a low sintering temperature;the product exhibited a hardness of HRA 88.5 and a flexural strength of 1360 MPa. The grain size of the fine-grained TiC and special surface structure of the spherical powder played the key roles in the fabrication process.

  16. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    Energy Technology Data Exchange (ETDEWEB)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  17. Irradiation-Induced Solute Clustering in a Low Nickel FeMnNi Ferritic Alloy

    International Nuclear Information System (INIS)

    Meslin, E.; Barbu, A.; Radiguet, B.; Pareige, P.; Toffolon, C.

    2011-01-01

    Understanding the radiation embrittlement of reactor pressure vessel (RPV) steels is required to be able to operate safely a nuclear power plant or to extend its lifetime. The mechanical properties degradation is partly due to the clustering of solute under irradiation. To gain knowledge about the clustering process, a Fe-1.1 Mn-0.7 Ni (at.%) alloy was irradiated in a test reactor at two fluxes of 0.15 and 9 *10 17 n E≥1MeV . m -2 .s -1 and at increasing doses from 0.18 to 1.3 *10 24 n E≥1MeV ) . m -2 at 300 degrees C. Atom probe tomography (APT) experiments revealed that the irradiation promotes the formation in the α iron matrix of Mn/Mn and/or Ni/Ni pair correlations at low dose and Mn-Ni enriched clusters at high dose. These clusters dissolve partially after a thermal treatment at 400 degrees C. Based on a comparison with thermodynamic calculations, we show that the solute clustering under irradiation can just result from an induced mechanism. (authors)

  18. Magnetic properties and magnetocaloric effects in Mn1.2Fe0.8P1-xGex compounds

    International Nuclear Information System (INIS)

    Ou, Z Q; Wang, G F; Lin Song; Tegus, O; Brueck, E; Buschow, K H J

    2006-01-01

    We have studied the magnetic properties and magnetocaloric effects in the Mn 1.2 Fe 0.8 P 1-x Ge x compounds with x = 0.2, 0.22, 0.3, 0.4 and 0.5. X-ray diffraction patterns show that the Mn 1.2 Fe 0.8 P 1-x Ge x compounds crystallize in the hexagonal Fe 2 P-type crystal structure. The magnetic moments of the Mn 1.2 Fe 0.8 P 1-x Ge x compounds measured at 5 K and 5 T increase with increasing Ge content. The Curie temperature increases strongly and the magnetic entropy change has a maximum around 233 K for the compound with x = 0.22, which is about 19 and 31 J kg -1 K -1 for a field change of 2 and 5 T, respectively

  19. Synthesis and electronic properties of Fe2TiO5 epitaxial thin films

    Science.gov (United States)

    Osada, Motoki; Nishio, Kazunori; Hwang, Harold Y.; Hikita, Yasuyuki

    2018-05-01

    We investigate the growth phase diagram of pseudobrookite Fe2TiO5 epitaxial thin films on LaAlO3 (001) substrates using pulsed laser deposition. Control of the oxygen partial pressure and temperature during deposition enabled selective stabilization of (100)- and (230)-oriented films. In this regime, we find an optical gap of 2.1 eV and room temperature resistivity in the range of 20-80 Ω cm, which are significantly lower than α-Fe2O3, making Fe2TiO5 potentially an ideal inexpensive visible-light harvesting semiconductor. These results provide a basis to incorporate Fe2TiO5 in oxide heterostructures for photocatalytic and photoelectrochemical applications.

  20. Sintering behavior, microstructure and properties of TiC-FeCr hard alloy

    Institute of Scientific and Technical Information of China (English)

    Farid Akhtar; Shiju Guo; Jawid Askari; Jianjun Tian

    2007-01-01

    TiC based cermets were produced with FeCr,as a binder,by conventional P/M (powder metallurgy) to near >97% of the theoretical density.Sintering temperature significantly affects the mechanical properties of the composite.The sintering temperature of>1360 ℃ caused severe chemical reaction between TiC particles and the binder phase.In the TiC-FeCr cermets,the mechanical properties did not vary linearly with the carbide content.Optimum mechanical properties were found in the composite containing 57wt%TiC reinforcement,when sintered at 1360 ℃ for 1 h.Use of carbon as an additive enhanced the mechanical properties of the composites.Cermets containing carbon as an additive with 49wt% TiC exhibited attractive mechanical properties.The microstructure of the developed composite contained less or no debonding,representing good wettability of the binder with TiC particles.Homogeneous distribution of the TiC particles ensured the presence of isotropic mechanical properties and homogeneous distribution of stresses in the composite.Preliminary experiments for evaluation of the oxidation resistance of FeCr bonded TiC cermets indicate that they are more resistant than WC-Co hardmetals.

  1. Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity.

    Science.gov (United States)

    Semin, B К; Davletshina, L N; Seibert, M; Rubin, A B

    2018-01-01

    Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H 2 Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH5.7) than at neutral pH (3Mn/RC are extracted at pH6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extract only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster. Also we found that the presence of Fe cations in a heteronuclear cluster (2Mn/2Fe) increases the resistance of the remaining Mn cations to H 2 Q action, since H 2 Q can extract Mn cations from homonuclear Mn clusters of PSII(-Ca,4Mn) and PSII(-Ca,2Mn) membranes but not from the heteronuclear cluster in PSII(-Ca,2Mn,2Fe) membranes. H 2 Q also cannot extract Mn from PSII membranes obtained by incubation of PSII(-Ca,4Mn) membranes with Fe(II) cations at pH5.7, which suggests the formation of a heteronuclear 3Mn/1Fe cluster in the OEC. Functional activity of PSII with a 3Mn/1Fe cluster was investigated. PSII preparations with a 3Mn/1Fe cluster in the OEC are able to photoreduce the exogenous electron acceptor 2,6-dichlorophenolindophenol, possibly due to incomplete oxidation of water molecules as is the case with PSII(-Ca,2Mn,2Fe) samples. However, in the contrast to PSII(-Ca,2Mn,2Fe) samples PSII(-Ca,3Mn,1Fe) membranes can evolve O 2 at a low rate in the presence of exogenous Ca 2+ (at about 27% of the rate of O 2 evolution in native PSII membranes). The explanation for this phenomenon (either water splitting and production of molecular O 2 by the 3Mn/1Fe cluster or apparent O 2 evolution due to minor contamination of PSII(3Mn,1Fe) samples with PSII(-Ca,4Mn) membranes

  2. Effects of flue gas components on removal of elemental mercury over Ce–MnO_x/Ti-PILCs

    International Nuclear Information System (INIS)

    He, Chuan; Shen, Boxiong; Li, Fukuan

    2016-01-01

    Highlights: • Ce–MnO_x/Ti-PILC exhibited high Hg"0 removal activity. • SO_2 restrained Hg"0 oxidation and adsorption due to the formation of SO_4"2"−. • The formation of NH_3 to NH_4"+ restrained the Hg"0 adsorption and oxidation. - Abstract: The adsorption and oxidation of elemental mercury (Hg"0) under various flue gas components were investigated over a series of Ce–MnO_x/Ti-PILC catalysts, which were synthesized by an impregnation method. To discuss the mechanism, the catalysts were characterized by various techniques such as N_2 adsorption–desorption, scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) analysis and X-ray photoelectron spectroscopy (XPS). The results indicated that the presence of 500 ppm SO_2 in the flue gas significantly restrained the Hg"0 adsorption and oxidation over 6%Ce–6%MnO_x/Ti-PILC due to the formation of SO_4"2"− species. Hg"0 could be oxidized to HgCl_2 in the presence of HCl, because the Deacon process occurred. NO would react with active oxygen to form NO_2-containing species, which facilitated Hg"0 oxidation. While the presence of NO limited the Hg"0 adsorption on 6%Ce–6%MnO_x/Ti-PILC due to the competitive adsorption of NO with Hg"0. The addition of NH_3 in the flue gas significantly restrained Hg"0 adsorption and oxidation, because the formed NH_4"+ species covered the active adsorption sites on the surfaces, and further limited Hg"0 oxidation. However, when NO and NH_3 were simultaneously added into the flue gas, the Hg"0 oxidation efficiency of 6%Ce–6%MnO_x/Ti-PILC exhibited a relatively high value (72%) at 250 °C, which indicated the practicability to use Ce–MnO_x/Ti-PILC for Hg"0 removal under SCR conditions.

  3. Effect of Ti content in the photo catalytic behavior of Fe/TiO2-SiO2 systems

    International Nuclear Information System (INIS)

    Leon C, A.; Portillo V, N.; Hernandez P, I.; May L, M.; Gonzalez R, L.; Luna P, R.; Suarez P, R.

    2013-01-01

    In this work we report the synthesis of Fe/TiO 2 -SiO 2 systems with different concentrations of TiO 2 in order to determine the influence of titanium content on the structural, textural, optical properties and their photo catalytic behavior. The materials were synthesized by the sol-gel method and their modification was carried out by incipient impregnation. All samples were characterized be means of X-ray diffraction, N 2 physisorption (Bet method), Dr-UV-Vis and Raman spectroscopy. The modifications of the structural and optical properties are discussed on the basis of long-range order reduction, suggesting the formation of highly dispersed TiO 2 species. On the other hand, it was observed that the energy of the optical band gap decreases by introducing Fe. On the basis of these phenomena, the photo catalytic activity was measured, employing the degradation of orange II azo dye as a model reaction. (Author)

  4. Effect of partial substitution of Fe by Mn in Ni{sub 55}Fe{sub 19}Ga{sub 26} on its microstructure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sudip Kumar, E-mail: sudips@barc.gov.in [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Biswas, Aniruddha [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Babu, P.D.; Kaushik, S.D. [UGC–DAE Consortium for Scientific Research, Mumbai Centre, Mumbai 400 085 (India); Srivastava, Amita [Seismology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Siruguri, Vasudeva [UGC–DAE Consortium for Scientific Research, Mumbai Centre, Mumbai 400 085 (India); Krishnan, Madangopal [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-02-15

    Highlights: • Effect of Mn in Ni{sub 55}Fe{sub 19}Ga{sub 26} on microstructure and MCE is presented. • Mn stabilizes 14M martensite in place of NM martensite. • Increasing Mn also leads to a drastic reduction in γ-phase content. • MCE shows significant improvement with increasing Mn. • A maximum value of ΔS{sub M}= −19.8 J/kg K has been observed at 9 T for the Mn-10 alloy. -- Abstract: Ni–Fe–Ga-based Ferromagnetic Shape Memory Alloys (FSMAs) show considerable formability because of the presence of a disordered FCC γ-phase, but they lack in magnetocaloric property. Addition of Mn has been explored as a way to improve their magnetocaloric property. The current study presents a detailed structural and magnetization analyses of a two-phase ternary Ni{sub 55}Fe{sub 19}Ga{sub 26} alloy and its quaternary counterparts obtained by partial replacement of Fe by Mn, Ni{sub 55}Fe{sub 19−x}Mn{sub x}Ga{sub 26} (x = 2.5, 2.75, 3, 5, 10). Characterization of these alloys has been carried out using Optical and Scanning Electron Microscopy, Electron Probe Microanalysis, X-ray (XRD) and Neutron Diffraction (ND), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC) and DC magnetization measurement. Ni{sub 55}Fe{sub 19}Ga{sub 26} alloy shows predominantly non-modulated (NM) internally-twinned martensite, with traces of a modulated 14M martensite and the parent L2{sub 1} phase along with the FCC γ-phase. Quaternary addition of Mn in partial replacement of Fe stabilizes 14M martensite, drastically reduces the amount of γ-phase, keeps the martensitic transition temperatures unchanged, but raises T{sub C} considerably. Magnetocaloric effect improves significantly with increasing Mn-content and a maximum value of −19.8 J/kg K for ΔS{sub M} has been observed at 9 T for the alloy containing 10 at.% Mn.

  5. Surface structure of MgO underlayer with Ti diffusion for (002 oriented L10 FePt-based heat assisted magnetic recording media

    Directory of Open Access Journals (Sweden)

    Sintaro Hinata

    2018-05-01

    Full Text Available Surface morphology of the MgO layer and magnetic properties of FePt-C layer deposited on the MgO were investigated for the FePt-based heat assisted magnetic recording media. Stacking structure of the underlayer for the FePt-C layer was MgO (0-5 nm/Cr80Mn20 (0-30 nm/Cr50Ti50 (0-50 nm/glass sub.. Surface observation result for the MgO film by using an atomic force microscope revealed the existence of nodules with a height of about 2 nm and a network-like convex structure with a height difference of about sub nm (boundary wall, BW on the MgO crystal grain boundary. Density of the nodules largely depends on the surface roughness of the CrTi layer, RaCrTi and it is suppressed from 10 to 2/0.5 μm2 by reducing RaCrTi from 420 to 260 pm. Height of the BW depends on thickness of the MgO layer, tMgO and it can be suppressed by reducing tMgO to less than 4 nm. From the cross-sectional energy dispersive x-ray mapping, it is clarified that the BW is formed by atomic diffusion of Ti atoms from CrTi layer due to the substrate heating process, and a compound consists of Mg, Ti and O atoms. This BW can be used as a template to magnetically isolate the FePt column in the FePt-based granular film, such as FePt-SiO2, if the size of the BW is reduced to less than 10 nm. M-H loop of the FePt-C granular film deposited on the underlayer showed that the nodule and BW induce oxidation of the FePt grains, and reduction of intergranular exchange coupling.

  6. Surface structure of MgO underlayer with Ti diffusion for (002) oriented L10 FePt-based heat assisted magnetic recording media

    Science.gov (United States)

    Hinata, Sintaro; Jo, Shin; Saito, Shin

    2018-05-01

    Surface morphology of the MgO layer and magnetic properties of FePt-C layer deposited on the MgO were investigated for the FePt-based heat assisted magnetic recording media. Stacking structure of the underlayer for the FePt-C layer was MgO (0-5 nm)/Cr80Mn20 (0-30 nm)/Cr50Ti50 (0-50 nm)/glass sub.. Surface observation result for the MgO film by using an atomic force microscope revealed the existence of nodules with a height of about 2 nm and a network-like convex structure with a height difference of about sub nm (boundary wall, BW) on the MgO crystal grain boundary. Density of the nodules largely depends on the surface roughness of the CrTi layer, RaCrTi and it is suppressed from 10 to 2/0.5 μm2 by reducing RaCrTi from 420 to 260 pm. Height of the BW depends on thickness of the MgO layer, tMgO and it can be suppressed by reducing tMgO to less than 4 nm. From the cross-sectional energy dispersive x-ray mapping, it is clarified that the BW is formed by atomic diffusion of Ti atoms from CrTi layer due to the substrate heating process, and a compound consists of Mg, Ti and O atoms. This BW can be used as a template to magnetically isolate the FePt column in the FePt-based granular film, such as FePt-SiO2, if the size of the BW is reduced to less than 10 nm. M-H loop of the FePt-C granular film deposited on the underlayer showed that the nodule and BW induce oxidation of the FePt grains, and reduction of intergranular exchange coupling.

  7. First-principles calculation of the structure and electronic properties of Fe-substituted Bi2Ti2O7

    Science.gov (United States)

    Huang, Jin-Dou; Zhang, Zhenyi; Lin, Feng; Dong, Bin

    2017-12-01

    We performed first-principles calculations to investigate the formation energy, geometry structure, and electronic property of Fe-doped Bi2Ti2O7 systems with different Fe doping content. The calculated formation energies indicate that the substitutional configurations of Fe-doping Bi2Ti2O7 are easy to obtain under O-rich growth condition, but their thermodynamic stability decreases with the increase of Fe content. The calculated spin-resolved density of states and band structures indicate that the introduction of Fe into Bi2Ti2O7 brings high spin polarization. The spin-down impurity levels in Fe x Bi2-x Ti2O7 and spin-up impurity levels in Fe x Bi2Ti2-x O7 systems locate in the bottom of conduction band and narrow the band gap significantly, thus leading to the absorption of visible light. Interestingly, the impurity states in Fe x Bi2-x Ti2O7 are the efficient separation center of photogenerated electron and hole, and less affected by Fe doping content, in comparison, the levels of impurity band in Fe x Bi2Ti2-x O7 systems are largely effected by the Fe doping content, and high Fe doping content is the key factor to improve the separating rate of photogenerated electron and hole.

  8. Synergetic Fe substitution and carbon connection in LiMn1−xFexPO4/C cathode materials for enhanced electrochemical performances

    International Nuclear Information System (INIS)

    Yan, Su-Yuan; Wang, Cheng-Yang; Gu, Rong-Min; Sun, Shuai; Li, Ming-Wei

    2015-01-01

    Highlights: • LiMn 0.6 Fe 0.4 PO 4 /C cathode material shows enhanced rate capability. • The Fe doped in the partial Mn sites could significantly facilitate the Li ions transfer. • The enhanced Li + ions diffusion contributes to the optimized rate capability of LiMn 0.6 Fe 0.4 PO 4 . • ACM carbonization forms well carbon coating and a 3D carbon network structure. - Abstract: To enhance the rate and cyclic performances of LiMnPO 4 cathode material for lithium-ion batteries, Mn is partially substituted with Fe, and LiMn 1−x Fe x PO 4 (x = 0.2, 0.3, 0.4, 0.5) solid solutions are synthesized and investigated. Amphiphilic carbonaceous material (ACM) forms well carbon coating and connects the LiMn 1−x Fe x PO 4 crystallites by a three-dimensional (3D) carbon network. The synergetic Fe substitution and carbon connection obviously improve the samples’ rate capacities and cyclic stability. The optimized LiMn 0.6 Fe 0.4 PO 4 /C sample delivers discharge capacities of 160 mA h g −1 at 0.05 C, 148 mA h g −1 at 1 C, and 115 mA h g −1 at 20 C. All samples have well capacity retention (>92%) after 50 charge/discharge cycles at 1 C. The enhanced electrochemical properties are mainly attributed to the improvement of Li ion and electron transport in the LiMn 1−x Fe x PO 4 /C samples, respectively mainly resulting from their modified crystal structures caused by Fe substitution and the 3D carbon coating/connection originating from ACM carbonization. LiMn 1−x Fe x PO 4 materials exhibit two discharge plateaus at ∼4.0 and ∼3.5 V (vs. Li + /Li), whose heights respectively reflect the redox potentials of Mn 3+ /Mn 2+ and Fe 3+ /Fe 2+ couples. The plateaus’ lengths correspond to the Mn/Fe ratio in LiMn 1−x Fe x PO 4 and are affected by the kinetic behavior of samples. Though the ∼4.0 V plateau shrinks with increasing discharge rate, the ∼3.5 V plateau may slightly elongate. Moreover, the Fe substituted in the partial Mn sites could significantly improve

  9. Microstructure, tensile deformation mode and crevice corrosion resistance in Ti-10Mo-xFe alloys

    International Nuclear Information System (INIS)

    Min, X.H.; Emura, S.; Nishimura, T.; Tsuchiya, K.; Tsuzaki, K.

    2010-01-01

    The microstructure, the tensile deformation mode at ambient temperature and the crevice corrosion resistance at a high temperature of 373 K were investigated in the Ti-10Mo-xFe (x = 0, 1, 3, 5) alloys. The stability of the β phase increased, and the formation of the α'' martensite and the athermal ω phase was suppressed by the increase in the Fe content. EPMA examinations indicated that the existence of the α'' martensite in the Ti-10Mo alloy was caused by the solidification segregation of Mo atoms. EBSD observations showed that the deformation mode changed from a {3 3 2} twinning to a slip by an increase in the Fe content, which coincided with the prediction by the electron/atom (e/a) ratio. The Ti-10Mo-3Fe alloy showed the highest yield strength of 935 MPa among all the alloys, while the Ti-10Mo-1Fe alloy showed the lowest value of 563 MPa due to the change in the deformation mode. On the other hand, all the alloys exhibited a high crevice corrosion resistance in a high chloride and high acidic solution at the high temperature, although the corrosion resistance decreased with an increase in the Fe content. The decrease in the corrosion resistance can be explained by the bond order (Bo). A good combination of tensile properties and crevice corrosion resistance may be obtainable through a further optimization of the Fe content by the e/a ratio and the Bo.

  10. Magnetism of DyMn{sub 2} and HoMn{sub 2} - {sup 57}Fe and {sup 119}Sn Moessbauer studies

    Energy Technology Data Exchange (ETDEWEB)

    Krop, K. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Zukrowski, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Przewoznik, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Marzec, J. [University of Min. and Metall., Krakow (Poland). Dept. of Solid State Phys.; Wiesinger, G. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Haeufler, T. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Hilscher, G. [Institute for Experimental Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Steiner, W. [Institute for Applied and Technical Physics, Technical University, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria)

    1995-05-01

    Moessbauer spectra were measured for two Laves phase compounds DyMn{sub 2} and HoMn{sub 2} in which manganese was substituted to 0.5% with {sup 57}Fe and to 0.2% with {sup 119}Sn. At 4.2 K the {sup 57}Fe and {sup 119}Sn spectra of the Dy compound were unambiguously fitted each with two Zeeman patterns (with relative contributions to the spectra 3:1) corresponding to two different Mn sites - magnetic and nonmagnetic. Transferred hyperfine fields at {sup 119}Sn were found to be proportional to the magnetic moment of Dy and its ferromagnetic component, corroborating the magnetic structure found in neutron diffraction (ND) experiment. The same procedure was carried on with the spectra measured for the Ho compound, but the above mentioned proportionality was not found. ((orig.)).

  11. Novel Montmorillonite/TiO2/MnAl-Mixed Oxide Composites Prepared from Inverse Microemulsions as Combustion Catalysts

    Directory of Open Access Journals (Sweden)

    Bogna D. Napruszewska

    2017-11-01

    Full Text Available A novel design of combustion catalysts is proposed, in which clay/TiO2/MnAl-mixed oxide composites are formed by intermixing exfoliated organo-montmorillonite with oxide precursors (hydrotalcite-like in the case of Mn-Al oxide obtained by an inverse microemulsion method. In order to assess the catalysts’ thermal stability, two calcination temperatures were employed: 450 and 600 °C. The composites were characterized with XRF (X-ray fluorescence, XRD (X-ray diffraction, HR SEM (high resolution scanning electron microscopy, N2 adsorption/desorption at −196 °C, and H2 TPR (temperature programmed reduction. Profound differences in structural, textural and redox properties of the materials were observed, depending on the presence of the TiO2 component, the type of neutralization agent used in the titania nanoparticles preparation (NaOH or NH3 (aq, and the temperature of calcination. Catalytic tests of toluene combustion revealed that the clay/TiO2/MnAl-mixed oxide composites prepared with the use of ammonia showed excellent activity, the composites obtained from MnAl hydrotalcite nanoparticles trapped between the organoclay layers were less active, but displayed spectacular thermal stability, while the clay/TiO2/MnAl-mixed oxide materials obtained with the aid of NaOH were least active. The observed patterns of catalytic activity bear a direct relation to the materials’ composition and their structural, textural, and redox properties.

  12. Novel Montmorillonite/TiO₂/MnAl-Mixed Oxide Composites Prepared from Inverse Microemulsions as Combustion Catalysts.

    Science.gov (United States)

    Napruszewska, Bogna D; Michalik-Zym, Alicja; Rogowska, Melania; Bielańska, Elżbieta; Rojek, Wojciech; Gaweł, Adam; Wójcik-Bania, Monika; Bahranowski, Krzysztof; Serwicka, Ewa M

    2017-11-19

    A novel design of combustion catalysts is proposed, in which clay/TiO₂/MnAl-mixed oxide composites are formed by intermixing exfoliated organo-montmorillonite with oxide precursors (hydrotalcite-like in the case of Mn-Al oxide) obtained by an inverse microemulsion method. In order to assess the catalysts' thermal stability, two calcination temperatures were employed: 450 and 600 °C. The composites were characterized with XRF (X-ray fluorescence), XRD (X-ray diffraction), HR SEM (high resolution scanning electron microscopy, N₂ adsorption/desorption at -196 °C, and H₂ TPR (temperature programmed reduction). Profound differences in structural, textural and redox properties of the materials were observed, depending on the presence of the TiO₂ component, the type of neutralization agent used in the titania nanoparticles preparation (NaOH or NH₃ (aq)), and the temperature of calcination. Catalytic tests of toluene combustion revealed that the clay/TiO₂/MnAl-mixed oxide composites prepared with the use of ammonia showed excellent activity, the composites obtained from MnAl hydrotalcite nanoparticles trapped between the organoclay layers were less active, but displayed spectacular thermal stability, while the clay/TiO₂/MnAl-mixed oxide materials obtained with the aid of NaOH were least active. The observed patterns of catalytic activity bear a direct relation to the materials' composition and their structural, textural, and redox properties.

  13. Influence of Copper on the Hot Ductility of 20CrMnTi Steel

    Science.gov (United States)

    Peng, Hong-bing; Chen, Wei-qing; Chen, Lie; Guo, Dong

    2015-02-01

    The hot ductility of 20CrMnTi steel with x% copper (x = 0, 0.34) was investigated. Results show that copper can reduce its hot ductility, but there is no significant copper-segregation at the boundary tested by EPMA. The average copper content at grain boundaries and substrate is 0.352% and 0.318% respectively in steel containing 0.34% copper tensile-tested at 950 °C. The fracture morphology was examined with SEM and many small and shallow dimples were found on the fracture of steel with copper, and fine copper sulfide was found from carbon extraction replicas using TEM. Additionally, adding 0.34% copper caused an increase in the dynamic recrystallization temperature from 950 °C to 1000 °C, which indicates that copper can retard the dynamic recrystallization (DRX) of austenite. The detrimental influence of copper on hot ductility of 20CrMnTi steel is due mainly to the fine copper sulfide in the steel and its retarding the DRX.

  14. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    OpenAIRE

    Zhang, Xinyi; Yang, Le; Hao, Feng; Chen, Haosen; Yang, Meng; Fang, Daining

    2015-01-01

    Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4) cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD) experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM) images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests revea...

  15. Enhanced Water Splitting by Fe2O3-TiO2-FTO Photoanode with Modified Energy Band Structure

    Directory of Open Access Journals (Sweden)

    Eul Noh

    2013-01-01

    Full Text Available The effect of TiO2 layer applied to the conventional Fe2O3/FTO photoanode to improve the photoelectrochemical performance was assessed from the viewpoint of the microstructure and energy band structure. Regardless of the location of the TiO2 layer in the photoanodes, that is, Fe2O3/TiO2/FTO or TiO2/Fe2O3/FTO, high performance was obtained when α-Fe2O3 and H-TiNT/anatase-TiO2 phases existed in the constituent Fe2O3 and TiO2 layers after optimized heat treatments. The presence of the Fe2O3 nanoparticles with high uniformity in the each layer of the Fe2O3/TiO2/FTO photoanode achieved by a simple dipping process seemed to positively affect the performance improvement by modifying the energy band structure to a more favorable one for efficient electrons transfer. Our current study suggests that the application of the TiO2 interlayer, together with α-Fe2O3 nanoparticles present in the each constituent layers, could significantly contribute to the performance improvement of the conventional Fe2O3 photoanode.

  16. H-TiO2/C/MnO2 nanocomposite materials for high-performance supercapacitors

    Science.gov (United States)

    Di, Jing; Fu, Xincui; Zheng, Huajun; Jia, Yi

    2015-06-01

    Functionalized TiO2 nanotube arrays with decoration of MnO2 nanoparticles (denoted as H-TiO2/C/MnO2) have been synthesized in the application of electrochemical capacitors. To improve both areal and gravimetric capacitance, hydrogen treatment and carbon coating process were conducted on TiO2 nanotube arrays. By scanning electron microscopy and X-ray photoelectron spectroscopy, it is confirmed that the nanostructure is formed by the uniform incorporation of MnO2 nanoparticles growing round the surface of the TiO2 nanotube arrays. Impedance analysis proves that the enhanced capacitive is due to the decrease of charge transfer resistance and diffusion resistance. Electrochemical measurements performed on this H-TiO2/C/MnO2 nanocomposite when used as an electrode material for an electrochemical pseudocapacitor presents quasi-rectangular shaped cyclic voltammetry curves up to 100 mV/s, with a large specific capacitance (SC) of 299.8 F g-1 at the current density of 0.5 A g-1 in 1 M Na2SO4 electrolyte. More importantly, the electrode also exhibits long-term cycling stability, only 13 % of SC loss after 2000 continuous charge-discharge cycles. Based on the concept of integrating active materials on highly ordered nanostructure framework, this method can be widely applied to the synthesis of high-performance electrode materials for energy storage.

  17. TEM and Moessbauer Study of Nano Sized Fe2MnAl Flakes

    International Nuclear Information System (INIS)

    Vinesh, A.; Sudheesh, V. D.; Lakshmi, N.; Venugopalan, K.

    2011-01-01

    Magnetic and structural properties of L21 ordered Fe 2 MnAl Heusler alloy have been studied by X-ray diffraction, Transmission electron microscopy (TEM), Moessbauer spectroscopy and DC magnetization. Structural texturing induced by ball milling is destroyed on heating while Moessbauer and DC magnetization studies show magnetic texturing persists after thermal treatment. TEM shows large distribution in particle size with an average size of 27 nm. Thermal annealing of ball milled sample results L2 1 ordering and the needle shaped particle contributes spin texturing.

  18. Transformation lines in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy

    International Nuclear Information System (INIS)

    Tanaka, Kikuaki; Hayashi, Toshimitsu; Fischer, F.D.; Buchmayr, B.

    1994-01-01

    Transformation lines, the martensite/austenite start and finish conditions in the stress-temperature plane, are determined in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy with two different experimental procedures. The transformation lines are shown to be almost linear with nearly the same slope. The martensitic transformation zone and the reverse transformation zone do not coincide, and the reverse transformation zone is very wide; T Af -T As ∼ 180 K. The strong dependence on the preloading of the transformation lines, especially of the reverse transformation lines, is examined. (orig.)

  19. Hierarchically multifunctional K-OMS-2/TiO2/Fe3O4 heterojunctions for the photocatalytic oxidation of humic acid under solar light irradiation.

    Science.gov (United States)

    Zhang, Tong; Yan, Xiaoli; Sun, Darren Delai

    2012-12-01

    A multifunctional heterojunctioned K-OMS-2/TiO(2)/Fe(3)O(4) (KTF) nanocomposite was successfully synthesized using a combination of hydrothermal and co-precipitation techniques. The resultant sample was characterized by XRD, FESEM, TEM, N(2) adsorption, XPS and VSM. Its photocatalytic activity was demonstrated in the photocatalytic degradation of humic acid (HA). Morphology characterization showed the hierarchical structure of the synthesized material, and XRD results revealed that both the rutile and anatase TiO(2) structures are present in the sample. The average pore diameters and BET surface area of the synthesized KTF heterojunctions were 40 nm and 134.42 m(2)/g, respectively. XPS spectra confirmed the presence of Fe(3)O(4) and TiO(2) in the synthesized material, and the valences of Mn were kept at +3 and +4 after the grafting of Fe(3)O(4) and TiO(2). The synthesized material showed good magnetic response and photocatalytic activity under simulated solar light irradiation, and 85.7% of HA was decomposed after 120 min in the presence of KTF nanocomposites. The reusability study suggested that the magnetic recovered material was stable enough for multiple recycling usages, verifying its potential application in water purification. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. The effect of disorder on electronic and magnetic properties of quaternary Heusler alloy CoFeMnSi with LiMgPbSb-type structure

    International Nuclear Information System (INIS)

    Feng, Yu; Chen, Hong; Yuan, Hongkuan; Zhou, Ying; Chen, Xiaorui

    2015-01-01

    Thin films based on Heusler alloy often lost their theoretical predicted ultra-high spin polarization owing to the appearance of disorder. Using the first-principles calculations within density functional theory (DFT), we investigate the effect of disorder including antisite and swap on electronic and magnetic properties of quaternary Heusler alloy CoFeMnSi with LiMgPbSb-type structure. Twelve kinds of antisites and six kinds of swap disorders are proposed and studied comprehensively. In our calculations, Co(Fe)-, Mn(Fe)-, Si(Mn)-antisite and Co–Fe swap disorders are most favorable due to their lowest formation energies. Moreover, the positive binding energies of Co–Fe, Co–Si, Fe–Si and Mn–Si swap disorders with respect to their corresponding antisite disorders indicate that these complex swap disorders are more stable compared with their corresponding isolated antisite disorders. The investigations on density of states (DOS) show that the spin down energy gap of disordered structures suffers contraction and their DOS entirely move towards lower zone. Besides, the 100% spin polarization is maintained in all structures with antisite and swap disorders except for those with Co(Mn)-, Co(Si)-antisite and Co–Mn, Co–Si swap disorders. Therefore, the half-metallicity of quaternary Heusler alloy CoFeMnSi is quite robust against interfering effects such as Si(Mn), Co(Fe) and Co–Fe disorders most possibly formed in the growth. - Highlights: • CoFeMnSi with LiMgPbSb-type structure is found to be a half-metallic ferromagnet. • Si(Mn), Co(Fe), Mn(Fe) antisites and Co–Fe swap disorders are most likely to form. • The half-metallicity of CoFeMnSi is robust against the most possible disorders. • The magnetic moments of the most possible disorders follow the Pauli-Slater rule

  1. Mechanistic studies of mercury adsorption and oxidation by oxygen over spinel-type MnFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yingju [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Jing, E-mail: liujing27@mail.hust.edu.cn [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Shenzhen Institute of Huazhong University of Science and Technology, Shenzhen 518000 (China); Zhang, Bingkai; Liu, Feng [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2017-01-05

    Highlights: • Hg adsorption and oxidation mechanisms on MnFe{sub 2}O{sub 4} were studied using DFT method. • Hg{sup 0} adsorption on Mn-terminated MnFe{sub 2}O{sub 4} (100) surface is a chemisorption process. • HgO shows high chemical reactivity for its adsorption on MnFe{sub 2}O{sub 4} surface. • The reaction between adsorbed Hg and surface oxygen is the rate-determining step. - Abstract: MnFe{sub 2}O{sub 4} has been regarded as a very promising sorbent for mercury emission control in coal-fired power plants because of its high adsorption capacity, magnetic, recyclable and regenerable properties. First-principle calculations based on density functional theory (DFT) were used to elucidate the mercury adsorption and oxidation mechanisms on MnFe{sub 2}O{sub 4} surface. DFT calculations show that Mn-terminated MnFe{sub 2}O{sub 4} (1 0 0) surface is much more stable than Fe-terminated surface. Hg{sup 0} is physically adsorbed on Fe-terminated MnFe{sub 2}O{sub 4} (1 0 0) surface. Hg{sup 0} adsorption on Mn-terminated MnFe{sub 2}O{sub 4} (1 0 0) surface is a chemisorption process. The partial density of states (PDOS) analysis indicates that Hg atom interacts strongly with surface Mn atoms through the orbital hybridization. HgO is adsorbed on the MnFe{sub 2}O{sub 4} surface in a chemical adsorption manner. The small HOMO–LUMO energy gap implies that HgO molecular shows high chemical reactivity for HgO adsorption on MnFe{sub 2}O{sub 4} surface. The energy barriers of Hg{sup 0} oxidation by oxygen on Fe- and Mn-terminated MnFe{sub 2}O{sub 4} surfaces are 206.37 and 76.07 kJ/mol, respectively. Mn-terminated surface is much more favorable for Hg{sup 0} oxidation than Fe-terminated surface. In the whole Hg{sup 0} oxidation process, the reaction between adsorbed mercury and surface oxygen is the rate-determining step.

  2. 激光熔覆TiC/FeAl原位复合涂层%In-situ TiC/FeAl Composite Coating Fabricated by Laser Cladding

    Institute of Scientific and Technical Information of China (English)

    赵龙志; 杨海超; 赵明娟; 谢玉江

    2017-01-01

    用激光熔覆法制备了TiC/FeAl原位复合涂层,使用光学显微镜(OM)和扫描电镜(SEM)观察了熔覆层的微观结构,使用能谱分析仪(EDS)和X射线衍射仪(XRD)分析了涂层的化学成分和物相,研究了熔覆层的显微硬度和耐磨性.结果表明:沿着熔池深度的方向从熔池底部到熔池顶部,FeAl基体从粗大的树枝晶渐渐转变为细小的等轴晶.原位TiC越过熔池界面进入基板表层,大部分TiC颗粒存在FeA1晶粒内部,熔池顶部的TiC颗粒含量较多.沿着熔池深度的方向从涂层项部到基板,涂层的硬度呈阶梯形分布,熔池顶部涂层的硬度最高,涂层的硬度和耐磨性分别比基板高6倍和52倍.涂层的磨损机理为典型的磨粒磨损.%The in-situ TiC/FeAl composite coating was fabricated by laser cladding technology in this paper.The microstructure of the coating was characterized by metallographic microscope (OM),scanning electron microscopy(SEM).The phases in the coating were examined by energy dispersive spectrometry (EDS) and X-ray diffraction (XRD),microhardness and wear resistance of the coating were also investigated.The results show that from the bottom to the surface of the melt pool along the depth the coarse dendrite grain is changed into fine quiaxed rosette grain.Some TiC particles going across the interface exist in the surface layer of the substrate.Most of TiC particles existing in the grains are nucleation centers during FeAl matrix solidification.The content of TiC particles in the top of the coating is much higher than that in other zone of the coating.Meanwhile,the microhardness and wear resistance of in-situ laser cladding are 5 times and 52 higher than those of substrate,respectively.And the wear mechanism of the composite coating is abrasive wear.

  3. Synthesis and electromagnetic absorption properties of Ag-coated reduced graphene oxide with MnFe_2O_4 particles

    International Nuclear Information System (INIS)

    Wang, Yan; Wu, Xinming; Zhang, Wenzhi; Huang, Shuo

    2016-01-01

    A ternary composite of Ag/MnFe_2O_4/reduced graphene oxide (RGO) was synthesized by a facile hydrothermal method. The morphology, microstructure, magnetic and electromagnetic properties of as-prepared Ag/MnFe_2O_4/RGO composite were characterized by means of XRD, TEM, XPS, VSM and vector network analyzer. The maximum reflection loss (R_L) of Ag/ MnFe_2O_4/RGO composite shows maximum absorption of −38 dB at 6 GHz with the thickness of 3.5 mm, and the absorption bandwidth with the R_L below −10 dB is up to 3.5 GHz (from 3.7 to 7.2 GHz). The result demonstrates that the introduction of Ag significantly leads to the multiple absorbing mechanisms. It is believed that such composite could serve as a powerful candidate for microwave absorber. - Highlights: • A ternary composite of Ag/MnFe_2O_4/reduced graphene oxide (RGO) was synthesized by a facile method. • The morphology, microstructure, magnetic and electromagnetic properties were characterized. • The maximum reflection loss of Ag/MnFe_2O_4/RGO is −38 dB at 6 GHz with a thickness of 3.5 mm. • The composite shows a wide absorption band.

  4. Structural and magnetocaloric properties of (Mn,Fe){sub 2}(P,Si) materials with added nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Thang, N.V., E-mail: v.t.nguyen-1@tudelft.nl; Miao, X.F., E-mail: X.F.Miao@tudelft.nl; Dijk, N.H. van, E-mail: N.H.vanDijk@tudelft.nl; Brück, E., E-mail: E.H.Bruck@tudelft.nl

    2016-06-15

    Amongst magnetic materials that exhibit a giant magnetocaloric effect near room temperature, the (Mn,Fe){sub 2}(P,Si) system is one of the most promising candidates for magnetic refrigeration. Although the (Mn,Fe){sub 2}(P,Si) materials hold many advantages, controlling the magnetic entropy change ΔS{sub m}, the adiabatic temperature change ΔT{sub ad}, the thermal hysteresis and the mechanical stability across the ferromagnetic transition requires a delicate tuning of the composition. This work investigates the addition of nitrogen, as an interstitial or substitutional element, as a new parameter to tune the properties of (Mn,Fe){sub 2}(P,Si) materials. We found that the nitrogen addition results in a decrease of the Curie temperature, consistent with the observed increase in the c/a ratio. The introduction of nitrogen in (Mn,Fe){sub 2}(P,Si) materials also results in a strong enhancement of the mechanical stability. - Highlights: • N-doped materials were synthesized by high-energy ball milling and solid-state reactions. • Nitrogen atoms enter the structure both as substitutional and as interstitial element in (Mn,Fe){sub 2}(P,Si) materials. • Nitrogen addition leads to a decrease in the Curie temperature, while improving the mechanical stability and preserving the magnetocaloric properties. • The origin of the increase in the thermal hysteresis by increasing the N content has been investigated by analyzing the XRD data.

  5. Magnetic properties of the HoMn6-xFe xSn6 compounds

    International Nuclear Information System (INIS)

    Cakir, O.; Dincer, I.; Duman, E.; Krenke, T.; Elmali, A.; Elerman, Y.

    2007-01-01

    Intermetallic compounds of HoMn 6-x Fe x Sn 6 (0 ≤ x ≤ 1.2) were studied by means of field-cooled (FC) and zero-field-cooled (ZFC) magnetization measurements in the temperature range 5 K ≤ T ≤ 600 K. The unit cell parameters decrease with the increasing of Fe content. The compounds with x = 0 and 0.3 behave ferrimagnetically in the whole temperature range and spin reorientation transition is observed at 200 and 185 K, respectively. The x = 0.5 and 0.6 compounds show ferrimagnetic-helimagnetic-ferrimagnetic phase transitions with decreasing temperature while the compounds with x = 0.9 and 1.2 only show helimagnetic-ferrimagnetic phase transitions. Additionally, for the x = 0.6 compound the metamagnetic phase transition from helimagnetism to ferrimagnetism is induced by an applied field 20 kOe

  6. Magnetic behavior of PdFeMn on mesoscopic and macroscopic length scales

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, V. E-mail: volker.wagner@ptb.de; Ahlers, H.; Axelrod, L.; Gordeev, G.; Zabenkin, V

    2001-05-01

    By 3D neutron depolarization (ND) the magnetization and the domain structure were observed for FC and ZFC samples of (Pd{sub 0.9965}Fe{sub 0.0035}){sub 1-x} Mn{sub x} with x=0.05, showing both an FM and a spin-glass-like transition, and x=0 being ferromagnetic. The evolution of the domain structure along the magnetization/demagnetization process - as seen by depolarization - is strongly asymmetric, with maximum change in the domain structure only after magnetization reversal (typical domain size {delta}{approx}3 {mu}m in the virgin state). Near T{sub c}, the alloy approached the behavior of FM PdFe, showing a symmetric change of domain structure on the applied field.

  7. Annealing temperature dependent structural and magnetic properties of MnFe{sub 2}O{sub 4} nanoparticles grown by sol-gel auto-combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Bhandare, S.V. [Department of Physics, Gulbarga University, Gulbarga 585106 (India); Kumar, R.; Anupama, A.V.; Choudhary, H.K. [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India); Jali, V.M., E-mail: vmjali@gmail.com [Department of Physics, Gulbarga University, Gulbarga 585106 (India); Sahoo, B., E-mail: bsahoo@mrc.iisc.ernet.in [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India)

    2017-07-01

    Highlights: • Phase pure MnFe{sub 2}O{sub 4} samples were prepared by sol-gel auto-combustion method. • Annealing MnFe{sub 2}O{sub 4} below ∼500 °C, two spinel phases were observed indicating partial oxidation of Mn{sup 2+} to Mn{sup 3+}. • Oxidation of Mn{sup 2+} to Mn{sup 3+} results in decrease in lattice parameter of the spinel lattice. • Annealing at ≥ 600 °C, MnFe{sub 2}O{sub 4} decomposes into crystalline α-Mn{sub 2}O{sub 3} and α-Fe{sub 2}O{sub 3} along with amorphous-FeO phase. - Abstract: Manganese ferrite (MnFe{sub 2}O{sub 4}) nanoparticles were synthesized by sol-gel auto-combustion method using manganese nitrate and ferric nitrate as precursors and citric acid as a fuel. Scanning electron micrographs show irregularly shaped morphology of the particles. The as-prepared samples were annealed at 400, 500, 600 and 800 °C for 2 h in air. The phase identification and structural characterizations were performed using powder X-ray diffraction technique along with Mössbauer spectroscopy. Magnetization loops and {sup 57}Fe Mössbauer spectra were measured at RT. After annealing the sample at or below ∼ 500 °C, we observed two different spinel phases corresponding to two different lattice parameters. This is originating due to the partial oxidation of Mn{sup 2+} to Mn{sup 3+}. At high annealing temperatures (∼ 600 °C or above) the spinel MnFe{sub 2}O{sub 4} phase decomposes into crystalline α-Mn{sub 2}O{sub 3} and α-Fe{sub 2}O{sub 3} phases, and amorphous FeO phase.

  8. Carbothermic reduction behaviors of Ti-Nb-bearing Fe concentrate from Bayan Obo ore in China

    Science.gov (United States)

    Wang, Guang; Du, Ya-xing; Wang, Jing-song; Xue, Qing-guo

    2018-01-01

    To support the development of technology to utilize low-grade Ti-Nb-bearing Fe concentrate, the reduction of the concentrate by coal was systematically investigated in the present paper. A liquid phase formed when the Ti-Nb-bearing Fe concentrate/coal composite pellet was reduced at temperatures greater than 1100°C. The addition of CaCO3 improved the reduction rate when the slag basicity was less than 1.0 and inhibited the formation of the liquid phase. Mechanical milling obviously increased the metallization degree compared with that of the standard pellet when reduced under the same conditions. Evolution of the mineral phase composition and microstructure of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet at 1100°C were analyzed by X-ray diffraction and scanning electron microscopy-energy-dispersive spectroscopy. The volume shrinkage value of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet with a basicity of 1.0 was approximately 35.2% when the pellet was reduced at 1100°C for 20 min, which enhanced the external heat transfer to the lower layers when reduced in a practical rotary hearth furnace. The present work provides key parameters and mechanism understanding for the development of carbothermic reduction technology of a Ti-Nb-bearing Fe concentrate incorporated in a pyrometallurgical utilization flow sheet.

  9. Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

    Energy Technology Data Exchange (ETDEWEB)

    Kalisvaart, W.P., E-mail: pkalisvaart@gmail.com [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Mitlin, David, E-mail: dmitlin@ualberta.ca [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada)

    2011-03-15

    This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

  10. Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

    International Nuclear Information System (INIS)

    Kalisvaart, W.P.; Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi; Mitlin, David

    2011-01-01

    This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

  11. Wetting behavior of liquid Fe-C-Ti alloys on sapphire

    International Nuclear Information System (INIS)

    Gelbstein, M.; Froumin, N.; Frage, N.

    2008-01-01

    Wetting behavior in the (Fe-C-Ti)/sapphire system was studied at 1823 K. The wetting angle between sapphire and Fe-C alloys is higher than 90 deg. (93 deg. and 105 deg. for the alloys with 1.4 and 3.6 at.% C, respectively). The presence of Ti improves the wetting of the iron-carbon alloys, especially for the alloys with carbon content of 3.6 at.%. The addition of 5 at.% Ti to Fe-3.6 at.% C provides a contact angle of about 30 deg., while the same addition to Fe-1.4 at.% C decreases the wetting angle to 70 deg. only. It was established that the wetting in the systems is controlled by the formation of a titanium oxicarbide layer at the interface, which composition and thickness depend on C and Ti contents in the melt. The experimental observations are well accounted for by a thermodynamic analysis of the Fe-Ti-Al-O-C system

  12. Effect of Fe substitution on the structure and magnetocaloric effect of Mn{sub 5−x}Fe{sub x}GeSi{sub 2} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.W.; Yan, J.L., E-mail: yjl@gxu.edu.cn; Feng, E.L.; Tang, G.W.; Zhou, K.W.

    2017-01-15

    The structure and magnetocaloric effect of Mn{sub 5−x}Fe{sub x}GeSi{sub 2} compounds were studied. Analysis of X-ray powder diffraction and energy dispersive X-Ray spectroscopy revealed that Mn{sub 5−x}Fe{sub x}GeSi{sub 2} alloys with x<1 crystallize in the Mn{sub 5}Si{sub 3}-type structure (space group P6{sub 3}/mcm), maintaining the structure of Mn{sub 5}Ge{sub 3}; and alloys with x=1.5 and 2 consist of the major Mn{sub 5}Si{sub 3}-type phase and the minor Ni{sub 2}In-type phase (space group P6{sub 3}/mmc). The results of Rietveld refinement showed that the cell parameters for the Mn{sub 5}Si{sub 3}-type phase decrease with increasing Fe content. The positive slopes in Arrott plots indicate that a second-order ferromagnetic to paramagnetic transition occurs. The Curie temperature increases with increasing Fe content from 182 K for x=0.6 to 224 K for x=2. The maximum magnetic entropy change of 3.7 J/(kg K) for x=0.8 was found under a magnetic field change of 0–20 kOe. - Highlights: • Mn{sub 5−x}Fe{sub x}GeSi{sub 2} alloys with x<1 crystallize in the hexagonal Mn{sub 5}Si{sub 3}-type structure. Alloys with x=1.5 and 2 consist of a major Mn{sub 5}Si{sub 3}-type phase and a secondary Ni{sub 2}In-type phase. • The cell parameters decrease and the Curie temperature increases with increasing x in Mn{sub 5−x}Fe{sub x}GeSi{sub 2} alloys. • The maximum -∆S{sub M} of 3.7 J/(kg K) and RCP of 211 J/kg for x=0.8 was found under a magnetic field change of 0–20 kOe.

  13. Enhanced electrochemical performance of Ti substituted P2-Na2/3Ni1/4Mn3/4O2 cathode material for sodium ion batteries

    International Nuclear Information System (INIS)

    Zhao, Wenwen; Tanaka, Akinobu; Momosaki, Kyoko; Yamamoto, Shinji; Zhang, Fabi; Guo, Qixin; Noguchi, Hideyuki

    2015-01-01

    Highlights: • Ti substituted P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 cathode was synthesized. • Structural and electrochemical properties of Na 2/3 Ni 1/4 Ti x Mn 3/4-x O 2 were studied. • Ti substituted cathodes exhibit enhanced cycleability and rate performance. • Ti substitution has impact on stabilizing the P2 structure during cycling. -- Abstract: Ti substituted P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 cathode material with the composition of Na 2/3 Ni 1/4 Ti x Mn 3/4-x O 2 has been synthesized by solid state method. The influence of Ti substitution for Mn on the structure, morphology and electrochemical performances of P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 has been investigated. X-ray diffraction (XRD) results of Ti substituted sample show that they exhibit same diffraction patterns as those of pristine P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 . Progressive change in the lattice parameters of Ti substituted samples suggests that Mn was successfully substituted by Ti. In contrast to P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 which shows step-type voltage profiles, Ti substituted samples show sloping voltage profiles. Drastic capacity fade occurred for P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 cathode, while Ti substituted cathodes still show high capacity retention over 92% after 25 cycles at the voltage range of 2.0-4.3 V. Even cycled at high upper cut-off voltage of 4.5 V, Ti=0.20 sample can deliver a reversible capacity of 140 mAhg −1 with the capacity retention over 92% after 25 cycles. Furthermore, Ti substituted cathodes exhibit enhanced rate capability over pristine P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 cathode. Comparison of the Ex-situ XRD results of the cycled P2-Na 2/3 Ni 1/4 Mn 3/4 O 2 and its substituted samples provides evidence that the improved electrochemical performance of Ti substituted cathodes would be attributed to the stabilization of the structure with Ti substitution

  14. A double Fe-Ti oxide and Fe-sulphide liquid immiscibility in the Itsindro Gabbro Complex, Madagascar

    Science.gov (United States)

    Augé, Thierry; Bailly, Laurent; Roig, Jean-Yves

    2017-11-01

    The petrology and mineralogy of the Itsindro complex in south-central Madagascar has been investigated through samples obtained from the 320.7 m-deep Lanjanina borehole. The section consists of a 254 m-thick pyroxenite unit with interbedded gabbro layers that overlies a gabbro unit and is itself overlain by a 19 m-thick granite unit. Most of the structures are sub-horizontal. A weak magmatic layering is locally observed but at the scale of the core, the intrusion does not appear to be a layered complex. Pyroxenite and gabbro show a systematic disseminated mineralization consisting of Fe-Ti-P oxides and Fe-(Cu-Ni) sulphides that takes the form of ilmenite-titanomagnetite ± apatite and pyrrhotite ± chalcopyrite ± pentlandite. In the upper zone, from 90 to 72 m, sub-massive centimetre-to decimetre-sized layers of oxides and sulphides comprise a total of 16 m of sub-massive sulphide (the main mineralized zone). In this mineralized zone the oxide/sulphide ratio is close to 1/1. The sulphide is strongly dominated by pyrrhotite, which may locally contain inclusions of molybdenite crystals with the Re sulphide rheniite (ReS2). Oxides are generally euhedral, included in or attached to the Fe-sulphide, and also locally form sub-massive centimetre-sized bands. Apatite as a cumulus phase is ubiquitous. Locally it may account for 30% of the ore-rich samples and some samples consist of apatite-Fe-Ti oxides-Fe-Cu-Ni sulphides with virtually no silicate. Apatite is the main REE carrier but the total REE content remains low (<90 ppm). Mineral compositions and whole rock geochemistry indicate that the rocks are highly differentiated, and in spite of a relatively limited thickness, the differentiation process is observed. Two zones can be distinguished: from the bottom to 162.8 m we see a decrease in the Mg number of olivine and pyroxene, and a drop in TiO2 and Al2O3 for the latter. A reverse trend is then observed within the pyroxenite unit from the 162.8 m level upwards. The

  15. Magnetic properties of ball-milled Fe0.6Mn0.1Al0.3 alloys

    International Nuclear Information System (INIS)

    Rebolledo, A.F.; Romero, J.J.; Cuadrado, R.; Gonzalez, J.M.; Pigazo, F.; Palomares, F.J.; Medina, M.H.; Perez Alcazar, G.A.

    2007-01-01

    The FeMnAl-disordered alloy system exhibits, depending on the composition and the temperature, a rich variety of magnetic phases including the occurrence of ferromagnetism, antiferromagnetism, paramagnetism and spin-glass and reentrant spin glass behaviors. These latter phases result from the presence of atomic disorder and magnetic dilution and from the competing exchange interactions taking place between an Fe atom and its Mn and Fe first neighbors. The use of mechanical alloying in order to prepare these alloys is specially interesting since it allows to introduce in a progressive way large amounts of disorder. In this work, we describe the evolution with the milling time of the temperature dependence of the magnetic properties of mechanically alloyed Fe 0.6 Mn 0.1 Al 0.3 samples. The materials were prepared in a planetary ball mill using a balls-to-powder mass ratio of 15:1 and pure (99.95 at%) Fe, Mn and Al powders for times up to 19 h. The X-rays diffraction (XRD) spectra show the coexistence of three phases at short milling times. For milling times over 6 h, only the FeMnAl ternary alloy BCC phase is observed. Moesbauer spectroscopy reveals the complete formation of the FeMnAl alloy after 9 h milling time. The magnetic characterization showed that all the samples were ferromagnetic at room temperature with coercivities decreasing from 105 Oe (3 h milled sample) down to 5 Oe in the case of the sample milled for 19 h

  16. Mn(ii) mediated degradation of artemisinin based on Fe3O4@MnSiO3-FA nanospheres for cancer therapy in vivo

    Science.gov (United States)

    Chen, Jian; Zhang, Weijie; Zhang, Min; Guo, Zhen; Wang, Haibao; He, Mengni; Xu, Pengping; Zhou, Jiajia; Liu, Zhenbang; Chen, Qianwang

    2015-07-01

    Artemisinin (ART) is a natural drug with potent anticancer activities related with Fe2+ mediated cleavage of the endoperoxide bridge in ART. Herein, we reported that Mn2+ could substitute for Fe2+ to react with ART and generate toxic products, inducing a much higher anticancer efficiency. On this basis, we prepared pH-responsive Fe3O4@MnSiO3-FA nanospheres which can efficiently deliver hydrophobic ART into tumors in mice models. Mn2+ was released in acidic tumor environments and intracellular lysosomes, interacting with ART to kill cancer cells. The ART-loaded nanocarriers could suppress tumor growth more efficiently than free ART, which could be further illustrated by magnetic resonance imaging (MRI). Histological analysis revealed that the drug delivery system had no obvious effect on the major organs of mice. ART has been reported to have lower toxicity than chemotherapeutics. The ART-loaded nanocarriers are promising to be used in improving the survival of chemotherapy patients, providing a novel method for clinical tumor therapy.Artemisinin (ART) is a natural drug with potent anticancer activities related with Fe2+ mediated cleavage of the endoperoxide bridge in ART. Herein, we reported that Mn2+ could substitute for Fe2+ to react with ART and generate toxic products, inducing a much higher anticancer efficiency. On this basis, we prepared pH-responsive Fe3O4@MnSiO3-FA nanospheres which can efficiently deliver hydrophobic ART into tumors in mice models. Mn2+ was released in acidic tumor environments and intracellular lysosomes, interacting with ART to kill cancer cells. The ART-loaded nanocarriers could suppress tumor growth more efficiently than free ART, which could be further illustrated by magnetic resonance imaging (MRI). Histological analysis revealed that the drug delivery system had no obvious effect on the major organs of mice. ART has been reported to have lower toxicity than chemotherapeutics. The ART-loaded nanocarriers are promising to be used in

  17. The effect of nano-TiC addition on sintered Nd-Fe-B permanent magnets

    International Nuclear Information System (INIS)

    Mural, Zorjana; Kollo, Lauri; Xia, Manlong; Bahl, Christian R.H.; Abrahamsen, Asger Bech; Bez, Henrique Neves; Link, Joosep; Veinthal, Renno

    2017-01-01

    This paper addresses the effect of nano-TiC addition on sintered Nd-Fe-B permanent magnets. TiC nanoparticles were added to sintered Nd-Fe-B magnets with a specific aim to improve the Curie temperature and thermal stability. A standard powder metallurgy route was adopted to prepare the magnets. It was found that introducing nano-TiC prior to jet milling was effective as the nanoparticles dispersed in the final alloy, concentcalcrating in the neodymium-rich phase of the magnets. Magnets with optimal properties were obtained with the addition of 1 wt% TiC nanoparticles. The hysteresis loop for such magnets showed an improved shape and VSM analysis a coercivity value of 1188 kA/m, a remanence value of 0.96 T and a maximum energy product of 132 kJ/m 3 . The maximum working point and the Curie temperature of the developed magnets were 373 K and 623 K respectively. - Highlights: • Improvement of thermal stability of Nd-Fe-B magnets by introducing nano-TiC prior sintering is proposed. • The mechanism relies on nano-TiC particles behaving as grain growth inhibitors between thin RE-rich phase regions. • The concentration of up to 1 wt% of nano-TiC appears to increase coercivity without a significant decrease in remanence. • The maximum working point and the Curie temperature of the developed magnets are 373 K and 623 K respectively.

  18. The effect of nano-TiC addition on sintered Nd-Fe-B permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Mural, Zorjana, E-mail: zorjana.mural@ttu.ee [Department of Materials Engineering, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Kollo, Lauri [Department of Materials Engineering, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Xia, Manlong; Bahl, Christian R.H. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark); Abrahamsen, Asger Bech [Department of Wind Energy, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark); Bez, Henrique Neves [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark); Link, Joosep [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Veinthal, Renno [Department of Materials Engineering, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia)

    2017-05-01

    This paper addresses the effect of nano-TiC addition on sintered Nd-Fe-B permanent magnets. TiC nanoparticles were added to sintered Nd-Fe-B magnets with a specific aim to improve the Curie temperature and thermal stability. A standard powder metallurgy route was adopted to prepare the magnets. It was found that introducing nano-TiC prior to jet milling was effective as the nanoparticles dispersed in the final alloy, concentcalcrating in the neodymium-rich phase of the magnets. Magnets with optimal properties were obtained with the addition of 1 wt% TiC nanoparticles. The hysteresis loop for such magnets showed an improved shape and VSM analysis a coercivity value of 1188 kA/m, a remanence value of 0.96 T and a maximum energy product of 132 kJ/m{sup 3}. The maximum working point and the Curie temperature of the developed magnets were 373 K and 623 K respectively. - Highlights: • Improvement of thermal stability of Nd-Fe-B magnets by introducing nano-TiC prior sintering is proposed. • The mechanism relies on nano-TiC particles behaving as grain growth inhibitors between thin RE-rich phase regions. • The concentration of up to 1 wt% of nano-TiC appears to increase coercivity without a significant decrease in remanence. • The maximum working point and the Curie temperature of the developed magnets are 373 K and 623 K respectively.

  19. Atomistic modeling determination of placeholder binding energy of Ti, C, and N atoms on a-Fe (100) surfaces

    International Nuclear Information System (INIS)

    Wei, X J; Liu, Y P; Han, S P

    2015-01-01

    A Fe(100) surface containing Ti, C, and N was constructed and optimized to study the placeholder binding energy of the Ti, C, and N surface atoms; this was achieved by searching the transition state with the LST (linear synchronous transit) method of the CASTEP (Cambridge Serial Total Energy Package) module. Also, the authors analyzed electron structures to determine how Ti, C, and N atoms strengthen the Fe(100) surface. The results show that when Ti, C, or N atoms take placeholder alone, or simultaneously at the Fe(100) surface, the structure stability is at its best. When including Ti, C, and N as solid solutions on the Fe(100) surface, orbital electrons of Fe3d, Ti3d, C2p, and N2p hybridize near the Fermi level; the number of electronic bonding peaks increase and bonding capacity enhances. Also, a large amount of covalent bonds formed. Covalent bonds and metallic bond coexisted. (paper)

  20. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO{sub 2}-Fe and TiO{sub 2}-reduced graphene oxide nanocomposites immobilized on optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Lu; Wang, Huiyao, E-mail: huiyao@nmsu.edu; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei, E-mail: pxu@nmsu.edu

    2017-07-05

    Highlights: • Incorporating rGO or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalysis. • TiO{sub 2}-rGO exhibited higher photocatalytic activity under UV irradiation. • TiO{sub 2}-Fe demonstrated more suitable for visible light irradiation. • Reduced recombination rate contributed to enhanced photocatalysis of TiO{sub 2}-rGO. • Narrower band gap accounted for increased photocatalytic activity of TiO{sub 2}-Fe. - Abstract: Incorporating reduced graphene oxide (rGO) or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO{sub 2}-Fe and TiO{sub 2}-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO{sub 2}-rGO and TiO{sub 2}-Fe nanocomposites. Doping Fe into TiO{sub 2} particles (2.40 eV) could reduce more band gap energy than incorporating rGO (2.85 eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO{sub 2} decreased significantly the intensity of TiO{sub 2} photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO{sub 2}-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO{sub 2}-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO{sub 2}-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO{sub 2}-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic

  1. Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

    International Nuclear Information System (INIS)

    Wirth, B D; Asoka-Kumar, P; Howell, R H; Odette, G R; Sterne, P A

    2001-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characterization of irradiated and thermally aged Fe-Cu and Fe-Cu-Mn alloys. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of CRPs and VSCs in both alloys. The CRPs are coarser in the Fe-Cu alloy and the number densities of CRP and VSC increase with the addition of Mn. The PAS involved measuring both the positron lifetimes and the Doppler broadened annihilation spectra in the high momentum region to provide elemental sensitivity at the annihilation site. The spectra in Fe-Cu-Mn specimens thermally aged to peak hardness at 450 C and irradiated at 288 C are nearly identical to elemental Cu. Positron lifetime and spectrum measurements in Fe-Cu specimens irradiated at 288 C clearly show the existence of long lifetime (∼500 ps) open volume defects, which also contain Cu. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of CRPs and VSCs and tend to discount high Fe concentrations in the CRPs

  2. Fe-Ti-O based catalyst for large-chiral-angle single-walled carbon nanotube growth

    DEFF Research Database (Denmark)

    He, Maoshuai; Zhang, Lili; Jiang, Hua

    2016-01-01

    Catalyst selection is very crucial for controlled growth of single-walled carbon nanotubes (SWNTs). Here we introduce a well-designed Fe-Ti-O solid solution f