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  • 1.
    Akhtar, Farid
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Microstructure evolution and wear properties of in situ synthesized TiB 2 and TiC reinforced steel matrix composites2008Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 459, nr 1-2, s. 491-497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Steel matrix composite reinforced with TiB2 and TiC reinforcements (30 to 70wt%) have been produced through the synthesis reaction from Ti, C and FeB. The sintered composites were characterized by X-ray diffraction and scanning electron microscopy. TiB2, TiC and steel were detected by X-ray diffraction analysis. The scanning electron micrographs revealed the morphology and distribution of the reinforcements. TiB2 and TiC were thermally stable in the steel matrix. The results showed that different mechanisms of evolution of reinforcements in steel matrix were operative. TiB2 grew in hexagonal prismatic or rectangular shape and TiC in spherical shape. The reciprocating sliding wear test was conducted on the composite. The results of sliding wear showed that the wear loss decreased with increase in the reinforcement content. The wear mechanisms were polishing wear and microploughing for the composites containing high volume fraction of the reinforcements, whereas microploughing and grooving were the dominant wear mechanisms for the composites containing low volume fraction of the reinforcements.

  • 2.
    Akhtar, Farid
    et al.
    Department of Materials and Environmental Chemistry, Stockholm University.
    Ali, Liaqat
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Peizhong, Feng
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Shah, Jawad Ali
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Enhanced sintering, microstructure evolution and mechanical properties of 316l stainless steel with MoSi 2 addition2011Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 509, nr 35, s. 8794-8797Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sintering 316L stainless steel to near full density with an appropriate sintering additive can ensure high mechanical properties and corrosion resistance. We present here a sintering approach which exploits the dissociation of ceramics in steels at high temperatures to activate sintering densification to achieve near full dense 316L stainless steel materials. MoSi2 ceramic powder was used as a sintering additive for pre-alloyed 316L stainless steel powder. Sintering behavior and microstructure evolution were investigated at various sintering temperatures and content of MoSi2 as sintering additive. The results showed that the sintering densification was enhanced with temperature and MoSi2 content. The distribution of MoSi2 was characterized by XMAPs. It was found that MoSi2 dissociated during sintering and Mo and Si segregated at the grain boundaries. Excess Mo and Si were appeared as separate phases in the microstructure. Above 98% of theoretical density was achieved when the specimens were sintered at 1300 °C for 60 min with 5 wt.% MoSi2 content. The stainless steel sintered with 5 wt.% MoSi2 exhibited very attractive mechanical properties.

  • 3.
    Akhtar, Farid
    et al.
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Askari, Syed Jawid
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Shaft, Jawad Ali
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Guo, Shiju
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Processing, microstructure and mechanical properties of TiC-465 stainless steel/465 stainless steel layer composites2007Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 439, nr 1-2, s. 287-293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Layered composites of carbide reinforcements and stainless steel have been prepared successfully by powder technology. The layer material consisted of two layers. Top layer consisted of reinforcements (TiC and NbC) and 465 stainless steel as binder material for carbides. The substrate material was of binder material (465 stainless steel). The microstructure of the composite was characterized by scanning electron microscopy. The microstructural study revealed that top layer (TiC-NbC/465 stainless steel) showed the typical core-rim microstructure of conventional steel bonded cermets and the substrate material showed the structure of sintered steel. An intermediate layer was formed due to diffusion reaction of top layer and substrate material. This intermediate layer showed a gradient microstructure. The bending strength of layered material measured in the direction perpendicular to the layer alignment was remarkably higher. Nineteen percent increase in bending strength in case of 53 wt% reinforcement in top layer and 35% increase in case of 73 wt% reinforcement in top layer was found. The variation of strength as a function of thickness of substrate material revealed that the character of material changed from cermet to a layer composite and then towards metallic materials. The fracture morphologies of top layer, substrate material and intermediate layer are also reported

  • 4.
    Feng, Peizhong
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Akhtar, Farid
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Wang, Xiaohong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Liu, Weisheng
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Wu, Jie
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Zhang, Shuai
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Qiang, Yinghuai
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Effect of diluent on the synthesis of molybdenum disilicide by mechanically-induced self-propagating reaction2010Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 494, nr 1-2, s. 301-304Artikel i tidskrift (Refereegranskat)
  • 5.
    Feng, Peizhong
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Qu, Xuanhui
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Akhtar, Farid
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Du, Xueli
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Islam, Humail S
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Jia, Chengchang
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Effect of the composition of starting materials of Mo--Si on the mechanically induced self-propagating reaction2008Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 456, nr 1-2, s. 304-307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of the raw materials composition of Mo–Si powders mixture on mechanical alloying has been investigated using a high-energy vibratory type ball-milling machine. The phase transformation of powders mixture is characterized by means of X-ray diffractometer. The results show that the molybdenum silicide is formed by the mechanically induced self-propagating reaction in relatively broad composition range from the molar ratio of Mo:1.5Si to Mo:2.5Si. As the content of silicon increases, the amount of critical stored energy for mechanically induced self-propagating reaction is increased, whereas the favorable Mo–Si reactive interface is decreased, and the difficulty of formation of Mo(Si) supersaturated solid solution is enhanced. These factors prolong the incubation period of mechanically induced self-propagating reaction from 60 to 130 min. Compared to stoichiometry of MoSi2, the excess amount of Mo acts as accelerant, and the redundant Si acts as diluting agent.

  • 6.
    Galstyan, V.
    et al.
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Comini, E.
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Vomiero, Alberto
    SENSOR Lab, Department of Chemistry and Physics, Brescia University and CNR-IDASC.
    Ponzoni, A.
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Concina, Isabella
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Brisotto, M.
    INSTM and Chemistry for Technologies Laboratory.
    Bontempi, E.
    INSTM and Chemistry for Technologies Laboratory.
    Faglia, G.
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Sberveglieri, G.
    Department of Physics, Chemistry and Biology (IFM), Linköping University.
    Fabrication of pure and Nb-TiO 2 nanotubes and their functional properties2012Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 536, nr SUPPL.1, s. S488-S490Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    TiO 2 and Nb-doped TiO 2 nanotubes were obtained on flexible polymeric substrates (Kapton HN) and alumina with high roughness (alumina substrate with granular surface). Nanotubes were prepared by electrochemical anodization of a Ti thick film. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to investigate the morphology of the structures and the roughness of the substrates. The functional properties of tubular arrays obtained on flexible and rough substrates were investigated towards two applications, namely, chemoresistive gas sensors and flexible dye sensitized solar cells. © 2011 Elsevier B.V. All rights reserved.

  • 7.
    Garcia, Gustavo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Aguilar, Wilson
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Carabante, Ivan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Cabrera, Saúl
    Chemistry Research Institute IIQ, San Andres Mayor University UMSA, La Paz.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Preparation of zeolite A with excellent optical properties from clay2015Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 619, s. 771-777Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Discoloration of zeolite A powder is a common problem when natural raw materials such as kaolin clay are used because of the formation of colored iron compounds. In this study, we report on a novel method to produce zeolite A with excellent optical properties, from clays. The brightness is as high as 94.5 and the yellowness is as low as 3.0. The product is comprised of intergrown zeolite A crystals with cubic habit and a length ranging between 0.5 and 2 μm. Good optical properties are obtained when the raw material contains magnesium, as some natural raw materials do, or alternatively, when a magnesium compound is added to the raw material. Magnesium probably forces iron inside colorless extraneous magnesium aluminosilicate compounds. This simple process appears very promising for the preparation of zeolite A with good optical properties from inexpensive natural raw materials.

  • 8.
    Jiao, Xinyang
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, China. School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, China.
    Feng, Peizhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, China.
    Wang, Jianzhong
    State Key Laboratory of Porous Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xi'an, China.
    Ren, Xuanru
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, China.
    Akhtar, Farid
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Exothermic behavior and thermodynamic analysis for the formation of porous TiAl3 intermetallics sintering with different heating rates2019Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 811, artikel-id 152056Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Porous TiAl3 intermetallcis are of great interest due to its excellent properties and widely applied in filtering apparatus, separation material and catalyst carrier. In this study, interconnected pore-structures have been synthesized by diffusion or thermal explosion (TE) reaction sintering with different heating rates. The thermal characteristics such as temperature-time curves, exothermic change and visual images indicate that the sample experienced a significant TE reaction at higher heating rates. Results shown that the sample was ignited at 672 °C and then rapidly increased to combustion temperature of 1169, 1110 and 933 °C in tens of seconds with the heating rate of 15, 10 and 5 °C∙min−1 respectively. Meanwhile, TE represented the uniformity of volume combustion, instantaneous reaction and rapid cooling to furnace temperature, the amount of heat released during TE reaction dropped from 1303 to 963 J g−1. This indicates that the entire sintering process was controlled by TE and the pre-diffusion reaction before the melting temperature of Al atom, which would affect the subsequent combustion reaction. Thermodynamic data explained that the reaction mechanism is mainly step-controlled diffusion reaction at a low heating rate (1 °C∙min−1), while the energy gradually accumulated and thermal explosion (TE) reaction become obvious with the increasing of heating rate (from 2 to 15 °C∙min−1).

  • 9.
    Mouzon, Johanne
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Dujardin, C.
    Claude Bernard/Lyon1 University.
    Tillement, O.
    Claude Bernard/Lyon1 University.
    Odén, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Synthesis and optical properties of Yb0.6Y1.4O3 transparent ceramics2008Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 464, nr 1-2, s. 407-411Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent yttrium oxide ceramics doped with 30 at.% ytterbium were successfully produced by a combination of pre-sintering and hot isostatic pressing. The influence on the final transparency of different densification states and porosity configurations obtained by varying pre-sintering conditions were investigated by optical and electron microscopy. Our results show that densification prior to the final stage of sintering is necessary to limit final porosity. Samples showing open porosity were found to lead to pore entrapment because of the diffusion of argon inside the glass capsule during hot isostatic pressing. Transmittance measurements showed that the valence charge of the ytterbium ions was 3+ at the end of the process, indicating no effect of reduction when pre-sintering in vacuum was employed.

  • 10.
    Ran, Huashen
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Song, Binbin
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Niu, Ijnan
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    wang, Xiaohong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Feng, Peizhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Wang, Jianzhong
    State Key Laboratory of Porous Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xi’an.
    Ge, Yuan
    State Key Laboratory of Porous Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xi’an.
    Akhtar, Farid
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Microstructure and properties of Ti5Si3-based porous intermetallic compounds fabricated via combustion synthesis2014Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 612, s. 337-342Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Porous titanium silicides (Ti5Si3-based) were produced by combustion synthesis process from reaction mixtures of titanium to silicon in varying molar ratios. The effects of combustion characteristics of the reaction mixtures on the phase formation, microstructure, porosity, pore size and compressive strength of porous titanium silicide intermetallic compounds were investigated. The results showed that the flame-front propagation velocity and temperature of the combustion reaction were the maximum for the reaction mixture containing Ti and Si in the ratio of 5 to 3 (Ti5Si3), 32.7 mm/s and 2205 K, respectively. X-ray diffraction analysis confirmed that the dominant phase formed was Ti5Si3 in all combustion synthesized porous intermetallic compounds. Ti5Si3-based intermetallic compounds were highly porous. The porosity and pore size of these intermetallics were dependent on the initial composition of the reaction mixture. The total and open porosities of Ti5Si3-based intermetallics varied from 33 to 61% and 17 to 55%, respectively. The porous titanium silicide intermetallic materials displayed high mechanical strength, in the range of 6-35 MPa, duly required for their use as filters.

  • 11.
    Santiago, A.A.G.
    et al.
    LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
    Tranquilin, R.L.
    LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
    Botella, Pablo
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Manjón, F.J.
    Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, València, Spain.
    Errandonea, D.
    Departamento de Física Aplicada-ICMUV, Universidad de Valencia, MALTA Consolider Team, Edificio de Investigación, Burjassot, Spain.
    Paskocimas, C.A.
    LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
    Motta, F.V.
    LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
    Bomio, M.R.D.
    LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
    Spray pyrolysis synthesis and characterization of Mg1-xSrxMoO4 heterostructure with white light emission2020Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 813, artikel-id 152235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Molybdates are inorganic materials with great potential in white phosphors application, being an alternative to traditional lighting sources. In this study, we report the synthesis and characterization of Mg1-xSrxMoO4 (x = 0, 0.25, 0.50, 0.75, and 1) powders with white light-emitting properties. Using X-ray diffraction, the formation of the monoclinic β-MgMoO4 phase was observed for x = 0 and the formation of the tetragonal scheelite phase of SrMoO4 was observed for x = 1. The formation of a heterostructure composed of both phases was found for compositions with x = 0.25, 0.50 and 0.75. Scanning electron microscopy images showed that the Mg1-xSrxMoO4 particles exhibit a spherical morphology formed by several primary nanoparticles. Raman scattering spectroscopy enabled the accurate identification of the Raman modes for different compositions and their assignment to either the SrMoO4 or β-MgMoO4 modes. The bandgap energies were determined to fluctuate between 4.25 eV and 4.44 eV, being influenced by the degree of structural disorder. The photoluminescence emission spectra of the nanoparticles showed neutral- and cool-white emission with high-quality white light (CRI > 80%). The samples synthesized with x ≤ 0.50 are potential materials for the application in LED lamps (6500 K) and pure white-light sources (5500 K).

  • 12.
    Shi, P.
    et al.
    Xi'an Jiaotong University, Xi'an, China.
    Zhu, L.
    Xi'an Jiaotong University, Xi'an, China.
    Gao, W.
    Xi'an Jiaotong University, Xi'an, China.
    Yu, Z.
    Xi'an Jiaotong University, Xi'an, China.
    Lou, X.
    Xi'an Jiaotong University, Xi'an, China.
    Wang, Xiangjian
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Yang, Z.
    Xi'an Jiaotong University, Xi'an, China.
    Yang, S.
    Xi'an Jiaotong University, Xi'an, China.
    Large energy storage properties of lead-free (1-x)(0.72Bi0.5Na0.5TiO3-0.28SrTiO3)-xBiAlO3 ceramics at broad temperature range2019Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 784, s. 788-793Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    (1-x)(0.72Bi0.5Na0.5TiO3-0.28SrTiO3)-xBiAlO3 (BNT-ST-xBA) lead-free ceramics were prepared through solid-state sintering methods. The structural, dielectric and energy storage properties of the ceramics were studied in this work. A large energy storage density of BNT-ST-0.01BA ceramics exceeding 1.746 J/cm3 has been obtained. The ceramics exhibit a good thermal stability at the temperature ranging from 20 °C to 120 °C. In addition, energy storage properties are relatively stable after completing 10000 electrical cycles, which shows promising potential for energy storage devices at a high temperature region.

  • 13.
    Shmakov, I. G.
    et al.
    Institute of Metal Physics, Ural Division RAS, 620219, Ekaterinburg, Russia.
    Gorbatov, Oleg
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. KTH Royal Institute of Technology, Nosov Magnitogorsk State Technical University, 455000, Magnitogorsk, Russia.
    Serikov, V. V.
    Institute of Metal Physics, Ural Division RAS, 620219, Ekaterinburg, Russia.
    Kleinerman, N. M.
    Institute of Metal Physics, Ural Division RAS, 620219, Ekaterinburg, Russia.
    Golovnya, O. A.
    Institute of Metal Physics, Ural Division RAS, 620219, Ekaterinburg, Russia.
    Gornostyrev, Yu. N.
    Institute of Metal Physics, Ural Division RAS, 620219, Ekaterinburg, Russia.
    Short-range order formation in Fe-Co alloys: NMR study and first-principles calculations2019Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 782, s. 1008-1014Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The short/long-range order formation in Fe1-x-Cox (x < 0.3) alloys has been studied by the nuclear magnetic resonance (NMR) technique, as well as ab initio based atomistic simulation. The NMR measurements show up the formation of a certain short-range order (SRO) in dilute limit above the Curie temperature TC and of the D03-type SRO (with the dominance of 3rd Co-Co nearest neighbors) in the concentration range 0.2 < x < 0.3 after quenching and subsequent annealing in the ferromagnetic state. The results of Monte Carlo simulations of binary Fe-Co alloys with ab initio interatomic interactions predict SRO in agreement with the experiment for small concentrations of Co (CCo< 0.1), while the B2-type ordering is preferable in binary alloy in the ferromagnetic state. We demonstrate that the presence of point defects (vacancies, interstitial) can change essentially the ordering in alloys with the Co content 20-30% and result in the D03-type SRO formation in a reasonable agreement with the experiment.

  • 14.
    Tian, Jianjun
    et al.
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Zhang, Shengen
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Qu, Xuanhui
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Akhtar, Farid
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Tao, Siwu
    Institute of Powder Metallurgy, School of Materials Science and Engineering, University of Science and Technology, Beijing.
    Behavior of residual carbon in Sm(Co, Fe, Cu, Zr)z permanent magnets2007Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 440, nr 1-2, s. 89-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When sintered Sm(Co, Fe, Cu, Zr)z permanent magnets are prepared by metal injection molding, some organic binders are added in alloy powder, which leads to much residual carbon in the magnets. The residual carbon decreases magnetic properties and destroys the microstructure of the magnets. In this paper, the behavior of carbon in Sm(Co, Fe, Cu, Zr)z permanent magnets has been studied. The results indicate that Sm(Co, Fe, Cu, Zr)z magnets can keep excellent magnetic properties when the carbon content is below 0.1 wt.%: Br ≥ 10 kGs, Hcj ≥ 22 kOe, BHmax ≥ 25 MGOe. When the carbon content is above 0.1 wt.%, Br, Hcj and BHmax decrease with increasing carbon content evidently. Carbon consumes Zr content and forms ZrC, which reduces the volume fraction of the lamella and Sm(Co, Cu)5 phases. Thus, the cell size increases and the cellular microstructure deteriorates. When the carbon content reaches 0.43 wt.%, there is not enough Sm(Co, Cu)5 phase to form a uniform cellular microstructure. Br, Hcj and BHmax are approximate to zero. Since carbon has little influence on the content of Sm2(Co, Fe)17 phase, Ms can keep a high value (≥100 emu/g). ZrC has high melting point (3420 °C) and acts as dispersion particle in the magnets, which prevents the grains of SEM structure growing and reduces the liquid content of green compacts during sintering. Therefore, the density of the magnets decreases

  • 15.
    Wang, Xiaohong
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Feng, Peizhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Akhtar, Farid
    Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore.
    Wu, Jie
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Liu, Weisheng
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Qiang, Yinghuai
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Wang, Zhenzhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Effects of tungsten and aluminum additions on the formation of molybdenum disilicide by mechanically-induced self-propagating reaction2010Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 490, nr 1, s. 388-392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of tungsten and aluminum additions to Mo–Si system on the formation of MoSi2 by mechanically-induced self-propagating reaction in a high-energy ball mill were investigated by X-ray diffraction. The incubation time for mechanically-induced self-propagating reaction to form MoSi2 was 90 min in Mo–Si system. With the addition of tungsten to Mo–Si system, the incubation time of mechanically-induced self-propagating reaction of (Wx,Mo1−x)Si2 system was prolonged. It was due to the decrease of adiabatic temperature with increase in x, and the mechanically-induced self-propagating reaction was not observed until 150 min of high-energy milling in (Wx,Mo1−x)Si2 powder sample with x equals to 0.4. Conversely, the minor aluminum (y < 0.2 in Mo(Si1−y,Aly)2 system) substituting for silicon had shorten the incubation period and accelerated the reaction. When tungsten and aluminium were added simultaneously to Mo–Si system, the mechanically-induced self-propagating reaction was observed in (W0.1,Mo0.9)(Si0.9,Al0.1)2 sample, but it was not observed in (W0.2,Mo0.8)(Si0.8,Al0.2)2 and (W0.3,Mo0.7)(Si0.7,Al0.3)2 samples.

  • 16.
    Wei, L.Y.
    et al.
    Luleå tekniska universitet.
    Dunlop, G.L.
    University of Queensland.
    Solidification behaviour of Mg-Al-rare earth alloys1996Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 232, nr 1-2, s. 264-268Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solidification paths and as-cast microstructures were determined for the Mg-Al-MM (misch metal) alloys: AE21, AE41 and AE91. Two types of interdendritic phase were identified using analytical electron microscopy. These were Al4MM and Al12Mg17. Only Al4MM was found in AE21 while both phases were found in the other two alloys. Most of the solidification in AE21 takes place in a rather narrow solidification gap (approx.40°C), while this gap is much greater (approx. 150°C) in the higher Al alloys. This combined with the large volume fraction of interdendritic eutectic phases explains the good castability of AE91

  • 17.
    Xue, Peng
    et al.
    Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing.
    He, Dongfeng
    Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing.
    Xu, Anjun
    Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing.
    Gu, Zongxi
    Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing.
    Yang, Qixing
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Modification of industrial BOF slag: Formation of MgFe2O4 and recycling of iron2017Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 712, s. 640-648Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient recycling of iron oxide from industrial BOF (basic oxygen furnace) slags has always been an issue in metallurgy. In this study, a new method was developed for the efficient recycling of iron oxide: It was transformed into magnesioferrite spinel (MgFe2O4) by mixing the industrial BOF slag with 6.00% SiO2 first, and then the modified slag got cooled down from 1400 °C to 1270 °C at a rate of 1 °C/min. Finally, the Fe resources were recycled by magnetic separation. Various experiments and analyses such as XRD, SEM–EDS analyses, Factsage thermodynamic simulation, magnetization characterization, dry magnetic separation, and chemical analysis were carried out. The results show that the obtained MgFe2O4 has a high melting point (1716.76 °C in theory) and ferromagnetism (specific magnetic susceptibility of (8.03–206.84) × 10−5 m3/kg). Therefore, it could be separated from the weakly magnetic industrial BOF slag (specific magnetic susceptibility of (0.024–0.136) × 10−5 m3/kg). Furthermore, this new method could be applied to different BOF slags. The yield of MgFe2O4 increased to above 80% when the content of Fe2O3 was in the range 25.81–46.90%. After the modification and magnetic separation, the total Fe content increased by 15.80%, from 21.20% in the industrial BOF slag to 37.00% in the magnetic slag. This is better than the direct magnetic separation of iron oxide without any treatment. The magnetic slag could be reused as either a sintering or slag splashing material. The nonmagnetic slag can be used to produce high value-added building materials. Hence, this new method can be used to recycle the iron oxide from industrial BOF slags, achieving the sustainable development of the iron and steel industry.

  • 18.
    Yusupov, Khabib
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Functional Nanosystems and High Temperature Materials, NUST MISiS, Moscow, Russia. Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Germany.
    Zakhidov, A.
    Department of Functional Nanosystems and High Temperature Materials, NUST MISiS, Moscow, Russia. NanoTech Institute, University of Texas at Dallas, USA.
    You, Shujie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Stumpf, S.
    Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Germany. Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Germany.
    Martinez, P.M.
    NanoTech Institute, University of Texas at Dallas, USA.
    Ishteev, A.
    Department of Functional Nanosystems and High Temperature Materials, NUST MISiS, Moscow, Russia.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Khovaylo, V.
    Department of Functional Nanosystems and High Temperature Materials, NUST MISiS, Moscow, Russia. National Research South Ural State University, Chelyabinsk, Russian Federation.
    Schubert, U.
    Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Germany; Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Germany. Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Germany.
    Influence of oriented CNT forest on thermoelectric properties of polymer-based materials2018Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 741, s. 392-397Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermoelectric (TE) materials are highly important due to their ability to convert wasted heat energy into electricity. Among the different TE materials, organic-based or polymer-based TE systems are among the most promising due to their sustainability, non-toxicity and good electrical properties. In our research, we have investigated for the first time the application of vertically aligned carbon nanotubes forest (VA-CNTF) as a filler for TE composite; compared to unconnected carbon nanotubes (CNT), which are typically used in polymer/CNT composites, dry pulled VA-CNTF sheets have more ordered structure, which is supposed to improve the TE efficiency of the material. VA-CNTF and short unoriented multiwalled carbon nanotubes (MWCNT) were used as fillers of a polymeric matrix, to prepare TE composites. Various stacking configurations were explored by using CNTF. All the samples were examined by scanning electron microscopy (SEM), micro-Raman spectroscopy, and four-point probe electrical measurements; MWCNT-based samples were used as benchmarking systems.

    The results revealed a dramatic increase of the Seebeck coefficient up to 46 μV/K for the VA-CNTF-based sample, while the best MWCNTs-based sample (MWCNT concentration 50 wt%) provided only 21.49, which is roughly the Seebeck coefficient of pure polymer. This research represents the first application of VA-CNTF as a promising material for TE systems and demonstrates that oriented nanoforests and related CNT sheets are a very perspective material for promising developments in the field.

  • 19.
    Zhu, Gaoming
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Wang, Xiaohong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Feng, Peizhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Li, Dehu
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Yang, Ting
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Akhtar, Farid
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Synthesis, microstructure and mechanical properties of (Mo,Ti)Si2/Al2O3 composites prepared by thermite-reaction-assisted combustion synthesis2016Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 688, s. 870-877Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    (Mo0.95Ti0.05)Si2/3.3mol%Al2O3 composites were synthesized by self-propagating high-temperature synthesis using Mo, Si, Al and TiO2 powders. The addition of alloying element Ti to MoSi2 and the synthesis of reinforcing particulate Al2O3 phase were achieved through the thermite reaction, Al + TiO2→Ti + Al2O3. The results showed that the combustion synthesis reaction mode in the Mo, Si, Al and TiO2 reaction mixture was spiral and self-propagating, and the reaction product was composed of MoSi2, (Mo,Ti)Si2 and Al2O3. The combustion products were consolidated by vacuum hot-pressing at 1773 K and 27.5 MPa for 90 min to consolidate composites with relative densities above 95% of theoretical. The hot-pressed (Mo0.95Ti0.05)Si2/3.3mol%Al2O3 composite with relative density of 97.5% exhibited finer microstructure and superior mechanical properties compared to MoSi2 monolithic material; Vicker's hardness of 12.9 GPa, bending strength of 320 MPa and fracture toughness of 3.37 MPa m1/2.

  • 20.
    Zhu, Gaoming
    et al.
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Wang, Xiaohong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Sun, Zhi
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Feng, Peizhong
    School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou.
    Akhtar, Farid
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Effect of annealing environment on the crack healing and mechanical properties of (Mo0.97Nb0.03)(Si0.97Al0.03)22015Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 634, s. 109-114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Crack healing of Nb and Al alloyed MoSi2 notched ceramics had been investigated during thermal treatment from 900 to 1500 °C in air, vacuum, argon and nitrogen environments. Notched (Mo0.97Nb0.03)(Si0.97Al0.03)2 ceramics showed significant recovery of bending strength after heat treatment in air. Bending strength recovery of 250% was found after heat treatment in air at 1200 °C. Oxide layer formation healed the cracks during annealing in air. Re-sintering was found dominant mechanism of crack healing during annealing in vacuum, argon and nitrogen atmosphere. Bending strength recovery of 208% was found after heat treatment in vacuum at 1200 °C.

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