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Sample records for ball milling materials

  1. Ball-milled sulfur-doped graphene materials contain metallic impurities originating from ball-milling apparatus: their influence on the catalytic properties.

    Science.gov (United States)

    Chua, Chun Kiang; Sofer, Zdeněk; Khezri, Bahareh; Webster, Richard D; Pumera, Martin

    2016-07-21

    Graphene materials have found applications in a wide range of devices over the past decade. In order to meet the demand for graphene materials, various synthesis methods are constantly being improved or invented. Ball-milling of graphite to obtain graphene materials is one of the many versatile methods to easily obtain bulk quantities. In this work, we show that the graphene materials produced by ball-milling are spontaneously contaminated with metallic impurities originating from the grinding bowls and balls. Ball-milled sulfur-doped graphene materials obtained from two types of ball-milling apparatus, specifically made up of stainless steel and zirconium dioxide, were investigated. Zirconium dioxide-based ball-milled sulfur-doped graphene materials contain a drastically lower amount of metallic impurities than stainless steel-based ball-milled sulfur-doped graphene materials. The presence of metallic impurities is demonstrated by their catalytic effects toward the electrochemical catalysis of hydrazine and cumene hydroperoxide. The general impression toward ball-milling of graphite as a versatile method for the bulk production of 'metal-free' graphene materials without the need for post-processing and the selection of ball-milling tools should be cautioned. These findings would have wide-reaching implications for graphene research. PMID:27314607

  2. Nickel sulfide synthesized by ball milling as an attractive cathode material for rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Nickel sulfide (NiS) powders were prepared by ball milling and melting as cathode materials for a lithium rechargeable battery which was charged and discharged at room temperature (30 deg. C). The NiS powders prepared by melting were composed of several phases such as Ni3S2, Ni7S6, NixS6, and Ni3S4, as derived from XRD. In order to synthesize a homogeneous nickel sulfide (NiS) phase, ball milling (BM) was adopted. A homogeneous NiS phase was easily formed after ball milling up to 12 h under an Ar atmosphere. The ball milled NiS particles were relatively large compared to those of the starting materials and they had a nanocrystalline structure. The initial discharge capacity of the NiS positive electrode prepared by ball milling is 580 mAh/g-NiS, at 1.4 V vs. Li/Li+. The NiS powders synthesized by ball milling show a better cycling property than NiS prepared by melting and also had a better rate capability. It exhibited 87% of its theoretical capacity at a current rate of 2C, comparable with that of 1/6C. This may be related with the small sized grains of NiS prepared by ball milling

  3. Effect of ball milling materials and methods on powder processing of Bi2223 superconductors

    Science.gov (United States)

    Yavuz, M.; Maeda, H.; Vance, L.; Liu, H. K.; Dou, S. X.

    1998-10-01

    Various milling systems consisting of agate and polypropylene grinding containers, agate and YSZ balls, and dry and wet milling were used in planetary ball-milling and YSZ balls and YSZ container were used in wet and dry attrition milling. The differently milled powders were then evaluated by measurements of particle size, surface area, porosity, size distribution and chemical analysis of the Si, Zr and C contents. The results show that dry milling is much more efficient for particle size reduction in planetary milling than wet milling, whereas wet milling and dry milling gave quite similar results in attrition milling. Meanwhile 0953-2048/11/10/056/img6 contamination was found in powder milled with an agate container with agate balls. Some C contamination from the polypropylene container was detected after milling, but negligible Zr from YSZ balls and C from the grinding carrier (hexane). It was found that after 1 h milling in the planetary mill fracture mechanisms transform from the elastic to the plastic region. Therefore, further milling is not very effective. It was also shown that the Bi2212 phase decomposes into several non-superconducting oxides such as 0953-2048/11/10/056/img7, CuO and a main amorphous phase after extensive dry milling.

  4. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2013-08-01

    Full Text Available In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200–600 rpm, grinding time of 5–180 min and sample mass of 1–10 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity. The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrogen adsorption/desorption isotherms. Under the optimal conditions at the rotational speed of 400 rpm, grinding time of 30 min and sample mass of 5 g, the resulting calcite-based powder had larger specific surface area (i.e., 10.64 m2·g−1 than the starting material (i.e., 4.05 m2·g−1. This finding was also consistent with the measurement of laser-diffraction (i.e., 9.7 vs. 15.0 μm of mean diameter. In addition, the results from the scanning electron microscope (SEM observation indicated that surface roughness can be enhanced as particle size decreases as a result of particle-particle attrition. Thus, grinding the aquacultural bioresource by a high-energy ball milling can create the fine materials, which may be applied in the fields of inorganic minerals like aggregate and construction material.

  5. Design and development of a micro polycrystalline diamond ball end mill for micro/nano freeform machining of hard and brittle materials

    International Nuclear Information System (INIS)

    Micro end mills play a key role in micro/nano milling applications for intricate three-dimensional die/molds or sensors for micro-electro-mechanical systems (MEMS). In order to achieve higher machining accuracy and longer tool life, micro end mills are usually made of ultra-hard materials such as polycrystalline diamond (PCD) or cubic boron nitride (CBN). One of the best choices for their fabrication is the wire electrical discharge machining (WEDM) method. There are two basic categories of micro end mills, namely the ball end mill for 3D freeform surface machining and straight/round edge end mills for non-freeform surface machining. This paper focuses on the design and development of the micro ball end mill for hard and brittle materials. Firstly, the available typical ball end mill is analyzed. Secondly, a micro ball end mill with uniform axial rake and clearance angles is designed and analyzed by the finite element method (FEM). The designed micro ball end mill only needs simultaneously three linear and one index rotational WEDM axes instead of simultaneously five WEDM axes for traditional ball end mills. Then, micro PCD ball end mills are fabricated and the radius variation follows in ±2.0 µm, which is more accurate than commercially available ones. Finally, the 3D freeform geometry milling on tungsten carbide (WC) and silicon wafer successfully demonstrated the possibility of micro-mechanical freeform machining by the developed micro ball end mill

  6. Ball-milled Li7MnN4: An attractive negative electrode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    The high rate performance of ball-milled Li7MnN4 as negative electrode material in lithium-ion batteries has been investigated at C and 5 C rates. An optimization of ball-milling experimental conditions allows to synthesize this metallic nitride with attractive and improved specific capacity and cycle life compared to the pristine compound. The outstanding finding is its excellent cycle life over 50 cycles with a capacity of 240 mAh g−1 at 1 C rate in the potential range 1.6 V/1 V. Even at 5 C the promoting effect of ball-milling results in a remarkable high and stable capacity of 120 mAh g−1 upon cycling, which compares very well with the behavior achieved for Li4Ti5O12 while the pristine material is practically inactive

  7. Coercivity and superparamagnetic evolution of high energy ball milled (HEBM) bulk CoFe2O4 material

    International Nuclear Information System (INIS)

    Ball milling (BM) of bulk CoFe2O4 powder material carried out in order to study its structural stability and attendant property changes with respect to coercivity enhancements and superparamagnetic behaviors, showed that drastic crystallite size reduction occurred within the first 1 h of ball milling. Crystallite size dropped from 74 nm for the as-received material to a value of 11.6 nm for 600 min of ball milling. Combined X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed crystallite size reduction with corresponding increase in interparticle agglomeration/pores with increasing milling time. The maximum coercivity of 0.46 T and the crystallite size of 15.6 nm were recorded with 20 min, while peak residual strain of 0.0066 mm/mm was for 180 min of BM. Material with peak coercivity value did not have peak residual strain, or minimum crystallite size, thereby suggesting that other structural defects contributed to coercivity enhancement. The saturation magnetization (Ms) value decreased continuously with increasing milling time, while remanence magnetization (Mr) and coercivity decreased with increasing BM time, after an initial increase. Moessbauer spectroscopy (MS) measurements confirmed both particle size distribution and decomposition/disordering of the material together with superparamagnetism as BM time increased. The degree of inversion ranged from 41% to 71.7% at different milled states from Moessbauer spectroscopy. The internal magnetic fields of the Fe sites associated with the tetrahedral and octahedral sites were 507.4 kOe and 492 kOe respectively in the unmilled state, while 484 kOe and 468.5 kOe in the 600 min milled state correspondingly.

  8. High-energy ball milling technique for ZnO nanoparticles as antibacterial material

    Directory of Open Access Journals (Sweden)

    Salah N

    2011-04-01

    Full Text Available Numan Salah1, Sami S Habib1, Zishan H Khan1, Adnan Memic1, Ameer Azam1, Esam Alarfaj2, Nabeel Zahed3, Salim Al-Hamedi31Center of Nanotechnology, King Abdulaziz University, Jeddah; 2Department of Physics, Umm Al Qura University, Makkah Al Mukarramah; 3Department of Biological Science, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: Nanoparticles of zinc oxide (ZnO are increasingly recognized for their utility in biological applications. In this study, the high-energy ball milling (HEBM technique was used to produce nanoparticles of ZnO from its microcrystalline powder. Four samples were ball milled for 2, 10, 20, and 50 hours, respectively. The structural and optical modifications induced in the 'as synthesized' nanomaterials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscope (TEM, and photoluminescence emission spectra (PL. SEM and TEM results show a gradual decrease in particle size from around 600 to ~30 nm, with increased milling time. The initial microstructures had random shapes, while the final shape became quite spherical. XRD analysis showed ZnO in a hexagonal structure, broadening in the diffracted peaks and going from larger to smaller particles along with a relaxation in the lattice constant c. The value of c was found to increase from 5.204 to 5.217 Å with a decrease in particle size (600 to ~30 nm. PL result showed a new band at around 365 nm, whose intensity is found to increase as the particles size decreases. These remarkable structural and optical modifications induced in ZnO nanoparticles might prove useful for various applications. The increase in c value is an important factor for increasing the antibacterial effects of ZnO, suggesting that the HEBM technique is quite suitable for producing these nanoparticles for this purpose.Keywords: ZnO nanoparticles, antibacterial, HEBM, SEM, XRD, photoluminescence

  9. Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Li

    2011-05-04

    In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

  10. Preparation and characterization of planetary ball milled Si-based clathrates and their spark plasma sintered materials

    Science.gov (United States)

    Shirataki, R.; Hokazono, M.; Nakabayashi, T.; Anno, H.

    2011-05-01

    Ba8Ga16Si30 clathrate particles ranging in size from several tens nanometers to submicron have been prepared by a planetary ball milling technique, and their sintered materials with microstructures have been prepared by a spark plasma sintering (SPS) technique. Relatively low temperature, short time and high pressure conditions of SPS are needed for the densification without the decomposition and/or the oxidation of clathrate phase. In comparison with Ba8Ga16Si30 prepared by SPS of micro powders, Ba8Ga16Si30 prepared by SPS of pulverized powders shows relatively large Seebeck coefficient about -100 μV/K at middle temperature range, low thermal diffusivity as low as 0.6 mm2/s (RT) and extremely low electrical conductivity of the orders of 0.1 - 1 S/cm (RT), due probably to the increased scattering at the interfaces and pores in the microstructures.

  11. Fabrication and characterization of 900 °C-sintered Ni/Cu/YSZ cermet high temperature electrolysis cathode material prepared by high-energy ball-milling method

    International Nuclear Information System (INIS)

    Highlights: ► Ni/Cu/YSZ cermet cathodes were fabricated by high energy ball-milling and sintering. ► Electrical conductivity and microstructure of the cermet cathode were investigated. ► Fabrication of the cermets showed a good prospect for HTE cathode material. - Abstract: Ni/Cu/YSZ cermet (volume ratio of Ni:Cu:YSZ = 40:20:40) is more electronically conductive than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of nickel, copper, and YSZ powders, pressing into pellets (Ø 10 mm × 1 mm) and subsequent sintering process at 900 °C under flowing 5%-H2/Ar gas. The Ni/Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as SEM, XRD, and laser diffraction and scattering method. Electrical conductivity of sintered Ni/Cu/YSZ cermet pellets fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermet. The effect of ball-milling time on electrical conductivity and microstructure of Ni/Cu/YSZ cermets for HTE was investigated. The particle size of Ni/Cu/YSZ decreased while electrical conductivity increased with milling time: enhanced electrical conductivity is attributed to well-connected Ni/Cu/YSZ particles rendered by increased ball-milling time.

  12. Multifractal properties of ball milling dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Budroni, M. A., E-mail: mabudroni@uniss.it; Pilosu, V.; Rustici, M. [Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via Vienna 2, Sassari 07100 (Italy); Delogu, F. [Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Università degli Studi di Cagliari, via Marengo 2, Cagliari 09123 (Italy)

    2014-06-15

    This work focuses on the dynamics of a ball inside the reactor of a ball mill. We show that the distribution of collisions at the reactor walls exhibits multifractal properties in a wide region of the parameter space defining the geometrical characteristics of the reactor and the collision elasticity. This feature points to the presence of restricted self-organized zones of the reactor walls where the ball preferentially collides and the mechanical energy is mainly dissipated.

  13. High performance amorphous-Si@SiOx/C composite anode materials for Li-ion batteries derived from ball-milling and in situ carbonization

    Science.gov (United States)

    Wang, Dingsheng; Gao, Mingxia; Pan, Hongge; Wang, Junhua; Liu, Yongfeng

    2014-06-01

    Amorphous-Si@SiOx/C composites with amorphous Si particles as core and coated with a double layer of SiOx and carbon are prepared by ball-milling crystal micron-sized silicon powders and carbonization of the citric acid intruded in the ball-milled Si. Different ratios of Si to citric acid are used in order to optimize the electrochemical performance. It is found that SiOx exists naturally at the surfaces of raw Si particles and its content increases to ca. 24 wt.% after ball-milling. With an optimized Si to citric acid weight ratio of 1/2.5, corresponding to 8.4 wt.% C in the composite, a thin carbon layer is coated on the surfaces of a-Si@SiOx particles, moreover, floc-like carbon also forms and connects the carbon coated a-Si@SiOx particles. The composite provides a capacity of 1450 mA h g-1 after 100 cycles at a current density of 100 mA g1, and a capacity of 1230 mA h g-1 after 100 cycles at 500 mA g1 as anode material for lithium-ion batteries. Effects of ball-milling and the addition of citric acid on the microstructure and electrochemical properties of the composites are revealed and the mechanism of the improvement in electrochemical properties is discussed.

  14. Effects of Raw Material Content on Efficiency of TiN Synthesized by Reactive Ball Milling Ti and Urea

    International Nuclear Information System (INIS)

    Ti and urea mixed according to the molar ratios of 2:1, 3:1 and 4:1 are milled under the same condition. The structures of the as-synthesized powders are analyzed by an x-ray diffractometer (XRD). The decomposed temperature of the urea and the products decomposed are characterized by differential scanning calorimetry (DSC) and thermogravimetry analysis-Fourier transform infrared (TG-FTIR) spectrometry. The results show that the reaction progress is a diffusion reaction. The efficiency of TiN synthesized by reactive ball milling can be increased by increasing the content of Ti. The reactive ball milling time decreases from more than 90 h to 40 h corresponding to the content ratio between Ti and urea increasing from 2:1 to 4:1. Ammonia gas (NH3) and cyanic acid (HNCO), the decomposed products of urea, react with the refined Ti to form TiN. The grain refinement of Ti has a significant effect on the efficiency of reactive ball milling. (cross-disciplinary physics and related areas of science and technology)

  15. Preparation and Characterization of Nano structured Materials from Fly Ash: A Waste from Thermal Power Stations, by High Energy Ball Milling

    Directory of Open Access Journals (Sweden)

    Manna I

    2007-01-01

    Full Text Available AbstractThe Class F fly ash has been subjected to high energy ball milling and has been converted into nanostructured material. The nano structured fly ash has been characterized for its particle size by using particle size analyzer, specific surface area with the help of BET surface area apparatus, structure by X-ray diffraction studies and FTIR, SEM and TEM have been used to study particle aggregation and shape of the particles. On ball milling, the particle size got reduced from 60 μm to 148 nm by 405 times and the surface area increased from 0.249 m2/gm to 25.53 m2/gm i.e. by more than 100%. Measurement of surface free energy as well as work of adhesion found that it increased with increased duration of ball milling. The crystallite was reduced from 36.22 nm to 23.01 nm for quartz and from 33.72 nm to 16.38 nm for mullite during ball milling to 60 h. % crystallinity reduced from 35% to 16% during 60 h of ball milling because of destruction of quartz and hematite crystals and the nano structured fly ash is found to be more amorphous. Surface of the nano structured fly ash has become more active as is evident from the FTIR studies. Morphological studies revealed that the surface of the nano structured fly ash is more uneven and rough and shape is irregular, as compared to fresh fly ash which are mostly spherical in shape.

  16. Suppressing Heavy Metal Leaching through Ball Milling of Fly Ash

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    Zhiliang Chen

    2016-07-01

    Full Text Available Ball milling is investigated as a method of reducing the leaching concentration (often termed stablilization of heavy metals in municipal solid waste incineration (MSWI fly ash. Three heavy metals (Cu, Cr, Pb loose much of their solubility in leachate by treating fly ash in a planetary ball mill, in which collisions between balls and fly ash drive various physical processes, as well as chemical reactions. The efficiency of stabilization is evaluated by analysing heavy metals in the leachable fraction from treated fly ash. Ball milling reduces the leaching concentration of Cu, Cr, and Pb, and water washing effectively promotes stabilization efficiency by removing soluble salts. Size distribution and morphology of particles were analysed by laser particle diameter analysis and scanning electron microscopy. X-ray diffraction analysis reveals significant reduction of the crystallinity of fly ash by milling. Fly ash particles can be activated through this ball milling, leading to a significant decrease in particle size, a rise in its BET-surface, and turning basic crystals therein into amorphous structures. The dissolution rate of acid buffering materials present in activated particles is enhanced, resulting in a rising pH value of the leachate, reducing the leaching out of some heavy metals.

  17. Transport in rotary drums and ball mills

    International Nuclear Information System (INIS)

    This report contains investigations into the influence exerted by operating conditions, material properties and geometry of the apparatus and of the discharge plate on the transport behaviour of narrow quartz sand fractions in a model apparatus. The transport coefficients are determined in residence time experiments with Na-24-labelling. The dependence obtained between the transport coefficients and the experimental parameters permits a coherent interpretation if the assumption is made that the two types of transport occur in different phases of radial motion: Convection takes place during ascend while axial dispersion is generated in the falling and ranging process. Furthermore, a model has been developed for evaluating the throughput of rotary drums and ball mills, respectively; it is based on the assumption that the throughput is governed by the material flux through the discharge plate. The efflux takes place only in the ascending zone as a result of gravity and centrifugal forces acting parallel to the discharge plate. A deduced relationship describing the material flow through the discharge apertures in connection with the calculable zone of ascend leads to an expression allowing to determine the mass flow rate as a function of material properties, operating conditions and geometry of the discharge plate. A comparison between experimental and calculated data shows good agreement. (orig.)

  18. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  19. Preparation of tungsten-iron carbide by ball milling

    International Nuclear Information System (INIS)

    Several sets of elemental powder mixtures of Fe-W-C (W46Fe46C8, W60Fe20C20 and W34Fe33C33) were ball milled using Uni-Ball mill for periods of up to 550 h in vacuum with a ball - to - powder ratio of about 35:1. Depending on the milling time, the main component of the as-milled materials was found to be solid solutions of Fe-W-C or Fe-C. Ternary phase W3Fe3C was obtained on annealing the as-milled materials at about 700 deg C. This product was then found to transfer to (FeW)6C on heat treatment at about 800 deg C. The resultant products of the annealing processes were found to depend not only on the annealing temperature, but also the starting composition, especially the initial carbon concentration. Detailed information on the structural and phase evolution during thermal treatment as measured using x-ray diffraction, Moessbauer spectroscopy and thermal analysis is presented. Special interest is focused on the competition for formation in this system between the Fe-C, W-Fe and W-C phases

  20. Reduced graphene oxide synthesis by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, O. [Department of Physics, M.U.C Women' s College, Burdwan 713104 (India); Mitra, S. [MLS Prof' s Unit, Indian Association for the Cultivation of Science, Kolkata 700032 (India); Pal, M. [CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Datta, A. [University School of Basic and Applied Science (USBAS), Guru Gobind Singh Indraprastha University, New Delhi 110075 (India); Dhara, S. [Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Chakravorty, D., E-mail: mlsdc@iacs.res.in [MLS Prof' s Unit, Indian Association for the Cultivation of Science, Kolkata 700032 (India)

    2015-07-01

    Graphene oxide is transformed to reduced graphene oxide by high energy ball milling in inert atmosphere. The process of ball milling introduces defects and removes oxygen functional groups, thereby creating the possibility of fine tuning the band gap of all intermediate stages of the structural evolution. A limit of the backbone sp{sup 2} network structure has been found which should be able to accommodate defects, before amorphization sets in. The amorphization of graphene oxide is achieved rather quickly in comparison to that of graphite. From thermogravimetric and differential scanning calorimetric analysis along with Fourier transform infrared (FTIR) and Raman spectroscopic studies, it is found that the number of oxygen-containing groups decreases at a faster rate than that of aromatic double bonds with increasing ball milling time with a maximum limit of 3 h. Several characterization techniques (FTIR, Raman, UV–Visible and X-ray photoelectron spectroscopy) have confirmed that the material synthesized is, indeed, reduced graphene oxide. - Highlights: • Graphene oxide is transformed to reduced graphene oxide by high energy ball milling in inert atmosphere. • Fine tuning the band gap by introducing defects and removing oxygen functional groups. • Introduction of excess defects leads to amorphization. • Photoluminescence has been observed in the UV-blue region.

  1. Reduced graphene oxide synthesis by high energy ball milling

    International Nuclear Information System (INIS)

    Graphene oxide is transformed to reduced graphene oxide by high energy ball milling in inert atmosphere. The process of ball milling introduces defects and removes oxygen functional groups, thereby creating the possibility of fine tuning the band gap of all intermediate stages of the structural evolution. A limit of the backbone sp2 network structure has been found which should be able to accommodate defects, before amorphization sets in. The amorphization of graphene oxide is achieved rather quickly in comparison to that of graphite. From thermogravimetric and differential scanning calorimetric analysis along with Fourier transform infrared (FTIR) and Raman spectroscopic studies, it is found that the number of oxygen-containing groups decreases at a faster rate than that of aromatic double bonds with increasing ball milling time with a maximum limit of 3 h. Several characterization techniques (FTIR, Raman, UV–Visible and X-ray photoelectron spectroscopy) have confirmed that the material synthesized is, indeed, reduced graphene oxide. - Highlights: • Graphene oxide is transformed to reduced graphene oxide by high energy ball milling in inert atmosphere. • Fine tuning the band gap by introducing defects and removing oxygen functional groups. • Introduction of excess defects leads to amorphization. • Photoluminescence has been observed in the UV-blue region

  2. SnSe/carbon nanocomposite synthesized by high energy ball milling as an anode material for sodium-ion and lithium-ion batteries

    International Nuclear Information System (INIS)

    Graphical abstract: A homogeneous nanocomposite of SnSe and carbon black was synthesised by high energy ball milling and empolyed as an anode material for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). The nanocomposite anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Highlights: • A homogeneous nanocomposite of SnSe and carbon black was fabricated by high energy ball milling. • SnSe and carbon black are homogeneously mixed at the nanoscale level. • The SnSe/C anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Abstract: A homogeneous nanocomposite of SnSe and carbon black, denoted as SnSe/C nanocomposite, was fabricated by high energy ball milling and empolyed as a high performance anode material for both sodium-ion batteries and lithium-ion batteries. The X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy observations confirmed that SnSe in SnSe/C nanocomposite was homogeneously distributed within carbon black. The nanocomposite anode exhibited enhanced electrochemical performances including a high capacity, long cycling behavior and good rate performance in both sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). In SIBs, an initial capacitiy of 748.5 mAh g−1 was obtained and was maintained well on cycling (324.9 mAh g−1 at a high current density of 500 mA g−1 in the 200 th cycle) with 72.5% retention of second cycle capacity (447.7 mAh g−1). In LIBs, high initial capacities of approximately 1097.6 mAh g−1 was obtained, and this reduced to 633.1 mAh g−1 after 100 cycles at 500 mA g−1

  3. Fabrication and characterization of Cu/YSZ cermet high temperature electrolysis cathode material prepared by high-energy ball-milling method

    International Nuclear Information System (INIS)

    Cu/YSZ cermet (40 and 60 vol.% Cu powder with balance YSZ) is a more economical cathode material than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of Cu and YSZ powders, pressing into pellets (o 13 mm x 2 mm) and subsequent sintering process at 700 deg. C under flowing 5%-H2/Ar gas. The Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as XRD, SEM, and laser diffraction and scattering method. Electrical conductivity of sintered Cu/YSZ cermet pellets thus fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermets. The effect of composite composition on the electrical conductivity was investigated and a marked increase in electrical conductivity for copper contents greater than 40 vol.% in the composite was explained by percolation threshold. Also, Cu/YSZ cermet was selected as a candidate for HTE cathode of self-supporting planar unit cell and its electrochemical performance was investigated, paving the way for preliminary correlation of high-energy ball-milling parameters with observed physical and electrochemical performance of Cu/YSZ cermets

  4. Energy efficiency definition of a grinding process in a ball mill

    OpenAIRE

    Кузнецова, Мария Максимовна; Ведь, Валерий Евгеньевич; Вамболь, Сергей Александрович

    2014-01-01

    Theoretical, analytical and experimental studies of the solid materials grinding process in the ball mill have shown that it is possible to improve the energy efficiency of the grinding process by implementing the direct blow effect, ensuring rational grinding mode and correlation of destructive loads during dispersion of specific material with the prescribed physical and mechanical properties. A phenomenological model of energy efficiency of grinding solid materials in the ball mill was deve...

  5. Effect of high-energy ball milling in the structural and textural properties of kaolinite

    Directory of Open Access Journals (Sweden)

    E. C. Leonel

    2014-06-01

    Full Text Available Through the process of high-energy ball milling it is possible to obtain solid materials with higher surface area and different particle sizes. These characteristics are very important for some application such as adsorption. Besides, applications of some clays depend on the functionalization which, for kaolinite, takes place in the aluminol groups. Modification in the structural and textural properties of kaolinite by high-energy milling can improve functionalization of kaolinite due to the exposure of aluminol groups. In this work studies were done on the influence of high-energy ball milling on the morphological properties of kaolinite, taking into account parameters such as filling of the miller, number of balls and amount of mass to be milled. Moreover, studies involving milling kinetics of purified kaolinite were carried out to verify modification in the morphology of kaolinite with milling time.

  6. Effect of ball-milling duration and dehydrogenation on the morphology, microstructure and catalyst dispersion in Ni-catalyzed MgH2 hydrogen storage materials

    International Nuclear Information System (INIS)

    The effects of high-energy ball-milling on catalyst morphology and dispersion as a function of milling duration and on hydrogen desorption were investigated. Samples of MgH2 doped with 0.05 Ni catalyst were examined after 1, 5 and 10 h of milling. Longer milling durations produced finer catalyst particle sizes and more uniform dispersions, but yielded higher hydrogen desorption temperatures. This behavior is attributed to the formation of Mg2NiH4 with increased milling times. Electron tomography was used to show that the Ni particles reside both inside and outside the MgH2 particles. On dehydrogenation there was a redistribution of catalyst and continued formation of Mg2Ni. The formation of this phase is proposed to explain the reported degradation of hydrogen capacity and the change in kinetics of this system with cycling

  7. Microstructure Evolution of Ti/BN Powder Blend during Ball Milling and Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    Jianlin LI; Keao HU; Yong ZHONG

    2001-01-01

    Ball milled Ti/BN composite powder was prepared by high energy ball milling for 40 h, using Ti and BN (the molar ratio of Ti/BN is 3:2) as starting materials. The as-milled composite powder consists of TiN, Ti and amorphous phase. TiN formed while the milled powder was annealed at 400℃. The heat treatment at 700℃ led to the formation of TiB2 and TiB. The nanocrystalline Ti and amorphous phase converted to TiN and TiB2 when the powder was heated to 1300℃.

  8. Formation of surface coating on milling balls during milling of Cr powders

    Institute of Scientific and Technical Information of China (English)

    王成国; 齐宝森; 王瑞华

    2002-01-01

    The formation regularity of surface coating on milling balls during milling of Cr powders was investigated, revealing that the plastic deformation of the balls surface plays an important role in the formation of coating and that the stronger affinity between the powders and the balls is a necessary pre-condition for the coating. The size of Cr powders, the coating thickness and the microhardness vary consistently with milling time during milling. At initial milling stage, the powder size decreases, while the coating thickness and the microhardness increase, however, after milling for 24h, they all change slightly with prolonged milling, indicating a dynamic equilibrium between the powders cold welding and crashing, i.e. an almost equal rate for the powders attaching to and breaking off the milling balls.

  9. The effect of intermediate stop and ball size in fabrication of recycled steel powder using ball milling from machining steel chips

    International Nuclear Information System (INIS)

    A feasibility study for producing recycled steel powder from steel scrap by ball milling was carried out. Steel scrap from machining was used as a raw material and was milled using planetary ball milling. Three samples were prepared in order to study the effect of intermediate stop and ball size. Sample with intermediate stop during milling process showed finer particle size compared to the sample with continuous milling. Decrease in the temperature of the vial during the intermediate stop milling gives less ductile behaviour to the steel powder, which is then easily work-hardened and fragmented to fine powder. Mixed small and big size ball give the best production of recycled steel powder where it gives higher impact force to the scrap and accelerate the fragmentation of the steel scrap into powder. (author)

  10. Fabrication and characterization of Cu/YSZ cermet high-temperature electrolysis cathode material prepared by high-energy ball-milling method

    International Nuclear Information System (INIS)

    Cu/YSZ composites (40 and 60 vol.% Cu powder with balance YSZ) was successfully fabricated by high-energy ball-milling of Cu and YSZ powders at 400 rpm for 24 h, pressing into pellets (O 13 mm x 2 mm) and subsequent sintering process at 900 deg. C under flowing 5%-H2/Ar gas for use as cermet cathode material of high-temperature electrolysis (HTE) of water vapor in a more economical way compared with conventional Ni/YSZ cermet cathode material. The Cu/YSZ composite powders thus synthesized and sintered were characterized using various analytical tools such as XRD, SEM, and laser diffraction and scattering method. Electrical conductivity of sintered Cu/YSZ cermet pellets thus fabricated was measured using 4-probe technique and compared with that of Ni/YSZ cermets. The effect of composites composition on the electrical conductivity was investigated and marked increase in electrical conductivity for copper contents greater than 40 vol.% in the composite was explained by percolation threshold

  11. THEORETICAL AND EXPERIMENTAL STUDIES OF ENERGY-EFFICIENT GRINDING PROCESS OF CEMENT CLINKER IN A BALL MILL

    Directory of Open Access Journals (Sweden)

    Kuznetsova M.M.

    2014-08-01

    Full Text Available The article presents results of theoretical and experimental research of grinding process of bulk materials in a ball mill. The new method of determination of energy efficiently mode of operation of ball mills in a process of a cement clinker grinding is proposed and experimentally tested.

  12. Contribution to the physics of high energy ball milling

    International Nuclear Information System (INIS)

    We have characterized the parameters which control the stability of amorphous phases under ball milling on the model alloys (NixZry). We have improved a vibrating frame grinder to perform experiments at several controlled temperatures under static vacuum. Based on analyzing the movement of the milling ball, we have evaluated the frequency of impact (f) and the relative velocity of the ball at the time impact (Vmax) for different vibration amplitudes of the frame. The kinetic of amorphization by ball milling, studied by x-ray diffraction and transmission electron microscopy, shows that: - a fully amorphous phase is obtained provided that the 'specific milling intensity' is larger than a threshold value. The specific milling intensity is defined as the impact momentum times the impact frequency divided by the mass of powder (MbVmaxf/Mp): Mp, Mb are the mass of the ball and the powder). The threshold is composition and temperature dependent; - below the amorphization threshold, a two-phase microstructure (crystalline phase imbedded in an amorphous cement) is stabilized. The alloy achieves a steady state fraction of amorphous phase, which increases with the milling intensity and decreases with increasing the milling temperature. A study of the mechanical alloying of NbTiAl2 starting from elemental powders is also presented. (Author). refs., figs., tabs

  13. Mechanically enhanced p- and n-type Bi2Te3-based thermoelectric materials reprocessed from commercial ingots by ball milling and spark plasma sintering

    International Nuclear Information System (INIS)

    Highlights: • Comparing TE properties of ingots and sintered materials with the same sources. • BM and SPS showed different effects on p- and n-type Bi2Te3 based materials. • BM and SPS changed carrier concentration and mobility in n-type Bi2(Se,Te)3. • Mechanical strength improved greatly for both types after BM and SPS. - Abstract: Ball milling (BM) combined with spark plasma sintering (SPS) is increasingly used for fabricating high-performance thermoelectric materials. This work was conducted to clarify the effects of BM and SPS on the electrical transport and thermoelectric properties of both p- and n-type Bi2Te3 based materials using commercially available p-type (Bi,Sb)2Te3 and n-type Bi2(Se,Te)3 ingots. Interestingly, it is found that BM and SPS differently affected the electrical properties of p- and n-type Bi2Te3-based thermoelectric materials; the dimensionless thermoelectric figure of merit (ZT) increases in p-type Bi0.5Sb1.5Te3 but decreases somewhat in n-type Bi2Te2.7Se0.3 after BM and SPS. Hall experiments reveal the reason for this difference. Both p-type and n-type sintered materials show 2–3 times higher mechanical strength than the ingots because of microstructure refinement effect, which has been measured by using a small-sized biaxial bending test. The improved mechanical properties are in favor for device fabrication

  14. Effects of magnetic field heat treatment on Sm–Co/α-Fe nanocomposite permanent magnetic materials prepared by high energy ball milling

    International Nuclear Information System (INIS)

    Effects of magnetic field heat treatment on the structure and magnetic properties of Sm–Co/α-Fe nanocomposite permanent magnetic materials fabricated by high energy ball milling are investigated in the present work. After a magnetic field heat treatment below 700 °C on as-milled amorphous Sm–Co/α-Fe samples, the nanocomposite magnets with strong hard and soft magnetic interaction, showing a hysteresis loop of single phase characteristic, are obtained. The coercivity increases with the increase of annealing temperature. The coercivity, remanence and remanence ratio of the Sm–Co/Fe nanocomposite magnets are all enhanced after a heat treatment at a magnetic field as compared with those of nanocomposite magnets heat treated without a magnetic field. X ray diffraction analysis shows that the diffusion between the Sm–Co hard and α-Fe soft phases is suppressed by the magnetic field applied during the heat treatment process, leading to the inhibition of the grain growth of nanocrystal Sm–Co and α-Fe phases, and a finer nanostructure is obtained. Thus, a higher coercivity, remanence and remanence ratio are realized in Sm–Co/α-Fe nanocomposite magnets after the magnetic field heat treatment. Magnetic field heat treatment also makes the direction of c axis of Sm–Co hard grains along the heat treatment magnetic field direction, leading to an enhancement of magnetic anisotropy of the Sm–Co/Fe nanocomposite magnets. - Highlights: • Effects of magnetic field heat treatment on SmCo5/Fe magnets were investigated. • Magnetic properties are improved obviously after magnetic field heat treatment. • The reasons for the improvement of magnetic properties were discussed. • The results are significant for fabrication of anisotropic nanocomposite magnets

  15. Effects of magnetic field heat treatment on Sm–Co/α-Fe nanocomposite permanent magnetic materials prepared by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yanfeng [Faculty of Science, Ningbo University, Ningbo 315211 (China); Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Su, Hao [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhu, Yuejin [Faculty of Science, Ningbo University, Ningbo 315211 (China); Wang, Fang [School of Materials Science and Engineering, NingBo University of Technology, Ningbo, Zhe Jiang Province (China); Du, Juan; Xia, Weixing; Yan, Aru; Liu, J. Ping [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhang, Jian, E-mail: zhangj@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-10-25

    Effects of magnetic field heat treatment on the structure and magnetic properties of Sm–Co/α-Fe nanocomposite permanent magnetic materials fabricated by high energy ball milling are investigated in the present work. After a magnetic field heat treatment below 700 °C on as-milled amorphous Sm–Co/α-Fe samples, the nanocomposite magnets with strong hard and soft magnetic interaction, showing a hysteresis loop of single phase characteristic, are obtained. The coercivity increases with the increase of annealing temperature. The coercivity, remanence and remanence ratio of the Sm–Co/Fe nanocomposite magnets are all enhanced after a heat treatment at a magnetic field as compared with those of nanocomposite magnets heat treated without a magnetic field. X ray diffraction analysis shows that the diffusion between the Sm–Co hard and α-Fe soft phases is suppressed by the magnetic field applied during the heat treatment process, leading to the inhibition of the grain growth of nanocrystal Sm–Co and α-Fe phases, and a finer nanostructure is obtained. Thus, a higher coercivity, remanence and remanence ratio are realized in Sm–Co/α-Fe nanocomposite magnets after the magnetic field heat treatment. Magnetic field heat treatment also makes the direction of c axis of Sm–Co hard grains along the heat treatment magnetic field direction, leading to an enhancement of magnetic anisotropy of the Sm–Co/Fe nanocomposite magnets. - Highlights: • Effects of magnetic field heat treatment on SmCo{sub 5}/Fe magnets were investigated. • Magnetic properties are improved obviously after magnetic field heat treatment. • The reasons for the improvement of magnetic properties were discussed. • The results are significant for fabrication of anisotropic nanocomposite magnets.

  16. Ball milling of chalcopyrite: Moessbauer spectroscopy and XRD studies

    International Nuclear Information System (INIS)

    The aim of this project is to study the behavior of chalcopyrite under ball milling for extended periods in order to determine how it's decompose or transform. Tests were done with chalcopyrite mixed with iron and zinc with and without surfactant. The use of surfactants has various effects such as avoiding oxidation and clustering of the fine particles. In all case magnetic chalcopyrite is transformed into a paramagnetic component showing a disordered structure, thus revealing that Cu atoms have replaced Fe atoms. In the case of ball milling in air, chalcopyrite is decomposed with the lost of iron, while in milling under surfactants, iron enters into the chalcopyrite structure. (author)

  17. Preparation of magnesium ferrite nanoparticles by ultrasonic wave-assisted aqueous solution ball milling.

    Science.gov (United States)

    Chen, Ding; Li, Dian-yi; Zhang, Ying-zhe; Kang, Zhi-tao

    2013-11-01

    Magnesium ferrite, MgFe2O4 nanoparticles with high saturation magnetization were successfully synthesized using ultrasonic wave-assisted ball milling. In this study, the raw materials were 4MgCO3·Mg(OH)2·5H2O and Fe2O3 powders and the grinding media was stainless steel ball. The average particle diameter of the product MgFe2O4 powders was 20 nm and the saturation magnetization of them reached 54.8 emu/g. The different results of aqueous solution ball milling with and without ultrasonic wave revealed that it was the coupling effect of ultrasonic wave and mechanical force that played an important role during the synthesis of MgFe2O4. In addition, the effect of the frequency of the ultrasonic wave on the ball milling process was investigated. PMID:23622867

  18. Reasonable Ball Size of Ball Mill for Preparing Coal Water Fuel and Forecasting Productive Capacity

    Institute of Scientific and Technical Information of China (English)

    张荣曾; 刘炯天; 徐志强; 郑明

    2002-01-01

    By using the matrix theory, a 5-parameter grinding mathema tical model is established. Based on the properties of feed coal and requirement s for size distribution of final product, the model gives the required grinding probability for various particles and corresponding ball size distribution. By u sing this model, 3 different sizes of ball mill are designed and put into commer cial use for coal water fuel. The forecasted ball mill capacity, the particle si zes and particle size distribution as well as the coal water fuel quality parame ters are all in line with industrial operation results, which have proved the su itability of the model.

  19. Preparation of Sn-Si-C Composite as Li-ion Battery Anode Material by High Energy Ball Milling and Its Properties

    Institute of Scientific and Technical Information of China (English)

    LI Yan-hong; LIU Yuan; QIUXin-ping

    2011-01-01

    Electrochemically active Sn-Si-C composite was synthesized by high energy ball milling (HEBM) in Ar atmosphere.The so-obtained composite was characterized by X-ray diffraction and field emission scanning electron microscopy. Lithium insertion/extraction characteristics of the composites were examined by constant current charge-discharge and cyclic voltammetry methods.The results show that there is no new alloy generated by HEBM.The composite synthesized by two-step HEBM resulted in initial lithium insertion specific capacity as high as 1224 mA.h/g and higher reversible lithium extraction specific capacity of 855 mA.h/g.

  20. Influence of process variables of ball milling and hot pressing on the thermoelectric performance of type I clathrates

    International Nuclear Information System (INIS)

    Full text: To achieve a high thermoelectric performance, materials with a low lattice thermal conductivity are needed. One promising method to reduce the lattice thermal conductivity is to use nanostructured materials. In this study, we prepare nanopowders of type I clathrates by the ball milling technique, and compact them by hot pressing. The relation between the process variables for ball milling and hot pressing, the microstructures and thermoelectric properties of the final hot pressed samples will be presented. (author)

  1. Ceramic and metal-ceramic nanostructures obtained by reactive ball milling

    OpenAIRE

    Secondi, J; R. Yavari

    1993-01-01

    We review ceramic and metal-ceramic nanostructures obtained by ball milling. We then report on the formation of titanium nitride by ball milling elemental titanium powder under nitrogen gas and on TiN-copper nanocomposites produced by ball milling a CuTi alloy under N2 gas.

  2. Formation of ball-milled Fe-Mo nanostructured powders

    Energy Technology Data Exchange (ETDEWEB)

    Moumeni, H. [Laboratoire de Magnetisme et de Spectroscopie des Solides, LM2S, Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, 23000 Annaba-Algerie (Algeria) and Departement de Physique, Faculte des Sciences et de l' Ingenierie, Universite de Guelma, B.P. 401, 24000 Guelma-Algerie (Algeria)]. E-mail: hmoumeni@yahoo.fr; Alleg, S. [Laboratoire de Magnetisme et de Spectroscopie des Solides, LM2S, Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, 23000 Annaba-Algerie (Algeria); Greneche, J.M. [Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, Faculte des Sciences, F-72085, Le Mans Cedex 9 (France)

    2006-08-10

    Nanostructured Fe-6 wt.%Mo powders were prepared by mechanical alloying in a high-energy planetary ball-mill. The structural changes and the kinetics of Mo dissolution were studied by using X-ray diffraction. The crystallite size reduction down to about 11 nm is accompanied by the introduction of internal strains up to 1.1% (root-mean square strain, rms). After 24 h of milling, a bcc Fe(Mo) solid solution is formed. The kinetics of Mo dissolution into the Fe matrix during the milling process can be described by two regimes characterized by small values of Avrami parameter which do not exceed unit.

  3. Thermal behaviour of amorphous zircon prepared by ball milling

    International Nuclear Information System (INIS)

    Results are presented on the recrystallisation behaviour of the mineral zircon (ZrSiO4) which has been amorphised by ball milling. X-ray diffraction and thermal analysis techniques were used to investigate the structural evolution after mechanical treatment. Phase transformations detected by the differential thermal analysis technique included transient formation of tetragonal or pseudo cubic ZrO2, followed by recrystallisation of zircon at reduced temperatures of around 1000 C. The behaviour of the milled samples was compared to literature data concerning amorphous zircon prepared by other techniques, including natural and ion beam radiation damage and sol-gel processing. The ball milled zircon was found to have similar thermal behaviour, but had a structural recovery temperature 180-600 C lower than that found for other amorphous samples. (orig.)

  4. Fabrication and microstructure of nanostructured Mg-3Ni-2MnO_2 by ball milling in hydrogen atmosphere

    Institute of Scientific and Technical Information of China (English)

    FANG Wen-bin; FANG Wa; SUN Hong-fei; YU Zhen-xing

    2009-01-01

    Nanostructured Mg-3Ni-2MnO_2 was synthesized by ball milling elemental powders of Mg, Ni and MnO_2 in hydrogen atmosphere. The microstructures of the powder prepared at different milling time were analyzed by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and high resolution electron microscopy(HREM). The milling time is the most key parameter impacting on the grain size and the microstructure of material. With prolonging the milling time, particle size becomes smaller and smaller. But after the ball milling time reaches about 20 h, reduction of grain size becomes slowly. When the milling time is more than 50 h, nanocrystailine fully forms. When the milling time is more than 80 h, there are more amorphous phases in materials. The average particle diameter of material is about 1 μm and the grain size is 10-30 nm.

  5. Application of mechano-chemical synthesis for protective coating on steel grinding media prior to ball milling of copper

    Indian Academy of Sciences (India)

    Indranil Lahiri; K Balasubramanian

    2007-04-01

    One of the major sources of contamination during mechanical milling/alloying is from the surface erosion of the container and the grinding medium. This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill. Visual observation, XRD, optical micrography and EDS analysis were used to understand the progress of the reaction. Copper was successfully coated on the steel balls and vials. The method can easily be adopted in daily production purposes, prior to mechanical milling of a Cu-based powder for prevention of Fe contamination.

  6. Tetracycline-ferrite nanocomposites formed via high-energy ball milling and the influence of milling conditions.

    Science.gov (United States)

    Branham, Michael Lee; Moyo, Thomas; Abdallah, Hafiz M I; Masina, Patrick

    2013-02-01

    High-energy ball milling was used to mediate the formation of nanocomposites containing tetracycline and magnetic nanoparticles. Tetracycline-HCl was ball milled for 1, 3, 5, 15, and 30 h under argon or air atmosphere with preformed Mg 0.5 Zn 0.5 Fe2O4 nanoferrites prepared by glycolthermal method. The structural, thermal, and magnetic properties of these novel materials and the effect of milling atmosphere on composition, crystallinity and cation distribution were then characterized by ICP-OES, DSC/TGA, XRPD, ATR-IR, UV-Vis and Mössbauer spectroscopy. Tetracycline underwent rapid and consecutive metal coordination events in the milling process to yield complexes characterized by bathochromic shifts in its electronic spectra and suppression of electronic absorbance at 365 nm. Changes in stretching vibrations due to the A-ring carbonyl (1616 cm(-1)), amide II nitrogen (1602 cm(-1)), and CO bond (1039 cm(-1)) indicate Mg-type interactions imposed on the metals. Exothermic oxidation of the drug at 235°C disappeared after 5h milling with the nanoferrites, and the composites formed remained thermostable up to 500°C. Tetracycline-nanoferrites (Tet-NF) are magnetic-ordered materials with a well-defined spinel-type structure. Analysis of the Mössbauer data suggests that the milling time and atmosphere have significant influence on cation distributions in Tet-NF composites. PMID:23085583

  7. Experimental and theoretical study of phase transitions under ball milling

    International Nuclear Information System (INIS)

    The aim of this work was to determine how phase transition s under ball-milling depend on the milling conditions and to find out if one can rationalize such transitions with the theory of driven alloys. We have chosen two phase transitions: the order-disorder transition in Fe Al and the precipitation-dissolution NiGe. In the case of Fe Al we have found that the steady-state long range order parameter achieved under ball milling intensity; moreover the same degree of order is achieved starting from an ordered alloy or a disordered solid solution. On the way to fully disordered state the degree of order either decreases monotonically or goes through a short lived transient state. This behaviour is reminiscent of a first order transition while the equilibrium transition is second order. All the above features are well reproduced by a simple model of driven alloys, which was originally build for alloys under irradiation. The stationary degree of order results of two competitive atomic jump mechanisms: the forced displacements induced by the shearing of the grains, and the thermally activated jumps caused by vacancies migrations. Finally we have performed atomistic simulations with a Monte Carlo kinetic algorithm, which revealed the role of the fluctuations in the intensity of the forcing. Moreover we have shown that specific atomistic mechanisms are active in a dilute NiGe solid solution which might lead to ball milling induced precipitation in under-saturated solid solution. (author)

  8. Ball milling pretreatment of oil palm biomass for enhancing enzymatic hydrolysis.

    Science.gov (United States)

    Zakaria, Mohd Rafein; Fujimoto, Shinji; Hirata, Satoshi; Hassan, Mohd Ali

    2014-08-01

    Oil palm biomass, namely empty fruit bunch and frond fiber, were pretreated using a planetary ball mill. Particle sizes and crystallinity index values of the oil palm biomass were significantly reduced with extended ball mill processing time. The treatment efficiency was evaluated by the generation of glucose, xylose, and total sugar conversion yields from the pretreatment process compared to the amount of sugars from raw materials. Glucose and xylose contents were determined using high-performance liquid chromatography. An increasing trend in glucose and xylose yield as well as total sugar conversion yield was observed with decreasing particle size and crystallinity index. Oil palm frond fiber exhibited the best material yields using ball milling pretreatment with generated glucose, xylose, and total sugar conversion yields of 87.0, 81.6, and 85.4%, respectively. In contrast, oil palm empty fruit bunch afforded glucose and xylose of 70.0 and 82.3%, respectively. The results obtained in this study showed that ball mill-treated oil palm biomass is a suitable pretreatment method for high conversion of glucose and xylose. PMID:24908052

  9. Effects and mechanism of ball milling on torrefaction of pine sawdust.

    Science.gov (United States)

    Gong, Chunxiao; Huang, Jing; Feng, Chen; Wang, Guanghui; Tabil, Lope; Wang, Decheng

    2016-08-01

    The effects and mechanism of ball milling on the torrefaction process were studied. Ball- and hammer-milled (screen size 1mm) pine sawdust samples were torrefied at three temperatures (230, 260, and 290°C) and two durations (30 and 60min) to investigate into their torrefaction behavior and physicochemical properties. The results showed that, under identical torrefaction conditions, torrefied ball-milled pine sawdust had a higher carbon content and fixed carbon, and lower hydrogen and oxygen contents than torrefied hammer-milled pine sawdust. Torrefied ball-milled pine sawdust produced lower mass and energy yields, but higher heating values than torrefied hammer-milled pine sawdust. Ball milling destroyed the crystalline structure of cellulose and thus reduced the thermal stability of hemicellulose, cellulose, and lignin, causing them to degrade at relatively lower temperatures. In conclusion, biomass pretreated with a combination of ball milling and torrefaction has the potential to produce an alternative fuel to coal. PMID:27136611

  10. Microstructure and Physical Properties of Tb2TiO5 Neutron Absorber Synthesized by Ball Milling and Sintering

    Science.gov (United States)

    Huang, Jinghua; Ran, Guang; Liu, Tengjiao; Shen, Qiang; Li, Ning

    2016-08-01

    Tb2TiO5 neutron absorber was synthesized by ball milling and sintering. Microstructure character of ball-milled Tb4O7-17.605%TiO2 (mass fraction, %) powders and sintered bulks was analyzed using XRD, SEM and TEM. The microhardness, coefficient of thermal expansion and thermal conductivity of sintered bulks were measured. The experiment results showed that the nanocrystalline solid solution was obtained during ball milling. After 96 h of ball milling, TiO2 was completely solved in Tb4O7 and the crystal size of Tb4O7 was up to 37 nm. The bulk materials prepared by cold isostatic pressing were sintered at 1300 °C. Tb2TiO5 bulks with an orthorhombic structure were obtained. The microhardness of sintered bulks, as well as the thermal conductivity, increased firstly with increasing ball milling time and then decreased. The coefficient of thermal expansion decreased initially and then increased with increasing ball milling time. For the sintered bulk with powder milled for 48 h, the highest values of both microhardness and thermal conductivity were observed, whereas the lowest coefficient of thermal expansion was exhibited. In addition, with increasing testing temperature, the thermal conductivity of sintered bulks initially fell and then rebounded while an opposite trend was found in the coefficient of thermal expansion.

  11. Synthesis of magnetite nanoparticles by high energy ball milling

    International Nuclear Information System (INIS)

    We report on the preparation of magnetite nanoparticles, with size ranging from 12 nm to 20 nm, by high energy ball milling. The synthesis is made using stoichiometric amounts of distilled water and metallic iron powder. The milled powder samples were analyzed by Mossbauer spectroscopy (MS), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Our results indicate that the milling time is a key parameter of the synthesis. By increasing the milling time one achieves high purity magnetite samples. Also, the particle size decreases with the milling time. The sample milled during 10 h contained a fraction of 56 nm metallic Fe particles and 20 nm magnetite particles. By increasing the milling time to 96 h we have obtained a sample that is mainly composed of 12 nm magnetite particles. MS performed at room temperature showed a spectrum consisting of two sextets with hyperfine parameters related to iron ions occupying octahedral (A) and tetrahedral (B) sites. We have used a self-consistent method to investigate the impact of the dipolar interaction to drive the system to a magnetically blocked regime.

  12. Processing and microstructural characterization of a Ti-Cr-Nb alloy synthesized by high-energy ball-milling

    Directory of Open Access Journals (Sweden)

    José Fernando Ribeiro de Castro

    2012-10-01

    Full Text Available Ti-based body centered cubic (BCC solid solutions are promising materials for hydrogen storage. These alloys are usually synthesized by melting processes and have large amounts of vanadium as alloying element to stabilize the BCC phase at room temperature. In this work high energy ball-milling was evaluated as processing route for a Ti - based BCC solid solution. Moreover, the feasibility of Nb as stabilizer for the BCC phase is also investigated. The results show that the BCC phase is rapidly formed by ball-milling. After 2 hours of milling the alloy is mainly composed by BCC phase. Moreover, the time of milling must be limited in order to minimize the contamination with iron promoted by the wearing of milling balls and vials.

  13. Improvement of the sinterability of thermally-treated UO2 powder by horizontal rotary ball milling

    International Nuclear Information System (INIS)

    A horizontal rotary ball milling has been demonstrated as a useful method in reducing the particle size of ceramic powder in remote operation at shielded hot-cells. Techniques, equipment and operating parameters, such as milling media, media wear and rotor speed were investigated with Al2O3 powder to evaluate its performance prior to contamination with nuclear fuel material. The established operating parameter were then verified with the UO2 powder, which had been produced by a thermal process, to make fuel pellets. Sintering of milled UO2 powder showed the higher sintered densities obtainable by the milling, and the milling process seemed to be an important factor for improving the powder characteristics. (author)

  14. Influence of dry grinding in a ball mill on the length of multiwalled carbon nanotubes and their dispersion and percolation behaviour in melt mixed polycarbonate composites

    OpenAIRE

    Krause, Beate; Villmow, Tobias; Boldt, Regine; Mende, Mandy; Petzold, Gudrun; Pötschke, Petra

    2011-01-01

    Abstract Ball milling of carbon nanotubes (CNTs) in the dry state is a common way to produce tailored CNT materials for composite applications, especially to adjust nanotube lengths. For NanocylTM NC7000 nanotube material before and after milling for 5 and 10 hours the length distributions were quantified using TEM analysis, showing decreases of the mean length to 54 and 35%, respectively. With increasing ball milling time in addition a decrease of agglomerate size and an increase ...

  15. Following mechanical activation of salbutamol sulphate during ball-milling with isothermal calorimetry.

    Science.gov (United States)

    Gaisford, Simon; Dennison, Mansa; Tawfik, Mahmoud; Jones, Matthew D

    2010-06-30

    Formulation of actives for pulmonary delivery with dry powder inhaler devices frequently requires a particle size reduction step. The high-energy forces imparted to a material during milling, as well as reducing particle size, can cause a significant change in physicochemical properties, in particular mechanical activation of the surface (manifested as generation of amorphous regions) which can affect formulated product performance. It is not clear whether particle size reduction occurs prior to, or concomitantly with, generation of amorphous content. In this study the formation of amorphous content with time in crystalline salbutamol sulphate was quantified with isothermal gas perfusion calorimetry as the sample was ball-milled. The data showed that the most particle size reduction occurred initially (d(0.5) dropping from 12.83+/-0.4 to 4.2+/-0.4 within 5 min). During this time period, no detectable amorphous content was observed. Between 5 and 15 min milling time the particle size distribution remained relatively constant but the amorphous content increased non-linearly with time. After 20 min milling time the particle size increased slightly. The data suggest that particle size reduction occurs initially upon application of a force to the crystal. Once maximum particle size reduction has occurred the crystal absorbs the force being applied and the crystal lattice becomes disordered. After extended milling the conditions in the ball mill (heat and/or humidity) may cause crystallisation of some of the amorphous material resulting in particle-particle fusion. It would appear that the ball-milling process could be optimised to achieve the desired particle size distribution but without any loss of crystalline structure. PMID:20385222

  16. Structure and magnetism of SmCo5 nanoflakes prepared by surfactant-assisted ball milling with different ball sizes

    International Nuclear Information System (INIS)

    Anisotropic magnetic SmCo5 nanoflakes have been fabricated by surfactant-assisted ball milling (SABM) using hardened steel balls of one of the following sizes: 4, 6.5, 9.5 and 12.7 mm in diameters. The magnetic properties of SmCo5 particles prepared by SABM with different milling ball sizes in diameters were investigated systematically. It was showed that the nanoflakes milled by amount of small size balls had a higher coercivity and lower anisotropy, i.e., worse grain orientation although in a short milling time while the nanoflakes prepared with same weight of big balls tend to have a lower coercivity, better grain orientation. The coercivity mechanism of the nanoflake was studied and it was mainly dominated with the domain-wall pinning. The SEM analysis shows that the morphology of nanoflakes prepared with different ball sizes are almost the same when the balls to powder weight ratio is fixed. The different magnetic properties caused by different ball sizes are mainly due to the different microstructure changes, i.e, grain refinement and c-axis orientation, which are demonstrated by X-ray diffraction (XRD) analysis and transmission electron microscope (TEM). Based on the experiments above, a combined milling process was suggested and done to improve magnetic properties as your need. - Highlights: • We fabricated anisotropic magnetic SmCo5 nanoflakes by surfactant-assisted ball milling (SABM). • We investigated the magnetic properties of SmCo5 particles systematically. It was showed that the coercivity, high or low, and grain orientation, good or bad, were influenced strongly by balls size. The different magnetisms caused by different ball sizes is mainly due to the different microstructure changes. • The coercivity mechanism of the nanoflake was studied and it was mainly dominated with the domain-wall pinning

  17. Properties of Ultrafine-Grained Tungsten Prepared by Ball Milling and Spark Plasma Sintering

    Czech Academy of Sciences Publication Activity Database

    Vilémová, Monika; Nevrlá, Barbara; Pala, Zdeněk; Kocmanová, Lenka; Janata, Marek; Matějíček, Jiří; Tonarová, Dana

    Vol. 821. Zürich: Trans Tech Publications Inc, 2016 - (Fischer, C.), s. 399-404. (Engineering Mechanics. 821). ISBN 978-3-03835-700-1. ISSN 1660-9336. [Engineering Mechanics 2015, International conference engineering mechanics 2015/21./. Svratka (CZ), 11.05.2015-14.05.2015] R&D Projects: GA ČR(CZ) GA14-12837S Institutional support: RVO:61389021 Keywords : ultrafine-grained tungsten * planetary ball milling * spark plasma sintering Subject RIV: JJ - Other Materials

  18. Ball Milling Assisted Solvent and Catalyst Free Synthesis of Benzimidazoles and Their Derivatives.

    Science.gov (United States)

    El-Sayed, Taghreed H; Aboelnaga, Asmaa; Hagar, Mohamed

    2016-01-01

    Benzoic acid and o-phenylenediamine efficiently reacted under the green solvent-free Ball Milling method. Several reaction parameters were investigated such as rotation frequency; milling balls weight and milling time. The optimum reaction condition was milling with 56.6 g weight of balls at 20 Hz frequency for one hour milling time. The study was extended for synthesis of a series of benzimidazol-2-one or benzimidazol-2-thione using different aldehydes; carboxylic acids; urea; thiourea or ammonium thiocyanate with o-phenylenediamine. Moreover; the alkylation of benzimidazolone or benzimidazolthione using ethyl chloroacetate was also studied. PMID:27563861

  19. Ball Milling Assisted Solvent and Catalyst Free Synthesis of Benzimidazoles and Their Derivatives

    Directory of Open Access Journals (Sweden)

    Taghreed H. EL-Sayed

    2016-08-01

    Full Text Available Benzoic acid and o-phenylenediamine efficiently reacted under the green solvent-free Ball Milling method. Several reaction parameters were investigated such as rotation frequency; milling balls weight and milling time. The optimum reaction condition was milling with 56.6 g weight of balls at 20 Hz frequency for one hour milling time. The study was extended for synthesis of a series of benzimidazol-2-one or benzimidazol-2-thione using different aldehydes; carboxylic acids; urea; thiourea or ammonium thiocyanate with o-phenylenediamine. Moreover; the alkylation of benzimidazolone or benzimidazolthione using ethyl chloroacetate was also studied.

  20. Structural and magnetic properties of ball milled copper ferrite

    DEFF Research Database (Denmark)

    Goya, G.F.; Rechenberg, H.R.; Jiang, Jianzhong

    1998-01-01

    cation redistribution between A and B sites. These nanometer-sized particles show superparamagnetic relaxation effects at room temperature. It is found that the magnetization is not saturated even with an applied field of 9 T, possibly as the result of spin canting in the partially inverted CuFe2O4. The......The structural and magnetic evolution in copper ferrite (CuFe2O4) caused by high-energy ball milling are investigated by x-ray diffraction, Mössbauer spectroscopy, and magnetization measurements. Initially, the milling process reduces the average grain size of CuFe2O4 to about 6 nm and induces...... canted spin configuration is also suggested by the observed reduction in magnetization of particles in the blocked state. Upon increasing the milling time, nanometer-sized CuFe2O4 particles decompose, forming alpha-Fe2O3 and other phases, causing a further decrease of magnetization. After a milling time...

  1. Structure and Microstructure Properties of Ball Milled Fe-Zn

    Directory of Open Access Journals (Sweden)

    Bensalem R.

    2013-09-01

    Full Text Available Nanocrystalline Fe10%Zn and Fe30%Zn alloys have been prepared from pure elemental powders by mechanical alloying processing in a high energy planetary ball-mill. Microstructural, structural, and magnetic characterizations of the powders were investigated by X-ray diffraction, and vibrating sample magnometer. The crystallite size reduction to the nanometer scale is accompanied by an increase in the atomic level strain. The reaction between Fe and Zn leads to the formation of a bcc Fe(Zn solid solution with a lattice parameter close to (0.2912 nm for Fe30%Zn and 0,2885 nm for Fe10%Zn after 5 h of milling. The complete dissolution of the elemental Zn powders in the α-Fe lattice gives rise to the formation of a highly disordered Fe(Zn solid solution, where α-Fe(Zn nanograins have a crystallite size of (229,29 Å for Fe10%Zn (24h 30,09 Å for Fe30%Zn (24h, on prolonged milling time. The coercivity and magnetization values are 18,90 (Fe10%ZnOe and 26,59(Fe30%Zn emu/g, respectively, after 24 h of milling.

  2. Magnetic properties of magnetite prepared by ball-milling of hematite with iron

    International Nuclear Information System (INIS)

    Magnetic properties of magnetite powder prepared by ball-milling of stoichiometric mixture of hematite and iron in an inert atmosphere are reported. Hysteresis loops, isothermal remanence acquisition curves and temperature dependence of magnetic susceptibility measurements are used to characterise this material and to examine the effects of heating in air and in an argon atmosphere. Ball-milling of hematite with iron during periods ranging from 30 min up to almost 5 h yields magnetite which exhibits high magnetic hardness, characterised by coercive force three times higher than that typical for single-domain natural magnetites. However, the magnetite produced is unstable upon heating in air, reoxidising almost completely to hematite. Heating in an argon atmosphere causes enhancement of typical magnetic parameters, but decreases the magnetic hardness

  3. An analytical model for force prediction in ball nose micro milling of inclined surfaces

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2010-01-01

    Ball nose micro milling is a key process for the generation of free form surfaces and inclined surfaces often present in mould inserts for micro replication. This paper presents a new cutting force model for ball nose micro milling that is capable of taking into account the effect of the edge...

  4. A study of the mechanism of microwave-assisted ball milling preparing ZnFe2O4

    Science.gov (United States)

    Zhang, Yingzhe; Wu, Yujiao; Qin, Qingdong; Wang, Fuchun; Chen, Ding

    2016-07-01

    In this paper, well dispersed ZnFe2O4 nano-particles with high magnetization saturation of 82.23 emu/g were first synthesized by microwave assisted ball milling and then the influences of pre-treatments and microwave powers to the progress were studied. It was found that under the both function of crack effect induced by ball milling and rotary motion induced by microwave the synthesized ferrtie nano-particles were well dispersed that is much different from the powders synthesized by normal high energy ball milling. The pre-treatment of ball milling can only enhance the reaction rate in the first several hours but the pre-irradiation of microwave can enhance the hole reaction rate. Further more, it was also been found that with increasing the microwave power, the more raw materials will converted into zinc ferrite in the first 5 h. 5 h latter the microwave power of 720 W is high enough for the coupling effect of microwave and ball milling with stirrer rotation speed of 256 rpm.

  5. Efficient dehalogenation of automobile shredder residue in NaOH/ethylene glycol using a ball mill.

    Science.gov (United States)

    Kameda, Tomohito; Fukuda, Yuuzou; Park, Kye-Sung; Grause, Guido; Yoshioka, Toshiaki

    2009-01-01

    We investigated the effectiveness of sodium hydroxide/ethylene glycol (NaOH/EG) for dehalogenation of automobile shredder residue (ASR) using a ball mill. Efficient dehalogenation was achieved at atmospheric pressure by combining the use of EG (196 degrees C b.p.) as a replacement solvent for NaOH with ball milling, which improved contact between ASR and OH(-) in solution. Moderate NaOH concentrations and increased ball mill rotation speeds produced high dechlorination that was not significantly affected by the weight ratio of ASR to EG. NaOH/EG dechlorination increased with temperature with an apparent activation energy of 50 kJ mol(-1) confirming that the reaction proceeded under chemical reaction control. The modified shrinking-core model was appropriate to explain the dechlorination process. Low chloro levels in our NaOH/EG-treated ASR suggested that this material could be used for feedstock recycling and the wet process may be applicable for dehalogenation of other important waste streams. PMID:18929394

  6. Superconducting properties of MgB2 prepared from attrition ball-milled boron powder

    International Nuclear Information System (INIS)

    We report superconducting properties of the MgB2 pellets prepared from the attrition ball-milled boron, in order to control the grain size of the MgB2 that is formed from it. We observed that the semi-crystalline peaks in the ball-milled boron became broader when the ball-milling time was further increased, indicating that the boron powders had lost their crystalline. In addition, the B2O3 peak was appeared in the ball-milled powders, resulting in an increase in the amount of MgO. However, the sample prepared from boron that was ball milled for 5 h showed an improvement of critical current density (Jc), even with increased MgO phase, under an external magnetic field at 5 K and 20 K.

  7. Structural information on ball milled magnesium hydride from vibrational spectroscopy and ab-initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Schimmel, H.G. [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Johnson, M.R. [Institut Laue-Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Kearley, G.J. [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Ramirez-Cuesta, A.J. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Huot, J. [Institut de recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, 3351 des Forges, PO Box 500, Trois-Rivieres, Que., G9A 5H7 (Canada); Mulder, F.M. [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)]. E-mail: f.m.mulder@iri.tudelft.nl

    2005-05-03

    Ball milled magnesium hydride with an average size of about 40 nm and bulk magnesium hydride have been studied with vibrational spectroscopy together with density functional computer calculations. Using this combination of techniques structural information can now be obtained on a nanometer scale, which is especially important for nanosized samples. Such samples exhibit very broad diffraction lines, from which limited information about the structure can be extracted. It was found that ball milling distorts the vibrational spectra due to distribution in stresses over the sample. Cycling of the hydrogen content of ball milled samples results in the spectrum of unmilled samples, while the particle size remains small and hydrogen storage characteristics continue to be better for ball milled samples. We conclude that improved performance for hydrogen storage applications of ball milled magnesium hydride has to be attributed to the reduction of the particle size, while defect densities inside the particles play less of a role.

  8. Structural information on ball milled magnesium hydride from vibrational spectroscopy and ab-initio calculations

    International Nuclear Information System (INIS)

    Ball milled magnesium hydride with an average size of about 40 nm and bulk magnesium hydride have been studied with vibrational spectroscopy together with density functional computer calculations. Using this combination of techniques structural information can now be obtained on a nanometer scale, which is especially important for nanosized samples. Such samples exhibit very broad diffraction lines, from which limited information about the structure can be extracted. It was found that ball milling distorts the vibrational spectra due to distribution in stresses over the sample. Cycling of the hydrogen content of ball milled samples results in the spectrum of unmilled samples, while the particle size remains small and hydrogen storage characteristics continue to be better for ball milled samples. We conclude that improved performance for hydrogen storage applications of ball milled magnesium hydride has to be attributed to the reduction of the particle size, while defect densities inside the particles play less of a role

  9. Process Parameters Optimization of Silica Sand Nanoparticles Production Using Low Speed Ball Milling Method

    Directory of Open Access Journals (Sweden)

    Zulkhairi Rizlan

    2014-01-01

    Full Text Available Experiments are designed using Taguchi method to find the optimum parameters for silica sand nanoparticles production using low speed ball milling. Orthogonal array and signal-to-noise ratio are applied to study performance characteristics of machining parameters which are the ball to powder weight ratio, volume of milling jar, and rotation speed. Results obtained from signal-to-noise ratio analysis showed that ball to powder weight ratio is the most influential parameter.

  10. Application of planetary ball mill for manufacturing of shielding composite coatings based on polyester powder paints and carbon fillers

    Science.gov (United States)

    Panin, S. V.; Yazykov, S. Yu; Suslyaev, V. I.; Dorozhkin, K. V.

    2015-10-01

    Blend polyester powder paint and particulate carbon filler in the form of colloidal graphite and the carbon black product were investigated. Powder paint and carbon materials were treated together in a planetary ball mill. The data of the structural analysis and transmission coefficients of electromagnetic waves of terahertz range through the flat shape samples are presented.

  11. Response to Thermal Exposure of Ball-Milled Aluminum-Borax Powder Blends

    Science.gov (United States)

    Birol, Yucel

    2013-04-01

    Aluminum-borax powder mixtures were ball milled and heated above 873 K (600 °C) to produce Al-B master alloys. Ball-milled powder blends reveal interpenetrating layers of deformed aluminum and borax grains that are increasingly refined with increasing milling time. Thermal exposure of the ball-milled powder blends facilitates a series of thermite reactions between these layers. Borax, dehydrated during heating, is reduced by Al, and B thus generated reacts with excess Al to produce AlB2 particles dispersed across the aluminum grains starting at 873 K (600 °C). AlB2 particles start to form along the interface of the aluminum and borax layers. Once nucleated, these particles grow readily to become hexagonal-shaped crystals that traverse the aluminum grains with increasing temperatures as evidenced by the increase in the size as well as in the number of the AlB2 particles. Ball milling for 1 hour suffices to achieve a thermite reaction between borax and aluminum. Ball milling further does not impact the response of the powder blend to thermal exposure. The nucleation-reaction sites are multiplied, however, with increasing milling time and thus insure a higher number of smaller AlB2 particles. The size of the AlB2 platelets may be adjusted with the ball milling time.

  12. Reversible a-Fe2O3 to Fe3O4 transformation during ball milling

    DEFF Research Database (Denmark)

    Linderoth, Søren; Jiang, Jianzhong; Mørup, Steen

    The transformation of hematite to magnetite by high-energy ball milling in a sealed container has been studied by Mossbauer spectroscopy and x-ray diffraction. Mechanisms for this transformation are critically discussed. The dominant mechanism is concluded to be due to bond breaking during the high...... energy ball milling followed by release of the oxygen from the vial. The reverse transformation, magnetite to hematite, is demonstrated to occur by ball milling in air. Mechanisms for this reverse transformation are also put forward....

  13. Ferromagnetic behavior of nanocrystalline Cu–Mn alloy prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, B.N., E-mail: bholanath_mondal@yahoo.co.in [Department of Central Scientific Services, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Sardar, G. [Department of Zoology, Baruipur College, South 24 parganas 743 610 (India); Nath, D.N. [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Chattopadhyay, P.P. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India)

    2014-12-15

    50Cu–50Mn (wt%) alloy was produced by ball milling. The milling was continued up to 30 h followed by isothermal annealing over a four interval of temperature from 350 to 650 °C held for 1 h. Crystallite size, lattice strain, lattice parameter were determined by Rietveld refinement structure analysis of X-ray diffraction data. The amount of dissolved/precipitated Mn (wt%) after ball milling/milling followed by annealing was calculated by quantative phase analysis (QPA). The increase of coercivity could be attributed to the introduction of lattice strain and reduction of crystallite size as a function of milling time. Electron paramagnetic resonance and superconducting quantum interface device analysis indicate that soft ferromagnetic behavior has been achieved by ball milled and annealed Cu–Mn alloy. The maximum coercivity value of Cu–Mn alloy obtained after annealing at 350 °C for 1 h is 277 Oe. - Highlights: • A small amount of Mn has dissolved in Cu after ball milling for 30 h. • Coercivity of the Cu–Mn alloy has increased with an increase in milling time. • Substantial MnO has formed after annealing at 650 °C for 1 h. • The ball milled and annealed alloy have revealed soft ferromagnetic behavior. • The alloy annealed at 350 °C shows the maximum value of coercivity.

  14. Investigation of typical properties of nanocrystalline iron powders prepared by ball milling techniques

    International Nuclear Information System (INIS)

    Metallic powder has applications in many fields. In applications for preservation and anti-oxidation, iron powder has been used as an air oxygen reducer which is capable of decreasing microclimatic oxygen concentrations in a hermetic mini-environment. In this role, if we increase the specific surface area by reducing the particle size of the iron powder, the rate and performance of oxygen reduction will be improved significantly. In addition, the porosity of iron powder also contributes considerably. The iron powder can be fabricated using many methods: chemical deposition, powder metallurgy and mechanical milling. The technique of milling has certain advantages, especially for the formation of technical iron powder. The experimental equipment used was a Fritsch P-6 planetary ball mill. The iron powder was prepared with different milling times, from 1 up to 30 h in acetone as a protective environment. The powder products obtained were analyzed using field emission scanning electron microscope (FE-SEM), energy dispersive x-ray (EDX), x-ray diffraction (XRD), dynamic laser scattering (DLS), Brunauer–Emmett–Teller (BET) techniques and also magnetic characterization by vibrating sample magnetometer (VSM). The results show a correlation between the milling time and the crystallite and particle size, specific surface area, magnetic properties and nanoscale porosity of the iron powder. The iron powders obtained were a kind of mesoporous materials. The properties of the iron powder were examined with respect to their oxygen reducing kinetics. (paper)

  15. Thermal analysis of metastable phases formed by ball milling in some Zr-metal binary systems

    International Nuclear Information System (INIS)

    This paper reports that single-phase or two-phase mixture of metastable supersaturated solid solution and amorphous phase have been synthesized by ball milling in several Zr-metal (Al, Ni, Fe) binary systems. The enthalpy changes upon transformation of these metastable phases to equilibrium, as well as energy release during relaxation of the cold-worked, as-milled, materials, have been measured using differential scanning calorimetry. Enthalpy and free-energy versus composition diagrams have been constructed and compared with calculations using, e.g., the CALPHAD method. The amorphous phase was represented by the undercooled liquid in the calculations, with excess specific heat incorporated when appropriate. Crystallization temperatures and the corresponding apparent activation energies of the amorphous phases have been determined and compared with those in the literature for other amorphization techniques. The constrained thermodynamics underlying metastable phase formation by ball milling, e.g., metastable two-phase equilibrium vs. polymorphous transitions, are discussed in light of the measured thermodynamic characteristics of the systems

  16. Transforming from paramagnetism to room temperature ferromagnetism in CuO by ball milling

    Directory of Open Access Journals (Sweden)

    Daqiang Gao

    2011-12-01

    Full Text Available In this work, we experimentally demonstrate that it is possible to induce ferromagnetism in CuO by ball milling without any ferromagnetic dopant. The magnetic measurements indicate that paramagnetic CuO is driven to the ferromagnetic state at room temperature by ball milling gradually. The saturation magnetization of the milled powders is found to increase with expanding the milling time and then decrease by annealing under atmosphere. The fitted X-ray photoelectron spectroscopy results indicate that the observed induction and weaken of the ferromagnetism shows close relationship with the valence charged oxygen vacancies (Cu1+-VO in CuO.

  17. EXTREME MANAGEMENT OF PERFORMANCE GRINDING OF LIMESTONE INTO TWO-CHAMBER BALL MILLS

    Directory of Open Access Journals (Sweden)

    UZHELOVSKY V. A.

    2016-02-01

    Full Text Available Problem statement. The productivity of ball mills is an important process parameter. Optimization of loading of the mill will get the maximum efficiency of grinding limestone. Analysis of theresent research. In the scientific work on the process control of grinding in ball mills, particularly interesting are the work of Alekseev B. V., Maksimenko A. A., Uteush E. V., Bapat D. D., Kaminsky A. D. It is proved that the assessment of management effectiveness limestone grinding in a ball mill is a multiobjective and must provide to achieve the highest possible performance and the required fineness of electricity at the lowest cost. A significant factor affecting the performance of the mill is utilization level of limestone. Purpose. Performance of two-chamber ball mill increased by maintaining an optimal level of loading of the drum limestone. Conclusions. 1. In Matlab package developed and investigated simulation model of extreme performance management of a ball mill by optimizing the filling level of the drum limestone. 2. Simulation model allows you to study the influence of various factors on the performance of the mill and determine the previous settings establish extreme regulator to obtain the desired transition process with a given accuracy at the stage of design work.

  18. Kinetics of crystallite size evolution by ball milling

    Directory of Open Access Journals (Sweden)

    Zdujić Miodrag V.

    2002-01-01

    Full Text Available One of the distinguishing features of mechanochemical treatment is crystallite size reduction. The crystallite size of the powder subjected to milling decreases to some minimal value characteristic for the given material. Two processes occur concurrently during milling: reduction of the crystallite size and grain growth, whereby the steady-state crystallite size is attained when the rates of these processes are in equilibrium. This study deals with the kinetics of crystallite size evolution by milling. Published experimental data were analyzed using three kinetic models: dr / dt=-k1r2 + k2r-1; dr / dt=-k1r3 + k2r and dr / dt=-nktn-1(r - rs, where r and rs are the crystallite radius and steady-state crystallite radius respectively, t time, k1 and k2 the rate constants of crystallite reduction and grain growth, respectively, k the rate constant and n the Avrami exponent. The applied kinetic relations describe the crystallite size dependence on milling time in a satisfactory manner.

  19. Crystallite sizes of LiH before and after ball milling and thermal exposure

    International Nuclear Information System (INIS)

    The powder characteristics of lithium hydride (LiH) as a function of high-energy ball milling condition are systematically investigated via quantitative X-ray diffraction (XRD) analysis. The results obtained from the XRD analysis are compared with those attained from scanning electron microscopy (SEM), transmission electron microscopy (TEM), and specific surface area (SSA) analyses. The thermal stability of the ball-milled LiH is also investigated in order to provide physical insights into its cyclic stability in hydrogen sorption and desorption cycles. The results indicate that ball milling is effective in obtaining nano-crystalline LiH powder which is relatively stable with retention of nano-crystals after thermal exposure at 285 deg. C (equivalent to 0.58Tm) for 1 h. The good thermal stability observed is attributed to the presence of many pores in the agglomerates at the ball-milled condition. These pores effectively prevent crystal growth during the thermal exposure

  20. Athermal character of the solid state amorphization of lactose induced by ball milling

    Science.gov (United States)

    Willart, J. F.; Caron, V.; Lefort, R.; Danède, F.; Prévost, D.; Descamps, M.

    2004-12-01

    In this paper, we report the possibility to reach pure glassy amorphous lactose by ball milling of crystalline α lactose under a dry nitrogen atmosphere. This route to the glassy state is found to be free of mutarotation towards the anomer β while this mutarotation is unavoidable using the usual thermal route, i.e. the quench of the liquid. This result definitely makes the 'local quench melting' hypothesis unsuitable to account for amorphization by ball milling.

  1. Particle fracture and plastic deformation in vanadium pentoxide powders induced by high energy vibrational ball-mill

    Indian Academy of Sciences (India)

    Partha Chatterjee; S P Sen Gupta; Suchitra Sen

    2001-04-01

    An X-ray powder profile analysis in vanadium pentoxide powder milled in a high energy vibrational ball-mill for different lengths of time (0–250 h), is presented. The strain and size induced broadening of the Bragg reflection for two different crystallographic directions ([001] and [100]) was determined by Warren–Averbach analysis using a pattern-decomposition method assuming a Pseudo–Voigt function. The deformation process caused a decrease in the crystallite size and a saturation of crystallite size of ∼ 10 nm was reached after severe milling. The initial stages of milling indicated a propensity of size-broadening due to fracture of the powder particles caused by repeated ball-to-powder impact whereas with increasing milling time microstrain broadening was predominant. WA analysis indicated significant plastic strain along with spatial confinement of the internal strain fields in the crystallite interfaces. Significant strain anisotropy was noticed in the different crystallographic directions. A near-isotropy in the crystallite size value was noticed for materials milled for 200 h and beyond. The column-length distribution function obtained from the size Fourier coefficients progressively narrowed down with the milling time.

  2. Structural and magnetic stability of high energy ball milled Co2MnSi

    International Nuclear Information System (INIS)

    Structural and magnetic properties of ball milled Co2MnSi have been studied and compared with that of ordered bulk sample. The milled sample (with average size determined using the Williamson–Hall method) shows that the chemical ordering for this sample is very stable and is little effected by high energy ball milling. However, the reduction in the saturation magnetic moment of the milled sample shows that there is spin disordering induced on ball milling – attributable to the formation of a magnetically dead layer at the surface of the nano-sized samples. The ordered sample (unmilled) has a saturation moment value of 4.4 µB per formula unit at room temperature and is in agreement with the prediction of Slater Pauling curve. On milling it reduces to ~3 µB per formula unit at room temperature with an accompanying increase in the coercivity, retentivity and squareness factor. - Highlights: • We studied the magnetic and structural properties of bulk and ball milled Co2MnSi. • Structural disordering is minimal even at 36 nm. • Constant value of TC shows strong ferromagnetic interaction in smaller particles. • Formation of magnetically dead surface layer results reduction in magnetic moment. • Variation of magnetic parameters is systematic with variation in milling time/size

  3. Titania Prepared by Ball Milling: Its Characterization and Application as Liquefied Petroleum Gas Sensor

    CERN Document Server

    Yadav, B C; Singh, Satyendra; Yadav, T P

    2012-01-01

    Present paper reports the LPG sensing of TiO2 obtained through ball milling. The milled powder was characterized by XRD, TEM and UV-visible spectroscopy. Further the ball milled powder was compressed in to pellet using hydraulic press. This pellet was investigated with the exposure of LPG. Variations in resistance with exposure of LPG to the sensing pellet were recorded. The sensitivity of the sensor was ~ 11 for 5 vol.% of LPG. Response and recovery times of the sensor were ~ 100 and 250 sec. The sensor was quite sensitive to LPG and results were found reproducible within 91%.

  4. Electromagnetic properties of flake-shaped Fe–Si alloy particles prepared by ball milling

    International Nuclear Information System (INIS)

    Flake-shaped Fe–Si alloy particles with high aspect ratios were fabricated by ball milling commercially available Fe–Si powder, aiming to fabricate high-performance microwave absorbing fillers for coatings applied in 1–4 GHz range. To compare with spherical particles, higher permittivity and permeability was observed by using flaky particles as fillers. High aspect ratios contributed to an enhanced dielectric relaxation in the 1–4 GHz band, resulting in an increased permittivity. The thin thickness together with the high resistivity of Fe–Si flakes was believed to be helpful for suppressing the effect of eddy current and thus lead to an increase in the permeability. The electromagnetic wave absorbing (EMA) performances were observed to be enhanced. With a thin thickness of 2 mm, a wide absorption band with a minimum reflection loss of −12 dB was achieved in 1–4 GHz range, when using 75 wt% of flaky Fe–Si particles as fillers. The study indicated that flake-shaped Fe–Si particles were a promising candidate for EMA materials in L and S bands. - Highlights: • Flaky Fe–Si alloy particles were prepared in large scale via a simple ball milling method. • Coatings containing flakes Fe–Si particles present excellent EMA performance in L–S band. • The high shape anisotropy and the thin thickness contribute to the excellent EM property

  5. Synthesis of Cu(In,Ga)Se2 crystals using a crank ball mill

    International Nuclear Information System (INIS)

    Cu(In,Ga)Se2 (CIGS) crystals were synthesized by a mechanochemical (MC) process using a crank ball mill. The molar ratios of starting materials were Cu:In:Ga:Se=1:1-x:x:2 (0≤x≤1) and Cu:In:Ga:Se=1:0.7:0.3:y (2≤y≤3). The reaction time reduced with decreasing Se and Ga molar ratios. The collection rate decreased with longer reaction times. From XRD patterns, we confirmed that the CuInSe2 and/or CuGaSe2crystals were successfully grown when the powders reacted. Although the crystals grown with a selenium molar ration of 2 were Se-poor, those grown at a molar ratio of 3 were Se-rich. When Se increasing molar ratio, Cu, In, and Ga were away from the stoichiometric. With a molar ratio of Cu:In:Ga:Se=1:0.7:0.3:2.5∝2.7, their composition became stoichiometric. Crystal morphology was varied. CIGS crystals were thus successfully synthesized using a crank ball mill. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Synthesis of Cu(In,Ga)Se{sub 2} crystals using a crank ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Suzuka; Noji, Hideki; Akaki, Yoji [Miyakonojo National College of Technology, 473-1 Yoshio, Miyakonojo Miyazaki 885-8567 (Japan); Okamoto, Tomoichiro [Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

    2015-06-15

    Cu(In,Ga)Se{sub 2} (CIGS) crystals were synthesized by a mechanochemical (MC) process using a crank ball mill. The molar ratios of starting materials were Cu:In:Ga:Se=1:1-x:x:2 (0≤x≤1) and Cu:In:Ga:Se=1:0.7:0.3:y (2≤y≤3). The reaction time reduced with decreasing Se and Ga molar ratios. The collection rate decreased with longer reaction times. From XRD patterns, we confirmed that the CuInSe{sub 2} and/or CuGaSe{sub 2}crystals were successfully grown when the powders reacted. Although the crystals grown with a selenium molar ration of 2 were Se-poor, those grown at a molar ratio of 3 were Se-rich. When Se increasing molar ratio, Cu, In, and Ga were away from the stoichiometric. With a molar ratio of Cu:In:Ga:Se=1:0.7:0.3:2.5∝2.7, their composition became stoichiometric. Crystal morphology was varied. CIGS crystals were thus successfully synthesized using a crank ball mill. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Process intensification effect of ball milling on the hydrothermal pretreatment for corn straw enzymolysis

    International Nuclear Information System (INIS)

    Highlights: • Novel pretreatment of ball milling combined with hydrothermal method was presented. • Intensification effect of ball milling was significant for corn straw enzymolysis. • Ball milling destroyed the physical structure of corn straw. • Chemical (liquid mixture) method removed lignin and hemicellulose. • Glucose yield increased from 0.41 to 13.86 mg mL−1 under the optimized condition. - Abstract: Enhancement of the cellulose accessibility is significant for biomass enzymatic hydrolysis. Here, we reported an efficient combined pretreatment for corn straw enzymolysis using ball milling and dilute acid hydrothermal method (a mixture solvent of H2O/ethanol/sulfuric acid/hydrogen peroxide liquid). The process intensification effect of ball milling on the pretreatment of the corn straw was studied through the comparative characterization of the physical–chemical properties of the raw and pretreated corn straw using FT-IR, BET, XRD, SEM, and HPLC analysis. The effect of the pretreatment temperature was also investigated. Furthermore, various pretreatment methods were compared as well. Moreover, the pretreatment performance was measured by enzymolysis. The results showed that ball milling had a significant process intensification effect on the corn straw enzymolysis. The glucose concentration was dramatically increased from 0.41 to 13.86 mg mL−1 after the combined treatment of ball milling and hydrothermal. The efficient removal of lignin and hemicellulose and the enlargement of the surface area were considered to be responsible for this significant increase based on the intensive analysis on the main components and the physical–chemical properties of the raw and pretreated corn straw

  8. Synthesis of aluminum nitride powders from a plasma-assisted ball milled precursor through carbothermal reaction

    International Nuclear Information System (INIS)

    Highlights: • A novel and high efficiency synthesizing AlN powders method combining mechanical ball milling and DBDP has been developed. • The particle size, the crystallite size, the lattice distortion, the morphology of Al2O3 powders, and the AlN conversion rate are investigated and compared under the ball milled Al2O3 powders with DBDP and without DBDP. • The ball milled Al2O3 powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. - Abstract: In this paper, aluminum nitride (AlN) powers have been produced with a novel and high efficiency method by thermal annealing at 1100–1600 °C of alumina (Al2O3) powders which were previously ball milled for various time up to 40 h with and without the assistant of dielectric barrier discharge plasma (DBDP). The ball milled Al2O3 powders with DBDP and without DBDP and the corresponding synthesized AlN powers are characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. From the characteristics of the ball milled Al2O3 powders with DBDP and without DBDP, it can be seen that the ball milled Al2O3 powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. Meanwhile, the synthesized AlN powders can be known as hexagonal AlN with fine crystal morphology and irregular lump-like structure, and have uniform distribution with the average particle size of about between 500 nm and 1000 nm. This provides an important method for fabricating ultra fine powders and synthesizing nitrogen compounds

  9. Study on preparation of the core-nanoshell composite absorbers by high-energy ball milling at room temperature.

    Science.gov (United States)

    Che, Ruxin; Gao, Hong; Yu, Bing; Wang, Shuo; Wang, Chunxia

    2012-02-01

    Electromagnetic (EM) wave pollution has become the chief physical pollution for environment. In recent years, some researches have been focused on the preparation of nano-composite absorbers at low temperatures or even at room temperature. In this letter, preparation of nanocomposite by using high-energy ball milling at room temperature is reported. The core-nanoshell composite absorbers with magnetic fly-ash hollow cenosphere (MFHC) as nuclear and nanocrystalline magnetic material as shell were prepared by high-energy ball milling and vacuum-sintering in this paper. The pre-treatment of MFHC, the sintering process and the mol ratio of starting chemicals had a significant impact for property of composite absorbers. The results of X-ray diffraction analysis (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA) analysis indicated that perfect-crystalline nanomagnetic material coating was gotten with a particle size of 12 nm after ball milling. The results show the MFHC is dielectric loss and magnetic loss too; the exchange-coupling interaction happened between ferrite of the MFHC and nanocrystalline magnetic material coating. The exchange-coupling interaction enhances magnetic loss of composite absorbers. They have a perfect EM parameters at low microwave frequency. The core-nanoshell composite absorbers have a higher magnetic loss at low frequencies, and it is consistent with requirements of the microwave absorbing material at the low-frequency absorption. The microwave absorptivity of the core-nanoshell composite absorbers is better than single material. PMID:22630008

  10. High-energy ball milling of powder B-C mixtures

    International Nuclear Information System (INIS)

    The present work reports on the preparation of B-10 at.% C and B-18 at.% C powders by high-energy ball milling and further heat treatment. The milling process was carried out in a planetary ball mill. Following the milling process, powder samples were heat-treated at 1200 deg. C for 4 h using inert atmosphere. The milled and heat-treated B-10C and B-18C powders were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. A reduction on the intensity of B and C peaks was noticed after milling for 2 h, probably due the fine powder particle sizes because the pronounced fracture mechanism during ball milling of brittle starting components. The XRD patterns of B-10C and B-18C powders milled for 6 h indicated the presence of other peaks, suggesting that a metastable structure could have been formed. After milling for 90 h, these unknown peaks were still present. A large amount of B4C was formed after heat treatment at 1200 deg. C for 4 h beside these unknown peaks

  11. COMPARISON ON REFINEMENT OF IRON POWDER BY BALL MILLING ASSISTED BY DIFFERENT EXTERNAL FIELDS

    Institute of Scientific and Technical Information of China (English)

    L.Y. Dai; B. Cao; M. Zhu

    2006-01-01

    The cryogenic milling and milling in conjunction with dielectric barrier discharge plasma (DBDP)have been separately set up. The combined effect of low temperature and plasma on ball milling has been investigated by examining the refinement of particle size and grain size of iron powder using scanning electron microscopy, X-ray diffraction, and small angle X-ray scattering. It was found that the mean size of iron particles could reach 104nm only after 10 hours of ball milling in conjunction with DBDP, whereas a minimum average grain size of 8.4nm was obtained by cryomilling at -20℃; however, it is difficult to refine the particle size and grain size under the same milling condition in the absence of DBDP and cryogenic temperature.

  12. Nanocrystalline {beta}-sialon by reactive sintering of a SiO{sub 2}-AlN mixture subjected to high-energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Tessier, P. [Groupe Minutia, Boucherville, Que. (Canada)]. E-mail: pascal.tessier@airliquide.com; Alamdari, H.D. [Groupe Minutia, Boucherville, Que. (Canada)]. E-mail: alamdari.houshang@nanoxnps.com; Dubuc, R. [Groupe Minutia, Boucherville, Que. (Canada); Boily, S. [Groupe Minutia, Boucherville, Que. (Canada)

    2005-04-05

    A mixture of powders of silica and aluminum nitride is subjected to high-energy ball milling for different milling times. This material is subsequently compacted by uniaxial pressing and sintered at 1450 deg. C. The resulting pellets are crushed and analysed by X-ray diffraction. For short milling times, the amount of phase transformation is minimal and the resulting material mostly consists of cristobalite and aluminum nitride. For long milling times, nanocrystalline {beta}-SiAl{sub 2}O{sub 2}N{sub 2} is mainly produced.

  13. Effect of annealing on the magnetic properties of ball milled NiO powders

    Energy Technology Data Exchange (ETDEWEB)

    Kisan, Bhagaban [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Defence Metallurgical Research laboratory, Hyderabad 500058 (India); Layek, Samar; Verma, H.C. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Hesp, David; Dhanak, Vinod [Department of Physics, University of Liverpool, Liverpool L69 3BX (United Kingdom); Krishnamurthy, Satheesh [Materials Engineering, The Open University, Milton Keynes MK7 6AA (United Kingdom); Perumal, A., E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2015-06-15

    We report systematic investigations on structural and magnetic properties of nanosized NiO powders prepared by the ball milling process followed by systematic annealing at different temperatures. Both as-milled and annealed NiO powders exhibit face centered cubic structure, but average crystallite size decreases (increases) with increasing milling time (annealing temperature). Pure NiO exhibits antiferromagnetic nature, which transforms into ferromagnetic one with moderate moment at room temperature with decreasing crystallite size. The on-set of ferromagnetic behavior in the as-milled powders was observed at higher temperatures (>750 K) as compared to bulk Ni (~630 K). On the other hand, annealing of as-milled powders showed a large reduction in magnetic moment and the rate of decrease of moment strongly depends on the milling conditions. The observed properties are discussed on the basis of crystallite size variation, defect density, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. - Highlights: • Preparation of fine NiO powder using top-to-bottom approach using planetary ball mill. • Effect of milling on instituting room temperature ferromagnetism with size reduction. • Stability of ferromagnetic properties at high temperatures in milled NiO powders • Effect of annealing process on the structural properties of milled NiO powders. • Understanding the origin of ferromagnetism at 300 K in NiO powders through annealing.

  14. Microstructure studies of ball milled and vacuum hot pressed NiZrTiAl powders

    Directory of Open Access Journals (Sweden)

    A. Kovacova

    2007-11-01

    Full Text Available To determine microstructure and hardness of hot pressed mechanically alloyed MA NiZrTiAl powderwell known as a good glass formers.Design/methodology/approach: Powders has been ball milled r 40 hours starting from pure elementsChanges of particle’s size and crystallographic structure of nanocrystals embedded in the amorphous matrix durinmilling has been determined using High Resolution Transmission Electron Microscopy HRTEM.Findings: The MA particles first grow, then decrease after 40 hours of milling, when powders possess amorphoustructure. HRTEM studies of powders allowed to reveal small nanocrystals of NiTi2 within milled powders whicwere not detected using X-Ray diffraction. The powders show crystallization peak at temperature Tx near 553°CConsolidation of powders was performed under vacuum using uniaxial hot pressing method at temperature slightlbelow Tx. Mean microhardness was determined near 430 HV and the mean Young´s modulus as 81 GPa.Practical implications: It was shown a possibility of hot densification in vacuum of amorphous Ni base alloyallowing to obtain bulk amorphous compacts with embedded nanocrystals.Originality/value: The size and structure of nanmocrystals within the amorphous matrix after MA and aftehot vacuum densification has been determined. The microhardness and Young’s modulus of compacts showperspectives of application of such materials.

  15. Ball mill assisted synthesis of Ni-YSZ cermet anode by electroless technique and their characterization

    International Nuclear Information System (INIS)

    Ni-YSZ composite cermet used as the anode material for solid oxide fuel cell is prepared by electroless technique involving an important sensitization process of YSZ. In the present investigation, the sensitization process of YSZ is carried out through cost-effective controlled ball milling. The effect of milling speed on electrical, thermal and microstructural properties of such anodes is investigated and optimized at 45 rpm. Microstructural analysis of the synthesized Ni-YSZ cermets prepared under the optimized milling conditions showed a core-shell microstructure with YSZ as core and fine metallic Ni particulates as the shell. The interconnected metallic Ni creates a conductive pathway at room temperature. Such type of unique core-shell anode cermet, results in higher electrical conductivity (σ800deg.C ∼ 500 S/cm) at much lower Ni content (∼33 vol%) compared to conventional anode cermet with thermal expansion coefficient (∼11.48 x 10-6 K-1) compatible to other cell components.

  16. Mössbauer spectroscopic studies of Fe-20 wt.% Cr ball milled alloy

    Science.gov (United States)

    Pandey, Brajesh; Ananda Rao, M.; Verma, H. C.; Bhargava, S.

    Interesting differences were noticed in the alloying process during ball milling of Fe-10 wt.% Cr and Fe-20 wt.% Cr alloys by 57Fe Mössbauer spectroscopic studies. In both cases, there is almost no diffusion of Fein Cr or vice versa up to 20 h of milling time. As the powders are milled for another 20 h substantive changes occur in the Mössbauer spectra showing atomic level mixing. But the two. compositions behave differently with respect to alloying. Fe-20 wt.% Cr sample does not differ much in the hyperfine field distribution as it is milled from 40 to 100 h. On the other hand, the hyperfine field distribution keeps on changing with milling time for Fe-10 wt.% Cr sample even up to 100 h of milling. The average crystallite size is found to be 7.5 nm for Fe-10 wt.% Cr and 6.5 nm in Fe-20 wt.% Cr after milling.

  17. Moessbauer spectroscopic studies of Fe-20 wt.% Cr ball milled alloy

    International Nuclear Information System (INIS)

    Interesting differences were noticed in the alloying process during ball milling of Fe-10 wt.% Cr and Fe-20 wt.% Cr alloys by 57Fe Moessbauer spectroscopic studies. In both cases, there is almost no diffusion of Fe in Cr or vice versa up to 20 h of milling time. As the powders are milled for another 20 h substantive changes occur in the Moessbauer spectra showing atomic level mixing. But the two compositions behave differently with respect to alloying. Fe-20 wt.% Cr sample does not differ much in the hyperfine field distribution as it is milled from 40 to 100 h. On the other hand, the hyperfine field distribution keeps on changing with milling time for Fe-10 wt.% Cr sample even up to 100 h of milling. The average crystallite size is found to be 7.5 nm for Fe-10 wt.% Cr and 6.5 nm in Fe-20 wt.% Cr after milling.

  18. Effect of Milling Time on Al-Fe-Cr-20 Wt. % Al2O3composite Prepared Through Ball Milling

    Directory of Open Access Journals (Sweden)

    Hameedur Rehman Khan

    2014-07-01

    Full Text Available One of the main challenges towards achieving a homogeneous distribution of the ceramic phase in the metal matrix composites is agglomeration of the reinforcement particles. Mechanical alloying is among the most important processing techniques used for manufacturing of metal matrix composites (MMCs.An attempt was made to synthesize Al-Fe-Cr-Al2O3composites synthesized through mechanical alloying. Al2O3 is used as reinforcement. Ethanol (5 wt. % has been used as a process control agent (PCA. Mechanical alloying is carried out in a conventional ball mill using stainless steel grinding media at 115 rpm in the argon environment for 5h, 10h and 15h. The ball to powder weight ratio was maintained at 20:1. The characterization of the ball milled powder was followed by scanning electron microscopy (SEM. Showed the formation of a homogeneous phase for all compositions after milling for 15 h. XRD patterns were recorded for the milled powders, and analyzed using Williamson–Hall method and Scherrer’s equation to determine the lattice strain and grain size.EDX is performed to check the contamination of composites during the mechanical alloying.XRD is used to study structural evolution of synthesized aluminium composite. Effect of milling time is investigated on synthesized Al-Fe-Cr-20 wt. % Al2O3 composites.

  19. Preparation of Colloidal Dispersions of Graphene Sheets in Organic Solvents by Using Ball Milling

    International Nuclear Information System (INIS)

    A top-down method was developed for producing colloidal dispersions of graphene sheets. Graphite nano sheets comprising hundreds of carbon layers were dispersed and gently ball-milled to exfoliate into graphene in a variety of organic solvents. After 30 hours of the shear-force-dominated grinding and a subsequent 4000 r.p.m. of centrifugation, single- and few-layer graphene sheets were readily prepared and homogeneously and stably suspended in the good solvent medium which possesses a surface tension value close to 40 mJ m-2, such as in N,N-dimethylformamide, at a concentration up to 0.08 mgml-1, achieving a yield higher than 32.0 wt%. The graphene materials in the colloidal suspension were characterized using scanning microscopy and atomic force microscopy

  20. Preparation of Colloidal Dispersions of Graphene Sheets in Organic Solvents by Using Ball Milling

    Directory of Open Access Journals (Sweden)

    Weifeng Zhao

    2010-01-01

    Full Text Available A top-down method was developed for producing colloidal dispersions of graphene sheets. Graphite nanosheets comprising hundreds of carbon layers were dispersed and gently ball-milled to exfoliate into graphene in a variety of organic solvents. After 30 hours of the shear-force-dominated grinding and a subsequent 4000 r.p.m. of centrifugation, single- and few-layer graphene sheets were readily prepared and homogeneously and stably suspended in the good solvent medium which possesses a surface tension value close to 40 mJ m−2, such as in N,N-dimethylformamide, at a concentration up to 0.08 mg ml−1, achieving a yield higher than 32.0 wt%. The graphene materials in the colloidal suspension were characterized using scanning and transmission electron microscopy and atomic force microscopy.

  1. Ball milling improves extractability and affects molecular properties of psyllium (Plantago ovata Forsk) seed husk arabinoxylan.

    Science.gov (United States)

    Van Craeyveld, Valerie; Delcour, Jan A; Courtin, Christophe M

    2008-12-10

    Psyllium (Plantago ovata Forsk) seed husk (PSH) is very rich in arabinoxylan (AX). However, its high gelling capacity and the complex nature of the AX make it difficult to process. In this study, ball milling was investigated as a tool for enhancing PSH AX water extractability and molecular mass (MM). A 48 h laboratory-scale ball mill treatment under standardized optimal conditions reduced the PSH average particle size from 161 microm for the untreated sample to 6 microm. Concurrently, it increased the water-extractable AX (WE-AX) level from 13 (untreated PSH) to 90% of the total PSH AX. While the WE-AX of the untreated PSH had a peak MM of 216 kDa and an arabinose to xylose (A/X) ratio of 0.20, WE-AX fragments from ball mill-pretreated PSH had a peak MM of 22 kDa and an A/X ratio of 0.31. Ball milling further drastically reduced the intrinsic viscosity of PSH extracts and their water-holding capacity. Prolonged treatment brought almost all AX (98%) in solution and yielded WE-AX fragments with an even higher A/X ratio (0.42) and a lower peak MM (11 kDa). While impact and jet milling of PSH equally led to significant reductions in particle size, these technologies only marginally affected the water extractability of PSH AX. This implies that ball milling affects PSH particles and their constituent molecules differently than impact and jet milling. PMID:19007123

  2. Fabrication of Lead Zirconate Titanate Powder Using Ultrasonic Ball Milling Technique

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this research, the ultrasonic ball milling technique has been used to fabricate lead zirconate titanate (PZT) ceramics.PZT with the composition nearly the morphotropic phase boundary (MPB): Pb(Zr0.52 Ti0.48 )O3 was studied. The effect of milling time on phase formation of sample powder was examined by X-ray diffraction technique (XRD). Moreover, the physical, dielectric, piezoelectric properties and microstructure of PZT ceramics were investigated. The present results reveal that the ultrasonic ball milling technique results the homogeneous and small size of PZT powder. Furthermore, there is a significantly change occurs in the size of the particles with the short time of milling process.

  3. Microstructure and martensitic transformation in Si-coated TiNi powders prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-hyun; Cho, Gyu-bong; Im, Yeon-min [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Chun, Byong-sun [ReSEAT Program, KISTI, Daejeon 305-806 (Korea, Republic of); Kim, Yeon-wook [Department of Advanced Materials Engineering, Keimyung University, 1000 Shindang-dong, Dalseo-gu, Daegu 704-701 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-12-15

    Graphical abstract: - Highlights: • Amorphous Si-coated TiNi powders were prepared successfully by ball milling. • Ti{sub 4}Ni{sub 4}Si{sub 7} was formed at the interface between Si and TiNi after annealing. • Si-coated Ti–Ni powders displayed the R phase after annealing. - Abstract: Si was coated on the surface of Ti–49Ni (at%) alloy powders by ball milling in order to improve the electrochemical properties of the Si electrodes of secondary Li ion batteries and then the microstructure and martensitic transformation behavior were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Ti–Ni powders coated with Si were fabricated successfully by ball milling. As-milled powders consisted of highly deformed Ti–Ni powders with the B2 phase and amorphous Si layers. The thickness of the Si layer coated on the surface of the Ti–Ni powders increased from 3–5 μm to 10–15 μm by extending the milling time from 3 h to 48 h. However, severe contamination from the grinding media, ZrO{sub 2} occurred when the ball milling time was as long as 48 h. By heating as-milled powders to various temperatures in the range of 673–873 K, the highly deformed Ti–Ni powders were recovered and Ti{sub 4}Ni{sub 4}Si{sub 7} was formed. Two-stage B2–R–B19′ transformation occurred when as-milled Si-coated Ti–49Ni alloy powders were heated to temperatures below 873 K, above this temperature one-stage B2–B19′ transformation occurred.

  4. Nanostructured WC/Co composite powder prepared by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.L.; Wang, C.Y.; Zhu, M

    2003-12-15

    The microstructure of WC-10%Co nanocomposite prepared by high energy ball milling was investigated by X-ray diffraction and transmission electron microscopy. The WC phase was refined to a grain size of 11 nm after milling. The dislocation density in WC was high and caused severe lattice distortion. Dislocations with Burgers vector 1/3[1 2-bar 1 0] were identified in some areas.

  5. Effect of ball-milling time on the structural characteristics of biomedical porous Ti-Sn-Nb alloy

    International Nuclear Information System (INIS)

    The structural characteristics of biomedical porous materials are crucial for bone tissue to grow into a porous structure and can also influence the fixation and remodeling between the implant and the human tissues. The current study has been investigating the effect of the ball-milling variable of time on the structural characteristics and pore morphology of a biomedical porous Ti-16Sn-4Nb (wt.%) alloy. The alloy was synthesized using high-energy ball milling for different periods of time, and the porous Ti-16Sn-4Nb alloy was fabricated by using a space holder sintering process. The resultant powder particles, bulk, and porous samples were characterized using a scanning electron microscope (SEM), laser particle-size analyzer, chemical analysis, X-ray diffraction analysis (XRD), and the Vickers hardness test. The results indicated that the inner pore surface, pore wall architecture, degree of porosity, pore size and the inter-pore connectivity of the sintered porous alloy are all considerably affected by ball-milling time.

  6. Effect of Initial Aluminum Alloy Particle Size on the Damage of Carbon Nanotubes during Ball Milling

    Directory of Open Access Journals (Sweden)

    Xian Zhu

    2016-03-01

    Full Text Available Damage to carbon nanotubes (CNTs during the fabrication process of CNT reinforced composites has great influence on their mechanical properties. In this study, the 2014 Al with powder sizes of 20, 9 and 5 μm was selected to study the effect of initial particle size on the damage to carbon nanotubes (CNTs during ball milling. The result shows that for CNTs in the ball milled CNT/Al (with powder size of 20 and 9 μm mixtures, the intensity ratio of the D band and the G band (ID/IG first increased and then reached a plateau, mainly because most of the CNTs are embedded, to a certain extent, in the aluminum powder after milling, which could protect the CNTs from damage during further milling. While for CNTs in the ball milled CNT/Al (with powder size of 5 μm mixture, the ID/IG ratio continues to climb from 1.31 to 2.33 with time, indicating continuous damage to the CNTs occurs during the milling. Differential scanning calorimetry (DSC analysis demonstrates that the chemical instability increased with an increase in the damage level of CNTs, resulting in the formation of aluminum carbide (Al4C3 at a lower temperature before the melting of aluminum, which is detrimental to their mechanical properties.

  7. FePt magnetic particles prepared by surfactant-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Velasco, V., E-mail: vvjimeno@fis.ucm.es [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, P.O. Box 155, Las Rozas 28230 (Spain); Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid 28040 (Spain); Hernando, A.; Crespo, P. [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, P.O. Box 155, Las Rozas 28230 (Spain); Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid 28040 (Spain)

    2013-10-15

    High-energy ball milling of Fe and Pt elemental powders has been carried out under dry and wet (in presence of solvent and surfactants) conditions. Dry milling leads to the formation of the disordered FCC-FePt alloy whereas by the wet milling procedure the main process is the decrease of Fe and Pt particle size, although some dissolution of Pt into Fe grains cannot be ruled out, and no hint of the formation of the FCC-FePt phase is observed even to milling times up to 20 h, as X-ray diffraction, electron microscopy and Mössbauer spectroscopy indicates. The as-milled particles were annealed at 600 °C for 2 h under Ar atmosphere. It is noticed that the disordered fcc-FePt phase observed in particles milled under dry conditions transform to ordered fct phase characterized by a hard magnetic behavior with a coercive field up to 10,000 Oe. However, those particles milled in the surfactant/solvent medium exhibit a soft magnetic behavior with a coercive field of 600 Oe. These results indicate that wet high-energy ball milling is not an adequate technique for obtaining single-phase FePt particles. - Highlights: • FePt particles have been obtained by high-energy ball milling. • In the presence of surfactants and solvents, almost no alloying process takes place. • After annealing, the coercive field of the FePt alloy particles increases from 150 Oe to 10,000 Oe.

  8. Synthesis of BaTiO3 powders by a ball milling-assisted hydrothermal reaction

    International Nuclear Information System (INIS)

    The effects of ball milling during the hydrothermal BaTiO3 synthesis from nano- and sub-micron sized TiO2 powders were studied. The synthesized BaTiO3 powders were characterized by X-ray diffraction (XRD), a laser light scattering particle size distribution analyzer, and field emission scanning electron microscopy (FE-SEM). The XRD patterns showed that BaTiO3 powders could be synthesized using the ball milling system at 100 deg. C and for 5 h with little contamination. The BaTiO3 powders observed by FE-SEM were agglomerated. The agglomerated particle sizes of BaTiO3 prepared from nano- and sub-miron sized TiO2 particles were 152 ± 42 and 148 ± 21 nm, respectively. Furthermore, it was found that the rate constant of BaTiO3 powder prepared from Ba(OH)2 and sub-micrometer sized TiO2 powder with the ball milling process was twice as large compared to a hydrothermal route without ball milling

  9. Crystal growth and the steady-state grain size during high-energy ball-milling

    DEFF Research Database (Denmark)

    Mørup, Steen; Jiang, Jianzhong; Bødker, Franz;

    2001-01-01

    The change in crystal size during high-energy ball-milling of hematite and zinc sulphide powders with initial average crystal size of 8 nm and 4 nm, respectively, has been investigated by X-ray powder diffraction and transmission electron microscopy. It is found that the crystal size increases wi...

  10. DISSOLUTION OF HOLOCELLULOSE IN IONIC LIQUID ASSISTED WITH BALL-MILLING PRETREATMENT AND ULTRASOUND IRRADIATION

    Directory of Open Access Journals (Sweden)

    Fengxia Yue,

    2012-02-01

    Full Text Available One of the most promising technologies for lignocellulosic biomass utilization employs ionic liquids for the conversion of isolated components into fuels, pharmaceuticals, chemicals, and composites after fractionation of lignocellulose. However, the time required for dissolution of the whole cell wall has been excessive. To explore a possible dissolution and fractionation pathway of lignocelluloses, the dissolution of holocellulose isolated from bagasse was investigated in 1-butyl-3-methylimidazolium chloride ([C4mim]Cl assisted with ball-milling pretreatment and ultrasound irradiation. Ball milling pretreatment, ultrasonic irradiation assistance, and their combination were found to effectively improve the holocellulose dissolution in [C4mim]Cl. The effects of ultrasound power and irradiation duration on the dissolution time of ball-milled holocelluloses in [C4mim]Cl were studied. The regenerated holocelluloses were characterized with FT-IR, X-Ray, and CP/MAS 13C-NMR. It was found that there were no obvious changes of chemical structure after dissolution and regeneration of the holocellulose. The crystalline structure of cellulose was converted from cellulose I in native holocellulose to cellulose II in the regenerated holocellulose. The crystallinity decreased after the process of dissolution and regeneration assisted by ball-milling pretreatment and ultrasound irradiation.

  11. The effect of ball milling and rehydration on powdered mixtures of hydrocolloids.

    Science.gov (United States)

    Abbaszadeh, A; MacNaughtan, W; Foster, T J

    2014-02-15

    In many applications, particularly in food related work, it is assumed that ball milling merely serves as a means of reducing crystallinity by the steady attrition of crystals. In this work mixtures of cellulose with other biopolymers have been co-ball milled in the dry state typically at moisture contents of <12% (w/w) and the effects of recrystallizing these mixtures studied. We have found that recystallizing the mixtures under a humid (97%RH) atmosphere increases the crystallinity of the cellulose fraction in a fashion governed by the other hydrocolloid present in the mixture. Some of the measured effects occur during ball milling of the dry powders. A relative method of fitting mixtures of type I and type II cellulose is described. Progressive transition between these forms with time was discovered for eucalyptus and microcrystalline cellulose at 97%RH. Locust bean gum (LBG) appeared to exert a protective effect on both eucalyptus and microcrystalline cellulose against the destruction of crystallinity by ball milling. For eucalyptus cellulose high levels of type I were produced during recrystallization with LBG under humid conditions. Both cellulose samples crystallized in the type I form in the presence of LBG whereas type II was produced in the presence of other hydrocolloids. Possible mechanisms for these unusual observations are proposed. PMID:24507372

  12. Synthesis of aluminum nitride powders from a plasma-assisted ball milled precursor through carbothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhi-jie [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Dai, Le-yang [Marine Engineering Institute, Jimei University, Xiamen 361021 (China); Yang, De-zheng; Wang, Sen [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Zhang, Bao-jian [Marine Engineering Institute, Jimei University, Xiamen 361021 (China); Wang, Wen-chun, E-mail: wangwenc@dlut.edu.cn [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Cheng, Tie-han [Pinggao Group Co. Ltd., State Grid Corporation of China, Pingdingshan 467000 (China)

    2015-01-15

    Highlights: • A novel and high efficiency synthesizing AlN powders method combining mechanical ball milling and DBDP has been developed. • The particle size, the crystallite size, the lattice distortion, the morphology of Al{sub 2}O{sub 3} powders, and the AlN conversion rate are investigated and compared under the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP. • The ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. - Abstract: In this paper, aluminum nitride (AlN) powers have been produced with a novel and high efficiency method by thermal annealing at 1100–1600 °C of alumina (Al{sub 2}O{sub 3}) powders which were previously ball milled for various time up to 40 h with and without the assistant of dielectric barrier discharge plasma (DBDP). The ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP and the corresponding synthesized AlN powers are characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. From the characteristics of the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP, it can be seen that the ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. Meanwhile, the synthesized AlN powders can be known as hexagonal AlN with fine crystal morphology and irregular lump-like structure, and have uniform distribution with the average particle size of about between 500 nm and 1000 nm. This provides an important method for fabricating ultra fine powders and synthesizing nitrogen compounds.

  13. Analysis of the Magnetocaloric Effect in Powder Samples Obtained by Ball Milling

    Science.gov (United States)

    Blázquez, J. S.; Ipus, J. J.; Moreno-Ramírez, L. M.; Borrego, J. M.; Lozano-Pérez, S.; Franco, V.; Conde, C. F.; Conde, A.

    2015-06-01

    Since the discovery of the giant magnetocaloric effect (MCE) close to room temperature in FeRh and particularly in Gd5Si2Ge2 compounds, the study of this phenomenon has experienced an exponential growth. Among the different techniques used to produce magnetocaloric materials, ball milling has been shown as a very versatile one and presents several advantages over other preparation techniques ( e.g., easy scale-up to industrial production). Although a general decrease of the peak value of the magnetic entropy change is observed for milled samples, it can be compensated by the large broadening of the MCE peak, leading to an increase of the refrigeration capacity. In this short review, several aspects inherent to powder samples affecting MCE will be discussed, such as the relevant effect of the demagnetizing field, the possible multiphase character, and the presence of Curie temperature distributions. In mechanically alloyed samples, the two latter factors are typically affected by the degree of integration of the different starting constituents.

  14. Microwave absorption properties of FeSi flaky particles prepared via a ball-milling process

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chao [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yuan, Yong [Precision Machinery Research Institute of Shanghai Space Flight Academy, Shanghai 201600 (China); Jiang, Jian-tang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Gong, Yuan-xun [Aerospace Research Institute of Special Material and Processing Technology, Beijing 100074 (China); Zhen, Liang, E-mail: lzhen@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); MOE Key Laboratory of Micro-system and Micro-structures Manufacturing, Harbin Institute of Technology, Harbin 150080 (China)

    2015-12-01

    Flaky FeSi alloy particles with different aspect ratio were produced via ball-milling and a subsequent annealing. The microstructure and the morphology of the particles were examined by XRD and SEM. The dc resistivity, the static magnetization properties and electromagnetic properties were measured. Particles with high aspect ratio were found possess high permittivity and permeability. On the other hand, the variation of grain size and defects density was found influence the permittivity and permeability. High specific area was believed contribute to the intense dielectric loss and the high shape magnetic anisotropy lead to high permeability in the target band. Increased electromagnetic parameters compel the absorption peak’s shift to lower frequency. Coating using flaky FeSi particles milled for 12 h as fillers presented a reflection loss of −10 dB at 2 GHz and a matching thickness of 1.88 mm. The flaky FeSi alloy particles prepared through ball-milling and annealing can be promising candidates for EMA application at 1–4 GHz band. - Highlights: • Large quantity of flakey FeSi particles were produced through a simple way. • Coatings with as-milled FeSi particles exhibit excellent EMA performance in L-S band. • Shape and size of particles can be controlled via adjusting the ball-milling time. • Shape/size along with the microstructure influence the electromagnetic properties. • Shape/size contribute more to the excellent EMA performance compared to microstructure.

  15. Microwave absorption properties of FeSi flaky particles prepared via a ball-milling process

    International Nuclear Information System (INIS)

    Flaky FeSi alloy particles with different aspect ratio were produced via ball-milling and a subsequent annealing. The microstructure and the morphology of the particles were examined by XRD and SEM. The dc resistivity, the static magnetization properties and electromagnetic properties were measured. Particles with high aspect ratio were found possess high permittivity and permeability. On the other hand, the variation of grain size and defects density was found influence the permittivity and permeability. High specific area was believed contribute to the intense dielectric loss and the high shape magnetic anisotropy lead to high permeability in the target band. Increased electromagnetic parameters compel the absorption peak’s shift to lower frequency. Coating using flaky FeSi particles milled for 12 h as fillers presented a reflection loss of −10 dB at 2 GHz and a matching thickness of 1.88 mm. The flaky FeSi alloy particles prepared through ball-milling and annealing can be promising candidates for EMA application at 1–4 GHz band. - Highlights: • Large quantity of flakey FeSi particles were produced through a simple way. • Coatings with as-milled FeSi particles exhibit excellent EMA performance in L-S band. • Shape and size of particles can be controlled via adjusting the ball-milling time. • Shape/size along with the microstructure influence the electromagnetic properties. • Shape/size contribute more to the excellent EMA performance compared to microstructure

  16. Scale-up of organic reactions in ball mills: process intensification with regard to energy efficiency and economy of scale.

    Science.gov (United States)

    Stolle, Achim; Schmidt, Robert; Jacob, Katharina

    2014-01-01

    The scale-up of the Knoevenagel-condensation between vanillin and barbituric acid carried out in planetary ball mills is investigated from an engineering perspective. Generally, the reaction proceeded in the solid state without intermediate melting and afforded selectively only one product. The reaction has been used as a model to analyze the influence and relationship of different parameters related to operation in planetary ball mills. From the viewpoint of technological parameters the milling ball diameter, dMB, the filling degree with respect to the milling balls' packing, ΦMB,packing, and the filling degree of the substrates with respect to the void volume of the milling balls' packing, ΦGS, have been investigated at different reaction scales. It was found that milling balls with small dMB lead to higher yields within shorter reaction time, treaction, or lower rotation frequency, rpm. Thus, the lower limit is set considering the technology which is available for the separation of the milling balls from the product after the reaction. Regarding ΦMB,packing, results indicate that the optimal value is roughly 50% of the total milling beakers' volume, VB,total, independent of the reaction scale or reaction conditions. Thus, 30% of VB,total are taken by the milling balls. Increase of the initial batch sizes changes ΦGS significantly. However, within the investigated parameter range no negative influence on the yield was observed. Up to 50% of VB,total can be taken over by the substrates in addition to 30% for the total milling ball volume. Scale-up factors of 15 and 11 were realized considering the amount of substrates and the reactor volume, respectively. Beside technological parameters, variables which influence the process itself, treaction and rpm, were investigated also. Variation of those allowed to fine-tune the reaction conditions in order to maximize the yield and minimize the energy intensity. PMID:25406485

  17. Phase transformation of nanocrystalline anatase powders during high energy planetary ball milling

    Institute of Scientific and Technical Information of China (English)

    潘晓燕; 陈怡; 马学鸣; 朱丽慧

    2003-01-01

    The microstructure evolution of nanocrystalline anatase during high energy planetary milling was studied by X-ray diffraction and transmission electron microscopy. The results show that mechanical activation induces the transformations from anatase to srilankite and rutile at room temperature and under ambient pressure, which should primarily be attributed to the rise of local temperature and pressure at the collision sites of the powders and the balls. In addition, the additional energy caused by defects, lattice distortion and the refinement of the crystallite is responsible for the transformations. As milling time increases, anatase phase content reduces and the amounts of both srilankite and rutile phase increase. And the transformation from srilankite to rutile phase takes place by further milling. In anatase phase, the crystallite size decreases and lattice strain rises with milling time. There is no indication of the formation of amorphous phase during milling.

  18. Formation of budesonide/α-lactose glass solutions by ball-milling

    Science.gov (United States)

    Dudognon, E.; Willart, J. F.; Caron, V.; Capet, F.; Larsson, T.; Descamps, M.

    2006-04-01

    The possibility to obtain amorphous budesonide stabilised by blending with an excipient characterised by a higher glass transition temperature, namely α-lactose, has been studied. We carried out the mixing of the two compounds at room temperature by ball-milling. The four obtained blends (containing, respectively, 10, 30, 50 and 70% w of budesonide) are X-ray amorphous and exhibit a single glass transition located between the ones of pure milled crystalline compounds. This revealed that the two amorphous phases are miscible whatever the composition and sufficiently mixed to relax as a whole. Ball-milling thus appears as a powerful tool to form amorphous molecular alloys with enhanced stability properties.

  19. The effect of high energy ball milling on the crystal structure of GDNi 5

    Science.gov (United States)

    Stubičar, M.; Blažina, Ž.; Tonejc, A.; Stubičar, N.; Krumes, D.

    2001-09-01

    X-ray powder diffraction was used to determine the effect of, dry, in air performed high energy ball milling, on the intermetallic compound GdNi 5. It was found that the crystal structure of GdNi 5 is not stable. At the early stage of milling (up to after 10 h of milling) the gadolinium component oxidises causing thus the decomposition of GdNi 5 into monoclinic Gd 2O 3 and metallic nickel. Both, the crystallite (grain) size and the particle size of powder decrease during the early stage of milling. At the later stage of milling (up to 50 h) the nickel phase from the mixture of Gd 2O 3 and nanocrystalline nickel oxidises into nanocrystalline NiO. Therefore, the final product after 150 h of milling of GdNi 5 is a mixture of oxides of the constituent metals, i.e., amorphous Gd 2O 3 and nanocrystalline NiO. Traces of contamination by α-SiO 2 have been observed in the milled powder, being more pronounced as the milling process proceeds. This is ascribed to the wear effect of agate milling assembly.

  20. Magnetic properties of ball-milled TbFe2 and TbFe2B

    Indian Academy of Sciences (India)

    J Arout Chelvane; S Kasiviswanathan; M V Rao; G Markandeyulu

    2004-04-01

    The magnetic properties of ball-milled TbFe2 and TbFe2B were studied by magnetization measurements. X-ray diffraction studies on TbFe2B showed that boron occupied interstitial position in the crystal structure, just as hydrogen did. The value of the saturation magnetization of TbFe2B was found to be smaller than that of TbFe2. This is explained on the basis of a charge transfer between the boron atoms and the 3d band of Fe. The anisotropy of TbFe2B was found to be large compared to that of TbFe2. X-ray diffractograms for the ball milled samples showed that after 80 h of milling, a predominantly amorphous phase was obtained. TbFe2B was found to undergo easy amorphization compared to TbFe2. Magnetization of TbFe2 was found to decrease rapidly with initial milling hours and was found to be constant with further hours of milling. TbFe2B exhibited an anomalous behaviour with an increase in moment with milling hours and this may be due to the segregation of -Fe.

  1. Record critical current densities in IG processed bulk YBa2Cu3Oy fabricated using ball-milled Y2Ba1Cu1O5 phase

    International Nuclear Information System (INIS)

    The infiltration-growth (IG) technique enables the uniform and controllable Y2BaCuO5 (Y211) secondary phase particles formation within the YBa2Cu3Oy (Y123) matrix. Recent results clarified that the flux pinning performance of the Y123 material was dramatically improved by optimizing the processing conditions during the IG process. In this paper, we adapted the IG technique and produced several samples with addition of nanometer-sized Y211 secondary phase particles, which were produced by a ball milling technique. We found that the performance of the IG processed Y123 material dramatically improved in the low field region for a ball milling time of 12 h as compared to the samples without a ball milling step. Magnetization measurements showed a sharp superconducting transition with an onset Tc at around 92 K. The critical current density (Jc) at 77 K and zero field was determined to be 224 022 Acm-2, which is higher than the not ball-milled sample. Furthermore, microstructural observations exhibited a uniform microstructure with homogenous distribution of nanosized Y-211 inclusions within the Y-123 matrix. The improved performance of the Y-123 material can be understood in terms of fine distribution of the secondary phases. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Highly anisotropic SmCo5 nanoflakes by surfactant-assisted ball milling at low temperature

    International Nuclear Information System (INIS)

    Surfactant-assisted ball milling (SABM) has been shown to be a promising method for preparing rare earth-transition metal (RE-TM) nanoflakes and nanoparticles. In this work, we prepared SmCo5 nanoflakes by SABM at low temperature, and 2-methyl pentane and trioctylamine were specially selected as solvent and surfactant, respectively, due to their low melting points. The effects of milling temperature on the morphology, microstructure and magnetic performance of SmCo5 nanoflakes were investigated systematically. Comparing with the samples milled at room temperature, the SmCo5 nanoflakes prepared at low temperature displayed more homogeneous morphology and lower oxygen content. Remarkably, better crystallinity, better grain alignment and larger remanence ratio were shown in the samples milled at low temperature, which resulted from the distinct microstructure caused by low milling temperature. The differences in structural evolution between the SmCo5 nanoflakes milled at room temperature and low temperature, including the formation of nanocrystalline, grain boundary sliding, grain rotation, et al., were discussed. It was found that lowering the temperature of SABM was a powerful method for the fabrication of RE-TM nanoflakes, which showed better hard magnetic properties and lower oxygen content. This was important for the preparation of high-performance sintered magnets, bonded magnets and nanocomposite magnets. - Highlights: • We prepare SmCo5 nanoflakes by surfactant-assisted ball milling at low temperature. • Better grain alignment and higher remanence ratio are achieved. • The oxygen content is reduced by lowering the milling temperature. • A distinct microstructural evolution caused by low milling temperature is clarified

  3. A preliminary study on the development of La2O3-bearing nanostructured ferritic steels via high energy ball milling

    International Nuclear Information System (INIS)

    Elemental powder mixture of Fe–Cr–Ti–Mo and La2O3 were ball milled for different milling times in a high energy shaker mill. Effects of ball milling time on crystallite size, particle size and hardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester. After 10 h of ball milling, the smallest crystallite size and highest hardness were ∼24 nm and ∼970 HV, respectively. Transmission electron microscopy (TEM) studies have revealed nanoscale features 2–5 nm in diameter present in the milled powder. Local atom probe tomography studies have shown that these nanoscale features were possibly nanoclusters enriched in La, TiO and O

  4. Stacking faults and structure analysis of ball-milled Fe-50%Co powders

    Energy Technology Data Exchange (ETDEWEB)

    Moumeni, Hayet, E-mail: hmoumeni@yahoo.fr [Departement de Physique, Faculte des Sciences et de l' Ingenierie, Universite 08 Mai 1945 de Guelma, B.P. 401, Guelma 24000 (Algeria); Laboratoire de Magnetisme et de Spectroscopie des Solides, Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, Annaba 23000 (Algeria); Nemamcha, Abderrafik [Departement de Chimie Industrielle, Faculte des Sciences et de l' Ingenierie, Universite 08 Mai 1945 de Guelma, B.P. 401, Guelma 24000 (Algeria); Alleg, Safia [Laboratoire de Magnetisme et de Spectroscopie des Solides, Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, Annaba 23000 (Algeria); Greneche, Jean Marc [Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, Faculte des Sciences, F-72085 Le Mans Cedex 9 (France)

    2010-08-01

    Stacking faults probability, structure and microstructure parameters of different phases of ball milled Fe-50%Co powders have been quantitatively evaluated by X-ray diffraction profile analysis. It is observed that after short milling time, Co is found to undergo an allotropic transformation from FCC to HCP form. The Rietveld whole profile fitting results reveal an increase of the stacking fault probability with increasing milling time and that twin faults are more prevalent than deformation ones. In addition to the reduction of crystallite size to the nanometer level and the increase of internal strain, prolonged milling leads to the formation of a BCC Fe(Co) solid solution with a high dislocations density (3.8 x 10{sup 17} m{sup -2}).

  5. Preparation of ultrafine magnetic biochar and activated carbon for pharmaceutical adsorption and subsequent degradation by ball milling.

    Science.gov (United States)

    Shan, Danna; Deng, Shubo; Zhao, Tianning; Wang, Bin; Wang, Yujue; Huang, Jun; Yu, Gang; Winglee, Judy; Wiesner, Mark R

    2016-03-15

    Ball milling was used to prepare two ultrafine magnetic biochar/Fe3O4 and activated carbon (AC)/Fe3O4 hybrid materials targeted for use in pharmaceutical removal by adsorption and mechanochemical degradation of pharmaceutical compounds. Both hybrid adsorbents prepared after 2h milling exhibited high removal of carbamazepine (CBZ), and were easily separated magnetically. These adsorbents exhibited fast adsorption of CBZ and tetracycline (TC) in the initial 1h. The biochar/Fe3O4 had a maximum adsorption capacity of 62.7mg/g for CBZ and 94.2mg/g for TC, while values obtained for AC/Fe3O4 were 135.1mg/g for CBZ and 45.3mg/g for TC respectively when data were fitted using the Langmuir expression. Solution pH values slightly affected the sorption of TC on the adsorbents, while CBZ sorption was almost pH-independent. The spent adsorbents with adsorbed CBZ and TC were milled to degrade the adsorbed pollutants. The adsorbed TC itself was over 97% degraded after 3h of milling, while about half of adsorbed CBZ were remained. The addition of quartz sand was found to improve the mechanochemical degradation of CBZ on biochar/Fe3O4, and its degradation percent was up to 98.4% at the dose of 0.3g quarts sand/g adsorbent. This research provided an easy method to prepare ultrafine magnetic adsorbents for the effective removal of typical pharmaceuticals from water or wastewater and degrade them using ball milling. PMID:26685062

  6. Hydrogen Sorption Properties of the Intermetallic Mg2Ni Obtained by Using a Simoloyer Ball Milling

    Directory of Open Access Journals (Sweden)

    Bormann R.

    2010-07-01

    Full Text Available Intermetallic Mg2Ni was produced from elemental powder blends by mechanical alloying in a batch scale using a rotary horizontal mill (Simoloyer. Fast hydrogenation kinetics are obtained: 2.2 wt.% of hydrogen is absorbed within 10 minutes at 300 °C. Hydrogen sorption kinetics were further improved by adding Pd (1 mol% powder as a catalyst during ball milling. Crack formation and concomitant particle size reduction was observed by scanning electron microscopy after hydrogen cycling, which is attributed to internal stresses in the particles.

  7. Sintered Fe-Ni-Cu-Sn-C Alloys Made of Ball-Milled Powders

    Directory of Open Access Journals (Sweden)

    Romański A.

    2014-10-01

    Full Text Available The main objective of this paper was to perform sinterability studies of ball-milled Fe-12%Ni-6.4%Cu-1.6%Sn-0.6%C powders. A mixture of precisely weighed amounts of elemental iron, nickel and graphite, and pre-alloyed 80/20 bronze powders was ball-milled for 8, 30 and 120 hours. After cold-pressing at 400 MPa the specimens were sintered at 900oC for 30 minutes in a reducing atmosphere and subsequently tested for density and hardness as well as subjected to structural studies using scanning electron microscopy (SEM and X-ray diffraction (XRD analysis.

  8. The structure of nitrogen-supersaturated ferrite produced by ball milling

    OpenAIRE

    Aufrecht, Jochen; Leineweber, Andreas; Mittemeijer, Eric Jan; Foct, Jacques

    2008-01-01

    Abstract Highly supersaturated solid solutions of nitrogen in ferrite (bcc) were produced by ball milling of various powder mixtures of ?-iron and ?-Fe3N1.08. The microstructure and the crystal structure of the product phases were examined as function of nitrogen content using X-ray powder diffraction, high-resolution electron microscopy and Mossbauer spectroscopy. It was found that the grain size decreases with increasing nitrogen content. Unexpected shifts of the reflections in t...

  9. A Kinetic Study of Micronization Grinding of Dry Mica in a Planetary Ball Mill

    OpenAIRE

    Ljubica Pavlović; Milan Petrov; Milan Trumić; Zagorka Aćimović-Pavlović; Ljubiša Andrić; Anja Terzić

    2013-01-01

    This paper presents results of the research of micronization grinding of dry mica in a planetary ball mill. Investigation was conducted in order to improve the quality and to obtain clearly defined properties and characteristics of mica powder. The micronization grinding of dry mica was performed in four time periods: 30, 60, 120, and 360 minutes. The micronized powder was investigated by means of differential thermal and thermogravimetric analyses, analysis of the degree of micronization, th...

  10. Synthesis and characterization of ball milled Fe-doped ZnO diluted magnetic semiconductor

    Institute of Scientific and Technical Information of China (English)

    R. Elilarassi; G. Chandrasekaran

    2012-01-01

    Fe-doped ZnO (Zn0.99Fe0.01O) powders are successfully prepared by ball milling with different milling time,and are investigated using X-ray diffraction (XRD),scanning electron microscope (SEM),ultraviolet-visible (UV-VIS) spectroscopy,vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) spectroscopy.The structural analysis using XRD reveals that the Fe-doped ZnO milled at different milling time can crystallize in a wurtzite structure,and in the XRD patterns,the secondary phase related to Fe cluster with the sensitivity of the XRD instrument can not be found.The SEM image of the sample milled for 24 h shows the presence of spherical nanoparticles.From the optical analysis,the optical band gap is found to decrease with increasing the milling time,which indicates the incorporation of Fe2+ ions into the ZnO lattice.The magnetization measurement using VSM reveals that the nanoparticles exhibit ferromagnetic behavior at room temperature,and the magnetization increases gradually with increasing the milling time.The conclusion is further confirmed by the electron paramagnetic resonance of the nanoparticles examined at room temperature,which shows an intense and broad ferromagnetic resonance signal related to Fe ions.

  11. Magnetic and charge derived properties of ball milled dilute magnetic semiconductor Si0.98Mn0.02

    International Nuclear Information System (INIS)

    The dilute magnetic semiconductor (DMS) material Si0.98Mn0.02 was prepared by a ball milling technique at two different milling periods. The samples have been analyzed for electron density distribution and local structure using powder X-ray diffraction (XRD) data sets. The results were compared with those of pure silicon. Structural changes and their implications on the bond-length distributions were analyzed and compared. Electron density distributions of the defect structure were plotted on 2D planes and along the bonding direction in the unit cell for each case using the maximum entropy method (MEM). The incorporation of transition metal ion (Mn) at substitutional sites of the host lattice (Si) is verified for Si0.98Mn0.02 from XRD and magnetic hysteresis measurements were taken using vibrating sample magnetometer (VSM). Room temperature ferromagnetism due to Mn substitution was observed in the prepared samples

  12. Microstructural characteristics and mechanical properties of carbon nanotube reinforced aluminum alloy composites produced by ball milling

    International Nuclear Information System (INIS)

    Highlights: • 6082 Al alloy composite with 2 wt% multiwalled carbon nanotubes prepared by milling. • Effect of milling time on structure and property evolution has been studied. • The reinforced composite powders showed a drastic crystallite size refinement. • The presence of carbon nanotube led to a two fold increase in the hardness and modulus. • The composite powder showed good thermal stability studied by DTA. - Abstract: The influence of milling time on the structure, morphology and thermal stability of multi-walled carbon nanotubes (MWCNTs) reinforced EN AW6082 aluminum alloy powders has been studied. After structural and microstructural characterization of the mechanically milled powders micro- and nano-hardness of the composite powder particles were evaluated. The morphological and X-ray diffraction studies on the milled powders revealed that the carbon nanotubes (CNTs) were uniformly distributed and embedded within the aluminum matrix. No reaction products were detected even after long milling up to 50 h. Nanotubes became shorter in length as they fractured under the impact and shearing action during the milling process. A high hardness of about 436 ± 52 HV is achieved for the milled powders, due to the addition of MWCNTs, after milling for 50 h. The increased elastic modulus and nanohardness can be attributed to the finer grain size evolved during high energy ball milling and to the uniform distribution of hard CNTs in the Al-alloy matrix. The hardness values of the composite as well as the matrix alloy compares well with that predicted by the Hall–Petch relationship

  13. Optimum condition determination of Rirang uranium ores grinding using ball mill

    International Nuclear Information System (INIS)

    The grinding experiment on Rirang Uranium ore has been carried out with the aim is to find out the optimum condition of wet grinding using ball mill to produce particle size -325, -200 and -100 mesh. This will be used for decomposition feed the test was done by examine the parameters comparison of ore's weight against ball's weight and time of grinding. The test shown that the product of particle size -325 meshes was achieved optimum condition at the comparison ore's weight: ball = 1:3, grinding time 150 minutes, % solid 60, speed rotation of ball mill 60 rpm and recovery of grinding was 93.51 % of -325 mesh. The product of particle size -200 mesh was achieved optimum condition at comparison ore's weight: ball = 1:2, time of grinding 60 minutes, the fraction of + 200 mesh was regrind, the recovery of grinding 6.82% at particle size of (-200 + 250) mesh, 5.75 % at (-250 + 325)m mesh and, 47.93 % -325 mesh. The product of particle size -100 mesh was achieved the optimum condition at comparison ore's weight: ball = 1:2, time of grinding at 30 minutes particle size +100 mesh regrinding using mortar grinder, recovery of grinding 30.10% at particle size (-100 + 150) m, 12.28 % at (-150 + 200) mesh, 15.92 % at (-200 + 250) mesh, 12.44 % at (-250 + 325) mesh and 29.26 % -325 mesh. The determination of specific gravity of Rirang uranium ore was between 4.15 - 4.55 g/cm3

  14. Hydrogen storage performance of TiFe after processing by ball milling

    International Nuclear Information System (INIS)

    Activation of TiFe for hydrogen storage by severe plastic deformation (SPD) through ball milling technique and the effect of microstructure on this activation have been investigated. TiFe becomes activated after the ball milling and is not deactivated after exposure to air, similar to TiFe activated by high-pressure torsion (HPT). The hydrogenation capacity reaches 1.3–1.5 wt.% at 303 K for the first to third cycles and the hydrogen absorption plateau pressure decreases to ∼1 MPa for any hydrogenation cycles. Observation of the microstructure after ball milling shows that the average grain size and crystallite size are as small as ∼7 and ∼11 nm, respectively (smaller than that after HPT or rolling), but few dislocations are detected within the detection limit of high-resolution transmission electron microscopy. This study shows clearly that there is a strong relation between the grain size of TiFe and its activation for hydrogen absorption: the activation is easier and the hydrogen pressure for activation is smaller, when the grain size is smaller

  15. Homogeneous nanoparticle dispersion prepared with impurity-free dispersant by the ball mill technique

    Institute of Scientific and Technical Information of China (English)

    Lingyun Zhou; Hui Zhang; Hui Zhang; Zhong Zhang

    2013-01-01

    The homogeneous dispersion of nanoparticles in solvents or polymer matrices is essential tor prac tical application of nanocomposites.In this study,the planetary ball milling technique was used to de-agglomerate silica nanoparticles in butyl acetate.The size of the nanosilica aggregates was evaluated by TEM and SEM.With the addition of polyacrylate polymer to the organic solvent,the nanoparticle agglomerates were effectively broken up by planetary ball milling at the proper milling time; however,re-agglomeration occurred after a longer milling time.The results of TGA and FTIR indicated that the polyacrylate molecules could be adsorbed in situ onto the nanoparticles.Behaving similar to a dispersant,the adsorbed polyacrylate reduced the blend viscosity significantly and prevented re-agglomeration of the nanoparticles.Utilizing the polyacrylate polymer both as the dispersant and the polymer matrix,the polyacrylate-based nanocoatings were further prepared.The optical transmittance and haze value of the nanocoatings were found to be sensitive to the dispersion level of the nanoparticles,and the elastic modulus and hardness of the nanocoatings were improved in comparison with those of the neat polymer coating.

  16. Impact of high energy ball milling on the nanostructure of magnetite–graphite and magnetite–graphite–molybdenum disulphide blends

    International Nuclear Information System (INIS)

    Different, partly complementary and partly redundant characterization methods were applied to study the transition of magnetite, graphite and MoS2 powders to mechanically alloyed nanostructures. The applied methods were: Transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), Raman spectroscopy (RS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The main objective was to prepare a model material providing the essential features of a typical tribofilm forming during automotive braking, and to assess the impact of different constituents on sliding behaviour and friction level. Irrespective of the initial grain size, the raw materials were transferred to a nanocrystalline structure and mixed on a nanoscopic scale during high energy ball milling. Whereas magnetite remained almost unchanged, graphite and molybdenum disulphide were transformed to a nanocrystalline and highly disordered structure. The observed increase of the coefficient of friction was attributed to a loss of lubricity of the latter ingredient due to this transformation and subsequent oxidation. - Highlights: • Characterization of microstructural changes induced by high energy ball milling • Assessment of the potential of different characterization methods • Impact of mechanical alloying on tribological performance revealed by tests • Preparation of an artificial third body resembling the one formed during braking

  17. Iron Nanoparticles Fabricated by High-Energy Ball Milling for Magnetic Hyperthermia

    Science.gov (United States)

    Tung, D. K.; Manh, D. H.; Phong, L. T. H.; Nam, P. H.; Nam, D. N. H.; Anh, N. T. N.; Nong, H. T. T.; Phan, M. H.; Phuc, N. X.

    2016-05-01

    Iron nanoparticles (FeNPs) have been successfully prepared by high-energy ball milling in air for various milling times from 1 h to 32 h. Their structure, particle size, elemental composition, magnetic, and inductive heating properties were investigated by means of x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy, energy-dispersive x-ray (EDX) spectroscopy, vibrating-sample magnetometry, and magnetic induction heating, respectively. XRD analysis showed that the average crystallite size decreased to 11 nm after 10 h of milling, then remained almost unchanged for longer milling times. Coexistence of iron (Fe) and iron oxide (FeO) phases was detected after 12 h of milling. EDX analysis also confirmed the occurrence of oxidation, which can be reconciled with the corresponding decrease and increase in saturation magnetization ( M s) with milling time when exposed to oxygen and when annealed under H2 ambient due to oxygen reduction. The time-dependent magnetic and inductive heating responses of the FeNPs were investigated for prospective application in magnetic hyperthermia. The effect of varying the alternating-current (AC) magnetic field strength on the saturation heating temperature and specific loss power of FeNP-containing ferrofluid with concentration of 4 mg/mL was also studied and is discussed.

  18. Nanostructure formation mechanism during in-situ consolidation of copper by room-temperature ball milling

    International Nuclear Information System (INIS)

    Highlights: • Hollow spheres of Cu were produced with increasing diameter by milling time. • After 70 h of milling, the diameter of hollow spheres reached to ∼8 mm. • Its microstructure consisted of both elongated ultrafine together with nanometer level spherical grains. • Continuous dynamic recrystallization was the dominant mechanism for the formation of nanosized grains. • Evidences for discontinuous dynamic recrystallization were also found in some regions of the microstructure. - Abstract: Bulk nanostructured Cu was prepared by in-situ consolidation through room temperature ball milling. The consolidated parts consist of hollow spheres having a diameter which increases with increasing the milling time. Microhardness maps reveal that the distribution of the hardness is relatively homogeneous after 2 h of milling. After 34 h the hardness is higher at the outer edge and decreases toward the inner edge and, finally, after 70 h the distribution is uniform again. Electron microscopic results show that the microstructure after 70 h of milling consists of two types of grains: elongated ultrafine grains with high density of defects and equiaxed nanosized grains produced by dynamic recrystallization. Continuous dynamic recrystallization is the dominant mechanism for the formation of the nanosized grains. Evidence for the occurrence of discontinuous dynamic recrystallization through twinning was also found in a few regions of the in-situ consolidated samples

  19. Effect of ball milling time on nanocrystalline powders and bulk ultrafine-grained Mg-3Al-Zn alloy

    Directory of Open Access Journals (Sweden)

    Feng Jie

    2015-01-01

    Full Text Available Bulk ultrafine-grained Mg-3Al-Zn alloy has been made of elemental powders by mechanical milling, vacuum hot pressing and warm extrusion sequentially. As the only variable, ball milling time was 20 h, 40 h, 60 h and 80 h, respectively. Microstructural studies and mechanical strength were characterized by SEM, XRD, TEM and tensile tests. At 60 h, the particle size of the milled powders decreased to 10 μm. With extension of time, the grain sizes of nanocrystalline powders were 41, 39.5, 38.5 and 38 nm. Under the same hot pressing and extrusion conditions, the grain sizes of extruded materials were 600, 565, 555 and 550 nm, respectively. The results of tensile tests showed that increasing milling time under 60 h improved the strength of the extruded alloys, however, reduced the ductility due to lower relative density and more defects. This also indicated that better ductility with high strength should be obtained if densification process was further improved. Meanwhile, the high ultimate strength of 419 MPa results from oxide dispersion strengthening and dislocation strengthening besides grain refinement strengthening.

  20. Effects of ball milling on microstructures and thermoelectric properties of higher manganese silicides

    International Nuclear Information System (INIS)

    Highlights: • The already low κL of HMS can be suppressed further by decreasing the grain size. • The ball milling process can lead to the formation of secondary MnSi and W/C-rich phases. • The formation of the MnSi ad W/C rich phases is found to suppress the thermoelectric power factor. - Abstract: Bulk nanostructured higher manganese silicide (HMS) samples with different grain size are prepared by melting, subsequent ball milling (BM), and followed by spark plasma sintering (SPS). The effects of BM time on the microstructures and thermoelectric properties of these samples are investigated. It is found that BM effectively reduces the grain size to about 90 nm in the sample after SPS, which leads to a decrease in both the thermal conductivity and electrical conductivity. By prolonging the BM time, MnSi and tungsten/carbon-rich impurity phases are formed due to the impact-induced decomposition of HMS and contamination from the tungsten carbide jar and balls during the BM, respectively. These impurities result in a reduced Seebeck coefficient and increased thermal conductivity above room temperature. The measured size-dependent lattice thermal conductivities agree qualitatively with the reported calculation results based on a combined phonon and diffuson model. The size effects are found to be increasingly significant as temperature decreases. Because of the formation of the impurity phases and a relatively large grain size, the ZT values are not improved in the ball-milled HMS samples. These findings suggest the need of alternative approaches for the synthesis of pure HMS with further reduced grain size and controlled impurity doping in order to enhance the thermoelectric figure-of-merit of HMS via nanostructuring

  1. Formation of a 25 mol% Fe2O3-Al2O3 solid solution prepared by ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Mørup, Steen; Linderoth, Søren

    1996-01-01

    The phase transformation process of a 25 mol% Fe2O3-Al2O3 powder mixture during high-energy ball milling has been studied by x-ray diffraction and Mossbauer spectroscopy. A metastable solid solution of 25 mol % Fe2O3 in Al2O3 with corundum structure has successfully been prepared after a milling...

  2. Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718

    OpenAIRE

    N.N. Bhopale; R.S. Pawade

    2012-01-01

    The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting p...

  3. Enhanced lithium storage in ZnFe2O4-C nanocomposite produced by a low-energy ball milling

    Science.gov (United States)

    Thankachan, Rahul Mundiyaniyil; Rahman, Md Mokhlesur; Sultana, Irin; Glushenkov, Alexey M.; Thomas, Sabu; Kalarikkal, Nandakumar; Chen, Ying

    2015-05-01

    Preparation of novel nanocomposite structure of ZnFe2O4-C is achieved by combining a sol-gel and a low energy ball milling method. The crucial feature of the composite's structure is that sol-gel synthesised ZnFe2O4 nanoparticles are dispersed and attached uniformly along the chains of Super P Li™ carbon black matrix by adopting a low energy ball milling. The composite ZnFe2O4-C electrodes are capable of delivering a very stable reversible capacity of 681 mAh g-1 (96% retention of the calculated theoretical capacity of ∼710 mAh g-1) at 0.1 C after 100 cycles with a remarkable Coulombic efficiency (82%) improvement in the first cycle. The rate capability of the composite is significantly improved and obtained capacity was as high as 702 at 0.1, 648 at 0.5, 582 at 1, 547 at 2 and 469 mAh g-1 at 4 C (2.85 A g-1), respectively. When cell is returned to 0.1 C, the capacity recovery was still ∼98%. Overall, the electrochemical performance (in terms of cycling stability, high rate capability, and capacity retention) is outstanding and much better than those of the related reported works. Therefore, our smart electrode design enables ZnFe2O4-C sample to be a high quality anode material for lithium-ion batteries.

  4. Strong textured SmCo5 nanoflakes with ultrahigh coercivity prepared by multistep (three steps) surfactant-assisted ball milling

    Science.gov (United States)

    Zuo, Wen-Liang; Zhao, Xin; Xiong, Jie-Fu; Zhang, Ming; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2015-08-01

    The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling. The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively. The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one step high energy ball-milling, which enhances the texture degree and coercivity. In addition, the mechanism of coercivity are also studied by the temperature dependence of demagnetization curves for aligned SmCo5 nanoflakes/resin composite, the result indicates that the magnetization reversal could be controlled by co-existed mechanisms of pinning and nucleation.

  5. Quenching ilmenite with a high-temperature and high-pressure phase using super-high-energy ball milling.

    Science.gov (United States)

    Hashishin, Takeshi; Tan, Zhenquan; Yamamoto, Kazuhiro; Qiu, Nan; Kim, Jungeum; Numako, Chiya; Naka, Takashi; Valmalette, Jean Christophe; Ohara, Satoshi

    2014-01-01

    The mass production of highly dense oxides with high-temperature and high-pressure phases allows us to discover functional properties that have never been developed. To date, the quenching of highly dense materials at the gramme-level at ambient atmosphere has never been achieved. Here, we provide evidence of the formation of orthorhombic Fe2TiO4 from trigonal FeTiO3 as a result of the high-temperature (>1250 K) and high-pressure (>23 GPa) condition induced by the high collision energy of 150 gravity generated between steel balls. Ilmenite was steeply quenched by the surrounding atmosphere, when iron-rich ilmenite (Fe2TiO4) with a high-temperature and high-pressure phase was formed by planetary collisions and was released from the collision points between the balls. Our finding allows us to infer that such intense planetary collisions induced by high-energy ball milling contribute to the mass production of a high-temperature and high-pressure phase. PMID:24763088

  6. High-Efficient Production of Boron Nitride Nanosheets via an Optimized Ball Milling Process for Lubrication in Oil

    Science.gov (United States)

    Deepika; Li, Lu Hua; Glushenkov, Alexey M.; Hait, Samik K.; Hodgson, Peter; Chen, Ying

    2014-12-01

    Although tailored wet ball milling can be an efficient method to produce a large quantity of two-dimensional nanomaterials, such as boron nitride (BN) nanosheets, milling parameters including milling speed, ball-to-powder ratio, milling ball size and milling agent, are important for optimization of exfoliation efficiency and production yield. In this report, we systematically investigate the effects of different milling parameters on the production of BN nanosheets with benzyl benzoate being used as the milling agent. It is found that small balls of 0.1-0.2 mm in diameter are much more effective in exfoliating BN particles to BN nanosheets. Under the optimum condition, the production yield can be as high as 13.8% and the BN nanosheets are 0.5-1.5 μm in diameter and a few nanometers thick and of relative high crystallinity and chemical purity. The lubrication properties of the BN nanosheets in base oil have also been studied. The tribological tests show that the BN nanosheets can greatly reduce the friction coefficient and wear scar diameter of the base oil.

  7. A software tool for simulation of surfaces generated by ball nose end milling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano

    2004-01-01

    The number of models available for prediction of surface topography is very limited. The main reason is that these models cannot be based on engineering principles like those for elastic deformations. Most knowledge about surface roughness and integrity is empirical and up to now very few mathema...... readable by a surface processor software (SPIP [2]), for calculation of a number of surface roughness parameters. In the next paragraph a description of the basic features of ball nose end milled surfaces is given, while in paragraph 3 the model is described....

  8. Generation of drugs coated iron nanoparticles through high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Radhika Devi, A.; Murty, B. S. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Chelvane, J. A. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Prabhakar, P. K.; Padma Priya, P. V.; Doble, Mukesh [Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036 (India)

    2014-03-28

    The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

  9. Low-temperature magnetic behavior of ball-milled copper ferrite

    DEFF Research Database (Denmark)

    Goya, G.F.; Rechenberg, H.R.; Jiang, Jianzhong

    1999-01-01

    We present a study on magnetic properties of CuFe2O4 nanoparticles, produced by high-energy ball milling. The series of samples obtained, with average particle sizes LFAN alpha d RTAN ranging from 61 nm to 9 nm, display increasing relaxation effects at room temperature. Irreversibility of the...... core. The temperature dependence of average hyperfine field, saturation magnetization and coercive field shows a change of slope at T-f, indicating the spin freezing of the disordered phase at T-f. From the H-C(T) curves below T-f, the thickness of the surface layer was found to increase as the average...

  10. Generation of drugs coated iron nanoparticles through high energy ball milling

    International Nuclear Information System (INIS)

    The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells

  11. Magnetization and Specific Absorption Rate Studies of Ball-Milled Iron Oxide Nanoparticles for Biomedicine

    Directory of Open Access Journals (Sweden)

    P. Burnham

    2013-01-01

    Full Text Available Comparative studies are presented of iron oxide nanoparticles in the 7–15 nm average diameter range ball milled in hexane in the presence of oleic acid. Transmission electron microscopy identified spherical particles of decreasing size as milling time and/or surfactant concentration increased. Micromagnetic characterization via Mössbauer spectroscopy at room temperature yielded broadened magnetic spectroscopic signatures, while macromagnetic characterization via vibrating sample magnetometry of 7-8 nm diameter particles showed largely superparamagnetic behavior at room temperature and hysteretic at 2 K. Zero-field and field-cooled magnetization curves exhibited a broad maximum at ~215 K indicating the presence of strong interparticle magnetic interactions. The specific absorption rates of ferrofluids based on these nanoparticle preparations were measured in order to test their efficacies as hyperthermia agents.

  12. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    Energy Technology Data Exchange (ETDEWEB)

    Lopez B, I.; Trapaga M, L. G. [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico); Martinez F, E. [Centro de Investigacion e Innovacion Tecnologica, Cerrada de Cecati s/n, Col. Santa Catarina Azcapotzalco, 02250 Mexico D. F. (Mexico); Zoz, H., E-mail: israelbaez@gmail.co [Zoz GmbH, D-57482, Wenden (Germany)

    2011-07-01

    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  13. Bulk Al/SiC nanocomposite prepared by ball milling and hot pressing method

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li

    2006-01-01

    Nano-sized Al/SiC powders were prepared by mechanical alloying method. Two sorts of SiC particle,i.e.,nano-sized and popular micron-sized SiC were utilized. The particle size and microstructure of the milled powder were characterised. Effects of the particle size and agglomerate state of SiC,as well as the microstructure of Al/SiC nanocomposite were studied by SEM and TEM. The results show that nano-sized SiC particles is dispersed in aluminium uniformly after ball milled for only 2 h,whereas the similar process need about 10 h for popular micron-sized SiC particle. The bulk Al/SiC nanocomposite can be fabricated by hot pressing the nano-sized Al/SiC powders at temperature about 723 K under pressure of 100 MPa.

  14. Synthesis of Nano-Size AlN Powders by Carbothermal Reduction from Plasma-Assisted Ball Milling Precursor

    Science.gov (United States)

    Liu, Zhijie; Wang, Wenchun; Yang, Dezheng; Wang, Sen; Dai, Leyang

    2016-07-01

    Nano-size aluminum nitride (AlN) powders have been successfully synthesized with a high efficiency method through annealing from milling assisted by discharge plasma (p-milling) alumina (Al2O3) precursors. The characterization of the p-milling Al2O3 powders and the synthesized AlN are investigated. Compared to conventional ball milling (c-milling), it can be found that the precursors by p-milling have a finer grain size with a higher specific surface area, which lead to a faster reaction efficiency and higher conversion to AlN at lower temperatures. The activation energy of p-milling Al2O3 is found to be 371.5 kJ/mol, a value that is much less than the reported value of the unmilled and the conventional milled Al2O3. Meanwhile, the synthesized AlN powders have unique features, such as an irregular lamp-like morphology with uniform particle distribution and fine average particle size. The results are attributed to the unique synergistic effect of p-milling, which is the effect of deformation, fracture, and cold welding of Al2O3 powders resulting from ball milling, that will be enhanced due to the introduction of discharge plasma. supported by National Natural Science Foundation of China (No. 51177008)

  15. Synthesis of the Mg{sub 2}Ni alloy prepared by mechanical alloying using a high energy ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J. L.; Lopez M, B. E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia N, M. R., E-mail: joseluis.iturbe@inin.gob.m [UNAM, Facultad de Estudios Superiores Zaragoza, Batalla 5 de Mayo s/n, Esq. Fuerte de Loreto, Col. Ejercito de Oriente, 09230 Mexico D. F. (Mexico)

    2010-07-01

    Mg{sub 2}Ni was synthesized by a solid state reaction from the constituent elemental powder mixtures via mechanical alloying. The mixture was ball milled for 10 h at room temperature in an argon atmosphere. The high energy ball mill used here was fabricated at ININ. A hardened steel vial and three steel balls of 12.7 mm in diameter were used for milling. The ball to powder weight ratio was 10:1. A small amount of powder was removed at regular intervals to monitor the structural changes. All the steps were performed in a little lucite glove box under argon gas, this glove box was also constructed in our Institute. The structural evolution during milling was characterized by X-ray diffraction and scanning electron microscopy techniques. The hydrogen reaction was carried out in a micro-reactor under controlled conditions of pressure and temperature. The hydrogen storage properties of mechanically milled powders were evaluated by using a thermogravimetric analysis system. Although homogeneous refining and alloying take place efficiently by repeated forging, the process time can be reduced to one fiftieth of the time necessary for conventional mechanical milling and attrition. (Author)

  16. Preparation, characterization and optoelectronic properties of nanodiamonds doped zinc oxide nanomaterials by a ball milling technique

    Science.gov (United States)

    Ullah, Hameed; Sohail, Muhammad; Malik, Uzma; Ali, Naveed; Bangash, Masroor Ahmad; Nawaz, Mohsan

    2016-07-01

    Zinc oxide (ZnO) is one of the very important metal oxides (MOs) for applications in optoelectronic devices which work in the blue and UV regions. However, to meet the challenges of obtaining ZnO nanomaterials suitable for practical applications, various modifications in physico-chemical properties are highly desirable. One of the ways adopted for altering the properties is to synthesize composite(s) of ZnO with various reinforcements. Here we report on the tuning of optoelectronic properties of ZnO upon doping by nanodiamonds (NDs) using the ball milling technique. A varying weight percent (wt.%) of NDs were ball milled for 2 h with ZnO nanoparticles prepared by a simple precipitation method. The effects of different parameters, the calcination temperature of ZnO, wt.% of NDs and mechanical milling upon the optoelectronic properties of the resulting ZnO–NDs nanocomposites have been investigated. The ZnO–NDs nanocomposites were characterized by IR spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The UV-vis spectroscopy revealed the alteration in the bandgap energy (Eg ) of ZnO as a function of the calcination temperature of ZnO, changing the concentration of NDs, and mechanical milling of the resulting nanocomposites. The photoluminescence (PL) spectroscopy showed a decrease in the deep level emission (DLE) peaks and an increase in near-band-edge transition peaks as a result of the increasing concentration of NDs. The decrease in DLE and increase in band to band transition peaks were due to the strong interaction between the NDs and the Zn+; consequently, the Zn+ concentration decreased on the interstitial sites.

  17. Melting process of nanometer-sized in particles embedded in an Al matrix synthesized by ball milling

    International Nuclear Information System (INIS)

    Dispersions of nanometer-sized In particles embedded in an Al matrix (10 wt.% In) have been synthesized by ball milling of a mixture of Al and In powders. The as-milled product was characterized by using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectrometer (EDX), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HREM), respectively. It was found that In and Al are pure components immiscible with each other, with nanometer-sized In particles dispersively embedded in the Al matrix. The melting behavior of In particles was investigated by means of differential scanning calorimeter (DSC). The calorimetric measurements indicate that both the melting point and the melting enthalpy of the In nanoparticles decrease with increasing milling time, or refinement of the In particles. Compared to its bulk melting temperature, a melting point depression of 13.4 K was observed when the mean grain size of In is 15 nm, and the melting point depression of In nanoparticles is proportional to the reciprocal of the mean grain size. The melting enthalpy depression was interpreted according to the two-state concept for the nanoparticles. Melting of the interface was deduced to be an exothermal process due to its large excess energy/volume. copyright 1996 Materials Research Society

  18. Ultrafine Sm-Fe-N Particles Prepared by Planetary Ball Milling

    Directory of Open Access Journals (Sweden)

    Neil D.

    2013-01-01

    Full Text Available Ultrafine magnetically hard particles are needed for the bottom­up fabrication of anisotropic exchanged­coupled permanent magnets. In this study we have chosen Sm2Fe17Nx because of its high anisotropy field and large saturation magnetization. A multi­stage planetary ball milling process was used. The key is to find the right balance of energy used to mill the precursor particles; it must be high enough to break the particles and reduce their size but, not so high as to destroy the crystal structure of the nanoparticles that would lead to deterioration of the magnetic properties. First the coarse powders were subjected to a wet milling with 2.0 mm diameter media. In each subsequent stage the media size was reduced to maintain the milling balance. Using such a process produced particles in a size range from 100 - 800 nm with a coercivity as high as 10 kOe at room temperature.

  19. Size effect on the melting temperature depression of Al12Mg17 complex metallic alloy nanoparticles prepared by planetary ball milling

    Science.gov (United States)

    Zolriasatein, Ashkan; Shokuhfar, Ali

    2015-11-01

    This research investigates the synthesis and size-dependent melting point depression of complex metallic alloy (CMA) nanoparticles. Al12Mg17 which belongs to this new category of intermetallic materials was initially produced as pre-alloyed ingot, then homogenized to achieve single phase compound and crushed into small size powder and finally, mechanically milled in a planetary ball mill to synthesize nanoparticles. Phase and microstructural characterizations of the as-crushed and milled powders were performed using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Effects of the mechanical milling on thermal behavior of the Al12Mg17 nanoparticles in comparison with as-cast Al12Mg17 ingot has been investigated by differential scanning calorimetry (DSC) measurement. It was found that an average particle size of 24 nm with crystallite size of 16 nm was achieved after 20 h of ball milling process. The size- dependent melting point depression of the Al12Mg17 nanoparticles has been experimentally observed and also comparison of the obtained results with theoretical models was carried out.

  20. Influence of Iron Oxide Particles on the Strength of Ball-Milled Iron

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D R; Syn, C K; Sherby, O D

    2005-12-07

    Detailed microstructural and mechanical property studies of ball-milled iron, in the powder and consolidated states, are reviewed and assessed. The analyses cover three and one-half orders of magnitude of grain size (from 6 nm to 20 mm) and focus on the influence of oxide particles on the strength. The study includes the early work of Koch and Yang, Kimura and Takaki and continues with the more recent work of Umemoto et al and Belyakov, Sakai et al. It is shown that the major contributors to strength are the nanooxide particles. These particles are created by adiabatic shear banding during ball-milling leading to a bimodal distribution of particles. The predicted strength from particles, {sigma}{sub p}, is given by {sigma}{sub p} = B {center_dot} (D*{sub S}){sup -1/2} where D*{sub S} is the surface-to-surface interparticle spacing, and B = 395 MPa {center_dot} {micro}m{sup -1/2}. A model is proposed that accounts for the influence of the bimodal particle size distribution on strength.

  1. Ball mill assisted rapid mechanochemical extraction method for natural products from plants.

    Science.gov (United States)

    Wang, Man; Bi, Wentao; Huang, Xiaohua; Chen, David Da Yong

    2016-06-01

    A ball mill assisted mechanochemical extraction method was developed to extract compounds of natural product (NP) from plant using ionic liquid (IL). A small volume ball mill, also known as PastPrep(®) Homogenizer, which is often used for high-speed lysis of biological samples and for other applications, was used to dramatically increase the speed, completeness and reproducibility of the extraction process at room temperature to preserve the chemical integrity of the extracted compounds. In this study, tanshinones were selected as target compounds to evaluate the performance of this extraction method. Factors affecting the extraction efficiency, such as the duration, IL concentration and solid/liquid ratio were systematically optimized using the response surface methodology. Under the optimized conditions, the described method was more efficient and much faster than the conventional extraction methods such as methanol based ultrasound assisted extraction (UAE) and heat reflux extraction (HRE) that consumes a lot more organic solvent. In addition, the natural products of interest were enriched by anion metathesis of ionic liquids, combining extraction and preconcentration in the same process. The extractant was analyzed by HPLC and LC-MS. The reproducibility (RSD, n=5), correlation coefficient (r(2)) of the calibration curve, and the limit of detection, were determined to be in the range of 4.7-5.2%, 0.9992-0.9995, and 20-51ng/mL, respectively. PMID:27157426

  2. Remarkable performance improvement of inexpensive ball-milled Si nanoparticles by carbon-coating for Li-ion batteries

    Science.gov (United States)

    Kasukabe, Takatoshi; Nishihara, Hirotomo; Iwamura, Shinichiroh; Kyotani, Takashi

    2016-07-01

    Si nanoparticles prepared by ball-milling (BM-Si) are expected as practical negative-electrode materials for lithium-ion batteries, but their performance is much lower than those of more expensive Si nanomaterials, such as chemical-vapor-deposition derived Si nanoparticles (CVD-Si) having a tight network structure. It is found that carbon-coating of aggregations of BM-Si forms a quasi-network structure, thereby making the performance comparable to that of CVD-Si under capacity restriction (to 1500 mAh g-1). In this case, the structural transition of BM-Si during charge/discharge cycling is characterized by the formation of a specific 'wrinkled structure', which is very similar to that formed in CVD-Si.

  3. Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling

    Science.gov (United States)

    Bobzin, Kirsten; Zhao, Lidong; Schlaefer, Thomas; Warda, Thomas

    2011-06-01

    High-energy ball milling is an effective method to produce nanocrystalline oxides. In this study, a conventional ZrO2-7%Y2O3 spray powder was ball-milled to produce nanocrystalline powders with high levels of crystalline disorders for deposition of thermal barrier coatings. The powder was milled both with 100Cr6 steel balls and with ZrO2-3%Y2O3 ceramic balls as grinding media. The milling time was varied in order to investigate the effect of the milling time on the crystallite size. The powders were investigated in terms of their crystallite sizes and morphologies by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that under given milling conditions the powder was already nanostructured after 40 min milling. The crystallite size decreased significantly with increasing milling time within first 120 min. After that, a further increase of milling time did not lead to a significant reduction of the crystallite size. Ball-milling led to lattice microstrains. Milling with the steel balls resulted in finer nano-sized crystal grains, but caused the contamination of the powder. The nano-sized crystal grains coarsened during the heat-treatment at 1250°C.

  4. Water Bouncing Balls: how material stiffness affects water entry

    Science.gov (United States)

    Truscott, Tadd

    2014-03-01

    It is well known that one can skip a stone across the water surface, but less well known that a ball can also be skipped on water. Even though 17th century ship gunners were aware that cannonballs could be skipped on the water surface, they did not know that using elastic spheres rather than rigid ones could greatly improve skipping performance (yet would have made for more peaceful volleys). The water bouncing ball (Waboba®) is an elastic ball used in a game of aquatic keep away in which players pass the ball by skipping it along the water surface. The ball skips easily along the surface creating a sense that breaking the world record for number of skips could easily be achieved (51 rock skips Russell Byers 2007). We investigate the physics of skipping elastic balls to elucidate the mechanisms by which they bounce off of the water. High-speed video reveals that, upon impact with the water, the balls create a cavity and deform significantly due to the extreme elasticity; the flattened spheres resemble skipping stones. With an increased wetted surface area, a large hydrodynamic lift force is generated causing the ball to launch back into the air. Unlike stone skipping, the elasticity of the ball plays an important roll in determining the success of the skip. Through experimentation, we demonstrate that the deformation timescale during impact must be longer than the collision time in order to achieve a successful skip. Further, several material deformation modes can be excited upon free surface impact. The effect of impact velocity and angle on the two governing timescales and material wave modes are also experimentally investigated. Scaling for the deformation and collision times are derived and used to establish criteria for skipping in terms of relevant physical parameters.

  5. Synthesis of nanodiamond-reinforced aluminum metal composite powders and coatings using high-energy ball milling and cold spray

    OpenAIRE

    Woo, D. J.; Sneed, B.; Peerally, F.; Heer, F. C.; Brewer, L.N.; Hooper, J. P.; OSSWALD, S

    2013-01-01

    Nanodiamond-reinforced aluminum metal matrix composites (ND–Al MMC) powders were synthesized by means of high energy ball milling. We present a systematic study of the effect of various milling conditions on the structure and properties of the resulting MMC powders. The described method can be used to control important powder characteristics, including particle size and shape, Al crystal size and residual strain, and structural integrity and dispersion of the nanoparticle inclusio...

  6. Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

    OpenAIRE

    Dazhong Wang; Yan Lu; Tongchao Zhang; Keyong Wang; Akira Rinoshika

    2015-01-01

    Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC) milling machine set ermined as a research object, the stiffness of its f...

  7. Synthesis of β-SiC nanowires by ball milled nanoparticles of silicon and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Pengchao, E-mail: kangpc@hit.edu.cn [Materials Science and Engineering School, Harbin Institute of Technology, P.O.B. 433, Harbin 150001 (China); Zhang, Bin; Wu, Gaohui; Gou, Huasong; Chen, Guoqin; Jiang, Longtao [Materials Science and Engineering School, Harbin Institute of Technology, P.O.B. 433, Harbin 150001 (China); Mula, Suhrit [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2014-08-01

    Highlights: • The β-SiC nanowires were synthesized only use milled Si and C nanoparticles. • No catalyst was used in this process. • The grown mechanism of β-SiC nanowires is nanoparticles self-assembly and solid–solid reaction. • This notion, together with the nanowires synthesis are expected to apply opens up other semiconductor nanomaterials. - Abstract: In the present investigation, we report a simple and new technique to synthesize silicon carbide nanowires by high energy ball milling of silicon and carbon powders followed by annealing at elevated temperatures. The detailed structural analysis was carried out by X-ray diffraction, scanning and transmission electron microscopy, and FT-IR analysis. Nanocrystalline silicon particles were detected to be covered by amorphous carbon after milling. This typical structure was transformed to β-SiC nanowires during annealing by new growth mechanism. The β-SiC nanoparticles were found to be self-assembled one by one and formed a curly chain, and then rotated gradually in accordance to the same crystal orientation along the β-SiC [1 1 1] direction.

  8. Surface Integrity of Titanium Alloy Ti-6Al-4 V in Ball end Milling

    Science.gov (United States)

    Mhamdi, M.-B.; Boujelbene, M.; Bayraktar, E.; Zghal, A.

    With the evolution of machine tools and the emergence of new cutting tools such as cermet, CBN; and in framework of the production of parts with complex geometry, the manufacturers were able to realize more and more parts of complex shape. The multi-axis machining is the main technique for achieving the free form; in fact the multi-axis milling with ball end tools attracts the interest of the aerospace industry and the mussel industry which continues to seek ways to improve the surface quality of finished parts. The titanium alloy is widely used in aerospace industry is the subject of this study in fact, the integrity of the surfaces of parts produced by multi-axis milling is an issue more relevant than ever for the aerospace industry. This paper aims to study the influence of the tool position and the parameters cutting precisely the speed feed Vf, the engagement of the tool on the roughness 3 D, micro-hardness and microstructure alteration created in sub-surface during the milling of concave surface of titanium alloy type Ti-6Al-4 V.

  9. Study of morphology and magnetic properties of the HoNi3 crystalline and ball-milled compound

    International Nuclear Information System (INIS)

    The morphology and magnetic properties of the HoNi3 crystalline and ball-milled intermetallic compounds are presented. The polycrystalline HoNi3 bulk compound crystallizes in the rhombohedral PuNi3 — type of crystal structure and indicates ferrimagnetic arrangement with the Curie temperature of TC = 57 ± 2 K, the helimagnetic temperature Th = 23 ± 2 K with the total saturation magnetic moment of 6.84 μB/f.u. at 2 K. The use of the ball-milling method leads to the formation of HoNi3 nanoflakes with typical thickness of less than 100 nm prone to agglomeration upon milling. The increase of grinding duration leads to the reduction in crystallite size, which was confirmed by various complementary microscopical and diffraction studies. Moreover, the increase in milling duration results in the emergence of the relatively small coercivity (HC), remanence (Mr) and a variation of the saturation magnetization (MS). - Graphical abstract: Display Omitted - Highlights: • The ball-milling method exhibits significant potential for producing RT3 nanopowders. • The AFM method was used for the first time in analysis of R–T nanoflakes morphology. • HoNi3 compound forms polycrystalline and textured nanoflakes evolving upon milling. • The decrease in crystallite size via grinding is confirmed by XRD, TEM and AFM. • The magnetic parameters were sensitive to the extension of pulverization b

  10. Magnetic and mechanical properties of Cu (75 wt%) – 316L grade stainless steels synthesized by ball milling and annealing

    International Nuclear Information System (INIS)

    Elemental powders of Cu (75 wt%) and 316-stainless steel (25 wt%) has been subjected to ball milling upto 70 h followed by isothermal annealing at the temperature range of 350–750 °C for 1 h to investigate the microstructural evolution along with magnetic and mechanical properties. After 40 h of milling, the bcc Fe is almost dissolved in the solid solution of Cu but no significant change has been observed in the XRD pattern after 70 h of milling, Annealing of the alloy has resulted in precipitation of nanocrystalline bcc-Fe in Cu which triggers the soft ferromagnetic properties. The extensive mechanical characterization has been done at the microstructural scale by nanoindentation technique which demonstrates a hardening behavior of the compacted and annealed alloys due to possible precipitation of nanocrystalline bcc-Fe in Cu. - Highlights: • Nanocrystalline phases with partial amorphorization obtained after 70 h of milling. • Precipitation and grain coarsening of Fe and Cu after annealing as observed by XRD. • Annealing of the ball milled sample upto 550 oC has evolved ferromagnetic behavior. • Nanoindentation predicts a hardening behavior of annealed ball milled samples

  11. Preparation of 50Ni-45Ti-5Zr powders by high-energy ball milling and hot pressing

    International Nuclear Information System (INIS)

    This study reports on the preparation of the 50Ni-45Ti-5Zr (at.%) alloy by high-energy ball milling and hot pressing. The elemental powder mixture was processed in silicon nitride and hardened steel vials, and samples were collected after different milling times. To recover the previous powders in addition wet milling isopropyl alcohol (for 20 min) was adopted. The mechanically alloyed powders were hot-pressed under vacuum at 900 oC for 1 h using pressure levels close to 200 MPa. The milled powders were characterized by means of scanning electron microscopy, X-ray diffraction, and energy dispersive spectrometry techniques. It was noted that the ductile starting powders were continuously cold-welded during ball milling. This fact was more pronounced during the processing of 50Ni-45Ti-5Zr powders in hardened steel vial. After milling for 5 h, the results suggested that amorphous and nanocrystalline structures were achieved. The complete consolidation was found after hot pressing of mechanically alloyed 50Ni-45Ti-5Zr powders, and a large amount of the B2-NiTi phase was formed mainly after processing in stainless steel balls and vial.

  12. Preparation of 50Ni-45Ti-5Zr powders by high-energy ball milling and hot pressing

    Energy Technology Data Exchange (ETDEWEB)

    Marinzeck de Alcantara Abdala, Julia, E-mail: juabdala@yahoo.com.b [Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi, 2911, 12244-000 Sao Jose dos Campos (Brazil); Bacci Fernandes, Bruno, E-mail: brunobacci@yahoo.com.b [Divisao de Engenharia Mecanica, Instituto Tecnologico de Aeronautica, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Santos, Dalcy Roberto dos, E-mail: dalcy@iae.cta.b [Instituto de Aeronautica e Espaco, Centro Tecnologico Aeroespacial, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Rodrigues Henriques, Vinicius Andre, E-mail: vinicius@iae.cta.b [Instituto de Aeronautica e Espaco, Centro Tecnologico Aeroespacial, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Moura Neto, Carlos de, E-mail: mneto@ita.b [Divisao de Engenharia Mecanica, Instituto Tecnologico de Aeronautica, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Saraiva Ramos, Alfeu, E-mail: alfeu@univap.b [Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi, 2911, 12244-000 Sao Jose dos Campos (Brazil)

    2010-04-16

    This study reports on the preparation of the 50Ni-45Ti-5Zr (at.%) alloy by high-energy ball milling and hot pressing. The elemental powder mixture was processed in silicon nitride and hardened steel vials, and samples were collected after different milling times. To recover the previous powders in addition wet milling isopropyl alcohol (for 20 min) was adopted. The mechanically alloyed powders were hot-pressed under vacuum at 900 {sup o}C for 1 h using pressure levels close to 200 MPa. The milled powders were characterized by means of scanning electron microscopy, X-ray diffraction, and energy dispersive spectrometry techniques. It was noted that the ductile starting powders were continuously cold-welded during ball milling. This fact was more pronounced during the processing of 50Ni-45Ti-5Zr powders in hardened steel vial. After milling for 5 h, the results suggested that amorphous and nanocrystalline structures were achieved. The complete consolidation was found after hot pressing of mechanically alloyed 50Ni-45Ti-5Zr powders, and a large amount of the B2-NiTi phase was formed mainly after processing in stainless steel balls and vial.

  13. Magnetic and mechanical properties of Cu (75 wt%) – 316L grade stainless steels synthesized by ball milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Bholanath, E-mail: bholanath_mondal@yahoo.co.in [Department of Central Scientific Services, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Chabri, Sumit [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Sardar, Gargi [Department of Zoology, Baruipur College, South 24 Parganas, 743610 (India); Bhowmik, Nandagopal [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Sinha, Arijit, E-mail: arijitsinha2@yahoo.co.in [School of Materials Science and Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Chattopadhyay, Partha Protim [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India)

    2015-05-01

    Elemental powders of Cu (75 wt%) and 316-stainless steel (25 wt%) has been subjected to ball milling upto 70 h followed by isothermal annealing at the temperature range of 350–750 °C for 1 h to investigate the microstructural evolution along with magnetic and mechanical properties. After 40 h of milling, the bcc Fe is almost dissolved in the solid solution of Cu but no significant change has been observed in the XRD pattern after 70 h of milling, Annealing of the alloy has resulted in precipitation of nanocrystalline bcc-Fe in Cu which triggers the soft ferromagnetic properties. The extensive mechanical characterization has been done at the microstructural scale by nanoindentation technique which demonstrates a hardening behavior of the compacted and annealed alloys due to possible precipitation of nanocrystalline bcc-Fe in Cu. - Highlights: • Nanocrystalline phases with partial amorphorization obtained after 70 h of milling. • Precipitation and grain coarsening of Fe and Cu after annealing as observed by XRD. • Annealing of the ball milled sample upto 550 {sup o}C has evolved ferromagnetic behavior. • Nanoindentation predicts a hardening behavior of annealed ball milled samples.

  14. Magnetic properties of ball-milled Fe{sub 0.6}Mn{sub 0.1}Al{sub 0.3} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rebolledo, A.F. [Insituto de Magnetismo Aplicado, P.O. Box 155, 28230 Las Rozas (Madrid) (Spain); Romero, J.J. [Insituto de Magnetismo Aplicado, P.O. Box 155, 28230 Las Rozas (Madrid) (Spain)]. E-mail: juanjromero@adif.es; Cuadrado, R. [Insituto de Magnetismo Aplicado, P.O. Box 155, 28230 Las Rozas (Madrid) (Spain); Gonzalez, J.M. [Insituto de Magnetismo Aplicado, P.O. Box 155, 28230 Las Rozas (Madrid) (Spain); Instittuo de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ines de la Cruz s/n, 28049 Madrid (Spain); Pigazo, F. [Instittuo de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ines de la Cruz s/n, 28049 Madrid (Spain); Palomares, F.J. [Instittuo de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ines de la Cruz s/n, 28049 Madrid (Spain); Medina, M.H. [Departamento de Fisica, Universidad Tecnologica de Pereira, La Julita, A. A. 097, Pereira (Colombia); Perez Alcazar, G.A. [Insituto de Magnetismo Aplicado, P.O. Box 155, 28230 Las Rozas (Madrid) (Spain); Depto. de Fisica, edificio 230, Universidad del Valle, A.A. 25360 Cali (Colombia)

    2007-09-15

    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{sub 0.6}Mn{sub 0.1}Al{sub 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.

  15. Use of high energy ball milling to study the role of graphene nanoplatelets and carbon nanotubes reinforced magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rashad, Muhammad, E-mail: rashadphy87@gmail.com [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Pan, Fusheng, E-mail: fspan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing, Chongqing 401123 (China); Zhang, Jianyue [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Asif, Muhammad [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2015-10-15

    Graphene nanoplatelets (few layer graphene) and carbon nanotubes were used as reinforcement fillers to enhance the mechanical properties of AZ31 magnesium alloy through high energy ball milling, sintering, and hot extrusion techniques. Experimental results revealed that tensile fracture strain of AZ31 magnesium alloy was enhanced by +49.6% with 0.3 wt.% graphene nanoplatelets compared to −8.3% regression for 0.3 wt.% carbon nanotubes. The tensile strength of AZ31 magnesium alloy was decreased (−11.2%) with graphene nanoplatelets addition, while increased (+7.7%) with carbon nanotubes addition. Unlike tensile test, compression tests showed different trend. The compression strength of carbon nanotubes-AZ31 composite was +51.2% greater than AZ31 magnesium alloy as compared to +0.6% increase for graphene nanoplatelets. The compressive fracture strain of carbon nanotubes-AZ31 composite was decreased (−14.1%) while no significant change in fracture strain of graphene nanoplatelets-AZ31 composite was observed. The X-ray diffraction results revealed that addition of reinforcement particles weaken the basal textures which affect the composite's yield asymmetry. Microstructure evaluation revealed the absence of intermetallic phase formation between reinforcements and matrix. The carbon reinforcements in AZ31 magnesium alloy dissolve and isolate β phases throughout the matrix. The increased fracture strain and mechanical strength of graphene nanoplatelets and carbon nanotubes-AZ31 composites are attributed to large specific surface area of graphene nanoplatelets and stiffer nature of carbon nanotubes respectively. - Highlights: • Powder metallurgy method was used to fabricate magnesium composites. • The AZ31-carbon materials composite were blended using ball milling. • The reinforcement particles weaken the basal texture which affects yield asymmetry of composites. • AZ31-graphene nanoplatelets composite exhibited impressive increase in tensile elongation

  16. Effect of zirconium on grain growth and mechanical properties of a ball-milled nanocrystalline FeNi alloy

    International Nuclear Information System (INIS)

    Highlights: ► Pure Fe, Fe92Ni8, and Fe91Ni8Zr1 powders were hardened up to 10 GPa by ball milling. ► Annealing of Fe and Fe92Ni8 leads to reduced hardness and extensive grain growth. ► The addition of Zr to Fe92Ni8 increases its stability and strength by second phases. ► The second phases are found to promote the stability of Fe91Ni8Zr1 by Zener pinning. ► The Zr-containing precipitates contribute to the overall strength of the material. - Abstract: Grain growth of ball-milled pure Fe, Fe92Ni8, and Fe91Ni8Zr1 alloys has been studied using X-ray diffractometry (XRD), focused ion beam (FIB) microscopy and transmission electron microscopy (TEM). Mechanical properties with respect to compositional changes and annealing temperatures have been investigated using microhardness and shear punch tests. We found the rate of grain growth of the Fe91Ni8Zr1 alloy to be much less than that of pure Fe and the Fe92Ni8 alloy at elevated temperatures. The microstructure of the ternary Fe91Ni8Zr1 alloy remains nanoscale up to 700 °C where only a few grains grow abnormally whereas annealing of pure iron and the Fe92Ni8 alloy leads to extensive grain growth. The grain growth of the ternary alloy at high annealing temperatures is coupled with precipitation of Fe2Zr. A fine dispersion of precipitated second phase is found to promote the microstructural stability at high annealing temperatures and to increase the hardness and ultimate shear strength of ternary Fe91Ni8Zr1 alloy drastically when the grain size is above nanoscale.

  17. Optical and dielectric study of strontium modified barium zirconium titanate ceramic prepared by high energy ball milling

    International Nuclear Information System (INIS)

    Highlights: • Submicron size strontium doped BZT ceramics were prepared by high energy ball milling. • Structural analysis was done by Reitveld refinement and Raman analysis. • Decrement in transition temperature and increment in diffusivity is observed with doping. • Remnant polarization decreases and coercive filed increases with doping. • Optical study was done by UV–vis spectroscopy and the optical band gap increases with doping. - Abstract: Strontium modified barium zirconium titanate with general formula Ba1−xSrxZr0.05Ti0.95O3 ceramics have been prepared by solid state and high energy ball milling technique. The X-ray diffraction and Rietveld refinement studies show that all the compositions have single phase symmetry. The composition BaZr0.05Ti0.95O3 shows orthorhombic symmetric with space group Amm2. The structure changes from orthorhombic to tetragonal with strontium doping up to x = 0.3 and with further addition, changes to cubic. The scanning electron micrographs show that the grain size decreases with increase in strontium content. The temperature dependent dielectric behavior shows three phase transition in the parent material which merges with an increase in Sr content. The transition temperature and dielectric constant decreases with an increase in Sr concentration. The phase transition becomes more diffused with increment in doping concentration. The ferroelectric behavior of the ceramics is studied by the hysteresis loop. The optical behavior is studied by the UV–visible spectroscopy and found that the optical band gap increases with Sr concentration

  18. Optical and dielectric study of strontium modified barium zirconium titanate ceramic prepared by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Badapanda, T., E-mail: badapanda.tanmaya@gmail.com [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar, Odisha 752054 (India); Sarangi, S.; Behera, B. [School of Physics, Sambalpur University, Jyoti Vihar, Sambalpur, Odisha 768019 (India); Parida, S. [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar, Odisha 752054 (India); Saha, S.; Sinha, T.P. [Department of Physics, Bose Institute, Kolkata 700009 (India); Ranjan, Rajeev [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Sahoo, P.K. [School of Physical Science, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha (India)

    2015-10-05

    Highlights: • Submicron size strontium doped BZT ceramics were prepared by high energy ball milling. • Structural analysis was done by Reitveld refinement and Raman analysis. • Decrement in transition temperature and increment in diffusivity is observed with doping. • Remnant polarization decreases and coercive filed increases with doping. • Optical study was done by UV–vis spectroscopy and the optical band gap increases with doping. - Abstract: Strontium modified barium zirconium titanate with general formula Ba{sub 1−x}Sr{sub x}Zr{sub 0.05}Ti{sub 0.95}O{sub 3} ceramics have been prepared by solid state and high energy ball milling technique. The X-ray diffraction and Rietveld refinement studies show that all the compositions have single phase symmetry. The composition BaZr{sub 0.05}Ti{sub 0.95}O{sub 3} shows orthorhombic symmetric with space group Amm2. The structure changes from orthorhombic to tetragonal with strontium doping up to x = 0.3 and with further addition, changes to cubic. The scanning electron micrographs show that the grain size decreases with increase in strontium content. The temperature dependent dielectric behavior shows three phase transition in the parent material which merges with an increase in Sr content. The transition temperature and dielectric constant decreases with an increase in Sr concentration. The phase transition becomes more diffused with increment in doping concentration. The ferroelectric behavior of the ceramics is studied by the hysteresis loop. The optical behavior is studied by the UV–visible spectroscopy and found that the optical band gap increases with Sr concentration.

  19. Use of high energy ball milling to study the role of graphene nanoplatelets and carbon nanotubes reinforced magnesium alloy

    International Nuclear Information System (INIS)

    Graphene nanoplatelets (few layer graphene) and carbon nanotubes were used as reinforcement fillers to enhance the mechanical properties of AZ31 magnesium alloy through high energy ball milling, sintering, and hot extrusion techniques. Experimental results revealed that tensile fracture strain of AZ31 magnesium alloy was enhanced by +49.6% with 0.3 wt.% graphene nanoplatelets compared to −8.3% regression for 0.3 wt.% carbon nanotubes. The tensile strength of AZ31 magnesium alloy was decreased (−11.2%) with graphene nanoplatelets addition, while increased (+7.7%) with carbon nanotubes addition. Unlike tensile test, compression tests showed different trend. The compression strength of carbon nanotubes-AZ31 composite was +51.2% greater than AZ31 magnesium alloy as compared to +0.6% increase for graphene nanoplatelets. The compressive fracture strain of carbon nanotubes-AZ31 composite was decreased (−14.1%) while no significant change in fracture strain of graphene nanoplatelets-AZ31 composite was observed. The X-ray diffraction results revealed that addition of reinforcement particles weaken the basal textures which affect the composite's yield asymmetry. Microstructure evaluation revealed the absence of intermetallic phase formation between reinforcements and matrix. The carbon reinforcements in AZ31 magnesium alloy dissolve and isolate β phases throughout the matrix. The increased fracture strain and mechanical strength of graphene nanoplatelets and carbon nanotubes-AZ31 composites are attributed to large specific surface area of graphene nanoplatelets and stiffer nature of carbon nanotubes respectively. - Highlights: • Powder metallurgy method was used to fabricate magnesium composites. • The AZ31-carbon materials composite were blended using ball milling. • The reinforcement particles weaken the basal texture which affects yield asymmetry of composites. • AZ31-graphene nanoplatelets composite exhibited impressive increase in tensile elongation

  20. Study of effect of planetary ball milling on ZnO nanopowder synthesized by co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, K.P., E-mail: kiranshinde_phy@yahoo.co.in [Superconductivity Research Centre, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Pawar, R.C. [Department of Materials Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Sinha, B.B. [Nano Functional Materials Research Group, Department of Powder Materials, Korea Institute of Material Science, Changwon 641-831 (Korea, Republic of); Kim, H.S.; Oh, S.S. [Superconductivity Research Centre, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Chung, K.C. [Nano Functional Materials Research Group, Department of Powder Materials, Korea Institute of Material Science, Changwon 641-831 (Korea, Republic of)

    2014-12-25

    Highlights: • Synthesis of ZnO nanopowder by co-precipitation method. • Particle size reduction using planetary ball milling. • PL spectra shows shifting towards higher wavelength with decrease in intensity. • The bandgap energy (E{sub g}) of ZnO powders varied from 3.13 to 2.85 eV. - Abstract: Nanocrystalline ZnO powders have been synthesized by co-precipitation method and investigated planetary ball milling effects on structural and optical properties. These powders were characterized using X-ray diffraction, field emission scanning electronic microscope, Infrared spectrophotometer, UV–vis spectrophotometer and Photoluminescence. It was found that prepared ZnO powders have hexagonal close packed structure which was annealed at 500 °C for 30 min. The bandgap energy of ZnO powders varied from 3.13 to 2.85 eV. The room temperature PL spectra exhibits low intensity UV emission peak at 383 nm and green emission band around 520 nm shows shifting towards higher wavelength with decrease in intensity of peak with time of planetary ball milling. Hence, it was observed that planetary ball milling can be used to tailor the optoelectronic properties of ZnO nanostructures.

  1. Structure and thermal stability of nanostructured iron-doped zirconia prepared by high-energy ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Poulsen, Finn Willy; Mørup, Steen

    1999-01-01

    Fury stability cubic zirconia doped with iron oxide has been synthesized by high-energy ball milling from powder mixtures of monoclinic zirconia and hematite. It is found that the iron ions dissolved in cubic ZrO2 are in substitutional positions with a maximum solubility of approximately 18.5 mol...

  2. Study of effect of planetary ball milling on ZnO nanopowder synthesized by co-precipitation

    International Nuclear Information System (INIS)

    Highlights: • Synthesis of ZnO nanopowder by co-precipitation method. • Particle size reduction using planetary ball milling. • PL spectra shows shifting towards higher wavelength with decrease in intensity. • The bandgap energy (Eg) of ZnO powders varied from 3.13 to 2.85 eV. - Abstract: Nanocrystalline ZnO powders have been synthesized by co-precipitation method and investigated planetary ball milling effects on structural and optical properties. These powders were characterized using X-ray diffraction, field emission scanning electronic microscope, Infrared spectrophotometer, UV–vis spectrophotometer and Photoluminescence. It was found that prepared ZnO powders have hexagonal close packed structure which was annealed at 500 °C for 30 min. The bandgap energy of ZnO powders varied from 3.13 to 2.85 eV. The room temperature PL spectra exhibits low intensity UV emission peak at 383 nm and green emission band around 520 nm shows shifting towards higher wavelength with decrease in intensity of peak with time of planetary ball milling. Hence, it was observed that planetary ball milling can be used to tailor the optoelectronic properties of ZnO nanostructures

  3. Microstructural changes and effect of variation of lattice strain on positron annihilation lifetime parameters of zinc ferrite nanocomposites prepared by high enegy ball-milling

    OpenAIRE

    Abhijit Banerjee; Srinjoy Bid; Hema Dutta; Sandeep Chaudhuri; Dipankar Das; Swapan Kumar Pradhan

    2012-01-01

    Zn-ferrite nanoparticles were synthesized at room temperature by mechanical alloying the stoichiometric (1:1 mol%) mixture of ZnO and α-Fe2O3 powder under open air. Formation of both normal and inverse spinel ferrite phases was noticed after 30 minutes and 2.5 hours ball milling respectively and the content of inverse spinel phase increased with increasing milling time. The phase transformation kinetics towards formation of ferrite phases and microstructure characterization of ball mille...

  4. Production of chromium base alloys by ball milling in hydrogen iodide

    Science.gov (United States)

    Arias, A.

    1975-01-01

    The effects of processing variables on the tensile properties and ductile-to-brittle transition temperature (DBTT) of Cr + 4 vol% ThO2 alloys and of pure Cr produced by ball milling in hydrogen iodide were investigated. Hot rolled Cr + ThO2 was stronger than either hot pressed Cr + ThO2 or pure Cr at temperatures up to 1540 C. Hot pressed Cr + ThO2 had a DBTT of 500 C as compared with -8 to 24 C for the hot rolled Cr + ThO2 and with 140 C for pure Cr. It is postulated that the dispersoid in the hot rolled alloys lowers the DBTT by inhibiting recovery and recrystallization of the strained structure.

  5. Solid acid-catalyzed depolymerization of barley straw driven by ball milling.

    Science.gov (United States)

    Schneider, Laura; Haverinen, Jasmiina; Jaakkola, Mari; Lassi, Ulla

    2016-04-01

    This study describes a time and energy saving, solvent-free procedure for the conversion of lignocellulosic barley straw into reducing sugars by mechanocatalytical pretreatment. The catalytic conversion efficiency of several solid acids was tested which revealed oxalic acid dihydrate as a potential catalyst with high conversion rate. Samples were mechanically treated by ball milling and subsequently hydrolyzed at different temperatures. The parameters of the mechanical treatment were optimized in order to obtain sufficient amount of total reducing sugar (TRS) which was determined following the DNS assay. Additionally, capillary electrophoresis (CE) and Fourier transform infrared spectrometry (FT-IR) were carried out. Under optimal conditions TRS 42% was released using oxalic acid dihydrate as a catalyst. This study revealed that the acid strength plays an important role in the depolymerization of barley straw and in addition, showed, that the oxalic acid-catalyzed reaction generates low level of the degradation product 5-hydroxymethylfurfural (HMF). PMID:26859328

  6. Controlling the number of walls in multi walled carbon nanotubes/alumina hybrid compound via ball milling of precipitate catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nosbi, Norlin [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia (USM), 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia); Akil, Hazizan Md, E-mail: hazizan@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia (USM), 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia); Cluster for Polymer Composite (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia (USM), 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

    2015-06-15

    Graphical abstract: - Highlights: • We report that, to manipulate carbon nanotubes geometry and number of walls are by controlling the precipitate catalyst size. • Number of walls and geometry effects depend on the milling time of the precipitate catalyst. • Increasing milling of time will decrease the carbon nanotubes number of walls. • Increasing milling of time will increase the carbon nanotubes thermal conductivity. - Abstract: This paper reports the influence of milling time on the structure and properties of the precipitate catalyst of multi walled carbon nanotubes (MWCNT)/alumina hybrid compound, produced through the chemical vapour deposition (CVD) process. For this purpose, light green precipitate consisted of aluminium, nickel(II) nitrate hexahydrate and sodium hydroxide mixture was placed in a planetary mill equipped with alumina vials using alumina balls at 300 rpm rotation speed for various milling time (5–15 h) prior to calcinations and CVD process. The compound was characterized using various techniques. Based on high-resolution transmission electron microscopy analysis, increasing the milling time up to 15 h decreased the diameter of MWCNT from 32.3 to 13.1 nm. It was noticed that the milling time had a significant effect on MWCNT wall thickness, whereby increasing the milling time from 0 to 15 h reduced the number of walls from 29 to 12. It was also interesting to note that the carbon content increased from 23.29 wt.% to 36.37 wt.% with increasing milling time.

  7. Controlling the number of walls in multi walled carbon nanotubes/alumina hybrid compound via ball milling of precipitate catalyst

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • We report that, to manipulate carbon nanotubes geometry and number of walls are by controlling the precipitate catalyst size. • Number of walls and geometry effects depend on the milling time of the precipitate catalyst. • Increasing milling of time will decrease the carbon nanotubes number of walls. • Increasing milling of time will increase the carbon nanotubes thermal conductivity. - Abstract: This paper reports the influence of milling time on the structure and properties of the precipitate catalyst of multi walled carbon nanotubes (MWCNT)/alumina hybrid compound, produced through the chemical vapour deposition (CVD) process. For this purpose, light green precipitate consisted of aluminium, nickel(II) nitrate hexahydrate and sodium hydroxide mixture was placed in a planetary mill equipped with alumina vials using alumina balls at 300 rpm rotation speed for various milling time (5–15 h) prior to calcinations and CVD process. The compound was characterized using various techniques. Based on high-resolution transmission electron microscopy analysis, increasing the milling time up to 15 h decreased the diameter of MWCNT from 32.3 to 13.1 nm. It was noticed that the milling time had a significant effect on MWCNT wall thickness, whereby increasing the milling time from 0 to 15 h reduced the number of walls from 29 to 12. It was also interesting to note that the carbon content increased from 23.29 wt.% to 36.37 wt.% with increasing milling time

  8. Fabrication mechanism of FeSe superconductors with high-energy ball milling aided sintering process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengnan, E-mail: snzhang@c-nin.com [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China); Liu, Jixing [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China); School of Materials and Metallurgical, Northeast University, Shenyang, 110016 (China); Feng, Jianqing; Wang, Yao; Ma, Xiaobo; Li, Chengshan; Zhang, Pingxiang [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China)

    2015-08-01

    FeSe Superconducting bulks with high content of superconducting PbO-type β-FeSe phase were prepared with high-energy ball milling (HEBM) aided sintering process. During this process, precursor powders with certain Fe/Se ratio were ball milled first then sintered. The influences of HEBM process as well as initial Fe/Se ratio on the phase evolution process were systematically discussed. With HEBM process and proper initial Fe/Se ratio, the formation of non-superconducting hexagonal δ-FeSe phase were effectively avoided. FeSe bulk with the critical temperature of 9.0 K was obtained through a simple one-step sintering process with lower sintering temperature. Meanwhile, the phase evolution mechanism of the HEBM precursor powders during sintering was deduced based on both the thermodynamic analysis and step-by-step sintering results. The key function of the HEBM process was to provide a high uniformity of chemical composition distribution, thus to successfully avoide the formation of intermediate product during sintering, including FeSe{sub 2} and Fe{sub 7}Se{sub 8}. Therefore, the fundamental principal for the synthesis of FeSe superconductors were concluded as: HEBM aided sintering process, with the sintering temperature of >635 °C and a slow cooling process. - Highlights: • A novel synthesis technique was developed for FeSe based superconductors. • FeSe bulks with high Tc and high β-FeSe phase content has been obtained. • Phase evolution process for the HEBM aided sintering process was proposed.

  9. Dielectric and photocatalytic properties of sulfur doped TiO2 nanoparticles prepared by ball milling

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Designing of visible light responsive photocatalyst utilizing ball milling. • Sulphur used as dopant in commercial TiO2 P25 at different atomic percentage. • S doping resulted in an intense increase in absorption in the visible light region. • Newly design photocatalyst exhibited excellent photocatalytic performance. • 0.11 at.% S-doped TiO2 shows 3-times higher activity than that of TiO2 P25. - Abstract: Sulfur (S) doped commercial TiO2 P-25 has been achieved by changing the amount of thiourea using ball milling technique. The results of XRD clearly reveal biphasial anatase and rutile mixtures for all prepared samples and doping of S does not change the morphology of the TiO2. The optical absorption edge of S-doped TiO2 was red shifted with indirect bandgap energy of 2.8 eV. The dielectric studies confirm that the dielectric constant of TiO2 increases after doping, however it becomes more conductive. Newly designed S-doped TiO2 photocatalysts exhibited excellent photocatalytic performance for the degradation of methylene blue (MB) under visible light. The overall photocatalytic activity of 0.11 at.% S-doped TiO2 was significantly 3-times higher than that of commercial TiO2 P-25 and complete degradation of MB has taken place after 90 min of irradiation under visible light while only 35% dye degraded when the reaction has been carried out in the presence of undoped TiO2

  10. Fabrication mechanism of FeSe superconductors with high-energy ball milling aided sintering process

    International Nuclear Information System (INIS)

    FeSe Superconducting bulks with high content of superconducting PbO-type β-FeSe phase were prepared with high-energy ball milling (HEBM) aided sintering process. During this process, precursor powders with certain Fe/Se ratio were ball milled first then sintered. The influences of HEBM process as well as initial Fe/Se ratio on the phase evolution process were systematically discussed. With HEBM process and proper initial Fe/Se ratio, the formation of non-superconducting hexagonal δ-FeSe phase were effectively avoided. FeSe bulk with the critical temperature of 9.0 K was obtained through a simple one-step sintering process with lower sintering temperature. Meanwhile, the phase evolution mechanism of the HEBM precursor powders during sintering was deduced based on both the thermodynamic analysis and step-by-step sintering results. The key function of the HEBM process was to provide a high uniformity of chemical composition distribution, thus to successfully avoide the formation of intermediate product during sintering, including FeSe2 and Fe7Se8. Therefore, the fundamental principal for the synthesis of FeSe superconductors were concluded as: HEBM aided sintering process, with the sintering temperature of >635 °C and a slow cooling process. - Highlights: • A novel synthesis technique was developed for FeSe based superconductors. • FeSe bulks with high Tc and high β-FeSe phase content has been obtained. • Phase evolution process for the HEBM aided sintering process was proposed

  11. Synthesis and characterizations of ball-milled nanocrystalline WC and nanocomposite WC-Co powders and subsequent consolidations

    Energy Technology Data Exchange (ETDEWEB)

    El-Eskandarany, M.S.; Mahday, A.A.; Amer, A.H. [Al-Azhar Univ., Cairo (Egypt). Faculty of Engineering; Ahmed, H.A. [Mining, Petroleum and Metallurgical Engineering Department, Faculty of Engineering, Cairo University, Giza (Egypt)

    2000-11-16

    The room-temperature ball-milling technique has been successfully employed for fabrication of nanocrystalline powders of equiatomic WC by high-energy ball milling of elemental W and C powders. The progress of the solid state reaction has been monitored by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM). A complete single phase of hcp-WC was obtained after 295 ks of milling. Increasing the milling time to 432 ks leads to dramatic grain refinement and the powder of this end-product consists of nanocrystalline grains of less than 5 nm in diameter. The fabricated WC powders possess excellent morphological characteristics, such as homogeneous shape (spherical-like morphology) with fine and smooth surface relief and uniform size (less than 0.5 {mu}m in diameter). Part of the powders of the end-product were further ball-milled, 259 ks together with different concentrations of metallic Co to obtain spherical fine nanocomposite WC-coated Co powders with an average particle size of less than 5 {mu}m in diameter. Both WC free Co and composite WC-Co powders were then consolidated into fully dense (>99.5%) compacts using cold and hot pressing techniques. The as-consolidated samples still maintained their nanocrystalline characteristics with an average grain size of less than 100 nm. Some of physical and mechanical properties of the consolidated samples are reported. (orig.)

  12. A combination method of the theory and experiment in determination of cutting force coefficients in ball-end mill processes

    Directory of Open Access Journals (Sweden)

    Yung-Chou Kao

    2015-10-01

    Full Text Available In this paper, the cutting force calculation of ball-end mill processing was modeled mathematically. All derivations of cutting forces were directly based on the tangential, radial, and axial cutting force components. In the developed mathematical model of cutting forces, the relationship of average cutting force and the feed per flute was characterized as a linear function. The cutting force coefficient model was formulated by a function of average cutting force and other parameters such as cutter geometry, cutting conditions, and so on. An experimental method was proposed based on the stable milling condition to estimate the cutting force coefficients for ball-end mill. This method could be applied for each pair of tool and workpiece. The developed cutting force model has been successfully verified experimentally with very promising results.

  13. Intelligent system for machining and optimization of 3D sculptured surfaces with ball-end milling

    Directory of Open Access Journals (Sweden)

    M. Milfelner

    2005-12-01

    Full Text Available Purpose: This paper describes about intelligent machining system which is applied in a high speed machining robot with on-line monitoring and optimization for ball-end milling process.Design/methodology/approach: Manufacturing of 3D sculptured surfaces on high speed machining robot involves a number of machining parameters and tool geometries. The system collects machining data and cutting parameters which are necessary for genetic algorithm optimization.Findings: An intelligent machining system is developed for the simulation and testing on the PC machine. It is based on a main PC computer, which is connected to the high speed machining robot main processor so that control and communication can be realized. The system collects the variables of the cutting process by means of sensors which are optimized with the genetic algorithms.Research limitations/implications: 3D sculptured milling covers a wide range of operations. In 3D metal cutting processes, cutting conditions have an influence on reducing the production cost and time and deciding the quality of a final product.Practical implications: Simulated results show that the proposed intelligent machining system is effective and efficient, and can be integrated into a real-time intelligent manufacturing system for solving complex machining optimization problems.Originality/value: The paper describes about intelligent machining system which can applied in intelligent manufacturing process.

  14. Properties of Y-TZP/Al2O3 ceramic nanocomposites obtained by high-energy ball milling

    International Nuclear Information System (INIS)

    In this work, the synthesis of Y2O3 stabilized tetragonal zirconia polycrystals (Y-TZP)-alumina (Al2O3) powder mixture was performed by high-energy ball milling and the sintering behavior of this composite was investigated. In order to understand the phase transformations occurring during ball milling, samples were collected after different milling times, from 1 to 60 h. The milled powders were compacted by cold uniaxial pressing and sintered at 1400 and 1600 deg. C. Both powders and sintered samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry analysis (EDS) and mechanical properties. Fully dense samples were obtained after sintering at 1600 deg. C, while the samples sintered at 1400 deg. C presented a full density for powder mixtures milled for 30 and 60 h. Fracture toughness and Vickers hardness values of the Y-TZP/Al2O3 nanocomposite were improved due to dispersed Al2O3 grains and reduced ZrO2 grain size. Samples sintered at 1400 deg. C, based on powders milled for 60 h, presented high KIC and hardness values near to 8.0 MPam1/2 and 15 GPa, respectively

  15. Facile synthesis and capacitive performance of the Co(OH){sub 2} nanostructure via a ball-milling method

    Energy Technology Data Exchange (ETDEWEB)

    Gong Liangyu, E-mail: lygong@163.com [College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Shandong 266109 (China); Su Linghao [College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Shandong 266109 (China)

    2011-09-15

    Co(OH){sub 2} nanoparticles were synthesized using only CoSO{sub 4}.7H{sub 2}O and NaOH as reactants without other auxiliary reagents via a simple, low-cost and practical ball-milling technique and investigated as the active electrode materials for supercapacitors. The structure and morphology of the resulting Co(OH){sub 2} samples were examined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The observations revealed the formation of brucite-like phase of {beta}-Co(OH){sub 2}, which had an irregular sphere-like shape with an average size of 50-100 nm. When investigated as electrode materials for supercapacitors, the {beta}-Co(OH){sub 2} exhibited good energy-storage performances in terms of high specific capacitance of 599 F g{sup -1} and excellent capacity retention, suggesting its potential application in the electrode material for supercapacitors.

  16. Micromorphological changes and mechanism associated with wet ball milling of Pinus radiata substrate and consequences for saccharification at low enzyme loading.

    Science.gov (United States)

    Vaidya, Alankar A; Donaldson, Lloyd A; Newman, Roger H; Suckling, Ian D; Campion, Sylke H; Lloyd, John A; Murton, Karl D

    2016-08-01

    In this work, substrates prepared from thermo-mechanical treatment of Pinus radiata chips were vibratory ball milled for different times. In subsequent enzymatic hydrolysis, percent glucan conversion passed through a maximum value at a milling time of around 120min and then declined. Scanning electron microscopy revealed breakage of fibers to porous fragments in which lamellae and fibrils were exposed during ball milling. Over-milling caused compression of the porous fragments to compact globular particles with a granular texture, decreasing accessibility to enzymes. Carbon-13 NMR spectroscopy showed partial loss of interior cellulose in crystallites, leveling off once fiber breakage was complete. A mathematical model based on observed micromorphological changes supports ball milling mechanism. At a low enzyme loading of 2FPU/g of substrate and milling time of 120min gave a total monomeric sugar yield of 306g/kg of pulp which is higher than conventional pretreatment method such as steam exploded wood. PMID:27131293

  17. Ball-milling-induced polytypic transformation of 6H-SiC→3C-SiC

    Institute of Scientific and Technical Information of China (English)

    杨晓云; 石广元; 黄和鸾; 吴玉琨

    1999-01-01

    The results of X-ray diffraction (XRD) and high resolution electron microscopy (HREM) show that ball milling at room temperature can induce the polytypic transformation of 6H-SiC→3C-SiC. HREM study reveals that a large number of partial dislocations which play an important role in the transformation can be introduced into SiC crystals during BM by the instant and repeated collisions between balls and powder. The phase transformation follows the route: 6H= (3~+,3~-)→(4~+,2~-)→(5~+, 1~- )→(6~+ ,0~- ).

  18. Spectroscopic studies on the formation kinetics of SnO2 nanoparticles synthesized in a planetary ball mill

    Science.gov (United States)

    Kozma, G.; Kukovecz, Á.; Kónya, Z.

    2007-05-01

    SnO2 nanoparticles with an average diameter of 9 nm were synthesized by the mechanochemical reaction between SnCl2 and Na2CO3 in a planetary ball mill. The pressure and the temperature were continuously monitored in the milling drum and the reaction products were characterized by TEM, SEM, FT-Raman, mid-IR and far-IR spectroscopy. The pressure in the drum was found to be a highly nonlinear function of the milling time. This finding could be adequately explained on the basis of the spectroscopic evidence collected. We suggest that the speed of the mechanochemical reaction is given by a fast-slow-fast(-slow) series which is caused by the variation of the wetness of the reaction mixture during milling. The measured pressure nonlinearity is thus a direct consequence of the kinetics of the mechanochemical reaction.

  19. Magnetic properties of ball-milled nanocrystalline alloys Fe sub 7 sub 8 B sub 1 sub 3 Si sub 9

    CERN Document Server

    Pekala, M; Jachimowicz, M

    2002-01-01

    Magnetic properties of nanocrystalline Fe sub 7 sub 8 B sub 1 sub 3 Si sub 9 alloys are studied for three series prepared by ball milling starting from amorphous ribbons, crystallized ribbons, and elemental powders. Temperature variation of static magnetization results in strong ferromagnetic interaction which is weakly dependent on the initial material. Magnetic hysteresis loops show that saturation magnetization, magnetic remanence, and coercive field increase with frequency for both series of ribbon samples, whereas they decrease for alloys prepared from elemental powders. Power losses raise faster for the alloys prepared from elemental powders than for the two other alloys. (author)

  20. Study of morphology and magnetic properties of the HoNi{sub 3} crystalline and ball-milled compound

    Energy Technology Data Exchange (ETDEWEB)

    Bajorek, Anna, E-mail: anna.bajorek@us.edu.pl [A. Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Skornia, Paweł [A. Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Prusik, Krystian [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Wojtyniak, Marcin [A. Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Institute of Materials Science, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Chełkowska, Grażyna [A. Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland)

    2015-03-15

    The morphology and magnetic properties of the HoNi{sub 3} crystalline and ball-milled intermetallic compounds are presented. The polycrystalline HoNi{sub 3} bulk compound crystallizes in the rhombohedral PuNi{sub 3} — type of crystal structure and indicates ferrimagnetic arrangement with the Curie temperature of T{sub C} = 57 ± 2 K, the helimagnetic temperature T{sub h} = 23 ± 2 K with the total saturation magnetic moment of 6.84 μ{sub B}/f.u. at 2 K. The use of the ball-milling method leads to the formation of HoNi{sub 3} nanoflakes with typical thickness of less than 100 nm prone to agglomeration upon milling. The increase of grinding duration leads to the reduction in crystallite size, which was confirmed by various complementary microscopical and diffraction studies. Moreover, the increase in milling duration results in the emergence of the relatively small coercivity (H{sub C}), remanence (M{sub r}) and a variation of the saturation magnetization (M{sub S}). - Graphical abstract: Display Omitted - Highlights: • The ball-milling method exhibits significant potential for producing RT{sub 3} nanopowders. • The AFM method was used for the first time in analysis of R–T nanoflakes morphology. • HoNi{sub 3} compound forms polycrystalline and textured nanoflakes evolving upon milling. • The decrease in crystallite size via grinding is confirmed by XRD, TEM and AFM. • The magnetic parameters were sensitive to the extension of pulverization b.

  1. Structure and electrochemical hydrogen storage properties of Ti2Ni alloy synthesized by ball milling

    International Nuclear Information System (INIS)

    Highlights: • The Ti2Ni alloy activation requires only one cycle of charge and discharge, regardless of the temperature. • By increasing the temperature the capacity loss, undergoes an increase and it is more pronounced for the 60 °C. • A good correlation is found between the evolutions of the different electrochemical parameters according to the temperature. - Abstract: The structure and the electrochemical hydrogen storage properties of amorphous Ti2Ni alloy synthesized by ball milling and used as an anode in nickel–metal hydride batteries were studied. Nominal Ti2Ni was synthesized under argon atmosphere at room temperature using a planetary high-energy ball mill. The structural and morphological characterization of the amorphous Ti2Ni alloy is carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical characterization of the Ti2Ni electrodes is carried out by the galvanostatic charging and discharging, the constant potential discharge, the open circuit potential and the potentiodynamic polarization techniques. The Ti2Ni alloy activation requires only one cycle of charge and discharge, regardless of the temperature. The electrochemical discharge capacity of the Ti2Ni alloy, during the first eight cycles, and at a temperature of 30 °C, remained practically unchanged and a good held cycling is observed. By increasing the temperature, the electrochemical discharge capacity loss after eight cycles undergoes an increase and it is more pronounced for the temperature 60 °C. At 30 °C, the anodic corrosion current density is 1 mA cm−2 and then it undergoes a rapid drop, remaining substantially constant (0.06 mA cm−2) in the range 40–60 °C, before undergoing a slight increase to 70 °C (0.3 mA cm−2). This variation is in good agreement with the maximum electrochemical discharge capacity values found for the different temperatures. By increasing the temperature, the

  2. Microstructural evolution during high energy ball milling of Fe2O3-SiO2 powders

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Zhou, Y.X.; Mørup, Steen;

    1996-01-01

    The reaction of a 25 mol% Fe2O3-SiO2 (hematite-amorphous silica) powder mixture during high energy ball milling in both closed and open containers has been studied by x-ray diffraction and Mossbauer spectroscopy. After around 21 h of milling, the alpha-Fe2O3 powders with an average particle size ...... atoms are found in a hematite phase. In the closed container the hematite phase transforms into an iron-rich spinel phase and some of the iron atoms react with the amorphous SiO2, forming a new Fe(II)-containing silicate compound....

  3. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2012-01-01

    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  4. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2013-02-01

    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  5. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    International Nuclear Information System (INIS)

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12−xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12−xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πMs and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πMs and composition x from 50 K to room temperature was revealed

  6. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daming [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States); College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States)

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (T{sub c}). We prepared aluminum doped barium ferrite ceramics (BaAl{sub x}Fe{sub 12−x}O{sub 19}, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate T{sub c} and magnetic properties of BaFe{sub 12−x}Al{sub x}O{sub 19}. It is found that T{sub c} decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πM{sub s}) decreases with increasing x, while the coercivity (H{sub c}) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πM{sub s} and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πM{sub s} and composition x from 50 K to room temperature was revealed.

  7. Acid-Assisted Ball Milling of Cellulose as an Efficient Pretreatment Process for the Production of Butyl Glycosides.

    Science.gov (United States)

    Boissou, Florent; Sayoud, Nassim; De Oliveira Vigier, Karine; Barakat, Abdellatif; Marinkovic, Sinisa; Estrine, Boris; Jérôme, François

    2015-10-12

    Ball milling of cellulose in the presence of a catalytic amount of H2SO4 was found to be a promising pre-treatment process to produce butyl glycosides in high yields. Conversely to the case of water, n-butanol has only a slight effect on the recrystallization of ball-milled cellulose. As a result, thorough depolymerization of cellulose prior the glycosylation step is no longer required, which is a pivotal aspect with respect to energy consumption. This process was successfully transposed to wheat straw from which butyl glycosides and xylosides were produced in good yields. Butyl glycosides and xylosides are important chemicals as they can be used as hydrotropes but also as intermediates in the production of valuable amphiphilic alkyl glycosides. PMID:26346950

  8. Synthesis of stoichiometric Ca2Fe2O5 nanoparticles by high-energy ball milling and thermal annealing

    Science.gov (United States)

    Amorim, B. F.; Morales, M. A.; Bohn, F.; Carriço, A. S.; de Medeiros, S. N.; Dantas, A. L.

    2016-05-01

    We report the synthesis of Ca2Fe2O5 nanoparticles by high-energy ball milling and thermal annealing from α-Fe2O3 and CaCO3. Magnetization measurements, Mössbauer and X-ray spectra reveal that annealing at high temperatures leads to better quality samples. Our results indicate nanoparticles produced by 10 h high-energy ball milling and thermal annealing for 2 h at 1100 °C achieve improved stoichiometry and the full weak ferromagnetic signal of Ca2Fe2O5. Samples annealed at lower temperatures show departure from stoichiometry, with a higher occupancy of Fe3+ in octahedral sites, and a reduced magnetization. Thermal relaxation for temperatures in the 700-1100 °C range is well represented by a Néel model, assuming a random orientation of the weak ferromagnetic moment of the Ca2Fe2O5 nanoparticles.

  9. Combined pretreatment using alkaline hydrothermal and ball milling to enhance enzymatic hydrolysis of oil palm mesocarp fiber.

    Science.gov (United States)

    Zakaria, Mohd Rafein; Hirata, Satoshi; Hassan, Mohd Ali

    2014-10-01

    Hydrothermal pretreatment of oil palm mesocarp fiber was conducted in tube reactor at treatment severity ranges of log Ro = 3.66-4.83 and partial removal of hemicellulose with migration of lignin was obtained. Concerning maximal recovery of glucose and xylose, 1.5% NaOH was impregnated in the system and subsequent ball milling treatment was employed to improve the conversion yield. The effects of combined hydrothermal and ball milling pretreatments were evaluated by chemical composition changes by using FT-IR, WAXD and morphological alterations by SEM. The successful of pretreatments were assessed by the degree of enzymatic digestibility of treated samples. The highest xylose and glucose yields obtained were 63.2% and 97.3% respectively at cellulase loadings of 10 FPU/g-substrate which is the highest conversion from OPMF ever reported. PMID:25058299

  10. Effect of soya milk on nutritive, antioxidative, reological and textural properties of chocolate produced in a ball mill

    OpenAIRE

    Zarić Danica B.; Pajin Biljana S.; Rakin Marica B.; Šereš Zita I.; Dokić Ljubica P.; Tomić Jelena M.

    2011-01-01

    Chocolate is a complex rheological system in which non-fat cocoa particles and sugar particles are enveloped by crystal matrix of cocoa butter. Physical properties of chocolate depend on ingredient composition, method of production and properly performed pre-crystallization phase. In this work, chocolate was produced in an unconventional way, i.e. in a ball mill applying variable refining time (30, 60 and 90 min) and pre-crystallization temperature in chocolate masses (26, 28 and 30⁰C)....

  11. Synthesis and characterization of FePt nanoparticles by high energy ball milling with and without surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Velasco, V., E-mail: vvjimeno@fis.ucm.es [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, 28230 Las Rozas (Spain); Martinez, A.; Recio, J. [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, 28230 Las Rozas (Spain); Hernando, A.; Crespo, P. [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, 28230 Las Rozas (Spain); Dpto. de Fisica de Materiales, UCM, 28040 Madrid (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Fe and Pt powders in the presence of surfactants don't alloyed by HEBM technique. Black-Right-Pointing-Pointer FePt alloys obtained by dry milling exhibit particle sizes of around 10 {mu}m. Black-Right-Pointing-Pointer FePt alloys obtained by dry milling exhibit soft magnetic behavior. Black-Right-Pointing-Pointer A thermal treatment induces a phase transformation from FCC to FCT. - Abstract: FePt nanoparticles were prepared by high energy ball milling (HEBM) in two different ways. In the first one, elemental powders were mixed and milled whereas in the second one the milling was performed in the presence of oleyl amine and oleic acid as surfactants and hexane as a solvent. X-ray diffraction shows that when the milling is performed in dry conditions, Fe and Pt are alloyed after 5 h, whereas in the wet milling procedure alloying does not take place. In the first case, the diffraction pattern corresponds to the disordered FCC phase. This behavior is also corroborated by the evolution of the magnetic characteristics. In the case of the alloy obtained in dry conditions, the powder was heat treated in order to induce the transformation to the ordered phase. Coercivities of 2.5 kOe are obtained after 650 Degree-Sign C for 2 h.

  12. Controlling the number of walls in multi walled carbon nanotubes/alumina hybrid compound via ball milling of precipitate catalyst

    Science.gov (United States)

    Nosbi, Norlin; Akil, Hazizan Md

    2015-06-01

    This paper reports the influence of milling time on the structure and properties of the precipitate catalyst of multi walled carbon nanotubes (MWCNT)/alumina hybrid compound, produced through the chemical vapour deposition (CVD) process. For this purpose, light green precipitate consisted of aluminium, nickel(II) nitrate hexahydrate and sodium hydroxide mixture was placed in a planetary mill equipped with alumina vials using alumina balls at 300 rpm rotation speed for various milling time (5-15 h) prior to calcinations and CVD process. The compound was characterized using various techniques. Based on high-resolution transmission electron microscopy analysis, increasing the milling time up to 15 h decreased the diameter of MWCNT from 32.3 to 13.1 nm. It was noticed that the milling time had a significant effect on MWCNT wall thickness, whereby increasing the milling time from 0 to 15 h reduced the number of walls from 29 to 12. It was also interesting to note that the carbon content increased from 23.29 wt.% to 36.37 wt.% with increasing milling time.

  13. Formation of ultra-fine grained TiC-dispersed SUS316L by ball-milling and their consolidation by hot isostatic pressing

    International Nuclear Information System (INIS)

    In order to overcome the irradiation embrittlement in austenitic stainless steels, ultra-fine grained SUS316L steels with very fine TiC particles have been developed. The SUS316-TiC nanocomposite powders having 1.0 to 2.0 mass%TiC were prepared by ball-milling SUS316-TiC powder mixtures for 125h in an argon gas atmosphere. The milled powders were consolidated by hot isostatic pressing (HIP) under a pressure of 200 MPa at temperature between 700-1000degC, and the bulk materials with crystallite size ranging between 100-400 nm have been produced. The possibility of using fine-grained TiC particles for pinning grain boundaries and thereby to maintain the ultra-fine grained structures has been discussed. (author)

  14. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yongbing; Chen, Hongling, E-mail: hlchen@njut.edu.cn; Lin, Jinbin; Ji, Yan

    2013-11-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  15. Combined pretreatment using ozonolysis and ball milling to improve enzymatic saccharification of corn straw.

    Science.gov (United States)

    Shi, Feng; Xiang, Heji; Li, Yongfu

    2015-03-01

    Two clean pretreatments, ozonolysis (OZ) and planetary ball milling (BM) were applied separately and in combination to improve the enzymatic hydrolysis of corn straw. Pretreatment of corn straw by OZ and BM alone improved the enzymatic hydrolysis significantly, primarily through delignification and decrystallization of cellulose, respectively. When combined, OZ-BM and BM-OZ pretreatments made the enzymatic hydrolysis more efficient. The glucose and xylose yield of corn straw treated with OZ for 90 min followed by BM for 8 min (OZ90-BM8) reached to 407.8 and 101.9 mg/g-straw, respectively under cellulase loading of 15 FPU/g-straw, which was fivefold more than that of untreated straw. Under much lower cellulase loading of 1.5 FPU/g-straw, the glucose and xylose yield of treated straw OZ90-BM8 remained at 416.0 and 108.4 mg/g-straw, respectively, while the yield of untreated straw decreased. These findings indicate that the combined OZ-BM can be used as a promising pretreatment for corn straw. PMID:25569033

  16. Insertion compounds and composites made by ball milling for advanced sodium-ion batteries

    Science.gov (United States)

    Zhang, Biao; Dugas, Romain; Rousse, Gwenaelle; Rozier, Patrick; Abakumov, Artem M.; Tarascon, Jean-Marie

    2016-01-01

    Sodium-ion batteries have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. However, their future commercialization depends critically on control over the solid electrolyte interface formation, as well as the degree of sodiation at the positive electrode. Here we report an easily scalable ball milling approach, which relies on the use of metallic sodium, to prepare a variety of sodium-based alloys, insertion layered oxides and polyanionic compounds having sodium in excess such as the Na4V2(PO4)2F3 phase. The practical benefits of preparing sodium-enriched positive electrodes as reservoirs to compensate for sodium loss during solid electrolyte interphase formation are demonstrated by assembling full C/P'2-Na1[Fe0.5Mn0.5]O2 and C/`Na3+xV2(PO4)2F3' sodium-ion cells that show substantial increases (>10%) in energy storage density. Our findings may offer electrode design principles for accelerating the development of the sodium-ion technology.

  17. Characterization of cationic starch flocculants synthesized by dry process with ball milling activating method.

    Science.gov (United States)

    Su, Yuting; Du, Hongying; Huo, Yinqiang; Xu, Yongliang; Wang, Jie; Wang, Liying; Zhao, Siming; Xiong, Shanbai

    2016-06-01

    The cationic starch flocculants were synthesized by the reaction of maize starch which was activated by a ball-milling treatment with 2,3-epoxypropyl trimethyl ammonium chlorides (ETMAC) using the dry method. The cationic starches were characterized by several approaches including scanning electron microscope (SEM), degree of substitution (DS), infrared spectrum (IR), X-ray diffraction (XRD), flocculating activity, electron spin resonance (ESR), and solid-state nuclear magnetic resonance (NMR). The effect of mechanical activation on starch etherifying modification was investigated. The mechanical activation cracked starch granules and destructed their crystal structures. This resulted in enhancements to the reaction activity and reaction efficiency, which was approved by ESR and solid state NMR. The starch flocculants, synthesized by the reaction of mechanically activated starches at 90°C for 2.5h with ETMAC at molar ratio of 0.40:1.00, showed good flocculation activity. The substitution degree (0.300) and reaction efficiency (75.06%) of starch flocculants synthesized with mechanically activated starches were significantly greater than those of starch flocculants with native starches (P<0.05). PMID:26905465

  18. Insertion compounds and composites made by ball milling for advanced sodium-ion batteries

    Science.gov (United States)

    Zhang, Biao; Dugas, Romain; Rousse, Gwenaelle; Rozier, Patrick; Abakumov, Artem M.; Tarascon, Jean-Marie

    2016-01-01

    Sodium-ion batteries have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. However, their future commercialization depends critically on control over the solid electrolyte interface formation, as well as the degree of sodiation at the positive electrode. Here we report an easily scalable ball milling approach, which relies on the use of metallic sodium, to prepare a variety of sodium-based alloys, insertion layered oxides and polyanionic compounds having sodium in excess such as the Na4V2(PO4)2F3 phase. The practical benefits of preparing sodium-enriched positive electrodes as reservoirs to compensate for sodium loss during solid electrolyte interphase formation are demonstrated by assembling full C/P′2-Na1[Fe0.5Mn0.5]O2 and C/‘Na3+xV2(PO4)2F3' sodium-ion cells that show substantial increases (>10%) in energy storage density. Our findings may offer electrode design principles for accelerating the development of the sodium-ion technology. PMID:26777573

  19. Phase development during high-energy ball-milling of zinc oxide and iron - the impact of grain size on the source and the degree of contamination.

    Science.gov (United States)

    Štefanić, G; Krehula, S; Štefanić, I

    2015-11-21

    High-energy ball-milling of powder mixtures of zincite (ZnO) and iron (α-Fe) at different weight ratios was performed in air using a planetary ball mill with a stainless steel milling assembly. Structural and microstructural changes during the ball-milling (up to 30 h) were monitored using X-ray powder diffraction, field emission scanning electron microscopy (FE-SEM) and UV-Vis diffuse reflectance spectroscopy. The mechanism of iron oxidation was determined from the results of Mössbauer spectroscopy. It was found that an early phase of ball-milling caused the oxidation of iron from Fe(0) to Fe(2+) followed by the formation of a solid solution structurally similar to wüstite. The wüstite-type phase rapidly disappeared upon prolonged milling, which was accompanied by further oxidation of iron from Fe(2+) to Fe(3+) and the formation of spinel-type ferrite structurally similar to franklinite (ZnFe2O4) in the products with a high zinc content, or magnetite (Fe3O4) in the products with a high iron content. Further milling or annealing had a low impact on the franklinite-type phase, but caused the transition of the magnetite-type phase to the phase structurally similar to hematite (α-Fe2O3). The results of energy dispersive X-ray spectrometry (EDS) showed a dramatic increase in the degree of contamination with the increase in the proportion of the starting iron (∼9 times higher contamination during the milling of pure iron compared with pure zincite). It was shown that the source of contamination (balls or vial) strongly depends on the type of milled sample. Ball-milling of relatively big and heavy grains (starting iron) caused preferential contamination from the vial whereas ball-milling of smaller and lighter grains (products obtained after prolonged milling) caused preferential contamination from the balls. After prolonged milling the contamination due to wear of the balls was dominant in all the products. An explanation for the observed impact of grain size on

  20. Ball-milled CuPc/TiO{sub 2} hybrid nanocomposite and its photocatalytic degradation of aqueous Rhodamine B

    Energy Technology Data Exchange (ETDEWEB)

    Mekprasart, W., E-mail: wani.mek@gmail.com [Nanocomposite Material Research Laboratory, College of Nanotechnology, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); ThEP Center, CHE, 328 Si Ayutthaya Rd., Bangkok 10400 (Thailand); Vittayakorn, N. [Electroceramic Research Laboratory, College of Nanotechnology, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); ThEP Center, CHE, 328 Si Ayutthaya Rd., Bangkok 10400 (Thailand); Department of Chemistry, Faculty of Science, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Pecharapa, W. [Nanocomposite Material Research Laboratory, College of Nanotechnology, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); ThEP Center, CHE, 328 Si Ayutthaya Rd., Bangkok 10400 (Thailand)

    2012-11-15

    Graphical abstract: This work reports on the synthesis of hybrid composites of titanium dioxide and copper phthalocyanine via ball-milling assisted process in combination with mechanical mixing process. Their structural properties and photocatalytic degradation of aqueous RhB were investigated. The significant enhancement of the photocatalytic performance of the composite may be related to the charge recombination suppression guiding to the increase of free functional radicals participated in degradation process. Highlights: ► CuPc/TiO{sub 2} nanocomposite was synthesized by ball-milling assisted process and mechanical mixing method. ► Ball milling process can reduce CuPc size and assist the formation of well-dispersed composite. ► Loaded CuPc has inconsiderable influence on basic crystal structure of TiO{sub 2} matrix. ► The optical absorption properties of TiO{sub 2} in UV and visible light is improved with the existence of CuPc. ► CuPc/TiO{sub 2} nanocomposite can efficiently heighten the catalytic performance of TiO{sub 2} in the photodegradation of RhB. -- Abstract: Hybrid composites of titanium dioxide and copper phthalocyanine were synthesized by ball-milling assisted process in combination with mechanically stirring method. Structural properties of as-synthesized composites were characterized by X-ray diffraction (XRD), X-ray absorption fine structure (XANES) and scanning electron microscope (SEM). The optical absorbance of as-prepared composites and their photocatalytic activities were investigated by UV–vis spectroscopy. XRD and XANES results confirm that CuPc/TiO{sub 2} nanocomposite is still in the same structure of TiO{sub 2} and CuPc. SEM result reveals that the decreasing particle size of ball-milled CuPc has good dispersion on the surface of TiO{sub 2}. Absorptivity in UV region of the composites is heightened and shifted to visible light due to strong absorbance in blue-green spectrum of CuPc. The photocatalytic degradation of Rhodamine

  1. Ball-milled CuPc/TiO2 hybrid nanocomposite and its photocatalytic degradation of aqueous Rhodamine B

    International Nuclear Information System (INIS)

    Graphical abstract: This work reports on the synthesis of hybrid composites of titanium dioxide and copper phthalocyanine via ball-milling assisted process in combination with mechanical mixing process. Their structural properties and photocatalytic degradation of aqueous RhB were investigated. The significant enhancement of the photocatalytic performance of the composite may be related to the charge recombination suppression guiding to the increase of free functional radicals participated in degradation process. Highlights: ► CuPc/TiO2 nanocomposite was synthesized by ball-milling assisted process and mechanical mixing method. ► Ball milling process can reduce CuPc size and assist the formation of well-dispersed composite. ► Loaded CuPc has inconsiderable influence on basic crystal structure of TiO2 matrix. ► The optical absorption properties of TiO2 in UV and visible light is improved with the existence of CuPc. ► CuPc/TiO2 nanocomposite can efficiently heighten the catalytic performance of TiO2 in the photodegradation of RhB. -- Abstract: Hybrid composites of titanium dioxide and copper phthalocyanine were synthesized by ball-milling assisted process in combination with mechanically stirring method. Structural properties of as-synthesized composites were characterized by X-ray diffraction (XRD), X-ray absorption fine structure (XANES) and scanning electron microscope (SEM). The optical absorbance of as-prepared composites and their photocatalytic activities were investigated by UV–vis spectroscopy. XRD and XANES results confirm that CuPc/TiO2 nanocomposite is still in the same structure of TiO2 and CuPc. SEM result reveals that the decreasing particle size of ball-milled CuPc has good dispersion on the surface of TiO2. Absorptivity in UV region of the composites is heightened and shifted to visible light due to strong absorbance in blue-green spectrum of CuPc. The photocatalytic degradation of Rhodamine B dye solution using as-synthesized composites

  2. Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718

    Directory of Open Access Journals (Sweden)

    N.N. Bhopale

    2012-12-01

    Full Text Available The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting parameters. It is observed that at large cutting speed as well as feeds, thicker work piece with larger work piece inclination shows higher micro hardness as compared to the other machining conditions.

  3. Magnetic and mechanical properties of Cu (75 wt%) - 316L grade stainless steels synthesized by ball milling and annealing

    Science.gov (United States)

    Mondal, Bholanath; Chabri, Sumit; Sardar, Gargi; Bhowmik, Nandagopal; Sinha, Arijit; Chattopadhyay, Partha Protim

    2015-05-01

    Elemental powders of Cu (75 wt%) and 316-stainless steel (25 wt%) has been subjected to ball milling upto 70 h followed by isothermal annealing at the temperature range of 350-750 °C for 1 h to investigate the microstructural evolution along with magnetic and mechanical properties. After 40 h of milling, the bcc Fe is almost dissolved in the solid solution of Cu but no significant change has been observed in the XRD pattern after 70 h of milling, Annealing of the alloy has resulted in precipitation of nanocrystalline bcc-Fe in Cu which triggers the soft ferromagnetic properties. The extensive mechanical characterization has been done at the microstructural scale by nanoindentation technique which demonstrates a hardening behavior of the compacted and annealed alloys due to possible precipitation of nanocrystalline bcc-Fe in Cu.

  4. Contamination introduced during rock sample powdering. Effects from different mill materials on trace element contamination

    International Nuclear Information System (INIS)

    We examined blanks during powdering processes for thirty-three trace elements using ICP-MS (inductively coupled plasma mass spectrometry). Quartz sand was used as target of powdering with grinding mills of several kinds: an agate hand mill, agate ball mill, Fe hand mill, alumina ceramic hand mill and artificial crystalline quartz hand mill. The results show that the artificial crystalline quartz hand mill is the purest grinder among the analyzed ones. This grinder is suitable for soft rock samples such as limestone. The alumina ceramic hand mill can reduce contamination, except for Cs, W and Pb. The agate hand mill and the agate ball mill introduce contamination whose level is depending on the individual device due to heterogeneity of the natural agate. The Fe hand mill introduces contamination of some si-derophile elements such as Mo and W. The results of this study emphasize careful choice of a grinding mill for sample pulverizing. (author)

  5. Effect of starting composition on formation of MoSi2–SiC nanocomposite powder via ball milling

    Indian Academy of Sciences (India)

    M Zakeri; M Ahmadi

    2012-08-01

    MoSi2–SiC nanocomposite powders were successfully synthesized by ball milling Mo, Si and graphite elemental powders. Effects of milling time and annealing temperature were also investigated. The composite formation and phase transformation were monitored by X-ray diffraction. The microstructure of milled powders was studied by SEM, TEM and XRD peak profile analysis. Formation of this composite was completed after 10 and 20 h of milling for 25%SiC and 50%SiC, respectively. High temperature polymorph (HTP) of MoSi2 was obtained at the end of milling (20 h). On the other hand, annealing led to transformation of HTP to low temperature polymorph (LTP) of MoSi2. Mo5Si3 was formed during annealing as a product of a reaction between MoSi2 and excess graphite. Mean grain size <50 nm was obtained for 20 h milled sample on the basis of peak profile analysis and TEM images.

  6. Synthesis of Barium Hexaferrite/iron Oxides Magnetic Nano-Composites via High Energy Ball Milling and Subsequent Heat Treatment

    Science.gov (United States)

    Molaei, M. J.; Ataie, A.; Raygan, S.

    Barium hexaferrite (BaFe12O19) is a hard magnetic ceramic with superior magnetic properties and in powder form has potential for application in high density recording media. In this research a mechano-chemical approach was applied in order to achieve a nano-structured magnetic composite. Graphite was used to reduce barium hexaferrite in mechanical milling medium under argon atmosphere. Milling was carried out with a ball to powder mass ratio of 35 and rotation speed of 300 rpm. Effects of milling time on phase composition and morphology of the samples were evaluated by XRD and SEM techniques, respectively. XRD results revealed that after 20 hours of milling, nano-composite of BaFe12O19/Fe3O4/Fe2O3 was obtained. By extending the milling time to 40 hours, FeO was detected as the dominant crystalline phase with crystallite size of 22 nm. Composite of Fe/FeO/Fe3O4 was synthesized by controlled heat treatment of the 40 hours milled sample. SEM results revealed that particle size in the aforementioned heat treated composite sample reached to about 89 nm and the morphology of the samples changed slightly.

  7. The coercivity mechanism of Pr–Fe–B nanoflakes prepared by surfactant-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Wen-Liang, E-mail: wlzuo@iphy.ac.cn; Zhang, Ming; Niu, E.; Shao, Xiao-Ping; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen, E-mail: shenbg@aphy.iphy.ac.cn

    2015-09-15

    The strong (00l) textured Pr{sub 12+x}Fe{sub 82−x}B{sub 6} (x=0, 1, 2, 3, 4) nanoflakes with high coercivity were prepared by surfactant-assisted ball milling (SABM). The thickness and length of the flakes are mainly in the range of 50−200 nm and 0.5−2 μm, respectively. A coercivity of 4.16 kOe for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes was obtained, which is the maximum coercivity of R{sub 2}Fe{sub 14}B (R=Pr, Nd) nanoflakes or nanoparticles reported up to now. The results of XRD and SEM for the aligned Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes indicate that a strong (00l) texture is obtained and the easy magnetization direction is parallel to the surface of the flakes. The angular dependence of coercivity for aligned sample indicates that the coercivity mechanism of the as-milled nanoflakes is mainly dominated by domain wall pinning. Meanwhile, the field dependence of coercivity, isothermal (IRM) and dc demagnetizing (DCD) remanence curves also indicate that the coercivity is mainly determined by domain wall pinning, and nucleation also has an important effect. In addition, the mainly interaction of flakes is dipolar coupling. The research of coercivity mechanism for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes is important for guidance the further increase its value, and is useful for the future development of the high performance nanocomposite magnets and soft/hard exchange spring magnets. - Highlights: • A coercivity of 4.16 kOe for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes was obtained. • The strong (00l) textured is obtained for Pr{sub 15}Fe{sub 79}B{sub 6} nanoflakes. • The interaction of nanoflakes is mainly dipolar coupling. • Domain wall pinning is the mainly coercivity mechanism.

  8. Contamination Effects on Improving the Hydrogenation/Dehydrogenation Kinetics of Binary Magnesium Hydride/Titanium Carbide Systems Prepared by Reactive Ball Milling

    Directory of Open Access Journals (Sweden)

    M. Sherif El-Eskandarany

    2015-10-01

    Full Text Available Ultrafine MgH2 nanocrystalline powders were prepared by reactive ball milling of elemental Mg powders after 200 h of high-energy ball milling under a hydrogen gas pressure of 50 bar. The as-prepared metal hydride powders were contaminated with 2.2 wt. % of FeCr-stainless steel that was introduced to the powders upon using stainless steel milling tools made of the same alloy. The as-synthesized MgH2 was doped with previously prepared TiC nanopowders, which were contaminated with 2.4 wt. % FeCr (materials of the milling media, and then ball milled under hydrogen gas atmosphere for 50 h. The results related to the morphological examinations of the fabricated nanocomposite powders beyond the micro-and nano-levels showed excellent distributions of 5.2 wt. % TiC/4.6 wt. % FeCr dispersoids embedded into the fine host matrix of MgH2 powders. The as-fabricated nanocomposite MgH2/5.2 wt. % TiC/4.6 wt. % FeCr powders possessed superior hydrogenation/dehydrogenation characteristics, suggested by the low value of the activation energy (97.74 kJ/mol, and the short time required for achieving a complete absorption (6.6 min and desorption (8.4 min of 5.51 wt. % H2 at a moderate temperature of 275 C under a hydrogen gas pressure ranging from 100 mbar to 8 bar. van’t Hoff approach was used to calculate the enthalpy (DH and entropy (DS of hydrogenation for MgH2, which was found to be 72.74 kJ/mol and 112.79 J/mol H2/K, respectively. Moreover, van’t Hoff method was employed to calculate the DH and DS of dehydrogenation, which was found to be 76.76 kJ/mol and 119.15 J/mol H2/K, respectively. This new nanocomposite system possessed excellent absorption/desorption cyclability of 696 complete cycles, achieved in a cyclic-life-time of 682 h.

  9. Development and evaluation of optimized sucrose ester stabilized oleanolic acid nanosuspensions prepared by wet ball milling with design of experiments.

    Science.gov (United States)

    Li, Wenji; Ng, Ka-yun; Heng, Paul Wan Sia

    2014-01-01

    The aim of this study was to develop optimized sucrose ester (SE) stabilized oleanolic acid (OA) nanosuspensions (NS) for enhanced delivery via wet ball milling by design of experiments (DOE). In this study, SEOA NS batches were prepared by wet ball milling method. Mean particle sizes and polydispersity indices were determined using a nanosizer. The percent encapsulation efficiency, saturation solubility and in vitro dissolution rate were obtained with analyses using HPLC. Preparation methods were optimized by DOE using the Minitab software. The in vitro bioefficacy was obtained by methyl thiazolyl tetrazolium (MTT) measurements in A549 human non small cell lung cancer cell line. The in vivo pharmacokinetics profile was determined using LC-electrospray ionization (ESI)-MS/MS. The study produced spherical SEOA NS particles (ca. 100 nm in diameter) which were found to be able to increase OA saturation solubility considerably. Optimized SEOA-GBD NS (milled at 600 rpm for 3 h, sucrose monolaurate (SEL) : sucrose monopalmitate (SEP) at 9 : 1, w/w; SE : OA at 1 : 1, w/w) was found to be physically stable over 14 d at 4°C. The NS showed much higher dissolution rate, cytotoxicity and bioavailability when compared with the free drug. Thus, the prepared OA as SE stabilized NS particles by wet ball milling enhanced the saturation solubility, in vitro dissolution rate, bioefficacy and in vivo bioavailability of OA. The use of sugar esters may also be potentially applied to other hydrophobic drugs. PMID:24882406

  10. TiO2/CuPc hybrid nanocomposites prepared by low-energy ball milling for dye-sensitized solar cell application

    International Nuclear Information System (INIS)

    The hybrid nanocomposites of titanium dioxide nanoparticle (TNP) and copper phthalocyanine (CuPc) were successfully synthesized by low-energy ball milling as a main part of synthesis and processing via three different methods without additional heating. Structural properties of as-prepared composites were well characterized by X-ray diffraction, Raman spectroscopy, Field Emission-Scanning Electron Microscopy and Transmission Electron Microscopy. TNP/CuPc hybrid nanocomposites acting as photocatalyst were used as a modified working electrode materials in dye-sensitized solar cells. Among all prepared conditions, the composite with 0.05 wt.% CuPc prepared by homogenization and ball milling process exhibited the best performance with optimized solar energy conversion efficiency of 1.24% with fill factor of 0.45. The significant enhancement of current density of the device may be associated to the decrease of recombination of photo-injected electrons and reduction of charge transfer resistances at the interface caused by the presence of CuPc on TNP matrix.

  11. Effect of LiBr addition on the electrochemical performance of La{sub 2}Mg{sub 17}/Ni composites prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhuocheng, E-mail: liuzhuo567@eyou.com [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Hou, Zhonghui; Ruan, Fei; Yin, Yi [Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Zhang, Jieyu [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China)

    2015-03-05

    Highlights: • The addition of LiBr prevents the crystallization of La{sub 2}Mg{sub 17}/Ni composites. • Amorphous and nanocrystalline granules were obtained by ball milling. • The proportion of nanocrystalline granules increases with LiBr addition. • 5 wt.% LiBr is optimal for maximum discharge capacity and corrosion resistance . • The improved capacity with LiBr addition is due to a decrease in contact resistance. - Abstract: This study examines the microstructure of La{sub 2}Mg{sub 17}/Ni composites produced by ball-milling with lithium bromide, and the effect of varying this LiBr addition on the electrochemical properties of the resulting electrode material. Through this, it was found that LiBr helps prevent crystallization of the alloy, thereby refining the particle size and ensuring a uniform distribution of amorphous and nanocrystalline particles. This structure greatly improved the electrochemical properties of the composite, with the maximum discharge capacity increasing from 176.8 to 550.38 mA h/g. Further investigation of the electrochemical behaviour of the composite electrode revealed that the addition of 5 wt.% LiBr reduces the contact resistance, increases the electrochemical impedance, enhances the limiting current density and improves the charge/discharge equilibrium rate.

  12. A Mössbauer effect study of ball-milled strontium ferrite

    Science.gov (United States)

    Wu, E.; Campbell, S. J.; Kaczmarek, W. A.

    1998-01-01

    The effects of milling SrFe 12O 19 in air and vacuum for 800 h have been investigated by X-ray diffraction and Mössbauer effect spectroscopy measurements. Different levels of structural disorder along with partial decomposition of SrFe 12O 19 to nanocrystalline grains of haematite, α-Fe 2O 3, and magnetite, Fe 3O 4, are obtained for the air and vacuum milling. Superparamagnetic relaxation effects due to the fine particles produced on milling are observed for a significant fraction ( ˜ 10% air milled, ˜ 30% vacuum milled) of the milled samples.

  13. Perspectives on the amorphisation/milling relationship in pharmaceutical materials.

    Science.gov (United States)

    Descamps, M; Willart, J F

    2016-05-01

    This paper presents an overview of recent advances in understanding the role of the amorphous state in the physical and chemical transformations of pharmaceutical materials induced by mechanical milling. The following points are addressed: (1) Is milling really able to amorphise crystals?, (2) Conditions for obtaining an amorphisation, (3) Milling of hydrates, (4) Producing amorphous state without changing the chemical nature, (5) Milling induced crystal to crystal transformations: mediation by an amorphous state, (6) Nature of the amorphous state obtained by milling, (7) Milling of amorphous compounds: accelerated aging or rejuvenation, (8) Specific recrystallisation behaviour, and (9) Toward a rationalisation and conceptual framework. PMID:26826439

  14. Selective ensemble modeling load parameters of ball mill based on multi-scale frequency spectral features and sphere criterion

    Science.gov (United States)

    Tang, Jian; Yu, Wen; Chai, Tianyou; Liu, Zhuo; Zhou, Xiaojie

    2016-01-01

    It is difficult to model multi-frequency signal, such as mechanical vibration and acoustic signals of wet ball mill in the mineral grinding process. In this paper, these signals are decomposed into multi-scale intrinsic mode functions (IMFs) by the empirical mode decomposition (EMD) technique. A new adaptive multi-scale spectral features selection approach based on sphere criterion (SC) is applied to these IMFs frequency spectra. The candidate sub-models are constructed by the partial least squares (PLS) with the selected features. Finally, the branch and bound based selective ensemble (BBSEN) algorithm is applied to select and combine these ensemble sub-models. This method can be easily extended to regression and classification problems with multi-time scale signal. We successfully apply this approach to a laboratory-scale ball mill. The shell vibration and acoustic signals are used to model mill load parameters. The experimental results demonstrate that this novel approach is more effective than the other modeling methods based on multi-scale frequency spectral features.

  15. Influence of the duration of high energy ball milling on the microstructure and mechanical properties of a 9Cr oxide dispersion strengthened ferritic–martensitic steel

    International Nuclear Information System (INIS)

    Oxide dispersion strengthened (ODS) 9Cr steel was prepared by milling atomised steel powder (Fe–0.1C–9Cr–2W–0.2Ti) with nano yttria powder in a high energy horizontal ball mill (Simoloyer CM-08) for 1, 2, 3 and 4 h. Both particle as well as crystallite sizes of milled ODS steel powder reduced with milling time reaching steady state after 3 h. The grain size of the heat treated ODS steel also reduces with milling time reaching a steady state after 3 h. Four hours of milling is sufficient to get the dispersoids of less than 5 nm in heat treated ODS steel. Both yield and tensile strengths increase with milling time up to 673 K and there is no effect of milling on the strength levels beyond 673 K

  16. A structural and Moessbauer study of Y{sub 3}Fe{sub 5}O{sub 12} nanoparticles prepared with high energy ball milling and subsequent sintering

    Energy Technology Data Exchange (ETDEWEB)

    Widatallah, H. M., E-mail: hishammw@squ.edu.om [Sultan Qaboos University, Department of Physics (Oman); Johnson, C. [Open University, Chemistry Department (United Kingdom); Al-Harthi, S. H.; Gismelseed, A. M.; Al-Rawas, A. D.; Stewart, S. J.; Elzain, M. E.; Al-Omari, I. A.; Yousif, A. A. [Sultan Qaboos University, Department of Physics (Oman)

    2008-04-15

    The influence of ball milling and subsequent sintering of a 3:5 molar mixture of Y{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3} on the formation of nanocrystalline Y{sub 3}Fe{sub 5}O{sub 12} (YIG) particles is studied. Pre-milling the mixture for 100 h lowers the onset temperature at which the material forms to 900 deg. C which is 200 deg. C lower than that reported when a similar mixture of reactants was premilled for shorter times. A single-phased nanocrystalline Y{sub 3}Fe{sub 5}O{sub 12} phase develops as a sole product when the pre-milled mixture is heated at 1,000 deg. C (12 h). This temperature is {approx}300-400 deg. C lower than those used to prepare the material conventionally. The bulk and surface crystal structure of the nanoparticles is studied with X-ray diffraction, Moessbauer spectroscopy, Atomic Force Microscope (AFM) and X-ray photoelectron spectroscopy.

  17. An investigation of the microstructure and hydrogenation/dehydrogenation properties of ball-milled CeMg{sub 12} alloys with Ni powders

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Feng [Inner Mongolia Univ. of Science and Technology, Baotou (China). The School of Rare Earth; Inner Mongolia Univ. of Science and Technology, Baotou (China). Elected State Key Lab.; Zhang, Yanghuan [Inner Mongolia Univ. of Science and Technology, Baotou (China). Elected State Key Lab.; Central Iron and Steel Research Institute, Beijing (China). Depts. of Functional Material Research; Zhang, Yin; Xu, Jianyi; Cai, Ying [Inner Mongolia Univ. of Science and Technology, Baotou (China). The School of Rare Earth; Deng, Leibo [Inner Mongolia Univ. of Science and Technology, Baotou (China). Elected State Key Lab.

    2014-01-15

    CeMg{sub 12} + 100 wt.% Ni composite hydrogen storage alloys were prepared using ball-milling. The phase structure, morphologies, and hydrogen absorption and desorption kinetics of these alloys were systematically investigated. The results show that the milled CeMg{sub 12} + 100 wt.% Ni alloys consisted of Mg{sub 2}Ni and Ni phase with nanocrystalline and amorphous structures. Additionally, the volume fractions of the phase increased with prolonged ball-milling times, which improved the hydrogenation rates and the hydrogen storage capacities of the alloy samples. However, the dehydrogenation kinetics of the alloy samples were also impaired by the increased milling times. The poor dehydriding kinetics of the alloy samples milled for 80 h and 100 h were primarily attributed to grain size effects. (orig.)

  18. Improving the adsorption ability of graphene sheets to uranium through chemical oxidation, electrolysis and ball-milling

    International Nuclear Information System (INIS)

    Three types of graphene sheets (GS) were decorated by chemical oxidation, electrolysis and ball-milling, respectively. These oxidized samples were characterized using SEM, XRD, Raman, FT-IR and XPS, and then were employed to enrich U(VI) from aqueous solutions as a function of pH, contact time and initial concentration of U(VI). These results displayed that the quantities and types of oxygen-functional groups were extremely different through these methods, which highly determined the adsorption capacity of graphene oxide to uranium. This work may provide some helpful information to optimize these fabrication processes and improve the adsorption ability of GS to uranium. (author)

  19. Influence of emulsifiers on the optimization of processing parameters of refining milk chocolate in the ball mill

    Directory of Open Access Journals (Sweden)

    Pajin Biljana

    2011-01-01

    Full Text Available Chocolate manufacture is a complex process which includes a large number of technology operations. One of the obligatory phases is milling, called refining, which aims at obtaining the appropriate distribution of particle size, resulting in the chocolate with optimal physical and sensory characteristics. The aim of this work was to define and optimize the process parameters for the production of milk chocolate by a non-conventional procedure, using the ball mill. The quality of chocolate mass, produced on this way, is determined by measuring the following parameters: moisture, size of the largest cocoa particle, yield flow, and Casson plastic viscosity. A special consideration of this study is the optimization of the types and amounts of emulsifiers, which are responsible for achieving the appropriate rheological and physical characteristics of the chocolate mass. The obtained parameters are compared with those which are typical for the standard procedure.

  20. Synthesis of Fe–Si–B–Mn-based nanocrystalline magnetic alloys with large coercivity by high energy ball milling

    Indian Academy of Sciences (India)

    P D Reddi; N K Mukhopadhyay; B Majumdar; A K Singh; S S Meena; S M Yusuf; N K Prasad

    2014-06-01

    Alloys of Fe–Si–B with varying compositions of Mn were prepared using high energy planetary ball mill for maximum duration of 120 h. X-ray diffraction (XRD) analysis suggests that Si gets mostly dissolved into Fe after 80 h of milling for all compositions. The residual Si was found to form an intermetallic Fe3Si. The dissolution was further confirmed from the field emission scanning electron microscopy/energy dispersive X-ray analysis (FE-SEM/EDX). With increased milling time, the lattice parameter and lattice strain are found to increase. However, the crystallite size decreases from micrometer (75–95 m) to nanometer (10–20 nm). Mössbauer spectra analysis suggests the presence of essentially ferromagnetic phases with small percentage of super paramagnetic phase in the system. The saturation magnetization (s), remanance (r) and coercivity (c) values for Fe–0Mn sample after 120 h of milling were 96.4 Am2/kg, 11.5 Am2/kg and 12.42 k Am-1, respectively. However, for Fe–10Mn–5Cu sample the s, c and r values were found to be 101.9 Am2/kg, 10.98 kA/m and 12.4 Am2/kg, respectively. The higher value of magnetization could be attributed to the favourable coupling between Mn and Cu.

  1. Effect of ball milling and dynamic compaction on magnetic properties of Al2O3/Co(P) composite particles

    Science.gov (United States)

    Denisova, E. A.; Kuzovnikova, L. A.; Iskhakov, R. S.; Bukaemskiy, A. A.; Eremin, E. V.; Nemtsev, I. V.

    2014-05-01

    The evolution of the magnetic properties of composite Al2O3/Co(P) particles during ball milling and dynamic compaction is investigated. To prepare starting composite particles, the Al2O3 granules were coated with a Co95P5 shell by electroless plating. The magnetic and structural properties of the composite particles are characterized by scanning electron microscopy, X-ray diffraction, and the use of the Physical Property Measurement System. The use of composite core-shell particles as starting powder for mechanoactivation allows to decrease treatment duration to 1 h and to produce a more homogeneous bulk sample than in the case of the mixture of Co and Al2O3 powders. The magnetic properties of the milled composite particles are correlated with changes in the microstructure. Reduction in grain size of Co during milling leads to an increase of the volume fraction of superparamagnetic particles and to a decrease of the saturation magnetization. The local magnetic anisotropy field depends on the amount of hcp-Co phase in sample. The anisotropy field value decreases from 8.4 kOe to 3.8 kOe with an increase in milling duration up to 75 min. The regimes of dynamic compaction were selected so that the magnetic characteristics—saturation magnetization and coercive field—remained unchanged.

  2. Highly Al-doped TiO2 nanoparticles produced by Ball Mill Method: structural and electronic characterization

    International Nuclear Information System (INIS)

    Highlights: • Highly Al-doped TiO2 nanoparticles were synthesized using a Ball Mill Method. • Al doping delayed anatase to rutile phase transformation. • Al doping allow controlling the structural and electronic properties of nanoparticles. - Abstract: This study presents an easy method for synthesizing highly doped TiO2 nanoparticles. The Ball Mill method was used to synthesize pure and Al-doped titanium dioxide, with an atomic percentage up to 15.7 at.% Al/(Al + Ti). The samples were annealed at 773 K, 973 K and 1173 K, and characterized using ICP-AES, XRD, Raman spectroscopy, FT-IR, TG, STEM, XPS, and UV–vis spectroscopy. The effect of doping and the calcination temperature on the structure and properties of the nanoparticles were studied. The results show high levels of internal doping due to the substitution of Ti4+ ions by Al3+ in the TiO2 lattice. Furthermore, anatase to rutile transformation occurs at higher temperatures when the percentage of doping increases. Therefore, Al doping allows us to control the structural and electronic properties of the nanoparticle synthesized. So, it is possible to obtain nanoparticles with anatase as predominant phase in a higher range of temperature

  3. Highly Al-doped TiO{sub 2} nanoparticles produced by Ball Mill Method: structural and electronic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Desireé M. de los, E-mail: desire.delossantos@uca.es; Navas, Javier, E-mail: javier.navas@uca.es; Sánchez-Coronilla, Antonio; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

    2015-10-15

    Highlights: • Highly Al-doped TiO{sub 2} nanoparticles were synthesized using a Ball Mill Method. • Al doping delayed anatase to rutile phase transformation. • Al doping allow controlling the structural and electronic properties of nanoparticles. - Abstract: This study presents an easy method for synthesizing highly doped TiO{sub 2} nanoparticles. The Ball Mill method was used to synthesize pure and Al-doped titanium dioxide, with an atomic percentage up to 15.7 at.% Al/(Al + Ti). The samples were annealed at 773 K, 973 K and 1173 K, and characterized using ICP-AES, XRD, Raman spectroscopy, FT-IR, TG, STEM, XPS, and UV–vis spectroscopy. The effect of doping and the calcination temperature on the structure and properties of the nanoparticles were studied. The results show high levels of internal doping due to the substitution of Ti{sup 4+} ions by Al{sup 3+} in the TiO{sub 2} lattice. Furthermore, anatase to rutile transformation occurs at higher temperatures when the percentage of doping increases. Therefore, Al doping allows us to control the structural and electronic properties of the nanoparticle synthesized. So, it is possible to obtain nanoparticles with anatase as predominant phase in a higher range of temperature.

  4. Finite size effects and spin transition in ball-milled γ-(FeMn)30Cu70 nanostructured alloys

    International Nuclear Information System (INIS)

    Fe15Mn15Cu70 alloys were prepared by high-energy ball milling over a wide range of grinding times from 15 min to 72 h. The corresponding magnetic properties were followed by means of vibrating sample magnetometry, magnetic susceptibility and Moessbauer spectroscopy. By using a Rietveld structural analysis of high-resolution X-ray diffraction data, lattice parameter and grain size correlations with magnetization and coercive force were carried out. Results revealed a strong microstructural dependence of the magnetic properties with the grain size, resembling a finite size-driven magnetic transition at a critical crystallite value of around 8.5 nm. This behavior is endorsed by a partial low- to high-spin transition according to isomer shift results, at a critical unit-cell volume of around 50 A3 at 77 K attributed to strong local variations of the interatomic spacing as a consequence of the employed ball-milling procedure. Finally, as concerns to temperature behavior, samples exhibited a freezing temperature at around 61 K and a wide distribution of relaxation times ascribed to the presence of interacting CuMn and FeMnCu clusters

  5. A comparison of cellulose nanocrystals and cellulose nanofibres extracted from bagasse using acid and ball milling methods

    Science.gov (United States)

    Rahimi Kord Sofla, M.; Brown, R. J.; Tsuzuki, T.; Rainey, T. J.

    2016-09-01

    This study compared the fundamental properties of cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF) extracted from sugarcane bagasse. Conventional hydrolysis was used to extract CNC while ball milling was used to extract CNF. Images generated by scanning electron microscope and transmission electron microscope showed CNC was needle-like with relatively lower aspect ratio and CNF was rope-like in structure with higher aspect ratio. Fourier-transformed infrared spectra showed that the chemical composition of nanocellulose and extracted cellulose were identical and quite different from bagasse. Dynamic light scattering studies showed that CNC had uniform particle size distribution with a median size of 148 nm while CNF had a bimodal size distribution with median size 240 ± 12 nm and 10 μm. X-ray diffraction showed that the amorphous portion was removed during hydrolysis; this resulted in an increase in the crystalline portion of CNC compared to CNF. Thermal degradation of cellulose initiated at a much lower temperature, in the case of the nanocrystals while the CNF prepared by ball milling were not affected, indicating higher thermal stability.

  6. Fast environment-friendly ball mill-assisted deep eutectic solvent-based extraction of natural products.

    Science.gov (United States)

    Wang, Man; Wang, Jiaqin; Zhang, Yue; Xia, Qian; Bi, Wentao; Yang, Xiaodi; Chen, David Da Yong

    2016-04-22

    A fast environment-friendly extraction method, ball mill-assisted deep eutectic solvent-based extraction, was used for the extraction of natural products from plants. In this study, tanshinones were selected as target compounds to evaluate the efficiency of the developed extraction method. Under the optimized experimental conditions, cryptotanshinone (0.176mg/g), tanshinone I (0.181mg/g), and tanshinone II A (0.421mg/g) were extracted from Salvia miltiorrhiza Bunge, and the developed method was found to be greener, more efficient, and faster than conventional, environmentally harmful extraction methods such as methanol-based ultrasound-assisted extraction and heat reflux extraction. The analytical performances including recovery, reproducibility (RSD, n=5), correlation of determination (r(2)), and the limit of detection, with the ranges of 96.1-103.9%, 1.6-1.9%, 0.9973-0.9984, and 5-8ng/mL, were respectively obtained. Application of ball mill-assisted deep eutectic solvent-based extraction may fundamentally shape the future development of extraction methods. PMID:27033981

  7. Mechanically driven nanocrystallization of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy induced by high-energy ball milling

    International Nuclear Information System (INIS)

    The mechanically driven nanocrystallization of amorphous Finemet alloy caused by high-energy ball milling was investigated by XRD, DSC and TEM techniques. A structural relaxation occurred in the amorphous Finemet alloy after milling for 0.5-2 h. Further milling for more than 3.5 h, uniformly and randomly distributed nanocrystalline α-Fe with grain size from ∝2 nm to ∝5 nm formed. The kinetics of the mechanical nanocrystallization of amorphous Finemet alloy was described by JMA model with the Avrami exponent n=1.55, which indicates a zero-nucleation rate and grain growth in all shapes from very small dimensions. In addition, the mechanical crystallization of amorphous Finemet alloys is mainly due to the severe deformation and local temperature rise during ball milling. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Polycrystalline Nd{sub 2}Fe{sub 14}B/α-Fe nanocomposite flakes with a sub-micro/nanometre thickness prepared by surfactant-assisted high-energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xin, E-mail: tangshincn@gmail.com [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Chen, Xi [Mechanical and Electrical Engineering College, Xinxiang University, No. 192, Jinsui Road, Xinxiang, Henan 453003 (China); Chen, Renjie; Yan, Aru [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-09-25

    Highlights: • Nd{sub 2}Fe{sub 14}B/α-Fe flakes are formed by peeling along preferential planes. • (0 0 l) planes are found to be preferential cleavage planes. • Magnetic properties degrade with increasing ball milling time. • Anisotropic nanocomposite magnets are fabricated. - Abstract: A surfactant-assisted high-energy ball milling technique was employed to synthesize Nd{sub 2}Fe{sub 14}B/α-Fe nanoparticles and nanoflakes from melt-spun nanocrystalline powders. The microstructure evolution in ball milling process was investigated. In the beginning stage (0–4 h) of ball milling, raw powders were crushed into micrometre-sized particles. While flakes were mainly formed by reducing thickness of particles via peeling layer by layer along preferential planes in the late stage (8–16 h). The selected area electron diffraction and high-resolution transmission electron microscopy images show that preferential cleavage planes are basal planes. With ball milling proceeding, more and more defects were induced by ball milling. As a result, the coercivity and remanence decreased to 1.6 kOe and 3.2 kGs, respectively. After 16 h ball milling, the exchange decoupling occurred due to severe amorphorization. A weakly-textured nanocomposite magnet was fabricated after 12 h ball milling and the anisotropy in magnetic properties can be further improved by employing settling down process to select particle size and aligning particles in external field.

  9. Effect of ball milling treatment on physicochemical property of wheat starch%球磨处理对小麦淀粉理化性质的影响

    Institute of Scientific and Technical Information of China (English)

    逯蕾; 韩小贤; 李淑鑫; 郑学玲; 刘翀; 侯蕾

    2014-01-01

    In this paper,wheat starch as raw material,the use of a planetary ball mill for mechanical damage to wheat starch,wheat starch,through different milling processing time injury,starch content, sedimentation volume,measured analysis of water rates,transparency and solubility and swelling power and other indicators,we know that:with the extension of milling time,the solubility of wheat starch swelling power,analysis of water damage rate and starch content were significantly increased,the peak viscosity of the starch paste,trough viscosity,final viscosity,attenuation values and the values of both regenerative showed a downward trend;gel hardness,brittleness,adhesion,elasticity and chewiness also decreased with increasing milling time.%该文以小麦淀粉为原料,采用行星式球磨机对小麦淀粉进行机械损伤,通过对不同球磨处理时间下小麦淀粉的损伤淀粉含量、沉降体积、析水率、透明度以及溶解度和膨润力等指标的测定,得出:随着球磨时间的延长,小麦淀粉的溶解度、膨润力、析水率和损伤淀粉含量均显著增加,淀粉糊的峰值黏度、谷值黏度、最终黏度、衰减值和回生值均呈明显下降趋势;凝胶的硬度、脆度、黏附性、弹性和咀嚼性也随球磨时间的增加而下降。

  10. Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

    Directory of Open Access Journals (Sweden)

    Dazhong Wang

    2015-01-01

    Full Text Available Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC milling machine set ermined as a research object, the stiffness of its fixed joint between the column and the body together with the stiffness parameters of the rolling joints is evaluated according to the Takashi Yoshimura method. Then, a finite element (FE model is established for the machine tool. The correctness of the FE model and the stiffness calculation method of the rolling joints are validated by theoretical and experimental modal analysis results of the machine tool’s workbench. Under the two modeling methods of joints incorporating the stiffness parameters and rigid connection, a theoretical modal analysis is conducted for the CNC milling machine. The natural frequencies and modal shapes reveal that the joints’ dynamic characteristic has an important influence on the dynamic performance of a whole machine tool, especially for the case with natural frequency and higher modes.

  11. Microstructural changes and effect of variation of lattice strain on positron annihilation lifetime parameters of zinc ferrite nanocomposites prepared by high enegy ball-milling

    Directory of Open Access Journals (Sweden)

    Abhijit Banerjee

    2012-12-01

    Full Text Available Zn-ferrite nanoparticles were synthesized at room temperature by mechanical alloying the stoichiometric (1:1 mol% mixture of ZnO and α-Fe2O3 powder under open air. Formation of both normal and inverse spinel ferrite phases was noticed after 30 minutes and 2.5 hours ball milling respectively and the content of inverse spinel phase increased with increasing milling time. The phase transformation kinetics towards formation of ferrite phases and microstructure characterization of ball milled ZnFe2O4 phases was primarily investigated by X-ray powder diffraction pattern analysis. The relative phase abundances of different phases, crystallite size, r.m.s. strain, lattice parameter change etc. were estimated from the Rietveld powder structure refinement analysis of XRD data. Positron annihilation lifetime spectra of all ball milled samples were deconvoluted with three lifetime parameters and their variation with milling time duration was explained with microstructural changes and formation of different phases with increase of milling time duration.

  12. Survival of the Fittest: Competitive Co-crystal Reactions in the Ball Mill.

    Science.gov (United States)

    Fischer, Franziska; Joester, Maike; Rademann, Klaus; Emmerling, Franziska

    2015-10-12

    The driving forces triggering the formation of co-crystals under milling conditions were investigated by using a set of multicomponent competitive milling reactions. In these reactions, different active pharmaceutical ingredients were ground together with a further compound acting as coformer. The study was based on new co-crystals including the coformer anthranilic acid. The results of the competitive milling reactions indicate that the formation of co-crystals driven by intermolecular recognition are influenced and inhibited by kinetic aspects including the formation of intermediates and the stability of the reactants. PMID:26332316

  13. Combined Cryo and Room-Temperature Ball Milling to Produce Ultrafine Halide Crystallites

    Science.gov (United States)

    Verma, Akash; Biswas, Krishanu; Tiwary, Chandra Sekhar; Mondal, Amit Kumar; Chattopadhyay, Kamanio

    2011-04-01

    The combined milling at cryogenic temperature as well as room temperature (RT) has been carried out to prepare ultrafine NaCl crystallites. The milling has been done in evacuated tungsten carbide vials backfilled with high-purity Ar. The results indicate the effect duration of cryomilling prior to RT milling has a strong effect on the final crystallite size. The deformation aided sintering of NaCl crystallites during RT milling and leads to the formation of bimodal distribution of crystallites. The cuboidal-shaped NaCl crystallite undergoes a roughening transition due to plastic deformation. The experimental results are explained using the temperature-dependent mechanical properties of NaCl single crystals and plastic-deformation-induced roughening.

  14. Study of Al composites prepared by high-energy ball milling; Effect of processing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza-Duarte, J.M.; Estrada-Guel, I.; Carreño-Gallardo, C.; Martínez-Sánchez, R.

    2015-09-15

    The present work deals with the synthesis of some Al-based composites prepared by mechanical milling and processing by powder metallurgy followed by the evaluation of process conditions as: type of additive, their concentration and milling intensity studying its effect on the characteristics of the powder composite and mechanical performance of the composite. Powder samples were microstructural characterized by electronic microscopy (SEM–TEM) and the mechanical response was followed by hardness and compressive tests. A pronounced effect on the mechanical response of the specimens was evident after the addition of reinforced particles and milling intensity. Microscopy studies showed a uniform dispersion of the reinforcing particles in the metallic matrix at nanometric scale and an important grain refinement of the Al matrix was confirmed. After processing, a 66% increase on the mechanical response was reached with 1% of additive complemented with short milling intensities.

  15. GEL-STATE NMR OF BALL-MILLED WHOLE CELL WALLS IN DMSO-d6 USING 2D SOLUTION-STATE NMR SPECTROSCOPY

    Science.gov (United States)

    Plant cell walls were used for obtaining 2D solution-state NMR spectra without actual solubilization or structural modification. Ball-milled whole cell walls were swelled directly in the NMR tube with DMSO-d6 where they formed a gel. There are relatively few gel-state NMR studies. Most have involved...

  16. Manganese(III) Acetate-Promoted Cross-Coupling Reaction of Benzothiazole/Thiazole Derivatives with Organophosphorus Compounds under Ball-Milling Conditions.

    Science.gov (United States)

    Li, Liang; Wang, Jun-Jie; Wang, Guan-Wu

    2016-07-01

    The first solvent-free manganese(III) acetate-promoted reaction of benzothiazole/thiazole derivatives with organophosphorus compounds including phosphine oxides, phosphinate ester, and phosphonate diester has been efficiently developed under ball-milling conditions, providing a highly efficient and green protocol to structurally diverse C2-phosphonylated benzothiazole/thiazole derivatives with remarkable functional group tolerance and excellent yields. PMID:27248000

  17. Superthermostability of nanoscale TIC-reinforced copper alloys manufactured by a two-step ball-milling process

    Science.gov (United States)

    Wang, Fenglin; Li, Yunping; Xu, Xiandong; Koizumi, Yuichiro; Yamanaka, Kenta; Bian, Huakang; Chiba, Akihiko

    2015-12-01

    A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms.

  18. Magnetic Properties of Nanocrystalline Fe{sub x}Cu{sub 1-x} Alloys Prepared by Ball Milling

    Energy Technology Data Exchange (ETDEWEB)

    Yousif, A.; Bouziane, K., E-mail: bouzi@squ.edu.om; Elzain, M. E. [Sultan Qaboos University, Physics Department, College of Science (Oman); Ren, X.; Berry, F. J. [The Open University, Department of Chemistry (United Kingdom); Widatallah, H. M. [Sudan Atomic Energy Commission, Institute of Nuclear Research (Sudan); Al Rawas, A.; Gismelseed, A.; Al-Omari, I. A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

    2004-12-15

    X-ray diffraction, Moessbauer and magnetization measurements were used to study Fe{sub x}Cu{sub 1-x} alloys prepared by ball-milling. The X-ray data show the formation of a nanocrystalline Fe-Cu solid solution. The samples with x{>=}0.8 and x{<=}0.5 exhibit bcc or fcc phase, respectively. Both the bcc and fcc phases are principally ferromagnetic for x{>=}0.2, but the sample with x=0.1 remains paramagnetic down to 78 K. The influence of the local environment on the hyperfine parameters and the local magnetic moment are discussed using calculations based on the discrete-variational method in the local density approximation.

  19. Effect of ball milling on properties of porous Ti–7.5Mo alloy for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsueh-Chuan; Wu, Shih-Ching; Hsu, Shih-Kuang [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC (China); Chang, Tien-Yu [Department of Mechanical and Automation Engineering, Da-Yeh University, Changhua, Taiwan, ROC (China); Ho, Wen-Fu, E-mail: fujii@mail.dyu.edu.tw [Advanced Materials and BioMaterials Lab, Department of Materials Science and Engineering, Da-Yeh University, Changhua, Taiwan, ROC (China)

    2014-01-05

    Highlights: • Porous Ti–7.5Mo was successfully prepared through a space-holder sintering method. • The mechanical properties of porous Ti–7.5Mo are comparable to those of natural bone. • Porous Ti–7.5Mo exhibited better apatite-forming abilities after surface treatment. • The inner surfaces of porous specimens exhibited better apatite-inducing ability. -- Abstract: Porous titanium has been used to anchor implants through bone growth into the porous structure. This bone ingrowth provides a strong implant/bone bond, and the pores may be interconnected three-dimensionally to provide enough space for the attachment and proliferation of new bone tissues and to facilitate the transport of body fluids. In the present study, porous scaffolds fabricated from three kinds of ball-milled Ti–7.5Mo alloy particles were successfully prepared through a space-holder sintering method, and the compressive strengths and moduli of all the sintered porous Ti–7.5Mo conform to the basic mechanical property requirement of cancellous bones. However, the porous Ti–7.5Mo fabricated from particles ball milled for 15 h (TM15) possesses a relatively higher strength. Moreover, the elastic modulus of TM15 is 1.72 GPa, which is comparable to that reported for cancellous bone. Furthermore, the porous TM15 alloy exhibited better apatite-forming abilities after pretreatment (with NaOH or NaOH + water) and subsequent immersion in simulated body fluid (SBF) at 37 °C. After soaking in a SBF solution for 21 days, a dense apatite layer covered the inner and outer surfaces of the pretreated porous TM15 substrates, thereby providing favorable bioactive conditions for bone bonding and growth.

  20. Effect of ball milling on properties of porous Ti–7.5Mo alloy for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: • Porous Ti–7.5Mo was successfully prepared through a space-holder sintering method. • The mechanical properties of porous Ti–7.5Mo are comparable to those of natural bone. • Porous Ti–7.5Mo exhibited better apatite-forming abilities after surface treatment. • The inner surfaces of porous specimens exhibited better apatite-inducing ability. -- Abstract: Porous titanium has been used to anchor implants through bone growth into the porous structure. This bone ingrowth provides a strong implant/bone bond, and the pores may be interconnected three-dimensionally to provide enough space for the attachment and proliferation of new bone tissues and to facilitate the transport of body fluids. In the present study, porous scaffolds fabricated from three kinds of ball-milled Ti–7.5Mo alloy particles were successfully prepared through a space-holder sintering method, and the compressive strengths and moduli of all the sintered porous Ti–7.5Mo conform to the basic mechanical property requirement of cancellous bones. However, the porous Ti–7.5Mo fabricated from particles ball milled for 15 h (TM15) possesses a relatively higher strength. Moreover, the elastic modulus of TM15 is 1.72 GPa, which is comparable to that reported for cancellous bone. Furthermore, the porous TM15 alloy exhibited better apatite-forming abilities after pretreatment (with NaOH or NaOH + water) and subsequent immersion in simulated body fluid (SBF) at 37 °C. After soaking in a SBF solution for 21 days, a dense apatite layer covered the inner and outer surfaces of the pretreated porous TM15 substrates, thereby providing favorable bioactive conditions for bone bonding and growth

  1. X-ray diffraction and Moessbauer spectroscopy of high energy ball-milled α-Fe2O3/TiO2 composite powders

    International Nuclear Information System (INIS)

    α-Fe2O3/TiO2 Composite powders have been prepared by high energy ball-milling for different times. The composites were studied using Moessbauer Spectroscopy (MS) and X-ray diffraction (XRD). The patterns of XRD show broadening in the diffraction peaks, indicating a decrease in the particle size of the composites with milling time. Also, the XRD patterns show an evolving new structural phase correlated with an evolving Titanium ferrite species with milling time. Moessbauer Spectroscopy shows the evolving titanium ferrite species characterized by a quadrupole doublet at the expense of the α-Fe2O3 represented by the magnetic sextet. The doublet corresponding to the Ti-ferrite phase dominates the Moessbauer spectra at long milling time (greater than 100 h of milling).

  2. Microstructural evolution of nanostructured Ti{sub 0.7}Ni{sub 0.3}N prepared by reactive ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskar, Ujjwal Kumar [Department of Physics, Sreegopal Banerjee College, Bagati, Magra, Hooghly 712148 (India); Pradhan, S.K., E-mail: skp_bu@yahoo.com [Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104 (India)

    2013-09-01

    Graphical abstract: - Highlights: • α-Ti to β-Ti phase conversion is observed during 1 h of milling. • Ti{sub 0.7}Ni{sub 0.3}N (fcc) phase is noticed to form after 1 h of milling. • Formation time of Ti(Ni,N) phase is same as TiN phase. • Both X-ray and HRTEM microstructure characterization revealed similar results. - Abstract: Nanocrystalline stoichiometric Ti{sub 0.7}Ni{sub 0.3}N powder has been synthesized by ball-milling the α-Ti (hcp) and Ni (fcc) powders under N{sub 2} gas at room temperature. The α-Ti phase partially transforms to the transient (-Ti phase after 1 h of milling. After 5.5 h of milling, very broad reflections of Ti{sub 0.7}Ni{sub 0.3}N phase is noticed. Complete formation of Ti{sub 0.7}Ni{sub 0.3}N phase is observed after 9 h of milling. Microstructure in terms of lattice imperfections of unmilled and all ball-milled powder mixtures are primarily characterized by analyzing the X-ray powder diffraction patterns employing the Rietveld structure refinement procedure. It clearly reveals the presence of Ti{sub 0.7}Ni{sub 0.3}N phase and inclusion of nitrogen atoms into the α-Ti–Ni matrix on the way to formation of nitride phase. Microstructure of the ball milled nitride powders is also characterized by HRTEM. Particle size of Ti{sub 0.7}Ni{sub 0.3}N phase obtained from XRD method of characterization is ∼5 nm which is very close to that obtained from HRTEM.

  3. Surface Generation Modeling in Ball Nose End Milling: a review of relevant literature

    DEFF Research Database (Denmark)

    Bissacco, Giuliano

    One of the most common metal removal operation used in industry is the milling process. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants/lubricants, ......One of the most common metal removal operation used in industry is the milling process. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants....../lubricants, milling strategies and controls. However, most of the times, the selection of the cutting parameters in order to achieve the best result on the manufactured part is still mostly an empirical process, based on the experience of engineers and technicians and very often the parameters first selected have to...... be adjusted afterwards. Nevertheless, many efforts have been done during the last 50 years in order to realize prediction tools for machining processes and particularly for conventional turning and milling operations. Most of these models aim at prediction of cutting forces tool wear and tool life...

  4. Abnormal grain growth in sintered YBa2Cu3O7-δ nanocrystalline powders produced by high energy ball milling

    International Nuclear Information System (INIS)

    The sintering and crystal growth of YBa2Cu3O7-δ (123) nanocrystalline powders produced by high energy ball milling has been studied. After rapid densification, microstructural examination indicates for the first time the occurrence of an abnormal grain growth phenomenon or secondary recrystallization (SR). This phenomenon was not observed during the sintering of unmilled YBa2Cu3O7-δ powders. Optical, TEM and calorimetric techniques were used to characterize the occurrence of SR in this system. Following an incubation period where normal grain growth is observed, large tabular grains progressively appear in the microstructure. Their length and shape factors (s=Lenght/Width) measured on a cross section can reach values as high as 0.5 mm and 46 respectively after 6 h. at 950 C. The bimodal grain size distribution typical of SR processes evolves toward a single distribution of large grains when the faster growing abnormal grains consume the remaining population of normal grains. The observations indicate that SR in YBa2Cu3O7-δ is the result of a combined effect of milling and the presence of a small amount of transient yttrium deficient liquid that wets some of the grain boundaries during the sintering step. The liquid originates either from an incomplete synthesis of the 123 compound and/or by air contamination of the milled powders. The control of this abnormal grain growth is of interest for the formation of bulk textured large grain microstructure desirable for the attainment of good superconducting properties. (orig.)

  5. Record critical current densities in IG processed bulk YBa{sub 2}Cu{sub 3}O{sub y} fabricated using ball-milled Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} phase

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, Miryala; Kenta, Nakazato; Murakami, Masato [Department of Materials Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Zeng, XianLin; Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany); Diko, Pavel [Institute of Experimental Physics, Material Physics Laboratory, Slovak Academy of Sciences, Kosice (Slovakia)

    2016-02-15

    The infiltration-growth (IG) technique enables the uniform and controllable Y{sub 2}BaCuO{sub 5} (Y211) secondary phase particles formation within the YBa{sub 2}Cu{sub 3}O{sub y} (Y123) matrix. Recent results clarified that the flux pinning performance of the Y123 material was dramatically improved by optimizing the processing conditions during the IG process. In this paper, we adapted the IG technique and produced several samples with addition of nanometer-sized Y211 secondary phase particles, which were produced by a ball milling technique. We found that the performance of the IG processed Y123 material dramatically improved in the low field region for a ball milling time of 12 h as compared to the samples without a ball milling step. Magnetization measurements showed a sharp superconducting transition with an onset T{sub c} at around 92 K. The critical current density (J{sub c}) at 77 K and zero field was determined to be 224 022 Acm{sup -2}, which is higher than the not ball-milled sample. Furthermore, microstructural observations exhibited a uniform microstructure with homogenous distribution of nanosized Y-211 inclusions within the Y-123 matrix. The improved performance of the Y-123 material can be understood in terms of fine distribution of the secondary phases. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Production of titanium-tin alloy powder by ball milling: Formation of titanium-tin oxynitride composite powder produced by annealing in air

    International Nuclear Information System (INIS)

    Highlights: • HCP solid solution of Ti75-Sn25 powder was synthesized by ball milling. • Formation of Ti-Sn to intermetallic Ti3Sn was realized after annealing in Ar. • Thermal analysis of milled Ti-Sn in air yielded HCP with a = 4.985 Å; c = 2.962 Å. • Thermal analysis of milled Ti3Sn in air yielded HCP with a = 4.582 Å; c = 2.953 Å. • Raman analysis has confirmed structural change upon annealing. - Abstract: Phase transformation was induced by ball milling and annealing of Ti75-Sn25 powder. HCP solid solution was induced by Ball milling and yielded a compressed lattice parameters a = 2.929 Å; c = 4.780 Å and c/a = 1.63. Upon annealing in Ar at 700 °C, Ti3Sn intermetallic with lattice parameters a = 5.916 Å; c = 4.764 Å with (c/a = 0.80) was detected. Subsequent TGA analysis of HCP milled Ti-Sn and Ti3Sn intermetallic in air have resulted in tetragonal oxynitride powders with lattice parameters a = 4.985 Å; c = 2.962 Å, c/a = 0.594 for the former and a = 4.582 Å; c = 2.953 Å and c/a = 0.644 for the latter, respectively. The powder morphology was monitored by the high-resolution transmission electron microscopy while the roughness of the milled was analysed by the atomic force microscopy. Phase transformation was monitored by the X-ray diffraction and complemented by the Raman spectroscopy

  7. Production of titanium-tin alloy powder by ball milling: Formation of titanium-tin oxynitride composite powder produced by annealing in air

    Energy Technology Data Exchange (ETDEWEB)

    Bolokang, A.S., E-mail: Sylvester.Bolokang@transnet.net [Department of Physics, University of the Western Cape, Private Bag x 17, Bellville 7535 (South Africa); DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001 (South Africa); Transnet Engineering, Product Development, Private Bag X 528, Kilnerpark, Pretoria 0127 (South Africa); Motaung, D.E., E-mail: dmotaung@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001 (South Africa); Arendse, C.J.; Muller, T.F.G. [Department of Physics, University of the Western Cape, Private Bag x 17, Bellville 7535 (South Africa)

    2015-02-15

    Highlights: • HCP solid solution of Ti{sub 75}-Sn{sub 25} powder was synthesized by ball milling. • Formation of Ti-Sn to intermetallic Ti{sub 3}Sn was realized after annealing in Ar. • Thermal analysis of milled Ti-Sn in air yielded HCP with a = 4.985 Å; c = 2.962 Å. • Thermal analysis of milled Ti{sub 3}Sn in air yielded HCP with a = 4.582 Å; c = 2.953 Å. • Raman analysis has confirmed structural change upon annealing. - Abstract: Phase transformation was induced by ball milling and annealing of Ti{sub 75}-Sn{sub 25} powder. HCP solid solution was induced by Ball milling and yielded a compressed lattice parameters a = 2.929 Å; c = 4.780 Å and c/a = 1.63. Upon annealing in Ar at 700 °C, Ti{sub 3}Sn intermetallic with lattice parameters a = 5.916 Å; c = 4.764 Å with (c/a = 0.80) was detected. Subsequent TGA analysis of HCP milled Ti-Sn and Ti{sub 3}Sn intermetallic in air have resulted in tetragonal oxynitride powders with lattice parameters a = 4.985 Å; c = 2.962 Å, c/a = 0.594 for the former and a = 4.582 Å; c = 2.953 Å and c/a = 0.644 for the latter, respectively. The powder morphology was monitored by the high-resolution transmission electron microscopy while the roughness of the milled was analysed by the atomic force microscopy. Phase transformation was monitored by the X-ray diffraction and complemented by the Raman spectroscopy.

  8. Study of magnetic properties in ball-milled MnFeCo

    International Nuclear Information System (INIS)

    A study of the magnetic properties in mechanical alloyed nanocrystalline MnO+FeCo was carried out. As-milled and annealed samples show a noticeable improvement of the coercivity, even at room temperature. A strong effect over the spin wave stiffness constant of the ferromagnetic α -FeCo, probably induced by the antiferromagnetic ordering of the MnO around to 120 K (the Neel temperature of MnO) was observed

  9. Study of magnetic properties in ball-milled MnFeCo

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo, D.R. E-mail: cornejo@df.ufpe.br; Padron Hernandez, E.; Rechenberg, H.R.; Azevedo, A.; Rezende, S.M

    2004-05-01

    A study of the magnetic properties in mechanical alloyed nanocrystalline MnO+FeCo was carried out. As-milled and annealed samples show a noticeable improvement of the coercivity, even at room temperature. A strong effect over the spin wave stiffness constant of the ferromagnetic {alpha} -FeCo, probably induced by the antiferromagnetic ordering of the MnO around to 120 K (the Neel temperature of MnO) was observed.

  10. Study of magnetic properties in ball-milled MnFeCo

    Science.gov (United States)

    Cornejo, D. R.; Padrón Hernández, E.; Rechenberg, H. R.; Azevedo, A.; Rezende, S. M.

    2004-05-01

    A study of the magnetic properties in mechanical alloyed nanocrystalline MnO+FeCo was carried out. As-milled and annealed samples show a noticeable improvement of the coercivity, even at room temperature. A strong effect over the spin wave stiffness constant of the ferromagnetic α -FeCo, probably induced by the antiferromagnetic ordering of the MnO around to 120K (the Néel temperature of MnO) was observed.

  11. Crystal structure and magnetic properties of SmCo6.6Nb0.4 nanoflakes prepared by surfactant-assisted ball milling

    Institute of Scientific and Technical Information of China (English)

    潘蕊; 岳明; 张东涛; 高学绪; 刘卫强; 张久兴; 郭朝辉; 李卫

    2013-01-01

    SmCo6.6Nb0.4 nanoflakes with TbCu7 structure were successfully prepared by surfactant-assisted high energy ball milling (SA-HEBM) with heptane and oleic acid as milling medium. The microstructure, crystal structure and magnetic properties were stud-ied by scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer, respectively. The effects of ball milling time on the c-axis crystallographic alignment and coercivity of the nanoflakes were systematically investigated. The research showed that the nanoflakes had an average thickness of 100 nm, an average diameter of 1 µm, with an aspect ratio as high as 100. As the ball milling time increased from 2 to 8 h, the reflection peaks intensity ratio I(002)/I(101), which indicated the degree of c-axis crystal texture of the SmCo6.6Nb0.4 phase, increased first, reached a peak at 4 h, and then decreased. Meanwhile, the coercivity of the nanoflakes also increased first, reached a peak at 13.86 kOe for 4 h, and then decreased.

  12. Experimental and theoretical study of phase transitions under ball milling; Etude experimentale et modelisation des changements de phases sous broyage a haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Pochet, P

    1997-12-31

    The aim of this work was to determine how phase transition s under ball-milling depend on the milling conditions and to find out if one can rationalize such transitions with the theory of driven alloys. We have chosen two phase transitions: the order-disorder transition in Fe Al and the precipitation-dissolution NiGe. In the case of Fe Al we have found that the steady-state long range order parameter achieved under ball milling intensity; moreover the same degree of order is achieved starting from an ordered alloy or a disordered solid solution. On the way to fully disordered state the degree of order either decreases monotonically or goes through a short lived transient state. This behaviour is reminiscent of a first order transition while the equilibrium transition is second order. All the above features are well reproduced by a simple model of driven alloys, which was originally build for alloys under irradiation. The stationary degree of order results of two competitive atomic jump mechanisms: the forced displacements induced by the shearing of the grains, and the thermally activated jumps caused by vacancies migrations. Finally we have performed atomistic simulations with a Monte Carlo kinetic algorithm, which revealed the role of the fluctuations in the intensity of the forcing. Moreover we have shown that specific atomistic mechanisms are active in a dilute NiGe solid solution which might lead to ball milling induced precipitation in under-saturated solid solution. (author). 149 refs.

  13. Magnetism and Moessbauer spectral study of the FeAlO3 ferro electromagnetic phase obtained by high-energy ball-milling

    International Nuclear Information System (INIS)

    Full text: Ferro electromagnetic materials have attracted much academic and technological attention in the last years. This is because they present potential applications in those areas where (anti)ferromagnetic and (anti)ferroelectric materials are extensively employed. In this way, the electric and magnetic order parameter coupling opens the possibility of the integration between the ferro electromagnetic physical properties through the magnetoelectric effects, and can promote interesting technological advances in many electro-electronic technologies, in spite of the open issues concerning to the origin of the ferro electromagnetism. The FeAlO3 phase is an extremely attractive ferro electromagnetic material, which presents ferrimagnetic, magnetoelectric and piezoelectric effects at low temperatures. The (Fe2O3)0.50(Al2O3).0.50 composite was prepared in a Fritsch Pulverisette 6 planetary ball-mill and a home-made high hard and abrasive ceramic medium (composed of an alumina vial charged with stabilized zirconia rods) - high-energy ball-milling was employed for the first time to produce the FeAlO3 ferro electromagnetic phase. The FeAlO3 structural and magnetic properties were studied through X-ray diffraction (XRD), Moessbauer spectroscopy (Ms) and magnetization measurements. The crystallographic parameters were refined using the Rietveld analysis. The XRD diffraction peaks were assigned as being for Fe AlO3 phase, plus a residual aluminum substituted hematite (Fe1xAlx)2O3 and iron substituted alumina (FeyAl1-y)2O3 solid solutions, besides a pattern of a very disordered phase. Magnetic and Moessbauer studies revealed a classical Neel ferrimagnetic ordering at low temperatures. Due to the high surface area, high defect density, and small particle size distribution, the superposition of the Moessbauer signals and the apparent existence of only two Moessbauer spectra, in spite of those four dissimilar irons sites in the FeAlO3 structure, were detected at room

  14. Structural evolution and surface magnetism in Mg-substituted Li0.5Fe2.5O4 nanoparticles prepared by ball milling

    International Nuclear Information System (INIS)

    The structural evolution and magnetic properties of Mg-substituted-Li0.5Fe2.5O4 nanocrystalline particles prepared by ball milling are investigated. The average crystallite size is found to decrease with increasing milling time approaching ∼ 12 nm after 50 h of milling. Rietveld refinement of the XRD data shows the cores of the nanoparticles and their surfaces to have different cation distributions. The increase in the average lattice constant with milling time up to 38 h and its subsequent decrease imply large strains and bond deformation, respectively. The shifts of infrared spectral bands of the milled samples relative to those of the non-milled one, suggest a milling-induced cation migration from the octahedral (B) to the tetrahedral (A) sites. Superparamagnetism is found to be enhanced with increasing milling time. A simple two-sextet fit for the 78.5 K Moessbauer spectrum of the nanoparticles and their core-to surface ratio, inferred from XRD Rietveld refinement, enabled the estimation of Fe3+ population at the A- and B-sites in the surface layers. While the measured magnetization of the nanoparticles reasonably agrees with that calculated using the Neel's collinear model it is, nonetheless, suggestive of a thermally-induced spin reversal and/or a minor canting effect that is more pronounced for the A-sub-lattice. (author)

  15. Effect of Ni addition on the preparation of Al2O3–TiB2 composites using high-energy ball milling

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2014-12-01

    Full Text Available Al2O3–TiB2 composites were synthesized using high-energy ball milling from starting powders containing Al, TiO2, and B2O3. To explore the effect of the addition of another ductile metallic phase during milling, 15 wt.% Ni was added to a sample of the starting powders. The phase transformations and microstructure of the milled powder mixtures were investigated using X-ray diffraction and electron microscopy. The results showed that the Ni addition facilitated the mechanochemical reaction between the Al, TiO2, and B2O3. Before the appearance of the Al2O3–TiB2 composite, the intermediate product NiAl was formed by a gradual exothermic reaction. With continued milling, the final phases of Al2O3–TiB2 and Ni were obtained.

  16. [Formula: see text]-mediated amination/cyclization of ketones with 2-aminopyridines under high-speed ball milling: solvent- and metal-free synthesis of 2,3-substituted imidazo[1,2-a]pyridines and zolimidine.

    Science.gov (United States)

    Wang, Fang-Jian; Xu, Hui; Xin, Ming; Zhang, Ze

    2016-08-01

    Under solvent-free high-speed ball milling, an I[Formula: see text]-promoted condensation/cyclization of easily available methyl ketones or 1,3-dicarbonyl compounds with 2-aminopyridines has been developed, which allows the quick assembly of 2,3-substituted imidazo[1,2-a]pyridines (IPs) with broad molecular diversity, including the antiulcer drug zolimidine. The advantages of high yields, good functional group compatibility, short reaction time (within 90 min), free use of heating, solvent and metal, employment of cheap starting materials, and simple work-up procedure make this protocol a very efficient alternative to traditional synthesis of IPs. PMID:26975201

  17. Structural characterization and Mössbauer studies of nanocrystalline Fe{sub 60}Ni{sub 20}Cr{sub 10}B{sub 10} alloy prepared by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Slimi, M., E-mail: msrammeh@yahoo.fr [Laboratoire de Chimie Inorganique, UR-11-ES-73, université de Sfax, B.P. 1171, 3000 Sfax (Tunisia); Azabou, M. [Laboratoire de Chimie Inorganique, UR-11-ES-73, université de Sfax, B.P. 1171, 3000 Sfax (Tunisia); Suñol, J.J. [Departament de Fisica, Universitat de Girona, Campus Montilivi, Girona 17071 (Spain); Khitouni, M. [Laboratoire de Chimie Inorganique, UR-11-ES-73, université de Sfax, B.P. 1171, 3000 Sfax (Tunisia); Greneche, J.M. [LUNAM, Institut des Molécules et Matériaux du Mans, IMMM UMR CNRS 6283, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France)

    2015-11-01

    Nanostructured Fe(Ni,Cr) and NiFe solid state powders were elaborated from elemental powders of Fe, Ni, Cr and B using planetary high-energy ball mill. Scanning electron microscopy (SEM) was employed to examine the morphology of the powdered samples as a function of milling time. The transformations occurring in the material during milling were studied at the atomic scale with the use of X-ray diffraction and {sup 57}Fe Mössbauer spectrometry. The thermal behavior of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 10 and 50 h of milling, indicated the formation of a nanostructured Fe(Ni,Cr) and NiFe solid solutions. - Highlights: • It is a complete study about the alloying process of a nanostructured alloy. • We establish the relation between microstructure and structure defects. • Mössbauer analysis confirms the coexistence of the bcc-Fe(Ni,Cr) and fcc-Ni(Fe) solid solutions.

  18. Synthesis of Fe/SiO2 and iron oxides/SiO2 nanocomposites by long-term ball milling

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Iron–iron oxides/silica composites are synthesized by long term dry ball-milling. • Bcc iron and α-quartz powders are used as precursors. • Surface effects enhance coercivity in iron/silica nanocomposites. • In spite of their small size, about 10 nm, iron particles are ferromagnetic. • Ferro and superparamagnetic particles are found in maghemite/silica composites. - Abstract: Iron oxide/SiO2 nanocomposites are synthesized by dry ball-milling a mixture of bcc Fe and α-quartz powders for prolonged times. A sequence of nanocomposites is obtained, with small magnetic particles dispersed in a non magnetic, amorphous matrix. The powders are characterized by X-ray diffraction and transmission electron microscopy. The magnetic hysteresis properties are investigated in the range 50–300 K. After 120 h milling, deformed, non-spherical, α-Fe nanocrystallites of about 10 nm in size and very few small (<10 nm) maghemite particles are found. At room temperature, iron particles are ferromagnetic and a large effective magnetic anisotropy is estimated, which is mainly attributed to surface effects. Between 160 and 200 h milling, maghemite nanoparticles are observed while after 220 h grinding, hematite phase appears; after 340 h milling, the sample consists of ferromagnetic hematite particles with a broad size distribution (5–50 nm) embedded in an amorphous matrix

  19. Competition between stable and metastable phases during mechanical alloying and ball milling

    International Nuclear Information System (INIS)

    The Ti-Al and the Ti-Si system are chosen as model systems to study the origin of metastable phase formation during mechanical alloying of elemental powder blends with a negative heat of mixing. The results demonstrate that kinetics play only a minor role in the pahse selection, in particular for the final state. Instead, the intermetallic phases are energetically destabilized with respect to the solid solutions and the amorphous phase due to the destruction of the chemical long-range order upon milling. Thus the latter phases tend to form during mechanical alloying of elemental powder blends as well as during milling of powders of the stable intermetallic compounds. The metastable phases can be predicted by the free energy curves which are calculated by the CALPHAD method. In case of the Ti-Al and Ti-Si alloys, metastable structures and grain sizes in the nm range can be obtained which promise improved mechanical behaviour with respect to the processing of light-weight intermetallic compounds for high-temperature applications. (orig.)

  20. Influence of workpiece inclination angle on the surface roughness in ball end milling of the titanium alloy Ti-6Al-4V

    OpenAIRE

    A. Daymi; M. Boujelbene; J.M. Linares; E. Bayraktar; A. Ben Amara

    2009-01-01

    Purpose: The aim of this work is to provide an in-depth understanding of the surface texture produced by various workpiece inclination angles using high speed finish ball end-milling of the titanium alloy Ti-6Al-4V.Design/methodology/approach: This paper presents an approach to develop a mathematical model of surface roughness in end-milling by the experimental design methodology. Machining variables such as cutting speed, feed and radial depth of cut, which are easily controllable, are consi...

  1. Characterization of structure and properties of TiN-TiB{sub 2} nano-composite prepared by ball milling and high pressure heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, L.X. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Department of Material Science and Engineering, Jilin University, Changchun 130012 (China); Yao, B. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun 130022 (China)], E-mail: binyao@jlu.edu.cn; Ding, Z.H. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zheng, Y.J.; Jia, X.P. [Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Zheng, W.T. [Department of Material Science and Engineering, Jilin University, Changchun 130012 (China)

    2008-05-29

    Synthesis of TiN-TiB{sub 2} nano-composite was investigated by mechanical milling of mixture of Ti and hexagonal boron nitride (h-BN) and subsequent sintering under high pressure and high temperature (HPHT). A TiN-TiB{sub 2} composite was fabricated by ball milling of the mixture for 70 h and then sintering at 5 GPa, 1300 deg. C. The composite has micro-hardness of 8.8 GPa and electrical resistivity of 2 x 10{sup -4} {omega} cm. The formation mechanism of the composite was discussed based on thermodynamics and kinetics.

  2. The grinding behavior of ground copper powder for Cu/CNT nanocomposite fabrication by using the dry grinding process with a high-speed planetary ball mill

    Science.gov (United States)

    Choi, Heekyu; Bor, Amgalan; Sakuragi, Shiori; Lee, Jehyun; Lim, Hyung-Tae

    2016-01-01

    The behavior of ground copper powder for copper-carbon nanotube (copper-CNT) nanocomposite fabrication during high-speed planetary ball milling was investigated because the study of the behavior characteristics of copper powder has recently gained scientific interest. Also, studies of Cu/CNT composites have widely been done due to their useful applications to enhanced, advanced nano materials and components, which would significantly improve the properties of new mechatronics-integrated materials and components. This study varied experimental conditions such as the rotation speed and the grinding time with and without CNTs, and the particle size distribution, median diameter, crystal structure and size, and particle morphology were monitored for a given grinding time. We observed that pure copper powders agglomerated and that the morphology changed with changing rotation speed. The particle agglomerations were observed with maximum experiment conditions (700 rpm, 60 min) in this study of the grinding process for mechanical alloys in the case of pure copper powders because the grinding behavior of Cu/CNT agglomerations was affected by the addition of CNTs. Indeed, the powder morphology and the crystal size of the composite powder could be changed by increasing the grinding time and the rotation speed.

  3. Effect of surface modification of Cu with Ag by ball-milling on the corrosion resistance of low infrared emissivity coating

    Energy Technology Data Exchange (ETDEWEB)

    Yan Xiaoxing, E-mail: yanxiaoxing@nuaa.edu.c [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Jiangjun Street, Nanjing 211100 (China); Xu Guoyue [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Jiangjun Street, Nanjing 211100 (China)

    2010-01-25

    The corrosion resistance of low infrared emissivity copper/polyurethane (Cu/PU) coating was markedly improved by surface modification of Cu with silver (Ag) using a ball-milling method. For the purpose of clarifying the effect of the surface modification, the phase and morphology of as-prepared products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the corrosion behavior was investigated with potentiodynamic polarization and electrochemical impedance spectra (EIS). As a result, it was found that Ag was homogeneously distributed in Cu and the encapsulation of oil layer on the surface of Ag-Cu composite powders was formed after ball-milling, therefore, compatibility with organic phase was improved, which often keeps the low infrared emissivity and enhances the anti-corrosion performance of the coating.

  4. Biodistribution of nanoparticles of hydrophobic gadopentetic-acid derivative prepared with a planetary ball mill for neutron-capture therapy of cancer

    International Nuclear Information System (INIS)

    Nanoparticles of hydrophobic gadopentetic-acid derivatives (Gd-nanoGR) were prepared with a wet ball-milling process for gadolinium neutron-capture therapy. Ball-milling of solid mass of gadopentetic acid distearylamide with soybean lecithin as a dispersant in the presence of water and subsequent sonication at 70degC resulted in the Gd-nanoGR with the particle size of 63 nm. Biodistribution study using melanoma-bearing hamsters demonstrated that the i.v. injection of the Gd-nanoGR made a higher gadolinium accumulation in tumor (109 μg Gd/g wet tumor at 6h after administration), when compared with the gadolinium-loaded micellar-like nanoparticles previously reported. (author)

  5. Effect of surface modification of Cu with Ag by ball-milling on the corrosion resistance of low infrared emissivity coating

    International Nuclear Information System (INIS)

    The corrosion resistance of low infrared emissivity copper/polyurethane (Cu/PU) coating was markedly improved by surface modification of Cu with silver (Ag) using a ball-milling method. For the purpose of clarifying the effect of the surface modification, the phase and morphology of as-prepared products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the corrosion behavior was investigated with potentiodynamic polarization and electrochemical impedance spectra (EIS). As a result, it was found that Ag was homogeneously distributed in Cu and the encapsulation of oil layer on the surface of Ag-Cu composite powders was formed after ball-milling, therefore, compatibility with organic phase was improved, which often keeps the low infrared emissivity and enhances the anti-corrosion performance of the coating.

  6. Preparation of fine-grained tungsten heavy alloys by spark plasma sintered W–7Ni–3Fe composite powders with different ball milling time

    International Nuclear Information System (INIS)

    Highlights: ► We fabricate fine-grained W–7Ni–3Fe alloys using HEBM assisted SPS method. ► The γ-(Ni, Fe, W) phase is not observed in HEBM raw powders. ► The density of the WHAs gradually decreased with increasing HEBM time. ► The hardness and bending strength of the WHAs show different trends of variation. ► The intergranular fracture was the main bending fracture mode of the WHAs. -- Abstract: The fine-grained tungsten heavy alloys (WHAs) with grain size of about 1–3 μm were successfully prepared by spark plasma sintered W–7Ni–3Fe composite powders with different high-energy ball milling (HEBM) time. This study analyzes the effects of HEBM time not only on the composite powders but on the microstructure and mechanical properties of WHAs. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the microstructure and phase evolution rules of powders and alloys, respectively. The γ-(Ni, Fe, W) is not observed in XRD patterns of the ball milled powders. With prolonging HEBM time, the W phase diffraction peak becomes increasingly wider, and its intensity continues to decline. However, the completely amorphous structures are not formed even after HEBM 40 h. The relative density of the WHAs prepared by HEBM assisted SPS technique decreases gradually with increasing the ball milling time. For the WHAs sintered in 1150 °C for 8 min, the W grains grow finer and the content of the γ-(Ni, Fe, W) binding phase greatly increases with prolonging the HEBM time. Meanwhile, over 5 h of HEBM time, the bending strength continuously decreases and the hardness slightly increases. The intergranular fracture of the W grains is the main bending fracture mode in all the WHAs. The microporous of different sizes are distributed on the bending fracture and progressively increased with prolonging the ball milling time

  7. Preparation of fine-grained tungsten heavy alloys by spark plasma sintered W–7Ni–3Fe composite powders with different ball milling time

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, D.P., E-mail: dpxiang@hainu.edu.cn [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Ding, L. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); Li, Y.Y.; Chen, G.B. [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Zhao, Y.W. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China)

    2013-06-15

    Highlights: ► We fabricate fine-grained W–7Ni–3Fe alloys using HEBM assisted SPS method. ► The γ-(Ni, Fe, W) phase is not observed in HEBM raw powders. ► The density of the WHAs gradually decreased with increasing HEBM time. ► The hardness and bending strength of the WHAs show different trends of variation. ► The intergranular fracture was the main bending fracture mode of the WHAs. -- Abstract: The fine-grained tungsten heavy alloys (WHAs) with grain size of about 1–3 μm were successfully prepared by spark plasma sintered W–7Ni–3Fe composite powders with different high-energy ball milling (HEBM) time. This study analyzes the effects of HEBM time not only on the composite powders but on the microstructure and mechanical properties of WHAs. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the microstructure and phase evolution rules of powders and alloys, respectively. The γ-(Ni, Fe, W) is not observed in XRD patterns of the ball milled powders. With prolonging HEBM time, the W phase diffraction peak becomes increasingly wider, and its intensity continues to decline. However, the completely amorphous structures are not formed even after HEBM 40 h. The relative density of the WHAs prepared by HEBM assisted SPS technique decreases gradually with increasing the ball milling time. For the WHAs sintered in 1150 °C for 8 min, the W grains grow finer and the content of the γ-(Ni, Fe, W) binding phase greatly increases with prolonging the HEBM time. Meanwhile, over 5 h of HEBM time, the bending strength continuously decreases and the hardness slightly increases. The intergranular fracture of the W grains is the main bending fracture mode in all the WHAs. The microporous of different sizes are distributed on the bending fracture and progressively increased with prolonging the ball milling time.

  8. MAGNETIC PROPERTIES OF BALL MILLED FexCu1-x (x-0.4, 0.5) ALLOY

    Institute of Scientific and Technical Information of China (English)

    LI YU-ZHI; LIN LEI; WANG WANG-CHEN; XIONG CAO-SHUI; SHEN BAO-GEN

    2000-01-01

    The samples Fe0.4Cu0.6 and Fe0.5Cu0.5 ball milled for 50h are investigated by X-ray diffraction, Mossbauer spectra, as well as magnetic measurement. The experiments show that the structure of the samples is fcc, with lattice constant 0.361 nm and there are fcc Fe-rich phase and fcc Cu-rich phase in the samples. Most of Fe atoms (91%) are in the fcc Fe-rich phase, which is a ferromagnetic phase. The M-H curve at 1.5 K shows the saturation magnetization of the samples are 80.5 emu/g and 101.6 emu/g for Fe0.4Cu0.6 and Fe0.5Cu0.5 respectively. The average magnetic moment of Fe atoms is deduced to be 2.40μB · Compared with theoretical predication, the Fe atoms in the fcc phase are in high spin state.

  9. Removal of fluoride from drinking water using modified ultrafine tea powder processed using a ball-mill

    Science.gov (United States)

    Cai, Huimei; Xu, Lingyun; Chen, Guijie; Peng, Chuanyi; Ke, Fei; Liu, Zhengquan; Li, Daxiang; Zhang, Zhengzhu; Wan, Xiaochun

    2016-07-01

    A low-cost and highly efficient biosorbent was prepared by loading zirconium(IV) onto ball-milled, ultrafine tea powder (UTP-Zr) for removal of fluoride from drinking water. To evaluate the fluoride adsorption capacity of UTP-Zr over a wide range of conditions, the biosorbent dosage, contact time, initial pH, initial fluoride concentration and presence of other ions were varied. UTP-Zr performed well over the considerably wide pH range of 3-10. The residual concentration of Zr in the treated water was below the limit of detection (0.01 mg/L). Fluoride adsorption by the UTP-Zr biosorbent followed the Langmuir model, with a maximum adsorption capacity of 12.43 mgF/g at room temperature. The fluoride adsorption kinetics fit the pseudo-second-order kinetic model. The synthesized biosorbent was characterized by BET, SEM, EDS, XRD and XPS to reveal how UTP-Zr interacts with fluoride. Results from this study demonstrated that UTP-based biosorbents will be useful and safe for the removal of fluoride from drinking water.

  10. Synthesis of Nd2Fe14C compound by high-energy ball-milling Nd–Fe alloy in heptane and annealing under vacuum

    Science.gov (United States)

    Geng, H. M.; Ji, Y.; Feng, X. Y.; Zhang, J. J.; Ran, Z.; Yan, Y.; Wang, W. Q.; Su, F.; Du, X. B.

    2016-06-01

    A simple synthesis route for the Nd2Fe14C compound with good permanent magnetic properties is presented. Being high-energy ball-milled in heptane (C7H16) for 8 h, the NdFe3.5 alloy consisting of Nd2Fe17 and Nd phases disproportionates into NdH2+δ and α-Fe. Subsequently, NdH2+δ decomposes when annealed from room temperature to 900 °C under vacuum, and H2 is released. Meanwhile Nd2Fe14C, NdC and little α-Fe phases are formed in the final product. H and C atoms come from the decomposition of heptane. Coercivity of 1.39 T and maximum magnetic energy product of 62.7 kJ m‑3 have been achieved. Too short a ball-milling time results in the insufficient disproportionation of NdFe3.5 alloy and the residue of Nd2Fe17 phase in the final product. Too long a ball-milling time results in the appearance of NdC2 and more α-Fe phases besides Nd2Fe14C and NdC phases. Hexane (C6H14), octane (C8H18) and nonane (C9H20) have been proved to have a similar effect to heptane.

  11. Crystallization behavior and consolidation of ball milled Zr60Ti5Ag5Cu12.5Ni10Al7.5 glassy powders

    International Nuclear Information System (INIS)

    Devitrification and consolidation of Zr60Ti5Ag5Cu12.5Ni10Al7.5 glassy powders produced by ball milling of intermetallic compounds have been investigated. The crystallization behavior is characterized by the formation of a nanoscale quasicrystalline phase along with a minor amount of tetragonal Zr2Cu phase during the first stage of the crystallization process. In the second crystallization event the metastable QC transform into the tetragonal Zr2Cu phase. The viscous flow of the supercooled liquid was studied by parallel plate rheometry, showing a distinct viscosity drop related to the glass transition, corroborating the results from DSC measurements. Consolidation of the glassy powders was performed by uniaxial hot pressing. The consolidation parameters were properly selected in order to obtain partially crystallized bulk samples with a composite microstructure characterized by the contemporary presence of glassy, quasicrystalline and tetragonal Zr2Cu phases. Hardness measurements reveal a Vickers hardness of 4.61 GPa and an estimated yield strength of 1.53 GPa. These results show that powder metallurgy methods are suitable for the production of Zr-based alloys characterized by a composite microstructure consisting of glassy, quasicrystalline and crystalline phases with mechanical properties similar to materials prepared by other techniques

  12. Fabrication, characterization and application of Cu{sub 2}ZnSn(S,Se){sub 4} absorber layer via a hybrid ink containing ball milled powders

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunran [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); College of Mathematics and Physics, Bohai University, Jinzhou 121013 (China); Yao, Bin, E-mail: binyao@jlu.edu.cn [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Li, Yongfeng, E-mail: liyongfeng@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Xiao, Zhenyu [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Ding, Zhanhui [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Zhao, Haifeng; Zhang, Ligong; Zhang, Zhenzhong [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033 (China)

    2015-09-15

    Highlights: • CZTS powders are prepared from binary sulfides by a low cost ball milling process. • Elaborated on phase evolution and formation mechanism of CZTS. • Proposed a hybrid ink approach to resolve difficulty in deposition of CZTS film. • CZTSSe solar cells with highest efficiency of 4.2% are fabricated. • Small-grained CZTS layer hinders the collection of minority carriers. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) powder with kesterite structure was prepared by ball milling of mixture of Cu{sub 2}S, ZnS and SnS{sub 2} powders for more than 15 h. By dispersing the milled CZTS powder in a Cu-, Zn- and Sn-chalcogenide precursor solution, a hybrid ink was fabricated. With the hybrid ink, a precursor CZTS film was deposited on Mo coated soda-lime glass by spin-coating. In order to obtain Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) absorber film with kesterite structure, the CZTS film was annealed at 560 °C for 15 min in Se ambient. It is demonstrated that the annealed film is dominated by a thick layer of kesterite CZTSSe with larger grain size and Cu{sub 8}Fe{sub 3}Sn{sub 2}(S,Se){sub 12} impurity phase with the exception of a very thin layer of kesterite CZTS with smaller grain size at interface between the CZTSSe and Mo layers. Solar cell device was fabricated by using the annealed CZTSSe film as absorber layer, and its conversion efficiency reached 4.2%. Mechanism of formation of the kesterite CZTS powder and CZTSSe film as well as effect of impurity phases on conversion efficiency are discussed in the present paper. The present results suggest that the hybrid ink approach combining with ball milling is a simple, low cost and promising method for preparation of kesterite CZTSSe absorber film and CZTSSe-based solar cell.

  13. Fabrication, characterization and application of Cu2ZnSn(S,Se)4 absorber layer via a hybrid ink containing ball milled powders

    International Nuclear Information System (INIS)

    Highlights: • CZTS powders are prepared from binary sulfides by a low cost ball milling process. • Elaborated on phase evolution and formation mechanism of CZTS. • Proposed a hybrid ink approach to resolve difficulty in deposition of CZTS film. • CZTSSe solar cells with highest efficiency of 4.2% are fabricated. • Small-grained CZTS layer hinders the collection of minority carriers. - Abstract: Cu2ZnSnS4 (CZTS) powder with kesterite structure was prepared by ball milling of mixture of Cu2S, ZnS and SnS2 powders for more than 15 h. By dispersing the milled CZTS powder in a Cu-, Zn- and Sn-chalcogenide precursor solution, a hybrid ink was fabricated. With the hybrid ink, a precursor CZTS film was deposited on Mo coated soda-lime glass by spin-coating. In order to obtain Cu2ZnSn(S,Se)4 (CZTSSe) absorber film with kesterite structure, the CZTS film was annealed at 560 °C for 15 min in Se ambient. It is demonstrated that the annealed film is dominated by a thick layer of kesterite CZTSSe with larger grain size and Cu8Fe3Sn2(S,Se)12 impurity phase with the exception of a very thin layer of kesterite CZTS with smaller grain size at interface between the CZTSSe and Mo layers. Solar cell device was fabricated by using the annealed CZTSSe film as absorber layer, and its conversion efficiency reached 4.2%. Mechanism of formation of the kesterite CZTS powder and CZTSSe film as well as effect of impurity phases on conversion efficiency are discussed in the present paper. The present results suggest that the hybrid ink approach combining with ball milling is a simple, low cost and promising method for preparation of kesterite CZTSSe absorber film and CZTSSe-based solar cell

  14. Fabrication of Al/A206–Al2O3 nano/micro composite by combining ball milling and stir casting technology

    International Nuclear Information System (INIS)

    Highlights: ► Uniform distribution of alumina particles in molten Al alloy by using MMMC. ► Improvement in wettability of alumina particles with molten Al alloy by using MMMC. ► Porosity content in Al/A206-alumina composite decreased by using MMMC. ► Improvement in tensile strength of Al/A206-alumina composite by using MMMC. ► Decrease in interfacial reaction product by incorporating MMMC in semi-solid state. - Abstract: Al206/5vol.%Al2O3p cast composites were fabricated by the injection of reinforcing particles into molten Al alloy in two different forms, i.e. as Al2O3 particles and milled particulates of alumina with Al and Mg powders. The resultant milled powders (Master Metal Matrix Composite (MMMC)) were then added into the molten Al alloy both in semi-solid state and above liquidus temperature. Effects of powder addition technique, reinforcement particle size and casting temperature on distribution and incorporation of reinforcing particles into molten Al alloy were investigated. Morphology evolution of powders during milling, microscopic examinations of composite and matrix alloy were studied by scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis was also used to determine the possible interaction between powders after ball milling process. Results showed that injection of powders in the form of MMMC leads to considerable improvement in incorporation and distribution of Al2O3p in the Al206 matrix alloy leading to the improvement in tensile properties. Improvement in tensile properties is attributed to the better wetting of Al2O3p by melt as well as removing microchannels and roughness on alumina particles as a consequence of ball milling process

  15. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    International Nuclear Information System (INIS)

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga2O3 and GaN to NaGaO2 revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved

  16. Friction and corrosion behavior of ceramic milling balls in milling-leaching combined digestion of ilmenites%钛铁矿研磨-浸出耦合工艺中陶瓷磨球磨损和腐蚀行为

    Institute of Scientific and Technical Information of China (English)

    罗文波; 袁绍军; 王小梅; 唐思扬; 李春; 岳海荣; 梁斌

    2015-01-01

    , which were much higher than those of zirconia and agate balls. The results provided good reference to chasing the grinding ball materials in the milling-leaching process for acidolysis of ilmenite.

  17. Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al2O3 under inspection

    Directory of Open Access Journals (Sweden)

    Franziska Bernhardt

    2010-01-01

    Full Text Available Although a plethora of synthetic procedures mediated by KF-loaded aluminas is available in the literature, there is almost no data concerning the influence of parameters such as alumina modification or KF-loading on experimental results. Hence, the Pd-catalyzed, solvent-free Suzuki–Miyaura reaction was chosen as model reaction to investigate the effect of the above mentioned parameters on the results of coupling reactions. The results from ball milling experiments led to the conclusion that self-prepared and commercially available KF–Al2O3 differ in water content. The higher the residual water content, the higher are the product yields.

  18. Structure-Property Correlation in Fe-Al2O3 In Situ Nanocomposite Synthesized by High-Energy Ball Milling and Spark Plasma Sintering

    Science.gov (United States)

    Udhayabanu, V.; Ravi, K. R.; Murty, B. S.

    2016-07-01

    In the present study, Fe-10 vol pct Al2O3 in situ nanocomposite has been derived by high-energy ball milling of Fe2O3-Fe-Al powder mixture followed by the consolidation using spark plasma sintering (SPS). The consolidated nanocomposite has bimodal-grained structure consisting of nanometer- and submicron-sized Fe grains along with nanometer-sized Al2O3, and Fe3O4 particles. The mechanical property analysis reveals that compressive yield strength of Fe-10 vol pct Al2O3 nanocomposite is 2100 MPa which is nearly two times higher than that of monolithic Fe processed by Mechanical Milling and SPS. The strengthening contributions obtained from matrix, grain size, and particles in the synthesized nanocomposite have been calculated theoretically, and are found to be matching well with the experimental strength levels.

  19. Atomic structure, magnetism, and transport properties of damaged La0.67Ca0.33MnO3-δ processed via high-energy ball milling

    International Nuclear Information System (INIS)

    A La0.67Ca0.33MnO3-δ alloy was produced via a low-temperature solid state reaction in a high-energy ball mill. The milled alloy is found to exhibit the paramagnetic-to-ferromagnetic (P endash F) transition at 150 K. However, the widely reported insulator-to-metal (I endash M) transition that usually accompanies the P endash F transition is totally suppressed. Anneals at 500 endash 1000 ampersand hthinsp;degree C in air (t=8 ampersand hthinsp;h) are found to lower the resistivity but not restore the I endash M transition. The suppression of the I endash M transition is attributed to anion defects in the structure that have not been annihilated during heat treatments. Extended x-ray absorption fine structure is employed to track the evolution of the atomic structure around the Mn cations at various stages of processing. copyright 1999 American Institute of Physics

  20. Effect of soya milk on nutritive, antioxidative, reological and textural properties of chocolate produced in a ball mill

    Directory of Open Access Journals (Sweden)

    Zarić Danica B.

    2011-01-01

    Full Text Available Chocolate is a complex rheological system in which non-fat cocoa particles and sugar particles are enveloped by crystal matrix of cocoa butter. Physical properties of chocolate depend on ingredient composition, method of production and properly performed pre-crystallization phase. In this work, chocolate was produced in an unconventional way, i.e. in a ball mill applying variable refining time (30, 60 and 90 min and pre-crystallization temperature in chocolate masses (26, 28 and 30⁰C. Two types of chocolate were produced: chocolate with 20% of powdered cow’s milk (R1 and chocolate with 20% of soya milk powder (R2. The quality of chocolate was followed by comparing nutritive composition, 23 polyphenol content, hardness of chocolate, solid triglyceride content (SFC and rheological parameters (Casson yield flow (Pa, Casson viscosity (Pas, the area of the thixotropic loop, elastic modulus and creep curves. The aim of this paper is determining changes caused by replacing cow’s milk with soya milk powder in respect of nutritive, rheological and sensory properties, as well as defining optimal parameters: precrystallization temperature and refining time of soya milk chocolate in order to obtain suitable sensory and physical properties identical to those of milk chocolate mass. The results show that replacing powdered cow’s milk with soya milk powder affects the increase in nutritive value of soya milk chocolate. R2 chocolate mass showed the increase in essential amino acids and fatty acids. This chocolate mass also showed the increase in total polyphenols by 28.1% comparing to R1 chocolate mass. By comparing viscosity, yield stress, shear stress and the area of the thixotropic loop, it can be observed that R1 chocolate mass represents a more organized and simpler system than the mass with soya milk (R2, as it shows lower values for all the above mentioned parameters, regardless of the refining time and pre-crystallization temperature

  1. Morphology and magnetic properties of CeCo{sub 5} submicron flakes prepared by surfactant-assisted high-energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.J.; Gao, H.M.; Yan, Y.; Bai, X.; Su, F.; Wang, W.Q. [State key Laboratory for Superhard Materials and Department of Physics, Jilin University, Changchun 130012 (China); Du, X.B., E-mail: duxb@jlu.edu.cn [State key Laboratory for Superhard Materials and Department of Physics, Jilin University, Changchun 130012 (China)

    2012-10-15

    CeCo{sub 5} permanent magnetic alloy has been processed by surfactant assisted high energy ball milling. Heptane and oleic acid were used as the solvent and surfactant, respectively. The amount of surfactant used was 50% by weight of the starting powder. The produced particles were deposited on a piece of copper (4 mm in length and width) under a magnetic field of 27 kOe applied along the copper surface and immobilized by ethyl {alpha}-cyanoacrylate. Scanning electron microscope pictures show that the particles are flakes, several {mu}m in length and width and tens of nm in thickness. X-ray diffraction patterns and magnetic measurements prove that the flakes are crystalline with c-axes magnetic anisotropy. The easy magnetization axis is oriented perpendicular to the surface of the flake. A maximum coercivity of 3.3 kOe was obtained for the sample milled for 40 min. - Highlights: Black-Right-Pointing-Pointer CeCo{sub 5} permanent magnetic alloy has been processed by surfactant assisted high energy ball milling (HEBM). Black-Right-Pointing-Pointer The particles show a flake-like morphology with several {mu}m in length and width and tens nm in thickness. Black-Right-Pointing-Pointer The flakes are crystallographic and magnetic anisotropic and the c-axes, also the easy magnetization directions are oriented perpendicular to the surface of the flake. Black-Right-Pointing-Pointer Maximum coercivity of 3.3 kOe has been obtained for the sample milled for 40 min.

  2. Development of new materials by high energy milling

    OpenAIRE

    Ruiz Navas, Elisa María; Gordo Odériz, Elena

    2008-01-01

    The Group of Powder Technology (GTP) of the University Carlos III has a wide experience in the development and processing of new materials by Powder Metallurgy (PM). The mechanical alloying (MA) process, or high energy milling, allows the attainment of powders with compositions impossible to produce by other techniques, with improved properties for structural applications, where mechanical properties are the main requirement, and for applications where other specific properties are needed....

  3. Effect of ball milling and dynamic compaction on magnetic properties of Al{sub 2}O{sub 3}/Co(P) composite particles

    Energy Technology Data Exchange (ETDEWEB)

    Denisova, E. A. [Kirensky Institute of Physics SB RAS, Krasnoyarsk (Russian Federation); Krasnoyarsk Institute of Railways Transport, Krasnoyarsk (Russian Federation); Kuzovnikova, L. A. [Krasnoyarsk Institute of Railways Transport, Krasnoyarsk (Russian Federation); Iskhakov, R. S., E-mail: rauf@iph.krasn.ru; Eremin, E. V. [Kirensky Institute of Physics SB RAS, Krasnoyarsk (Russian Federation); Bukaemskiy, A. A. [Institut fur Sicherheitsforschung und Reaktortechnik, D-52425 Juelich (Germany); Nemtsev, I. V. [Krasnoyarsk Scientific Center SB RAS, Krasnoyarsk (Russian Federation)

    2014-05-07

    The evolution of the magnetic properties of composite Al{sub 2}O{sub 3}/Co(P) particles during ball milling and dynamic compaction is investigated. To prepare starting composite particles, the Al{sub 2}O{sub 3} granules were coated with a Co{sub 95}P{sub 5} shell by electroless plating. The magnetic and structural properties of the composite particles are characterized by scanning electron microscopy, X-ray diffraction, and the use of the Physical Property Measurement System. The use of composite core-shell particles as starting powder for mechanoactivation allows to decrease treatment duration to 1 h and to produce a more homogeneous bulk sample than in the case of the mixture of Co and Al{sub 2}O{sub 3} powders. The magnetic properties of the milled composite particles are correlated with changes in the microstructure. Reduction in grain size of Co during milling leads to an increase of the volume fraction of superparamagnetic particles and to a decrease of the saturation magnetization. The local magnetic anisotropy field depends on the amount of hcp-Co phase in sample. The anisotropy field value decreases from 8.4 kOe to 3.8 kOe with an increase in milling duration up to 75 min. The regimes of dynamic compaction were selected so that the magnetic characteristics—saturation magnetization and coercive field—remained unchanged.

  4. Magneto-optical properties of α-Fe2O3@ZnO nanocomposites prepared by the high energy ball-milling technique

    Science.gov (United States)

    Chaudhury, Chandana Roy; Roychowdhury, Anirban; Das, Anusree; Das, Dipankar

    2016-05-01

    Magnetic-fluorescent nanocomposites (NCs) with 10 wt% of α-Fe2O3 in ZnO have been prepared by the high energy ball-milling. The crystallite sizes of α-Fe2O3 and ZnO in the NCs are found to vary from 65 nm to 20 nm and 47 nm to 15 nm respectively as milling time is increased from 2 to 30 h. XRD analysis confirms presence of α-Fe2O3 and ZnO in pure form in all the NCs. UV-vis study of the NCs shows a continuous blue-shift of the absorption peak and a steady increase of band gap of ZnO with increasing milling duration that are assigned to decreasing particle size of ZnO in the NCs. Photoluminescence (PL) spectra of the NCs reveal three weak emission bands in the visible region at 421, 445 and 485 nm along with the strong near band edge emission at 391 nm. These weak emission bands are attributed to different defect - related energy levels e.g. Zn-vacancy, Zn interstitial and oxygen vacancy. Dc and ac magnetization measurements show presence of weakly interacting superparamagnetic (SPM) α-Fe2O3 particles in the NCs. 57Fe-Mössbauer study confirms presence of SPM hematite in the sample milled for 30 h. Positron annihilation lifetime measurements indicate presence of cation vacancies in ZnO nanostructures confirming results of PL studies.

  5. Influence of ball milling and annealing conditions on the properties of L1{sub 0} FePt nanoparticles fabricated by a new green chemical synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Hu, X. C., E-mail: xiaocaoh@udel.edu [Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); Capobianchi, A. [Istituto di Struttura della Materia. CNR, Rome (Italy); Gallagher, R. [Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Hadjipanayis, G. C. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2014-05-07

    In this work, a new green chemical strategy for the synthesis of L1{sub 0} FePt alloy nanoparticles is reported. The precursor is a polycrystalline molecular complex (Fe(H{sub 2}O){sub 6}PtCl{sub 6}), in which Fe and Pt atoms are arranged on alternating planes and milled with NaCl to form nanocrystals. Then the mixture was annealed under reducing atmosphere (5% H{sub 2} and 95% Ar) at temperatures varying from 350 °C to 500 °C for 2 h with a heating rate of 5 °C/min. After the reduction, the mixture was washed with water to remove the NaCl and L1{sub 0} FePt nanoparticles were obtained. The X-Ray Diffraction pattern showed the presence of the characteristic peaks of the fct phase of FePt nanoparticles. Influence of precursor/NaCl ratio and ball milling time on particle size was investigated. Transmission electron microscopy images revealed that smaller precursor/NaCl ratio (10 mg/20 g) and longer milling time (15 h) lead to smaller particle size and narrower size distribution. Milling time does not influence the coercivity much but the decrease of the amount of precursor leads to a decrease of coercivity from 10.8 kOe to 4.8 kOe.

  6. Influence of ball milling and annealing conditions on the properties of L10 FePt nanoparticles fabricated by a new green chemical synthesis method

    Science.gov (United States)

    Hu, X. C.; Capobianchi, A.; Gallagher, R.; Hadjipanayis, G. C.

    2014-05-01

    In this work, a new green chemical strategy for the synthesis of L10 FePt alloy nanoparticles is reported. The precursor is a polycrystalline molecular complex (Fe(H2O)6PtCl6), in which Fe and Pt atoms are arranged on alternating planes and milled with NaCl to form nanocrystals. Then the mixture was annealed under reducing atmosphere (5% H2 and 95% Ar) at temperatures varying from 350 °C to 500 °C for 2 h with a heating rate of 5 °C/min. After the reduction, the mixture was washed with water to remove the NaCl and L10 FePt nanoparticles were obtained. The X-Ray Diffraction pattern showed the presence of the characteristic peaks of the fct phase of FePt nanoparticles. Influence of precursor/NaCl ratio and ball milling time on particle size was investigated. Transmission electron microscopy images revealed that smaller precursor/NaCl ratio (10 mg/20 g) and longer milling time (15 h) lead to smaller particle size and narrower size distribution. Milling time does not influence the coercivity much but the decrease of the amount of precursor leads to a decrease of coercivity from 10.8 kOe to 4.8 kOe.

  7. Synthesis, phase transformation, and hydrogen storage properties of ball-milled TiV{sub 0.9}Mn{sub 1.1}

    Energy Technology Data Exchange (ETDEWEB)

    Huot, J. [Physics Department and Institut de Recherche sur l' Hydrogene, Universite du Quebec a Trois-Rivieres, 3351, Boul. Des Forges, Trois-Rivieres, Que. G9A 5H7 (Canada)], E-mail: jacques.huot@uqtr.ca; Enoki, H.; Akiba, E. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

    2008-04-03

    The milling of body centered cubic (BCC) Laves phase-related alloy of composition TiV{sub 0.9}Mn{sub 1.1} was performed using a planetary mill under inert atmosphere. Starting materials were arc-melted alloys and elements mixtures. The arc-melted alloy consisted of two phases: the C14 Laves phase and a BCC solid solution. It was found that milling of the arc-melted alloy resulted in the disappearance of the C14 Laves phase and the formation of a face centered cubic (FCC) solid solution phase in addition to the BCC solid solution. Milling the pure elements also produced a mixture of FCC and BCC solid solution phases. Extensive milling resulted in a total loss of hydrogen capacity.

  8. Tb0.3Dy0.7Fe1.92 nanoflakes prepared by surfactant-assisted high energy ball milling

    International Nuclear Information System (INIS)

    Highlights: → Tb0.3Dy0.7Fe1.92 nanoflakes have been prepared by high energy ball milling (HEBM) with oleic acid. → The morphology, structure and magnetic properties of Tb0.3Dy0.7Fe1.92 have been investigated. → These Tb0.3Dy0.7Fe1.92 nanoflakes had a thickness of 50-400 nm and a grain size of 15-21 nm. → The as-made samples had sustained little oxidation after surfactant-assisted HEBM. → Oleic acid was efficient to protect the powders from oxidation. - Abstract: Tb0.3Dy0.7Fe1.92 nanoflakes with larger specific surface and higher resistance to oxidation have been prepared by high energy ball milling (HEBM) with oleic acid. The morphology, structure and magnetic properties of Tb0.3Dy0.7Fe1.92 have been investigated using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The experimental results showed that the as-made samples had sustained little oxidation after surfactant-assisted HEBM suggesting that oleic acid was efficient to protect the powders from oxidation. These Tb0.3Dy0.7Fe1.92 nanoflakes have great potential to be used for the preparation of high performance Terfenol composites with reduced eddy current heating.

  9. Synthesis of boron suboxide (B6O) with ball milled boron oxide (B2O3) under lower pressure and temperature

    International Nuclear Information System (INIS)

    Boron reacted with ball milled boron oxide under pressures between 1 and 5 GPa and at temperatures between 1300 and 1700 oC to afford boron suboxide (B6O). Icosahedral B6O grains with diameters ranging from 100 nm to 1.3 μm were prepared. The factors that affect the synthesis of B6O are investigated. The best sample with crystal size up to 1.3 μm is obtained at 2 GPa and 1400 oC for 6 h. The indentation experiment gave an average Vickers hardness of 32.3 GPa for bulk B6O sample, which is consistent with previous reports. Bulk B6O sample exhibits oxidation resistance in air up to 1000 oC and mild oxidation in the temperatures of 1000-1200 oC, which is more oxidation resistant than diamond. It is possible that B6O could be used as a substitute for diamond in industry because of its relatively mild synthesis conditions, high thermal stability and high hardness. - Graphical abstract: Icosahedral B6O grains were prepared for mixtures of boron and ball milled boron oxide at 2 GPa and 1400 oC, a milder synthesis condition in comparison with previous works.

  10. A comparison of electrochemical performance of natural graphite sulfurized by ball-milling and heat-treating as an anode for lithium ion batteries

    International Nuclear Information System (INIS)

    Natural graphite (NG) was sulfurized by heat-treating or by high energy ball-milling the blend of NG with sulfur powder. The effect of the surface functional groups, containing sulfur, on the performance of the NG anode for a lithium ion battery was then investigated. X-ray photoelectron spectroscopy revealed that the sulfur was introduced onto the surface of NG in both of these methods. The results of scanning electron microscopy and Raman spectroscopy showed that the surface disorder of NG increased after sulfurization. Charge/discharge tests showed that the reversible capacity of the first cycle was increased after surface sulfurization and that the coulombic efficiency of the first cycle increased for the heat-treated sample but decreased for the ball-milled one. The change in the electrochemical performance was due to a number of factors including an increase in new active sites for lithium storage and an increase in surface area and increased disorder of the sulfurized NG samples.

  11. Structural characterization of stainless steel/TiC nanocomposites produced by high-energy ball-milling method at different milling times

    International Nuclear Information System (INIS)

    Highlights: ► The effect of milling time on the morphology of TiC/steel was investigated. ► The nanocrystalline structure powder at 40 h milling time was obtained. ► The maximum hardness of consolidated composite powders was 67 HRC. -- Abstract: This paper presents the results of milling time on the structure and properties of obtained stainless steel/30%TiC nanocomposite prepared by planetary milling in argon atmosphere using stainless steel 316 and titanium carbide powders. Achievement of a fine distribution of TiC nanoparticles in the steel matrix was the main purpose of this study. The results showed that increasing of the milling time up to 40 h led to good distribution and grain refinement of nanocomposite powder. The microstructure evolution of milled powders and nanocomposite were investigated by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and optical microscopy. TEM image revealed clearly that TiC nanoparticles with grain size of 50 nm were distributed in steel matrix at milling time of 40 h. The maximum hardness and density were 67 HRC and 6.63 g/cm3, respectively, when the sample was pressed under 550 MPa pressure and sintered at 1400 °C.

  12. X-ray Diffraction and NMR Studies of Na3-nLinAlH6 (n=0, 1, 2) Alanates Synthesized by High-Pressure Reactive Ball Milling

    International Nuclear Information System (INIS)

    The present work combines X-ray diffraction (XRD) analysis and NMR Study of Na3-nLinAlH6 (n = 0, 1, 2) alanates synthesized by high-pressure reactive ball milling. Reactive ball-milling of alkali hydrides and Al Under it hydrogen pressure of 10 MN allows for the synthesis of Na3AlH6 and Na2LiAlH6 with a yield higher than 90 wt % When using 2 mol % of TiCl3 as a dopant The synthesis of NaLi2AlH6 compound by reactive ball Milling was not Successful The crystal Structure of both Na3AlH6 and Na2LiAlH6 phases are in agreement with previous publications. The phase compositions of the synthesized samples obtained from XRD analysis are in good agreement with the results determined from NMR refinements Without the addition of TiCl3, Na3AlH6 compound Could also be formed, although the reaction was not complete due to slow kinetics. For the magic angle spinning NMR 26Al, 23Na, 6Li, and 1H spectra, strong bulk magnetic Susceptibility (BMS) effects have been observed to affect to the same extent all detected lines and thus indicates that paramagnetic species (Ti3+ or Ti0 bearing phase) are present and well dispersed in the samples. 23Na and 27Al NMR spectra call be refined with very similar NMR parameters for both doped and non doped samples, suggesting that Ti does not incorporate the crystal structure of these materials. Accurate values of 23Na and 27Al NMR parameters and quantification of the studied phases have been obtained thanks to a new treatment allowing for taking into account the BMS effects. Finally, it good agreement of experimental 23Na and 27Al quadrupolar parameters with density functional theory using the gauge-including projector augmented wave (DFT-GIPAW) predicted values is obtained. This work validates the use of DFT-GIPAW calculations for future NMR studies. (authors)

  13. Inelastic neutron scattering investigation of ball-milled FeSiB described as a magnetic nanoglass-like structure

    International Nuclear Information System (INIS)

    Highlights: • Inelastic neutron scattering on FeSiB obtained by milling from amorphous ribbon. • Minor fraction of bcc-Fe detected by XRD and Mössbauer spectroscopy. • Reduction of the neutron magnetic cross section upon milling. • Alterations of the ferromagnetic order resulting in a nanoglass-like structure. - Abstract: An inelastic neutron scattering study has been carried out to assess the effects of mechanical milling treatments (10, 20 and 70 h) on an amorphous melt-spun FeSiB ribbon. Faint traces of crystallization were observed after 10 and 20 h milling by X-ray diffraction and Mössbauer spectroscopy and a minor fraction of bcc-Fe was clearly detected after 70 h. Whilst the neutron spectrum S(E) of the 10 h-milled sample, at temperature T = 300 K, does not differ from that of the precursor FeSiB ribbon, the area of the inelastic region of S(E) decreases more and more after 20 and 70 h milling. Moreover, in the samples milled for 20 and 70 h, also the area of the elastic region of the S(E) spectrum is definitely smaller than the one of the FeSiB ribbon. This is consistent with a reduction of the magnetic cross section upon milling and it agrees also with magnetization measurements. We interpret this behavior assuming that the milling treatment causes local alterations of the short-range atomic order within the amorphous phase, and hence of the precursor collinear ferromagnetic order, finally giving rise to a sort of magnetic nanoglass structure

  14. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Basudev, E-mail: swain@iae.re.kr; Mishra, Chinmayee; Kang, Leeseung; Park, Kyung-Soo, E-mail: kspark@iae.re.kr; Lee, Chan Gi; Hong, Hyun Seon, E-mail: hshong@iae.re.kr

    2015-04-15

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na{sub 2}CO{sub 3}, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na{sub 2}CO{sub 3}, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved.

  15. Evolution of long-range and short-range order in La0.67Ca0.33MnO3- during solid-state transformation using high-energy ball milling

    International Nuclear Information System (INIS)

    A novel processing scheme has been developed that allows for the single step processing of nanostructured complex oxides. This approach involves the high energy ball-milling (HEBM) of binary oxide precursors to form pure phase complex oxides at low-temperatures. Using this technique we have prepared La0.67Ca0.33MnO3-δ and studied the evolution of short range and long-range order, using EXAFS and XRD respectively, as a function of milling time during the solid state transformation. Transport properties of the milled perovskites are also discussed. (au)

  16. Performance of paper mill sludges as landfill capping material

    Energy Technology Data Exchange (ETDEWEB)

    Moo-Young, H.K. Jr. [Lehigh Univ., Bethlehem, PA (United States); Zimmie, T.F. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-12-31

    The high cost of waste containment has sparked interest in low cost and effective strategies of containing wastes. Paper mill sludges have been effectively used as the impermeable barrier in landfill covers. Since paper mill sludges are viewed as a waste material, the sludge is given to the landfill owner at little or no cost. Thus, when a clay soil is not locally available to use as the impermeable barrier in a cover system, paper sludge barriers can save $20,000 to $50,000 per acre in construction costs. This study looks at the utilization and performance of blended and primary paper sludge as landfill capping material. To determine the effectiveness of paper sludge as an impermeable barrier layer, test pads were constructed to simulate a typical landfill cover with paper sludge and clay as the impermeable barrier and were monitored for infiltration rates for five years. Long-term hydraulic conductivity values estimated from the leachate generation rates of the test pads indicate that paper sludge provides an acceptable hydraulic barrier.

  17. Performance of paper mill sludges as landfill capping material

    International Nuclear Information System (INIS)

    The high cost of waste containment has sparked interest in low cost and effective strategies of containing wastes. Paper mill sludges have been effectively used as the impermeable barrier in landfill covers. Since paper mill sludges are viewed as a waste material, the sludge is given to the landfill owner at little or no cost. Thus, when a clay soil is not locally available to use as the impermeable barrier in a cover system, paper sludge barriers can save $20,000 to $50,000 per acre in construction costs. This study looks at the utilization and performance of blended and primary paper sludge as landfill capping material. To determine the effectiveness of paper sludge as an impermeable barrier layer, test pads were constructed to simulate a typical landfill cover with paper sludge and clay as the impermeable barrier and were monitored for infiltration rates for five years. Long-term hydraulic conductivity values estimated from the leachate generation rates of the test pads indicate that paper sludge provides an acceptable hydraulic barrier

  18. Ultrathin SmCo5 nanoflakes with high-coercivity prepared by solid particle (NaCl) and surfactant co-assisted ball milling

    Science.gov (United States)

    Zuo, Wen-Liang; Zhao, Xin; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2016-05-01

    The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10–50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indicate that the magnetization reversal may be controlled by both nucleation and pinning. The results of X-ray powder diffraction and magnetic measurement for aligned SmCo5 nanoflakes resin composite indicate that the nanoflakes have a high texture degree. The ultrathin thickness and high coercivity are beneficial for preparing the high performance soft/hard coupling magnets and nanocomposite magnets.

  19. Ultrathin SmCo5 nanoflakes with high-coercivity prepared by solid particle (NaCl) and surfactant co-assisted ball milling.

    Science.gov (United States)

    Zuo, Wen-Liang; Zhao, Xin; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2016-01-01

    The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10-50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indicate that the magnetization reversal may be controlled by both nucleation and pinning. The results of X-ray powder diffraction and magnetic measurement for aligned SmCo5 nanoflakes resin composite indicate that the nanoflakes have a high texture degree. The ultrathin thickness and high coercivity are beneficial for preparing the high performance soft/hard coupling magnets and nanocomposite magnets. PMID:27174410

  20. Standard test method for ball punch deformation of metallic sheet material

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers the procedure for conducting the ball punch deformation test for metallic sheet materials intended for forming applications. The test applies to specimens with thicknesses between 0.008 and 0.080 in. (0.20 and 2.00 mm). 1.2 The values stated in inch–pound units are to be regarded as the standard. Note 1—The ball punch deformation test is intended to replace the Olsen cup test by standardizing many of the test parameters that previously have been left to the discretion of the testing laboratory. Note 2—The modified Erichsen test has been standardized in Europe. The main differences between the ball punch deformation test and the Erichsen test are the diameters of the penetrator and the dies. Erichsen cup heights are given in SI units. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does...

  1. Industrial recovered-materials-utilization targets for the textile-mill-products industry

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    The Congress, in the National Energy Conservation and Policy Act of 1978 (NECPA), directed the Department of Energy to establish materials recovery targets for the metals and metal products, paper and allied products, rubber, and textile-mill-products industries. The targets were developed to provide incentives for using energy-saving recorded materials and to provied a yardstick for measuring progress and improvement in this endeavor. The NECPA indicates that the targets should represent the maximum technically and economically feasible increase in the use of energy-saving recovered materials that each industry can achieve progressively by January 1, 1987. Materials affected by recovered-materials targets include and are limited to aluminum, copper, lead, zinc, iron, steel, paper and associated products, textile-mill, products, and rubber. Using information gathered from the textile-mill-products industry and from other textile-relaed sources, DOE has developed recovered materials targets for that industry. This report presents those targets and their basis and justification. Following an overview of the textile industry, the chapters are: Textile-Mill-Products Industry Operations; Economic Analysis of the Textile-Mill-Products Industry; Governmental and Regulatory Influence on the US Textile Industry; Current Mill Use of Recovered Materials in the Textile-Mill-Products Industry; Limitations on the Use of Recovered Materials in the US Textile-Mill-Products Industry; Materials-Recovery Targets; and Government and Industry Actions That Could Increase the Use of Recovered Materials.

  2. Ball-milling, a novel extraction process for production of W from WO3 using Mg as a reductant

    International Nuclear Information System (INIS)

    The synthesis of tungsten (W) metal by the chemical reduction of tungsten oxide (WO3), using magnesium (Mg) as a reductant, has been investigated by the mechanical alloying process. Complete transformation to W was observed after 60 sec of milling. W metal was recovered from the reaction products of W and magnesium oxide (MgO) by dilute nitric acid leaching. The powders were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Electron microscopic studies indicated that nano-meter sized grains were present in the W powder after leaching

  3. Rolling-element fatigue life of silicon nitride balls. [as compared to that of steel, ceramic, and cermet materials

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    The five-ball fatigue tester was used to evaluate silicon nitride as a rolling-element bearing material. Results indicate that hot-pressed silicon nitride running against steel may be expected to yield fatigue lives comparable to or greater than those of bearing quality steel running against steel at stress levels typical rolling-element bearing application. The fatigue life of hot-pressed silicon nitride is considerably greater than that of any ceramic or cermet tested. Computer analysis indicates that there is no improvement in the lives of 120-mm-bore angular--contact ball bearings of the same geometry operating at DN values from 2 to 4 million where hot-pressed silicon nitride balls are used in place of steel balls.

  4. A Mössbauer and magnetic study of ball milled Fe-doped ZnO Powders

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, Ligia E., E-mail: ligia.zamora@correounivalle.edu.co; Paz, J. C.; Piamba, J. F.; Tabares, J. A.; Alcázar, G. A. Pérez [Universidad del Valle, Departamento de física (Colombia)

    2015-06-15

    The structural and magnetic properties of Fe-doped ZnO are reported in this study, as obtained by mechanical alloying from elemental powders of ZnO and Fe. The properties of Zn{sub 0.90}Fe{sub 0.10}O samples alloying while varying the milling time (6, 12, 24 and 36 h) are also reported. The Rietveld refinement of X-ray Diffraction (XRD) patterns revealed that the system presents two structures: the würtzite structure of ZnO and the bcc structure of α-Fe. The Mössbauer spectra show that the samples present three components: a ferromagnetic component, associated with the Fe phase and two paramagnetic components, associated with the Fe atoms, which penetrate inside the ZnO matrix behaving as Fe{sup 3+} and Fe{sup 2+}. The milling time contributes to an increase in the paramagnetic sites, and a solubility limit of the Fe atoms in the ZnO lattice was detected. The VSM measurements at room temperature detected ferromagnetic behavior with a saturation magnetization of 11 emu/g and a coercive field of 330 Oe for the sample alloyed over 24 h. A similar behavior was shown by the other samples.

  5. Flank wear and I-kaz 3D correlation in ball end milling process of Inconel 718

    Directory of Open Access Journals (Sweden)

    M.A.S.M. Tahir

    2015-12-01

    Full Text Available Tool wear may deteriorate the machine product quality due to high surface roughness, dimension exceeding tolerance and also to machine tool itself. Tool wear monitoring system is vital to be used in machining process to achieve high quality of the machined product and at the same time improve the productivity. Nowadays, many monitoring system developed using various sensor and statistical technique to analyze the signals being used. In this paper, I-kaz 3D method is used to analyze cutting force signal in milling process of Inconel 718 for monitoring the status of tool wear in milling process. The results from analyzing cutting force show that I-kaz 3D coefficient has a correlation with cutting tool condition. Tool wear will generate high value of I-kaz 3D coefficient than the sharp cutting tool. Furthermore, the three dimension graphical representation of I-kaz 3D for all cutting condition shown that the degree of scattering data increases with tool wear progression.

  6. Dispersion of silicon carbide nanoparticles in a AA2024 aluminum alloy by a high-energy ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Carreño-Gallardo, C.; Estrada-Guel, I. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología-Chihuahua, Miguel de Cervantes No. 120, CP 31109, Chihuahua, México (Mexico); López-Meléndez, C. [Universidad La Salle Chihuahua, Prol. Lomas de Majalca No. 11201, CP 31020, Chihuahua, México (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología-Chihuahua, Miguel de Cervantes No. 120, CP 31109, Chihuahua, México (Mexico)

    2014-02-15

    Highlights: • Synthesis of 2024-SiC{sub NP} nanocomposite by mechanical milling process. • SiC nanoparticles improved mechanical properties of aluminum alloy 2024 matrix. • A homogeneous distribution of SiC nanoparticles were observed in the matrix • Compressive and hardness properties of the composite are improved significantly. -- Abstract: Al{sub 2024} alloy was reinforced with silicon carbide nanoparticles (SiC{sub NP}), whose concentration was varied in the range from 0 to 5 wt.%; some composites were synthesized with the mechanical milling (MM) process. Structure and microstructure of the consolidated samples were studied by X-ray diffraction and transmission electron microscopy, while mechanical properties were investigated by compressive tests and hardness measurements. The microstructural evidence shows that SiC{sub NP} were homogeneously dispersed into the Al{sub 2024} alloy using high-energy MM after 2 h of processing. On the other hand, an increase of the mechanical properties (yield stress, maximum strength and hardness) was observed in the synthesized composites as a direct function of the SiC{sub NP} content. In this research several strengthening mechanisms were observed, but the main was the obstruction of dislocations movement by the addition of SiC{sub NP}.

  7. Dispersion of silicon carbide nanoparticles in a AA2024 aluminum alloy by a high-energy ball mill

    International Nuclear Information System (INIS)

    Highlights: • Synthesis of 2024-SiCNP nanocomposite by mechanical milling process. • SiC nanoparticles improved mechanical properties of aluminum alloy 2024 matrix. • A homogeneous distribution of SiC nanoparticles were observed in the matrix • Compressive and hardness properties of the composite are improved significantly. -- Abstract: Al2024 alloy was reinforced with silicon carbide nanoparticles (SiCNP), whose concentration was varied in the range from 0 to 5 wt.%; some composites were synthesized with the mechanical milling (MM) process. Structure and microstructure of the consolidated samples were studied by X-ray diffraction and transmission electron microscopy, while mechanical properties were investigated by compressive tests and hardness measurements. The microstructural evidence shows that SiCNP were homogeneously dispersed into the Al2024 alloy using high-energy MM after 2 h of processing. On the other hand, an increase of the mechanical properties (yield stress, maximum strength and hardness) was observed in the synthesized composites as a direct function of the SiCNP content. In this research several strengthening mechanisms were observed, but the main was the obstruction of dislocations movement by the addition of SiCNP

  8. Morphological, Thermal, and Magnetic Analysis of Ball-Milled γ-Fe2O3 and Fe3O4 Nanoparticles for Biomedical Application

    Science.gov (United States)

    Burnham, Philip; Papaefthymiou, Georgia C.; Viescas, Arthur; Li, Calvin; Dollahon, Norman

    2013-03-01

    Superparamagnetic iron oxide nanoparticles are promising agents for hyperthermia cancer treatment, because, when exposed to an alternating magnetic field, they impart heat to surrounding tissue. A comparison of γ-Fe2O3 and Fe3O4 nanoparticles for such application is presented. The particles were obtained via surfactant-assisted high energy ball-milling in a hexane/oleic acid carrier-fluid environment. Particles with diameters of 5 to 16 nm were prepared with mass ratios (oleic acid):(γ-Fe2O3) of 0:1, 1:5, 1:10 and 1:20, with milling times of 3, 6, 9, and 12 hours. TEM micrographs revealed spherical morphology and the effect of oleic acid shells. Optimal size distributions were obtained for high oleic acid contents. At room temperature, a reduced internal magnetic field ~480 kOe) was recorded via Mössbauer spectroscopy compared to bulk γ-Fe2O3 ~500 kOe), due to magnetic relaxation; Fe3O4 particles produced similar results. For the γ-Fe2O3 and Fe3O4 nanoparticles with 20% oleic acid by mass, comparative ZFC/FC magnetization (Happ = 200 Oe in temperature range from 2 to 400 K) and hysteresis loops (T = 2 K and 300 K up to Happ = 6 kOe) were obtained. Thermal transport characteristics were verified by Specific Absorption Rate (SAR) measurements using an AC magnetic field (f = 282 kHz). Differences and similarities in behavior will be discussed.

  9. Studies of superspin glass state and AC-losses in La{sub 0.7}Sr{sub 0.3}MnO{sub 3} nanoparticles obtained by high-energy ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Phong, P.T., E-mail: ptphong.nh@khanhhoa.edu.vn [Department of Advanced Materials Chemistry, Dongguk University-Gyeongju, 707 Suckjang-dong, Gyeongbuk, Gyeongju-Si 780-714 (Korea, Republic of); Nha Trang Pedagogic College, 1 Nguyen Chanh Street, Khanh Hoa Province, Nha Trang City (Viet Nam); Manh, D.H. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Ha Noi City (Viet Nam); Nguyen, L.H. [Nha Trang Pedagogic College, 1 Nguyen Chanh Street, Khanh Hoa Province, Nha Trang City (Viet Nam); Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Ha Noi City (Viet Nam); Tung, D.K. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Ha Noi City (Viet Nam); Phuc, N.X., E-mail: phucnx1949@gmail.com [Nha Trang Pedagogic College, 1 Nguyen Chanh Street, Khanh Hoa Province, Nha Trang City (Viet Nam); Lee, I.-J., E-mail: lij@dongguk.ac.kr [Department of Advanced Materials Chemistry, Dongguk University-Gyeongju, 707 Suckjang-dong, Gyeongbuk, Gyeongju-Si 780-714 (Korea, Republic of)

    2014-11-15

    Single-phase perovskite compound La{sub 0.7}Sr{sub 0.3}MnO{sub 3} was synthesized by a high-energy ball milling method. Nanoparticle nature of this manganite with the average particle diameter of 11 nm was revealed from structure and morphology characterizations. The results of ac magnetic susceptibility measurements show that the system can be described as an ensemble of interacting magnetic nanoparticles, which indicates that the dipole–dipole interactions are strong enough to create superspin glass state in the sample. Furthermore, the specific loss power which is exhausted on the irradiation of an ensemble of particles with a magnetic field has been calculated and measured experimentally. - Highlights: • LSMO nanopowder was prepared by the high-energy ball-milling method. • The superspin glass state of LSMO nanopowder was studied. • The SLP has been calculated and measured experimentally.

  10. Studies of superspin glass state and AC-losses in La0.7Sr0.3MnO3 nanoparticles obtained by high-energy ball-milling

    International Nuclear Information System (INIS)

    Single-phase perovskite compound La0.7Sr0.3MnO3 was synthesized by a high-energy ball milling method. Nanoparticle nature of this manganite with the average particle diameter of 11 nm was revealed from structure and morphology characterizations. The results of ac magnetic susceptibility measurements show that the system can be described as an ensemble of interacting magnetic nanoparticles, which indicates that the dipole–dipole interactions are strong enough to create superspin glass state in the sample. Furthermore, the specific loss power which is exhausted on the irradiation of an ensemble of particles with a magnetic field has been calculated and measured experimentally. - Highlights: • LSMO nanopowder was prepared by the high-energy ball-milling method. • The superspin glass state of LSMO nanopowder was studied. • The SLP has been calculated and measured experimentally

  11. Magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite nanoparticles synthesized by starch-assisted sol–gel autocombustion method and its ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Raghvendra Singh, E-mail: yadav@fch.vutbr.cz [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic); Havlica, Jaromir [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic); Hnatko, Miroslav; Šajgalík, Pavol [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 36 Bratislava (Slovakia); Alexander, Cigáň [Institute of Measurement Science, Slovak Academy of Sciences, Dúbravská cesta 9, SK-841 04 Bratislava (Slovakia); Palou, Martin; Bartoníčková, Eva; Boháč, Martin; Frajkorová, Františka; Masilko, Jiri; Zmrzlý, Martin; Kalina, Lukas; Hajdúchová, Miroslava; Enev, Vojtěch [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic)

    2015-03-15

    In this article, Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0 and 0.5) spinel ferrite nanoparticles were achieved at 800 °C by starch-assisted sol–gel autocombustion method. To further reduce the particle size, these synthesized ferrite nanoparticles were ball-milled for 2 h. X-ray diffraction patterns demonstrated single phase formation of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0 and 0.5) spinel ferrite nanoparticles. FE-SEM analysis indicated the nanosized spherical particles formation with spherical morphology. The change in Raman modes and relative intensity were observed due to ball milling and consequently decrease of particle size and cationic redistribution. An X-ray Photoelectron Spectroscopy (XPS) result indicated that Co{sup 2+}, Zn{sup 2+} and Fe{sup 3+} exist in octahedral and tetrahedral sites. The cationic redistribution of Zn{sup 2+} and consequently Fe{sup 3+} occurred between octahedral and tetrahedral sites after ball-milling. The change in saturation magnetization (M{sub s}) and coercivity (H{sub c}) with decrease of nanocrystalline size and distribution of cations in spinel ferrite were observed. - Highlights: • Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite nanoparticles. • Starch-assisted sol–gel auto-combustion method. • Effect of ball-milling on particle size and cation distribution. • Magnetic property dependent on cations and particle size.

  12. Binding of carbon coated nano-silicon in graphene sheets by wet ball-milling and pyrolysis as high performance anodes for lithium-ion batteries

    Science.gov (United States)

    Sun, Wei; Hu, Renzong; Zhang, Miao; Liu, Jiangwen; Zhu, Min

    2016-06-01

    A novel approach has been developed to prepare silicon@carbon/graphene sheets (Si@C/G) composite with a unique structure, in which carbon coated Si nanoparticles are uniformly dispersed in a matrix of graphene sheets, to enhance the cycleability and electronic conductivity of Si-based anodes for Li-ion batteries. In this study, Si nanoparticles and expanded graphite (EG) are treated by combining high-energy wet ball-milling in sucrose solution with subsequent pyrolysis treatment to produce this Si@C/G composite. To achieve better overall electrochemical performance, the carbon content of the composites is also studied systematically. The as-designed Si30@C40/G30 (Si:C:G = 30:40:30, by weight) composite exhibits a high Li-storage capacity of 1259 mAh g-1 at a current density of 0.2 A g-1 in the first cycle. Further, a stable cycleability with 99.1/88.2% capacity retention from initial reversible charge capacity can be achieved over 100/300 cycles, showing great promise for batteries applications. This good electrochemical performance can be attributed to the uniform coating and binding effect of pyrolytic carbon as well as the network of graphene sheets, which increase the electronic conductivity and Li+ diffusion in the composite, and effectively accommodated the volume change of Si nanoparticles during the Li+ alloying and dealloying processes.

  13. Magnetic properties and coercivity mechanism of Sm1-xPrxCo5 (x=0-0.6) nanoflakes prepared by surfactant-assisted ball milling

    Science.gov (United States)

    Xu, M. L.; Yue, M.; Wu, Q.; Li, Y. Q.; Lu, Q. M.

    2016-05-01

    Sm1-xPrxCo5 (x=0-0.6) nanoflakes with CaCu5 structure were successfully prepared by surfactant-assisted high-energy ball milling (SAHEBM). The crystal structure and magnetic properties of Sm1-xPrxCo5 (x=0-0.6) nanoflakes were studied by X-ray diffraction and vibrating sample magnetometer. Effects of Pr addition on the structure, magnetic properties and coercivity mechanism of Sm1-xPrxCo5 nanoflakes were systematically investigated. XRD results show that all the nanoflakes have a hexagonal CaCu5-type (Sm, Pr)1Co5 main phase and the (Sm, Pr)2Co7 impurity phase, and all of the samples exhibit a strong (00l) texture after magnetic alignment. As the Pr content increases, remanence firstly increases, then slightly reduced, while anisotropy field (HA) and Hci of decrease monotonically. Maximum energy product [(BH)max] of the flakes increases first, peaks at 24.4 MGOe with Pr content of x = 0.4, then drops again. Magnetization behavior analysis indicate that the coercivity mechanism is mainly controlled by inhomogeneous domain wall pinning, and the pinning strength weakens with the increased Pr content, suggesting the great influence of HA on the coercivity of flakes.

  14. SiC/Al Composite Prepared by High Energy Ball Milling Method%高能球磨法制备SiC/Al复合材料

    Institute of Scientific and Technical Information of China (English)

    吴清军; 蔡晓兰; 乐刚

    2012-01-01

    SiC particle reinforced pure aluminum matrix composite was prepared using high energy ball milling method. The effects of the mass fraction of SiC particles on the mechanical properties of the composite were studied. The results indicate that the hardness, yield strength and tensile strength of the composite increase, but the elongation decreases with the increase of the weight fraction of the SiC particles. The fracture morphology indicates that SiC/Al composite shows both ductile and brittle fracture characteristics, and along with increasing the weight fraction of the SiC particles, and the ductile fracture feature decreases.%采用高能球磨法制备了SiC颗粒增强Al基复合材料,研究了SiC含量对该复合材料力学性能的影响.结果表明,SiC/Al复合材料的硬度、屈服强度以及抗拉强度随SiC含量的增加而增大,而伸长率随之减小;SiC/Al复合材料呈延性断裂和脆性断裂混合断裂;随着SiC含量的增加,材料延性断裂特征减少.

  15. Fabricating fine-grained tungsten heavy alloy by spark plasma sintering of low-energy ball-milled W–2Mo–7Ni–3Fe powders

    International Nuclear Information System (INIS)

    Fine-grained W–2Mo–7Ni–3Fe heavy alloys were fabricated by low-energy ball milling (LEBM)-assisted spark plasma sintering at a temperature range of 1000–1250 °C. The effects of sintering temperature on the phase evolution, microstructural characteristics, and mechanical properties of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), hardness testing, and universal testing. The XRD results show that small intermetallic compounds, such as NiW and Ni2W4C, form in the alloys. The W–2Mo–7Ni–3Fe alloys are characterized by white W grains, a gray W-rich microstructure that contains Mo, and a black γ–(Ni, Fe, W, Mo) binding phase. The X-ray energy dispersive analysis (EDS) shows that the Mo, Ni, and Fe that form a solid solution with W in the gray structure gradually decrease with increasing temperature. The hardness and bending strength of the alloys initially increase and then decrease with rising sintering temperature. Moreover, the alloys sintered at different temperatures exhibit dissimilar bending fracture modes

  16. Fabricating fine-grained tungsten heavy alloy by spark plasma sintering of low-energy ball-milled W–2Mo–7Ni–3Fe powders

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, D.P., E-mail: dpxiang@hainu.edu.cn [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Ding, L. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); Li, Y.Y. [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Chen, X.Y.; Zhang, T.M. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China)

    2013-08-20

    Fine-grained W–2Mo–7Ni–3Fe heavy alloys were fabricated by low-energy ball milling (LEBM)-assisted spark plasma sintering at a temperature range of 1000–1250 °C. The effects of sintering temperature on the phase evolution, microstructural characteristics, and mechanical properties of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), hardness testing, and universal testing. The XRD results show that small intermetallic compounds, such as NiW and Ni{sub 2}W{sub 4}C, form in the alloys. The W–2Mo–7Ni–3Fe alloys are characterized by white W grains, a gray W-rich microstructure that contains Mo, and a black γ–(Ni, Fe, W, Mo) binding phase. The X-ray energy dispersive analysis (EDS) shows that the Mo, Ni, and Fe that form a solid solution with W in the gray structure gradually decrease with increasing temperature. The hardness and bending strength of the alloys initially increase and then decrease with rising sintering temperature. Moreover, the alloys sintered at different temperatures exhibit dissimilar bending fracture modes.

  17. 高能球磨法制备SiC/Al复合粉末的工艺研究%Preparation of SiC/Al Composite Powder by High Energy Ball Milling

    Institute of Scientific and Technical Information of China (English)

    龚慧; 卢德宏; 蒋业华; 周荣; 王钊

    2011-01-01

    SiC/Al composite powder was prepared by high energy ball milling, and effects of milling time, process control agent (PCA), the weight ratio of ball to powder as well as quantity ratio of SiC to Al on the granularity of composite powder and the cladding effects of Al on SiC were investigated. The results show that the average granularity size of composite powder is closely related to the PCA, the quantity ratio of SiC to Al, ball milling time, and the weight ratio of ball to powder, and influencing order is as follows: PCA>quantity ratio of SiC to Al >ball milling time>weight ratio of ball to powder. The average size of powders are decreased dramatically with the increase of ball milling time, PCA and the weight ratio of ball to powder, and it exhibits firstly increased and then decreased with increasing in quantity ratio of SiC to Al, reaching the minimum value as the quantity ratio of SiC to Al of 3 to 7. The composite powder with fine particle size and desirable cladding effects can be successfully prepared with 1. 5% PCA, weight ratio of ball to powder of 12 ; 1 and quantity ratio of SiC to Al of 3 ! 7 and milling for 9 hours.%采用高能球磨技术制备SiC和Al的复合粉末,研究了球磨时间、过程控制剂(PCA)、球料比以及SiC与Al混粉质量比对复合粉末粒度和包覆效果的影响.结果表明,复合粉末平均粒径的大小与PCA、混粉比、球磨时间和球料比有关,其影响程度依次为:PCA>混粉比>时间>球料比;复合粉末的粒径大小随着球磨时间、PCA和球料比的增加而显著减小,而随着混粉质量比的增加呈现先减后增的趋势.混粉质量比为3∶7的复合粉末平均粒径达到最小值;球磨时间为9h、PCA添加量为1.5%、球料比为12∶1和Al与SiC混粉质量比为3∶7时,能制备出颗粒细小、包覆效果好的优质复合粉末.

  18. Influence of workpiece inclination angle on the surface roughness in ball end milling of the titanium alloy Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    A. Daymi

    2009-07-01

    Full Text Available Purpose: The aim of this work is to provide an in-depth understanding of the surface texture produced by various workpiece inclination angles using high speed finish ball end-milling of the titanium alloy Ti-6Al-4V.Design/methodology/approach: This paper presents an approach to develop a mathematical model of surface roughness in end-milling by the experimental design methodology. Machining variables such as cutting speed, feed and radial depth of cut, which are easily controllable, are considered in building the model. The influence of the workpiece inclination angle on the surface roughness of the machined workpiece was also investigated.Findings: According to the mathematical model, an increase in either the feed or the radial depth of cut increases the surface roughness, whilst an increase in cutting speed decreases it. The radial depth of cut ae is the most significant parameter in the model. Results analysis of the 2D/3D surface roughness parameters of the machined parts shows the improvement of the surface roughness quality when it is machined with a workpiece inclination angle of 25°.Research limitations/implications: As perspectives of this work, we can study the influence of the different machining strategies on the surface integrity of this titanium alloy, including the study of the residual stress.Practical implications: We propose to study the improvement of the surface quality of the orthopedic prostheses, which is an influencing parameter in their lifetime, by implementing the high speed cutting technique. The mathematical model of the surface roughness is a very important result of this work. In fact, it allows selecting the best cutting conditions to obtain a better workpiece surface quality.Originality/value: In this work, three dimensional surface roughness parameters were studied: the 3D surface topographies were obtained using a 3D measurement station and the mathematical model of Sa. The arithmetic mean deviation of the

  19. Real/binary co-operative and co-evolving swarms based multivariable PID controller design of ball mill pulverizing system

    International Nuclear Information System (INIS)

    Highlights: ► We extend the concept of co-operation and co-evolution in some PSO variants. ► We use developed co-operative PSOs in multivariable PID controller design/tuning. ► We find that co-operative PSOs converge faster and give high quality solutions. ► Dividing the search space among swarms improves search efficiency. ► The proposed methods allow the practitioner for heterogeneous problem formulation. - Abstract: In this paper, multivariable PID controller design based on cooperative and coevolving multiple swarms is demonstrated. A simplified multi-variable MIMO process model of a ball mill pulverizing system with steady state decoupler is considered. In order to formulate computational models of cooperative and coevolving multiple swarms three different algorithms like real coded PSO, discrete binary PSO (DBPSO) and probability based discrete binary PSO (PBPSO) are employed. Simulations are carried out on three composite functions simultaneously considering multiple objectives. The cooperative and coevolving multiple swarms based results are compared with the results obtained through single swarm based methods like real coded particle swarm optimization (PSO), discrete binary PSO (DBPSO), and probability based discrete binary PSO (PBPSO) algorithms. The cooperative and coevolving swarms based techniques outperform the real coded PSO, PBPSO, and the standard discrete binary PSO (DBPSO) algorithm in escaping from local optima. Furthermore, statistical analysis of the simulation results is performed to calculate the comparative reliability of various techniques. All of the techniques employed are suitable for controller tuning, however, the multiple cooperative and coevolving swarms based results are considerably better in terms of mean fitness, variance of fitness, and success rate in finding a feasible solution in comparison to those obtained using single swarm based methods.

  20. NON-DEGRADATIVE DISSOLUTION AND ACETYLATION OF BALL-MILLED PLANT CELL WALLS; HIGH-RESOLUTION SOLUTION-STATE NMR

    Science.gov (United States)

    We describe two solvent systems for fully dissolving, and optionally derivatizing, finely ground plant cell wall material at room temperature: dimethylsulfoxide and tetrabutylammonium fluoride or N-methylimidazole. In situ acetylation produces acetylated cell walls that are fully soluble in CDCl3. L...

  1. Control System of Ball Mill Based on Stair-like Generalized Predictive Control%基于阶梯式广义预测控制的钢球磨煤机控制系统

    Institute of Scientific and Technical Information of China (English)

    徐毅; 王恒; 樊培利; 王圣军; 万齐心

    2013-01-01

    It is difficult to realize automatic control in ball mill pulverizing system due to characteristics of long time-delay,big inertia,and strong interaction and so on.In view of the ball mill pulverizing system in one power plant,the mathematical model is constructed after onsite operation data analysis.A control scheme based on stair-like generalized predictive control (SGPC) is proposed after studying the operation features of the ball mill system.Three control loops are designed to realize the control for mill load,output temperature and input pressure respectively.Feed-forward compensators are introduced to reduce strong coupling between these three loops,and stair-like generalized predictive controller is designed for each loop.Simulation result shows that controllers with feed-forward compensators have a better control performance and less interaction.The operation result with application of the scheme in ball mill pulverizing system in the power plant has demonstrated that this scheme has less control deviation and high ratio of automatic control.%钢球磨煤机制粉系统,存在大滞后、大惯性、强耦合等特点,难以实现自动控制.针对某电厂钢球磨煤机制粉系统,对现场运行数据进行分析,建立数学模型.通过分析磨煤机的工作特性,提出了基于阶梯式广义预测控制(SGPC)的控制方案,通过3个回路分别实现磨机负荷、出口风温度、入口负压的控制,运用前馈补偿来减少各个回路之间的耦合,并分别对各个回路设计了阶梯式广义预测控制器.仿真分析表明,采用前馈补偿时,各个回路间耦合降低,控制性能较好.该控制方案在电厂钢球磨煤机制粉系统中的运行结果表明,控制方案具有较高的控制精度和自动投运率.

  2. Evaluation of Mechanical Properties of Nuclear Materials Using Non-Destructive Ball Indentation Technique

    International Nuclear Information System (INIS)

    Integrity of structural components depends on the deformation and fracture behavior of materials. For evaluating the material condition in-service, it is generally not feasible or practical or advisable to cut samples from operating structures. Non-destructive testing (NDT) techniques are required to evaluate the mechanical properties. Although several NDT techniques such as ultrasound, magnetic strength, Barkhausen noise, microhardness etc., are employed for estimating the mechanical property degradation, these methodologies are generally empirical and indirect. Automated Ball Indentation (ABI) is a non-destructive testing technique for direct measurement of mechanical and fracture properties of metallic engineering materials. Because of the small area over which the test is carried out, it is possible to determine point to point variations in the mechanical and fracture properties, such as those that exist in weldments. Although ABI technique is non-intrusive, it is a state-of-the-art mechanical test that measures directly the current/local deformation behavior of the material. In this paper, we present results from studies on the application of ABI technique to determine tensile and fracture properties of ferritic steels, an austenitic stainless steel, a nickel base superalloy and Zircaloy in different thermo-mechanical conditions. The effects of aging and cold work on these properties were determined from the ABI tests. Gradients in mechanical properties of ferritic steel welds, particularly in the narrow heat-affected zone, were clearly established. ABI technique was found to be useful in determining the anisotropy in the tensile properties of Zircaloy cladding tubes. The technique has potential as a non-destructive method for assessing structural integrity of aged components. (authors)

  3. Utilization of aluminum to obtaining a duplex type stainless steel using high energy ball milling; Obtencao de um aco inoxidavel de estrutura duplex do sistema FeMnAl processado por moagem de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Pavlak, I.E.; Cintho, O.M., E-mail: eng.igorpavlak@yahoo.com.b [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Capocchi, J.D.T. [Universidade de Sao Paulo (USP), SP (Brazil)

    2010-07-01

    The obtaining of stainless steel using aluminum in its composition - FeMnAl system, has been researches subject since the sixties, by good mechanical properties and resistance to oxidation presented, when compared with conventional FeNiCr stainless steel system. In another point, the aluminum and manganese are low cost then traditional elements. This work, metallic powders of iron, manganese and pure aluminum, were processed in a Spex type high-energy ball mill in nitrogen atmosphere. The milling products were compressed into pastille form and sintered under inert atmosphere. The final products were characterized by optical and electronic microscopy and microhardness test. The metallographic analysis shows a typical austenite and ferrite duplex type microstructure. The presence of these phases was confirmed according X ray diffraction analysis. (author)

  4. 球头铣刀铣削斜面的三维有限元仿真研究%Investigation on 3D Finite Element Analysis of Ball-end Milling with Tool-workpiece Inclination

    Institute of Scientific and Technical Information of China (English)

    董永旺; 赵军; 陈晓晓; 郭胜光; 李安海

    2012-01-01

    在能源动力、汽车、航空航天、模具制造等关键零部件的加工过程中,球头铣刀因其特有的刀具几何结构,常作为零件加工的最终成型刀具.考虑到在球头铣刀立铣加工中不同的刀具与工件相对姿态会对切削过程产生不同的影响,本文研究切屑形成和不同走刀方式下切削过程中各物理量(切削力、切削温度等)的变化情况,结合有限元仿真技术在切削加工中的应用,建立硬质合金球头铣刀铣削斜面的有限元模型,模拟相同切削参数下,八种不同走刀方式的球头铣削过程,分析刀具切入切出工件时切屑的形成过程,探究切削力和切削温度的变化规律.仿真结果表明:不同的走刀方式,平均切削合力各不相同,同时切屑和工件的最大切削温度也出现较大差异,而斜坡上坡逆铣的走刀方式所对应的平均切削合力和最大切削温度均最优.%In the manufacturing process of key components involving the fields of energy power, automotive) aerospace, and mould making, ball end mill often acts as the final cutting tool for processing the parts because of its special milling cutter geometrical structure. Considering that different tool-workpiece postures would produce different effects on the machining process in ball end milling process, this paper mainly focused on the chips formation process and the variation conditions of physical quantities (cutting forces and cutting temperature) in cutting process under different machining strategies. Combining the application of the finite element simulation technology in cutting process, the finite element model with regard to the cemented carbide ball end mill machining the surface with the feature of inclination angle was developed. The ball end milling processes with eight different tool path modes corresponding to the same cutting parameters were simulated, and the chip formation process when the cutter cutting into and cutting out the

  5. Thermodynamic and structural properties of ball-milled mixtures composed of nano-structural graphite and alkali(-earth) metal hydride

    International Nuclear Information System (INIS)

    Hydrogen desorption properties of mechanically milled materials composed of nano-structural hydrogenated-graphite (CnanoH x) and alkali(-earth) metal hydride (MH; M = Na, Mg and Ca) were investigated from the thermodynamic and structural points of view. The hydrogen desorption temperature for all the CnanoH x and MH composites was obviously lower than that of the corresponding each hydride. In addition, the desorption of hydrocarbons from CnanoH x was significantly suppressed by making composite of CnanoH x with MH, even though CnanoH x itself thermally desorbs a considerably large amount of hydrocarbons. These results indicate that an interaction exists between CnanoH x and MH, and hydrogen in both the phases is destabilized by a close contact between polar C-H groups in CnanoH x and the MH solid phase. Moreover, a new type of chemical bonding between the nano-structural carbon (Cnano) and the Li, Ca, or Mg metal atoms may be formed after hydrogen desorption. Thus, the above metal-C-H system would be recognized as a new family of H-storage materials

  6. RESEARCH ON THE STUDY OF MATERIAL DEFECTS AND SOMECOAL MILLS SUBASSEMBLIES LIFE TIME

    Directory of Open Access Journals (Sweden)

    Cristina LAPADUSI

    2013-05-01

    Full Text Available The defectsfrom the structureof metallic materials of whichare manufactured the pieces, canbeputoutbyNDT. One ofNDTmethods, commonly usedin practiceisultrasonicmethod.In this paper are rendered the results of the determinations by the effects of coal mills bars by type DGS 100,obtained with ultrasound devices by type PHASOR XS.

  7. Compressibility of nanostructured Fe-Cu materials prepared by mechanical milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J.S.; Gerward, Leif;

    1999-01-01

    The compressibility of nanostructured Fe-Cu materials prepared by mechanical milling has been investigated by in-situ high-pressure x-ray diffraction using synchrotron radiation. It is found that the bulk modulus of both fcc-Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable...

  8. Effects of Milling on the Fibrous Structure and Mechanical Behaviors of a Collagen Material--Leather

    Science.gov (United States)

    Leather, a fibrous collagen material, is a high value coproduct of the meat industry. Milling is being practiced in the tannery to mechanically tumble and therefore soften leather for adequate stiffness and feel. However, there is no report regarding its effects on the structure change and physica...

  9. Fast and slow dehydrogenation of ball milled lithium alanate (LiAlH{sub 4}) catalyzed with manganese chloride (MnCl{sub 2}) as compared to nanometric nickel catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Varin, R.A., E-mail: ravarin@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, N2L 3G1 (Canada); Zbroniec, L. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, N2L 3G1 (Canada)

    2011-09-15

    Research highlights: > Dehydrogenation behavior of ball milled LiAlH{sub 4} with 5 wt.% of MnCl{sub 2} catalytic precursor are reported. > A small amount of hydrogen desorbs during milling although no products of the possible reaction between LiAlH{sub 4} and MnCl{sub 2} (e.g. LiCl) are observed by X-ray diffraction. > In a DSC test most of LiAlH{sub 4} decomposes exothermically to Li{sub 3}AlH{sub 6} in a solid state while a small fraction of retained LiAlH{sub 4} melts and decomposes in a liquid state. > At 100 deg. C under 0.1 MPa H{sub 2} the ball milled LiAlH{sub 4} + 5 wt.% MnCl{sub 2} nanocomposite is able to desorb {approx}4.6 wt.% H{sub 2} within {approx}30,000 s in a solid state (LiAlH{sub 4} (solid){yields}1/3Li{sub 3}AlH{sub 6} + 2/3Al + H{sub 2}). > The apparent activation energy of dehydrogenation for this solid state reaction is equal to {approx}80 kJ/mol. > During decomposition at 100 deg. C a chemical reaction occurs between LiAlH{sub 4} and MnCl{sub 2} producing LiCl and most likely an amorphous Mn metal catalyzing the reaction. > The ball milled LiAlH{sub 4} + 5 wt.% MnCl{sub 2} nanocomposite is capable of desorbing substantial quantities of H{sub 2} during long term storage at room temperature (RT; {approx}21 deg. C), 40 and 80 deg. C. - Abstract: The results of the studies on the dehydrogenation behavior of the ball milled LiAlH{sub 4} catalyzed with 5 wt.% of manganese chloride (MnCl{sub 2}) are reported. During ball milling for 15 min the LiAlH{sub 4} + 5 wt.% MnCl{sub 2} nanocomposite releases a miniscule amount of {approx}0.25 wt.% H{sub 2}. However, no products of the possible reaction between LiAlH{sub 4} and MnCl{sub 2} (e.g. LiCl) are observed by X-ray diffraction (XRD). In a DSC test most of LiAlH{sub 4} decomposes exothermically to Li{sub 3}AlH{sub 6} in a solid state while a small fraction of retained LiAlH{sub 4} melts and decomposes in a liquid state. During dehydrogenation at 100 deg. C under 0.1 MPa H{sub 2} the ball milled Li

  10. Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

    International Nuclear Information System (INIS)

    Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions. (author)

  11. Analytical Prediction of Three Dimensional Chatter Stability in Milling

    Science.gov (United States)

    Altintas, Yusuf

    The chip regeneration mechanism during chatter is influenced by vibrations in three directions when milling cutters with ball end, bull nose, or inclined cutting edges are used. A three dimensional chatter stability is modeled analytically in this article. The dynamic milling system is formulated as a function of cutter geometry, the frequency response of the machine tool structure at the cutting zone in three Cartesian directions, cutter engagement conditions and material property. The dynamic milling system with nonlinearities and periodic delayed differential equations is reduced to a three dimensional linear stability problem by approximations based on the physics of milling. The chatter stability lobes are predicted in the frequency domain using the proposed analytical solution, and verified experimentally in milling a Titanium alloy with a face milling cutter having circular inserts.

  12. Transfer of molybdenum sulphide coating material onto corundum balls in fretting wear tests

    International Nuclear Information System (INIS)

    Transfer films on corundum balls from sulfur deficient molybdenum disulfide (MoSx) coatings with different crystallographic orientations were investigated after fretting tests performed in ambient air of different humidity levels. The morphology of wear tracks on MoSx coatings and of transfer films on corundum balls were investigated by light optical microscopy with Normarski contrast. The thickness of transfer films was measured by scanning white light and optical phase-shifting interferometry, and their composition was analyzed by X-ray photoelectron spectroscopy. The effect of relative humidity in fretting tests on the composition of the transfer films as well as the effect of the transfer film on the tribological performance of MoSx coatings in fretting wear tests is discussed

  13. Effect of Milling on the Mechanical Properties of Chopped SiC Fiber-Reinforced ZrB2

    Directory of Open Access Journals (Sweden)

    S. Guicciardi

    2013-05-01

    Full Text Available This work aims at studying the effect of the milling conditions on the microstructure and mechanical properties of a ZrB2-5 vol% Si3N4 matrix reinforced with chopped Hi-Nicalon SiC fibers. Several composites were obtained using different milling conditions in terms of time, speed and type of milling media. The composites were prepared from commercial powders, ball milled, dried and shaped, and hot pressed at 1720 °C. Their relative bulk densities achieved values as high as 99%. For each material the fiber length distribution, the extent of reacted fiber area and matrix mean grain size were evaluated in order to ascertain the effects of milling time, milling speed and type of milling media. While the fracture toughness and hardness were statistically the same independently of the milling conditions, the flexural strength changed. From the results obtained, the best milling conditions for optimized mechanical properties were determined.

  14. Mechanical Activation of Construction Binder Materials by Various Mills

    Science.gov (United States)

    Fediuk, R. S.

    2016-04-01

    The paper deals with the mechanical grinding down to the nano powder of construction materials. During mechanical activation a composite binder active molecules cement minerals occur in the destruction of the molecular defects in the areas of packaging and breaking metastable phase decompensation intermolecular forces. The process is accompanied by a change in the kinetics of hardening of portland cement. Mechanical processes during grinding mineral materials cause, along with the increase in their surface energy, increase the Gibbs energy of powders and, respectively, their chemical activity, which also contributes to the high adhesion strength when contacting them with binders. Thus, the set of measures for mechanical activation makes better use of the weight of components filled with cement systems and adjust their properties. At relatively low cost is possible to provide a spectacular and, importantly, easily repeatable results in a production environment.

  15. Clean and Efficient One-Pot Synthesis of New 2-Oxo-2,3-Dihydro-1H-Pyrrole-3-Carboxylic Acid and 2-Oxo-1,2-Dihydro-Pyridine-3-Carboxylic Acid Derivatives through Ball Milling under Catalyst-Free and Solvent-Free Conditions

    OpenAIRE

    Mohamed Ould M'hamed

    2015-01-01

    A high-yielding one-pot ball milling method for the synthesis of new 2-oxo-2,3-dihydro-1H-pyrrole-3-carboxylic acid and 2-oxo-1,2-dihydropyridine- 3-carboxylic acid was developed under solvent-free and catalystfree conditions. The proposed method is simple and has environmental and economic advantages.

  16. Mechanically milled aluminium matrix composites reinforced with halloysite nanotubes

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2012-12-01

    Full Text Available Purpose: The present work describes fabrication of aluminium AlMg1SiCu matrix composite materials reinforced with halloysite nanotubes by powder metallurgy techniques and hot extrusion.Design/methodology/approach: Mechanical milling, compacting and hot extrusion successively are considering as a method for manufacturing metal composite powders with a controlled fine microstructure and enhanced mechanical properties. It is possible by the repeated welding and fracturing of powders particles mixture in a highly energetic ball mill.Findings: The milling process has a huge influence on the properties of powder materials, changing the spherical morphology of as-received powder during milling process to flattened one due to particle deformation followed by welding and fracturing particles of deformed and hardened enough which allows to receive equiaxial particles morphology again. The investigation shows that so called brittle mineral particles yields to plastic deformation as good as ductile aluminium alloy particles. That indicates that the halloysite powder can play a role of the accelerator during mechanical milling. High energy ball milling as a method of mechanical milling improves the distribution of the halloysite reinforcing particles throughout the aluminium matrix, simultaneously reducing the size of particles. The apparent density changes versus milling time can be used to control the composite powders production by mechanical milling and the presence of halloysite reinforcements particles accelerates the mechanical milling process.Research limitations/implications: Contributes to knowledge about technology, structure and properties of aluminium alloy matrix composite material reinforced with mineral nanoparticles.Practical implications: Conducted research shows that applied technology allows obtaining very good microstructural characteristics.Originality/value: It has been confirmed that halloysite nanotubes can be applied as an effective

  17. Synthesis of the hydride mixtures (1 - x)AlH3/xMgH2 (0 ≤ x ≤ 0.3) by ball milling and their hydrogen storage properties

    International Nuclear Information System (INIS)

    In an effort to thermodynamically stabilize the alane (i.e., to increase the desorption enthalpy), partial substitution of Mg for Al was investigated by ball milling the mixtures (1 - x)AlH3/xMgH2 (x = 0.1, 0.2 and 0.3). Rietveld analysis of the XRD profiles showed that the cell volume of α-AlH3 increased with the Mg substitution rate, and thereby formation of solid solutions was assumed (x ≤ 0.05). In agreement with the experimental results, theoretical calculations indicated that a hypothetical supercell structure (MgAl15)H47 (x = 0.0625), which contained a hydrogen vacancy, was at least metastable. However, the effect of alane stabilization by Mg substitution for Al was not observed, either by experiment or by simulation, and only an increase in the activation energy was measured.

  18. Geochemical characterization of geologic materials beneath the proposed Burro Canyon uranium mill tailing disposal cell

    International Nuclear Information System (INIS)

    Geologic materials from beneath the proposed Burro Canyon uranium mill tailings disposal site near Slick Rock, Colorado, were characterized to determine hydraulic and geochemical properties. These parameters are crucial to predict if uranium mill tailings leachate represents a potential threat to underlying groundwater resources. Batch tests were conducted to determine the reactivity of geologic materials with respect to molybdenum, selenium, and uranium. Distribution coefficients for Se, Mo, and U are less than 1, indicating low attenuation. Analysis of the -2 μ fraction of the Burro Canyon Formation mudstone indicates that illites and glauconite are the major phases with minor montmorillonite and kaolinite. Adsorption of Mo, Se, and U onto clay minerals as a mechanism of attenuation is discussed. (author)

  19. Production of Stell Ball for E-type Coal Mill by Lost Foam Casting and Its Numerical Simulation%E型磨煤机钢球消失模铸造工艺及数值模拟

    Institute of Scientific and Technical Information of China (English)

    刘瑞丽; 叶升平; 薛国祯; 孙爱民

    2012-01-01

    用消失模工艺铸造E型磨煤机用耐磨空心钢球,设计了侧注、顶注两种工艺方案,并用华铸CAE分析系统对两种方案进行充型和凝固模拟,并对两种方案的模拟结果进行分析和对比.另将试验结果和模拟结果作对比.分析了在铸造大型空心钢球方面,用消失模工艺方法生产的优势和劣势.%A wear-resistant hollow stell ball for E-type coal mill was produced by lost foam casting process. Two pouring schemes including the top pouring and the side pouring were designed. The filling and solidification of the two schemes were simulated by the Huazhu CAE software. The simulated results were analyzed comparatively. And the experiment results were well in agreement with the simulated ones. The advantages and disadvantages of producing large wear-resistant hollow steel ball with lost foam casting process were described.

  20. Regression Models of Force in Milling Sandwich Polymer Composites Materials – Benefit for Marketing

    OpenAIRE

    ILIESCU Mihaiela; BIVOLARU Cătălina

    2012-01-01

    The latest trends in materials’ development proof that sandwich polymer composites do stay on top of materials, due to their interesting and special characteristics. Being used in various industrial filed, as automotive or spatial industries, this type ofmaterials usually needs their rough edges to be machined. So, milling is widely used and therefore, the forces involved by the process must be known. For designing experiments and determining the forceregression models, applied statistics met...

  1. Structural and magnetic properties of nanostructured (Fe70Co30)100−xCux alloy prepared by high energy ball milling

    International Nuclear Information System (INIS)

    Highlights: ► The Fe70–Co30 alloys are well known in having very high saturation magnetization. ► It has shown that Cu has a great effect in reducing the required milling time to accomplish solid solution process. ► Adding Cu to the alloy has led to crystallite size refinement and therefore has improved the magnetic properties. -- Abstract: In the present work, structural and magnetic properties of nanocrystalline (Fe70Co30)100−xCux (x = 0, 5, 9) powders produced by mechanical alloying (MA) have been Investigated. These properties were investigated by X-ray diffraction(XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). According to the results, a body-centered cubic nanostructured (Fe70Co30)91Cu9 alloy with an average crystallite size of about 13 nm has been produced by milling for 32 h. Whereas, in (Fe70Co30)95Cu5 and (Fe70Co30) the alloying process has accomplished after 45 h milling. It is found that Cu speeds up the formation of a bcc phase with finer microstructure (D = 12 nm for x = 9). With increasing the milling time, the crystallite size has decreased for all powders. Increase in microstrain was observed with increasing the milling time and also with increasing Cu content. The magnetic measurements show a contrasting saturation magnetization and coercivity (Hc) in Fe–Co–Cu alloys. These variations are explained on the basis of crystallite size and strain variations in the samples during milling.

  2. Holy balls!

    OpenAIRE

    Wright, Michael; Langley, Ken; Belden, Jesse; Truscott, Tadd

    2011-01-01

    We demonstrate the behavior of three balls skipping off of the water surface: a Superball, a racquetball, and a water bouncing ball (Waboba). The three balls have rebound coefficients of 0.9, 0.8 and 0.2, respectively. However, we notice that the Waboba bounces better than the others, but why? The Superball has a high coefficient of restitution, creating large rebounds. Here the impact is angled to the free surface, but the inelastic response and large mass ratio forces the ball underwater wi...

  3. Crystallization degree change of expanded graphite by milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Tang Qunwei [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China); Wu Jihuai [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China)], E-mail: jhwu@hqu.edu.cn; Sun Hui; Fang Shijun [Key Laboratory for Functional Materials of Fujian Higher Education, Institute of Material Physical Chemistry, Huaqiao University, Quanzhou 362021 (China)

    2009-05-05

    Expanded graphite was ball milled with a planetary mill in air atmosphere, and subsequently thermal annealed. The samples were characterized by using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). It was found that in the milling initial stage (less than 12 h), the crystallization degree of the expanded graphite declined gradually, but after milling more than 16 h, a recrystallization of the expanded graphite toke place, and ordered nanoscale expanded graphite was formed gradually. In the annealing initial stage, the non-crystallization of the graphite occurred, but, beyond an annealing time, recrystallizations of the graphite arise. Higher annealing temperature supported the recrystallization. The milled and annealed expanded graphite still preserved the crystalline structure as raw material and hold high thermal stability.

  4. Hydrogen storage performances of LaMg11Ni + x wt% Ni (x = 100, 200) alloys prepared by mechanical milling

    International Nuclear Information System (INIS)

    Highlights: • Amorphous and nanostructured alloys were prepared by mechanical milling. • The maximum discharge capacity of ball milled alloys reaches to 1053.5 mA h/g. • The addition of Ni significantly increases the discharge capacity. • Increasing milling time reduces the kinetic performances of ball milled alloys. - Abstract: In order to improve the hydrogen storage performances of Mg-based materials, LaMg11Ni alloy was prepared by vacuum induction melting. Then the nanocrystalline/amorphous LaMg11Ni + x wt% Ni (x = 100, 200) hydrogen storage alloys were synthesized by ball milling technology. The structure characterizations of the alloys were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical hydrogen storage characteristics were tested by using programmed control battery testing system. The electrochemical impedance spectra (EIS), potentiodynamic polarization curves and potential-step curves were also plotted by an electrochemical workstation (PARSTAT 2273). The results indicate that the as-milled alloys exhibit a nanocrystalline and amorphous structure, and the amorphization degree of the alloys visibly increases with extending milling time. Prolonging the milling duration markedly enhances the electrochemical discharge capacity and cyclic stability of the alloys. The electrochemical kinetics, including high rate discharge ability (HRD), charge transfer rate, limiting current density (IL), hydrogen diffusion coefficient (D), monotonously decrease with milling time prolonging

  5. Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

    Directory of Open Access Journals (Sweden)

    N. V. Dhandapani

    2015-01-01

    Full Text Available This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

  6. Characterization of Al2O3NP–Al2024 and AgCNP–Al2024 composites prepared by mechanical processing in a high energy ball mill

    International Nuclear Information System (INIS)

    Graphical abstract: Mechanical alloying was used to produce two kinds of metal matrix composites based on 2024 aluminum alloy, the nanocomposites were reinforced with different percentages of Al2O3 and AgC nanoparticles. The content of nanoparticles has a role important on the mechanical properties of the nanocomposite. 10 h of milling time are enough to former the Al2024 nanocomposites. The results obtained by differential scanning calorimeter show the temperatures of intermetallic precipitation, which were identified by X-ray diffraction. The results revealed that mechanical alloying is an excellent route to incorporate and distribute NP into Al2024. Highlights: ► Aluminum-based nanocomposites were synthesized bay milling process. ► An homogeneous nanoparticles dispersion was reached and mechanical properties were enhanced. ► Phase transformation during heating was characterized by XRD. - Abstract: Mechanical alloying was used to produce two kinds of metal matrix composites based on 2024 aluminum alloy. The nanocomposites were reinforced with different percentages of Al2O3 and AgC nanoparticles. The content of nanoparticles has an important role on the mechanical properties of the nanocomposites. A milling time of 10 h is enough to form the Al2024 nanocomposites. The thermograms obtained by differential scanning calorimeter show the temperatures of phase precipitation, which were identified by X-ray diffraction. The results revealed that mechanical alloying is an excellent route for the incorporation and distribution of nanoparticles into Al2024.

  7. Influence of Milling Media on Mechanically Exfoliated MoS2

    OpenAIRE

    Marek Kostecki; Elżbieta Jezierska

    2014-01-01

    Wet ball milling was used to exfoliate MoS2. The aim of the study was to examine how the surface energy of all the individual materials affected the formation of the nanosheets. Two types of milling balls were selected: one made of steel and one made of Al2O3. The liquids used were water (H2O), isopropyl alcohol (C3H8O) and kerosene. The obtained nanosheets were identified and characterized using transmission/scanning electron microscopy and electron diffraction. Follo...

  8. Processing of Polysulfone to Free Flowing Powder by Mechanical Milling and Spray Drying Techniques for Use in Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Nicolas Mys

    2016-04-01

    Full Text Available Polysulfone (PSU has been processed into powder form by ball milling, rotor milling, and spray drying technique in an attempt to produce new materials for Selective Laser Sintering purposes. Both rotor milling and spray drying were adept to make spherical particles that can be used for this aim. Processing PSU pellets by rotor milling in a three-step process resulted in particles of 51.8 μm mean diameter, whereas spray drying could only manage a mean diameter of 26.1 μm. The resulting powders were characterized using Differential Scanning Calorimetry (DSC, Gel Permeation Chromatography (GPC and X-ray Diffraction measurements (XRD. DSC measurements revealed an influence of all processing techniques on the thermal behavior of the material. Glass transitions remained unaffected by spray drying and rotor milling, yet a clear shift was observed for ball milling, along with a large endothermic peak in the high temperature region. This was ascribed to the imparting of an orientation into the polymer chains due to the processing method and was confirmed by XRD measurements. Of all processed powder samples, the ball milled sample was unable to dissolve for GPC measurements, suggesting degradation by chain scission and subsequent crosslinking. Spray drying and rotor milling did not cause significant degradation.

  9. Jet milling from a particle perspective : predicting particle fracture based on mechanical material properties

    NARCIS (Netherlands)

    Vegt, Onno Martinus

    2007-01-01

    Milling is a very old discipline originated in milling agricultural products to flour. Despite the enormous literature on size reduction, milling is a unit operation which has no sound underlying theory comparable to those existing for other unit operations. The design of milling equipment for a giv

  10. Jet milling from a particle perspective: predicting particle fracture based on mechanical material properties

    OpenAIRE

    Vegt, Onno Martinus

    2007-01-01

    Milling is a very old discipline originated in milling agricultural products to flour. Despite the enormous literature on size reduction, milling is a unit operation which has no sound underlying theory comparable to those existing for other unit operations. The design of milling equipment for a given application is based on accumulated experiences of the manufactures. It is not for lack of either interest or investigation that a quantitative theory of milling does not exist. In contrast, the...

  11. Surface state of Inconel 718 ultrasonic shot peened: Effect of processing time, material and quantity of shot balls and distance from radiating surface to sample

    International Nuclear Information System (INIS)

    Research highlights: → As USP processing time increases more compressive surface stresses are induced until a saturation level is reached. → The distance between part and radiating surface notably influences the surface state. → A greater number of shot balls leads to less impacts of lower energy on the part surface. → Surface nanocrystallization can only be achieved with large impacting energies of the balls. -- Abstract: Plates of Inconel 718 in precipitated state have been subjected to ultrasonic shot peening (USP), varying the distance from the radiating surface of the booster to the sample, the processing time and the material (WC/Co and steel) and number of shot balls, in order to study the effect of these parameters on the final state generated by the USP process. A change to more compressive residual stresses at the surface of the treated parts has been measured in all cases. For higher USP processing times and/or lower booster-sample distances, the degree of plastic deformation in the treated material increases, leading to a change to more compressive surface stresses and a higher density of impact marks in the treated surface. The same occurs when WC/Co balls are used instead of steel balls. The tendency to more compressive stresses reaches a saturation level after a certain processing time, when the system is not able to force the material to continue with more plastic deformation. If a higher quantity of balls is used, there will be less impacts of the shots with the surface and their energy will be lower (due to losses of energy after inelastic collisions). This diminishes the effect of the impacts in introducing compressive stresses and leads to less and shallower impact marks in the treated surface.

  12. Holy balls!

    Science.gov (United States)

    Truscott, Tadd; Belden, Jesse

    2011-11-01

    Why can some balls walk on water while others cannot? We investigate the rebound dynamics of elastic spheres impacting on a free-surface. Several variables determine whether or not a sphere will bounce when impacting a free-surface including velocity, impact angle, size and elasticity. Stiff elastic spheres, such as a racquetball, successfully skip at low impact angles and high velocities, but tend not to bounce when the impact angle becomes too large. However, the more compliant Waboba (WAter BOuncing BAll) bounces marvelously even at very high impact angles. Unlike a stiffer ball, the Waboba flattens out quickly as it is forming a cavity. The cavity lip forms a ramp and the flattened ball then skips off the water surface. We demonstrate how this phenomenon surprisingly resembles a skipping stone. Using high-speed video we explore the rebound dynamics for various values of elasticity, velocity, angle and size and determine when an object will bounce off the water surface.

  13. plasma ball

    CERN Multimedia

    When you touch the ball, by earthing the surface, you increase the voltage difference between it and the centre. So more electrons flow through the gas at that point, creating the filaments of light you see.

  14. Golf Ball

    Science.gov (United States)

    1998-01-01

    The Ultra 500 Series golf balls, introduced in 1995 by Wilson Sporting Goods Company, has 500 dimples arranged in a pattern of 60 spherical triangles. The design employs NASA's aerodynamics technology analysis of air loads of the tank and Shuttle orbiter that was performed under the Space Shuttle External Tank program. According to Wilson, this technology provides 'the most symmetrical ball surface available, sustaining initial velocity longer and producing the most stable ball flight for unmatched accuracy and distance.' The dimples are in three sizes, shapes and depths mathematically positioned for the best effect. The selection of dimples and their placement optimizes the interaction of opposing forces of lift and drag. Large dimples reduce air drag, enhance lift, and maintain spin for distance. Small dimples prevent excessive lift that destabilizes the ball flight and the medium size dimples blend the other two.

  15. Design and implementation of a system for laser assisted milling of advanced materials

    Science.gov (United States)

    Wu, Xuefeng; Feng, Gaocheng; Liu, Xianli

    2016-04-01

    Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining properties for laser assisted milling(LAML), few attempts have been made to extend LAML to machining parts with complex geometric features. A methodology for continuous path machining for LAML is developed by integration of a rotary and movable table into an ordinary milling machine with a laser beam system. The machining strategy and processing path are investigated to determine alignment of the machining path with the laser spot. In order to keep the material removal temperatures above the softening temperature of silicon nitride, the transformation is coordinated and the temperature interpolated, establishing a transient thermal model. The temperatures of the laser center and cutting zone are also carefully controlled to achieve optimal machining results and avoid thermal damage. These experiments indicate that the system results in no surface damage as well as good surface roughness, validating the application of this machining strategy and thermal model in the development of a new LAML system for continuous path processing of silicon nitride. The proposed approach can be easily applied in LAML system to achieve continuous processing and improve efficiency in laser assisted machining.

  16. Pengaruh Lama Miling Terhadap Sifat Absorpsi Material Penyimpan Hidrogen MgH2 yang Dikatalisasi Dengan Fe (The Role of Milling Time on the Absorption Behaviour of MgH2 Catalyzed by Fe

    Directory of Open Access Journals (Sweden)

    Mustanir Mustanir

    2009-12-01

    Full Text Available Hidrida logam berbasis MgH2 dengan sisipan 1 wt% katalis Fe telah berhasil disintesis dengan teknik ball milling. Hasil proses miling selama 80 jam menunjukkan bahwa ukuran butir material telah membentuk struktur nanokristal. Hal ini ditunjukkan oleh profil difraksi sinar-X dimana terjadi pelebaran puncakpuncak difraksinya dengan meningkatnya waktu miling. Hasil uji absorpsi secara gravimetrik diketahui bahwa MgH2 berkatalis 1 wt% Fe mampu menyerap hydrogen sebesar 5,5 wt% dalam waktu ~20 menit pada temperatur 300 oC. Hasil ini sekaligus memperlihatkan bahwa sejumlah kecil katalis Fe bekerja secara baik dalam memperbaiki sifat absorpsi material penyimpan hydrogen berbasis Mg.(Metal hydrides are of great interest as hydrogen storage media especially for automotive application. Hydrides of magnesium and magnesium alloys are particularly attractive as they combine potentially high hydrogen storage capacities, 7.6 wt%. But, unfortunately, the sorption properties are poor. For example, conventional hydrogenation of magnesium requires prolonged treatment at temperatures of 300 oC and above. Here, we report the absorption properties of MgH2 catalyzed with a small amount of Fe element (1wt% under argon atmosphere prepared by ball milling in 80 hours. As the results, it showed the influence of milling time on the absortion kinetics of material which could absorp hydrogen in amount 5.5 within 20 minutes at 300 oC. It is obvious that longer milling time and small amount of catalyst could improve the sorption properties of Mg-based hydrides. © 2009 BCREC UNDIP. All rights reserved[Received: 13rd November 2009, Revised: 25th December 2009, Accepted: 31st December 2009][How to Cite: M. Mustanir, Z. Jalil. (2009. Pengaruh Lama Miling Terhadap Sifat Absorpsi Material Penyimpan Hidrogen MgH2 yang Dikatalisasi Dengan Fe (The Role of Milling Time on the Absorption Behaviour of MgH2 Catalyzed by Fe. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 69

  17. Pengaruh Lama Miling Terhadap Sifat Absorpsi Material Penyimpan Hidrogen MgH2 yang Dikatalisasi Dengan Fe (The Role of Milling Time on the Absorption Behaviour of MgH2 Catalyzed by Fe

    Directory of Open Access Journals (Sweden)

    Mustanir Mustanir

    2009-12-01

    Full Text Available Hidrida logam berbasis MgH2 dengan sisipan 1 wt% katalis Fe telah berhasil disintesis dengan teknik ball milling. Hasil proses miling selama 80 jam menunjukkan bahwa ukuran butir material telah membentuk struktur nanokristal. Hal ini ditunjukkan oleh profil difraksi sinar-X dimana terjadi pelebaran puncakpuncak difraksinya dengan meningkatnya waktu miling. Hasil uji absorpsi secara gravimetrik diketahui bahwa MgH2 berkatalis 1 wt% Fe mampu menyerap hydrogen sebesar 5,5 wt% dalam waktu ~20 menit pada temperatur 300 oC. Hasil ini sekaligus memperlihatkan bahwa sejumlah kecil katalis Fe bekerja secara baik dalam memperbaiki sifat absorpsi material penyimpan hydrogen berbasis Mg.(Metal hydrides are of great interest as hydrogen storage media especially for automotive application. Hydrides of magnesium and magnesium alloys are particularly attractive as they combine potentially high hydrogen storage capacities, 7.6 wt%. But, unfortunately, the sorption properties are poor. For example, conventional hydrogenation of magnesium requires prolonged treatment at temperatures of 300 oC and above. Here, we report the absorption properties of MgH2 catalyzed with a small amount of Fe element (1wt% under argon atmosphere prepared by ball milling in 80 hours. As the results, it showed the influence of milling time on the absortion kinetics of material which could absorp hydrogen in amount 5.5 within 20 minutes at 300 oC. It is obvious that longer milling time and small amount of catalyst could improve the sorption properties of Mg-based hydrides. © 2009 BCREC UNDIP. All rights reserved[Received: 13rd November 2009, Revised: 25th December 2009, Accepted: 31st December 2009][How to Cite: M. Mustanir, Z. Jalil. (2009. Pengaruh Lama Miling Terhadap Sifat Absorpsi Material Penyimpan Hidrogen MgH2 yang Dikatalisasi Dengan Fe (The Role of Milling Time on the Absorption Behaviour of MgH2 Catalyzed by Fe. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 69

  18. Processing of Polysulfone to Free Flowing Powder by Mechanical Milling and Spray Drying Techniques for Use in Selective Laser Sintering

    OpenAIRE

    Nicolas Mys; Ruben Van De Sande; An Verberckmoes; Ludwig Cardon

    2016-01-01

    Polysulfone (PSU) has been processed into powder form by ball milling, rotor milling, and spray drying technique in an attempt to produce new materials for Selective Laser Sintering purposes. Both rotor milling and spray drying were adept to make spherical particles that can be used for this aim. Processing PSU pellets by rotor milling in a three-step process resulted in particles of 51.8 μm mean diameter, whereas spray drying could only manage a mean diameter of 26.1 μm. The resulting powder...

  19. Comparative evaluation of liner materials for inactive uranium-mill-tailings piles

    International Nuclear Information System (INIS)

    Under the funding of the Department of Energy's Uranium Mill Tailings Remedial Action (UMTRA) Program, Pacific Northwest Laboratory (PNL) has completed the initial accelerated testing phase of eight candidate liner materials. The tests were designed to comparatively evaluate the long term effectiveness of liner materials as a radionuclide and hazardous chemical leachate barrier. The eight materials tested were selected from a technical review of published literature and industrial specialists. Conditions were then identified that would accelerate the aging processes expected in a uranium tailings environment for 1000 years. High calcium leachates were forced through thin layers of clay liners to accelerate the ion exchange rate of sodium and calcium. Asphalt and synthetic materials were accelerated by exposure to elevate temperatures, high concentrations of oxygen, and increased strengths of aqueous oxidizing agents. By comparing the changes of permeability with time of exposure, the most acceptable materials were then identified. These materials are a catalytically airblown asphalt membrane and natural soil amended with sodium bentonite. Both materials showed an increased resistance to leachate penetration throughout the exposure period with final permeabilities less than 10-7 cm/s. In addition, the asphalt membrane and sodium bentonite are among the least expensive materials to install at a disposal site. Therefore based on their economic and technical merits, these two materials are being evaluated further in field tests at Grand Junction, Colorado

  20. Characterization of nanostructured alpha-Fe2O3-SnO2 solid solutions prepared by high energy ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lin, R.; Mørup, Steen

    Solid solutions of SnO2 in alpha-Fe2O3 with SnO2 contents up to 20+-4 mol% have been prepared by mechanical alloying of alpha-Fe2O3 and SnO2 powder blends. X-ray diffraction and Mossbauer spectroscopy investigations show that the mechanical milling results in alloying on an atomic scale and that...... true solid solution formation occurs. We suggest that the high defect concentration and the chemical enthalpy of Fe3+ -O2- -Sn4+ interfaces between nanostructured alpha-Fe2O3 and SnO2 regions may serve as a driving force for the formation of a solid solution in the immiscible ceramic system....

  1. Holy balls!

    CERN Document Server

    Wright, Michael; Belden, Jesse; Truscott, Tadd

    2011-01-01

    We demonstrate the behavior of three balls skipping off of the water surface: a Superball, a racquetball, and a water bouncing ball (Waboba). The three balls have rebound coefficients of 0.9, 0.8 and 0.2, respectively. However, we notice that the Waboba bounces better than the others, but why? The Superball has a high coefficient of restitution, creating large rebounds. Here the impact is angled to the free surface, but the inelastic response and large mass ratio forces the ball underwater without skipping. The racquetball has a lower mass ratio and a more elastic response to impacts. Also thrown at a shallow angle, it bounces off of the surface of the water 1-3 times before coming to rest. The Waboba flattens inside the cavity allowing it to skip off of the surface more easily. The flattened ball looks more like a skipping stone than a sphere due to its large elastic deformation at impact. Examining the reaction of a skipping stone we see that the stone creates a cavity in which it planes, slipping out of it...

  2. New technology for recycling materials from oily cold rolling mill sludge

    Institute of Scientific and Technical Information of China (English)

    Bo Liu; Shen-gen Zhang; Jian-jun Tian; De-an Pan; Ling Meng; Yang Liu

    2013-01-01

    Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of“hydrometallurgical treatment+hydrothermal synthesis”was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, eff ective, and economical technology off ers a new way to recycle oily CRM sludge.

  3. Comparative study on the corrosion behavior of milled and unmilled magnesium by electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    The corrosion behavior of milled Mg prepared by high-energy ball milling for 10 h has been investigated in alkaline solutions by electrochemical impedance spectroscopy and compared with that of unmilled Mg. X-ray powder diffraction indicates a crystallite size of 34 nm for the milled Mg compared to >100 nm for the unmilled powder. Chemical analyses show no significant iron contamination in milled Mg powder, indicating the absence of tools erosion during the milling procedure. In contrast, significant MgO enrichment in the milled powder is observed (6.5 wt.% after 10 h milling compared to 1.0 wt.% before milling). The oxygen contamination is mainly attributed to the powder oxidation occurring during milling. From XPS analyses, no MgO enrichment is detected on milled Mg electrode surface, confirming that MgO is dispersed homogeneously in the bulk of the material rather than to segregate on its surface. Electrochemical impedance spectroscopy demonstrates clearly the better corrosion resistance of milled Mg compared to unmilled Mg in passive conditions (KOH solution, pH=14) and in more active corrosion conditions (borate solution, pH=8.4). This is illustrated by a nobler corrosion potential and by a significant increase of the interfacial resistance related to the film and charge-transfer reaction. Moreover, the variation of the different electrochemical parameters (corrosion potential, interfacial resistance and capacitance) with immersion time is less accentuated and tends more rapidly to a steady state with milled Mg, suggesting an enhancement of the Mg(OH)2 formation kinetic. The origin of the distinctive passivation behavior of ball-milled Mg is discussed

  4. Hydrogen storage performances of LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) alloys prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Wang, Haitao [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Zhai, Tingting; Yang, Tai; Yuan, Zeming; Zhao, Dongliang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China)

    2015-10-05

    Highlights: • Amorphous and nanostructured alloys were prepared by mechanical milling. • The maximum discharge capacity of ball milled alloys reaches to 1053.5 mA h/g. • The addition of Ni significantly increases the discharge capacity. • Increasing milling time reduces the kinetic performances of ball milled alloys. - Abstract: In order to improve the hydrogen storage performances of Mg-based materials, LaMg{sub 11}Ni alloy was prepared by vacuum induction melting. Then the nanocrystalline/amorphous LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) hydrogen storage alloys were synthesized by ball milling technology. The structure characterizations of the alloys were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical hydrogen storage characteristics were tested by using programmed control battery testing system. The electrochemical impedance spectra (EIS), potentiodynamic polarization curves and potential-step curves were also plotted by an electrochemical workstation (PARSTAT 2273). The results indicate that the as-milled alloys exhibit a nanocrystalline and amorphous structure, and the amorphization degree of the alloys visibly increases with extending milling time. Prolonging the milling duration markedly enhances the electrochemical discharge capacity and cyclic stability of the alloys. The electrochemical kinetics, including high rate discharge ability (HRD), charge transfer rate, limiting current density (I{sub L}), hydrogen diffusion coefficient (D), monotonously decrease with milling time prolonging.

  5. Tunguska Dark Matter Ball

    CERN Document Server

    Froggatt, C D

    2014-01-01

    It is suggested that the Tunguska event in June 1908 cm-large was due to a cm-large ball of a condensate of bound states of 6 top and 6 anti-top quarks containing highly compressed ordinary matter. Such balls are supposed to make up the dark matter as we earlier proposed. The expected rate of impact of this kind of dark matter ball with the earth seems to crudely match a time scale of 200 years between the impacts. The main explosion of the Tunguska event is explained in our picture as material coming out from deep within the earth, where it has been heated and compressed by the ball penetrating to a depth of several thousand km. Thus the effect has some similarity with volcanic activity as suggested by Kundt. We discuss the possible identification of kimberlite pipes with earlier Tunguska-like events. A discussion of how the dark matter balls may have formed in the early universe is also given.

  6. Superelastic Ball Bearings: Materials and Design to Avoid Mounting and Dismounting Brinell Damage in an Inaccessible Press-Fit Application-. I ; Design Approach

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam

    2015-01-01

    Ball bearings require proper fit and installation into machinery structures (onto shafts and into bearing housings) to ensure optimal performance. For some applications, both the inner and outer race must be mounted with an interference fit and care must be taken during assembly and disassembly to avoid placing heavy static loads between the balls and races otherwise Brinell dent type damage can occur. In this paper, a highly dent resistant superelastic alloy, 60NiTi, is considered for rolling element bearing applications that encounter excessive static axial loading during assembly or disassembly. A small (R8) ball bearing is designed for an application in which access to the bearing races to apply disassembly tools is precluded. First Principles analyses show that by careful selection of materials, raceway curvature and land geometry, a bearing can be designed that allows blind assembly and disassembly without incurring raceway damage due to ball denting. Though such blind assembly applications are uncommon, the availability of bearings with unusually high static load capability may enable more such applications with additional benefits, especially for miniature bearings.

  7. Sub-micron scale relief structures of GMR materials fabricated by half-milling control

    International Nuclear Information System (INIS)

    We have investigated the magneto-transport properties of a GMR material consisting of CoPt(10 nm)/Cu(10 nm)/NiFe(6 nm) in which only the top NiFe layer is patterned by the half-milling technique. The top NiFe film was structured into a two-dimensional particle array with lateral dimensions of w=0.2 μm and aspect ratio L/w=1, 2, 4 or 8. From MR measurements, the remanent magnetization of the NiFe particle array was found to gradually decrease with L/w, which can be ascribed to the relative increase of an end domain area in the particles. The longitudinal switching field Hswt markedly decreases as L/wswt was caused by the change of switching configuration from an edge reversal to a coherent rotation with decreasing L/w

  8. Dropping the Ball: The effect of anisotropic granular materials on ejecta and impact crater shape

    CERN Document Server

    Drexler, Philip; Arratia, Paulo

    2013-01-01

    In this fluid dynamics video, we present an experimental investigation of the shape of impact craters in granular materials. Complex crater shapes, including polygons, have been observed in many terrestrial planets as well as moons and asteroids. We release spherical projectiles from different heights above a granular bed (sand). The experiments demonstrate two different techniques to create non-circular impact craters, which we measure by digitizing the final crater topography. In the first method, we create trenches in the sand to mimic fault lines or valleys on a planetary target. During impact, ejecta move faster in the direction of the trenches, creating nearly elliptical craters with the major axis running parallel to the trench. Larger trenches lead to more oblong craters. In the second method, a hose beneath the surface of the sand injects nitrogen gas. The pressure of the gas counters the hydrostatic pressure of the sand, greatly reducing static friction between grains above the injection point, with...

  9. Science of Ball Lightning (Fire Ball)

    Science.gov (United States)

    Ohtsuki, Yoshi-Hiko

    1989-08-01

    The Table of Contents for the full book PDF is as follows: * Organizing Committee * Preface * Ball Lightning -- The Continuing Challenge * Hungarian Ball Lightning Observations in 1987 * Nature of Ball Lightning in Japan * Phenomenological and Psychological Analysis of 150 Austrian Ball Lightning Reports * Physical Problems and Physical Properties of Ball Lightning * Statistical Analysis of the Ball Lightning Properties * A Fluid-Dynamical Model for Ball Lightning and Bead Lightning * The Lifetime of Hill's Vortex * Electrical and Radiative Properties of Ball Lightning * The Candle Flame as a Model of Ball Lightning * A Model for Ball Lightning * The High-Temperature Physico-Chemical Processes in the Lightning Storm Atmosphere (A Physico-Chemical Model of Ball Lightning) * New Approach to Ball Lightning * A Calculation of Electric Field of Ball Lightning * The Physical Explanation to the UFO over Xinjiang, Northern West China * Electric Reconnection, Critical Ionization Velocity, Ponderomotive Force, and Their Applications to Triggered and Ball Lightning * The PLASMAK™ Configuration and Ball Lightning * Experimental Research on Ball Lightning * Performance of High-Voltage Test Facility Designed for Investigation of Ball Lightning * List of Participants

  10. Steel balls forming by cross rolling with upsetting

    Directory of Open Access Journals (Sweden)

    Z. Pater

    2013-01-01

    Full Text Available The paper describes a process of forming four balls with a diameter of 22 mm by means of cross rolling with upsetting. The paper also presents the tool used to form semi-finished balls. Owing to the application of the finite element method (FEM, the course of the rolling process as well as temperature and strain distributions in the obtained balls could be presented. The rolling tests conducted in laboratory conditions at the Lublin University of Technology have proved that the balls produced with the developed rolling method meet the demands for grinding media used in ball mills.

  11. Steel mill products analysis using qualities methods

    Directory of Open Access Journals (Sweden)

    B. Gajdzik

    2016-10-01

    Full Text Available The article presents the subject matter of steel mill product analysis using quality tools. The subject of quality control were bolts and a ball bushing. The Pareto chart and fault mode and effect analysis (FMEA were used to assess faultiness of the products. The faultiness analysis in case of the bolt enabled us to detect the following defects: failure to keep the dimensional tolerance, dents and imprints, improper roughness, lack of pre-machining, non-compatibility of the electroplating and faults on the surface. Analysis of the ball bushing has also revealed defects such as: failure to keep the dimensional tolerance, dents and imprints, improper surface roughness, lack of surface premachining as well as sharp edges and splitting of the material.

  12. Simulation of water flow and retention in earthen-cover materials overlying uranium mill tailings

    International Nuclear Information System (INIS)

    The water retention characteristics of a multilayer earthen cover for uranium mill tailings were simulated under arid weather conditions common to Grand Junction, Colorado. The multilayer system described in this report consists of a layer of wet clay/gravel (radon barrier), which is separated from a surface covering of fill soil by a washed rock material used as a capillary barrier. The capillary barrier is designed to prevent the upward migration of water and salt from the tailings to the soil surface and subsequent loss of water from the wet clay. The flow model, UNSATV, described in this report uses hydraulic properties of the layered materials and historical climatic data for two years (1976 and 1979) to simulate long-term hydrologic response of the multilayer system. Application of this model to simulate the processes of infiltration, evaporation and drainage is described in detail. Simulations over a trial period of one relatively wet and two dry years indicated that the clay-gravel layer remained near saturation, and hence, that the layer was an effective radon barrier. Estimates show that the clay-gravel layer would not dry out (i.e., revert to drying dominated by isothermal vapor-flow conditions) for at least 20 years, provided that the modeled dry-climate period continues

  13. Barium ferrite powders prepared by milling and annealing

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-05-01

    Full Text Available Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment.Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950 °C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force (HC for mixture of powders annealed at 950 °C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. The arithmetic mean of diameter of Fe2O3 and BaCO3 mixture powders after 30 hours of milling is about 6.0 μm.Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable components to produce sintered and elastic magnets with polymer matrix.Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials.

  14. Aluminum-graphite composite produced by mechanical milling and hot extrusion

    International Nuclear Information System (INIS)

    Aluminum-graphite composites were produced by mechanical milling followed by hot extrusion. Graphite content was varied between 0 and 1 wt.%. Al-graphite mixtures were initially mixed in a shaker mill without ball, followed by mechanical milling in a High-energy simoloyer mill for 2 h under argon atmosphere. Milled powders were subsequently pressed at ∼950 MPa for 2 min, and next sintered under vacuum for 3 h at 823 K. Finally, sintered products were held for 0.5 h at 823 K and hot extruded using indirect extrusion. Tension and compression tests were carried out to determine the yield stress and maximum stress of the materials. We found that the mechanical resistance increased as the graphite content increased. Microstructural characterization was done by transmission electron microscopy. Al-O-C nanofibers and graphite nanoparticles were observed in extruded samples by transmission electron microscopy. These nanoparticles and nanofibers seemed to be responsible of the reinforcement phenomenon

  15. Math Academy: Play Ball! Explorations in Data Analysis & Statistics. Book 3: Supplemental Math Materials for Grades 3-8

    Science.gov (United States)

    Rimbey, Kimberly

    2008-01-01

    Created by teachers for teachers, the Math Academy tools and activities included in this booklet were designed to create hands-on activities and a fun learning environment for the teaching of mathematics to the students. This booklet contains the "Math Academy--Play Ball! Explorations in Data Analysis & Statistics," which teachers can use to…

  16. Prediction of tar ball formation

    Energy Technology Data Exchange (ETDEWEB)

    Khelifa, A.; Gamble, L. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Division, Environmental Technology Centre, Science and Technology Branch

    2006-07-01

    The presence of small tar balls ranging in size from less than a millimetre to 60 centimetres have been observed during cleanup assessment operations following accidental oil spills on water. The tar balls are composed of heavy oil residues and suspended particulate matter (SPM) from the water column. They can be found on shorelines, settled on the seafloor and floating at or near the water surface. Their abundance on the shorelines varies from site to site and depends on the conditions of the spill and mixing conditions. Aggregation between SPM and micro-sized oil droplets occurs naturally in coastal waters and enhances the dispersion of spilled oil. Although tar balls are among the important end states of spilled oil in the marine environment, no model exists to estimate the percentage of the spilled oil that becomes tar balls. This paper offered some insight into the modeling of tar ball formation. Current modeling understanding of oil-SPM aggregate formation was used to predict tar ball formation. The formation of oil droplets was examined with respect to a range of conditions under which the formation of large droplets is expected. The role of aggregation was then presented to demonstrate the effects of concentration and type of SPM on the buoyancy of tar balls. Good agreement was found between modeling results and field data reported in the literature regarding the size and density of tar balls. Oil viscosity and mixing energy were found to be the main factors controlling the formation of tar balls. The aggregation of tar balls with SPM and shoreline material results in significant increases or decreases in density, depending on the type and concentration of SPM. 42 refs., 2 tabs., 6 figs.

  17. Effect of milling on reduction behavior of blue dust

    International Nuclear Information System (INIS)

    Graphical abstract: Blue dust is a secondary source of hematite mineral reduced to wustite phase when it is subjected planetary ball milling in the presence of metallic iron power as a reducing reagent. Reduction characteristics of hematite (blue dust) can take place in the following reaction schemes. 4Fe2O3+Fe→3Fe3O4 Fe3O4+Fe→4FeO Fe2O3+Fe→3FeO The direct formation of wustite is possible only due to higher rate of hematite reduction which is driven by high energy planetary ball milling. X-ray diffraction and Mossbauer studies confirm the blue dust is reduced to wustite. Higher rate of reduction of blue dust (hematite) leading to the formation of wustite. Formation of magnetite from hematite could be a transient phase which reacts immediately with added metallic iron powder or iron comes out from the friction between the steel balls and jar to yield wustite. -- Highlights: • Natural mineral-blue dust (96% hematite) is reduced in the presence of metallic iron as reducing reagent. • Reaction milling provides the sufficient energy to facilitate the reduction of blue dust to undergo phase transformation from hematite to form wustite as major phase. • Reaction mechanism for formation of wustite phase is explained on the basis of the particle size of reactants. • XRD and Mossbauer studies confirm the phase change from hematite to wustite. -- Abstract: Blue dust is a high grade soft hematite material containing 96.14% Fe2O3. It is transformed into wustite when subjected to planetary ball milling in the presence of iron powder as a reducing reagent. The phase evolution, particle size distribution, and morphology of particles during milling are studied for various samples collected at various milling times by using X-ray diffractometer (XRD), Mössbauer spectrometer and field emission scanning electron microscope (FESEM). XRD and Mössbauer studies reveal that the blue dust is transformed into wustite after 50 h of milling. Vibrating sample magnetometry (VSM

  18. Novel method of manufacturing hydrogen storage materials combining with numerical analysis based on discrete element method

    Science.gov (United States)

    Zhao, Xuzhe

    High efficiency hydrogen storage method is significant in development of fuel cell vehicle. Seeking for a high energy density material as the fuel becomes the key of wide spreading fuel cell vehicle. LiBH4 + MgH 2 system is a strong candidate due to their high hydrogen storage density and the reaction between them is reversible. However, LiBH4 + MgH 2 system usually requires the high temperature and hydrogen pressure for hydrogen release and uptake reaction. In order to reduce the requirements of this system, nanoengineering is the simple and efficient method to improve the thermodynamic properties and reduce kinetic barrier of reaction between LiBH4 and MgH2. Based on ab initio density functional theory (DFT) calculations, the previous study has indicated that the reaction between LiBH4 and MgH2 can take place at temperature near 200°C or below. However, the predictions have been shown to be inconsistent with many experiments. Therefore, it is the first time that our experiment using ball milling with aerosol spraying (BMAS) to prove the reaction between LiBH4 and MgH2 can happen during high energy ball milling at room temperature. Through this BMAS process we have found undoubtedly the formation of MgB 2 and LiH during ball milling of MgH2 while aerosol spraying of the LiBH4/THF solution. Aerosol nanoparticles from LiBH 4/THF solution leads to form Li2B12H12 during BMAS process. The Li2B12H12 formed then reacts with MgH2 in situ during ball milling to form MgB 2 and LiH. Discrete element modeling (DEM) is a useful tool to describe operation of various ball milling processes. EDEM is software based on DEM to predict power consumption, liner and media wear and mill output. In order to further improve the milling efficiency of BMAS process, EDEM is conducted to make analysis for complicated ball milling process. Milling speed and ball's filling ratio inside the canister as the variables are considered to determine the milling efficiency. The average and maximum

  19. Four ball best ball 1.

    Science.gov (United States)

    Pollard, Geoff; Pollard, Graham

    2010-01-01

    In this paper a four-ball-best-ball (4BBB) model for pairs of golf players is set up. The 4BBB match-play scoring system is seen to satisfy a basic requirement of fairness. It is shown that it is not strictly possible to rate individual players as 4BBB players. However, a (reasonably broad) class of individual players is identified such that it is possible to rate them individually as 4BBB players. The capacity of an individual to play birdies is seen to be a very important determinant in being a successful member of a 4BBB pair, but there are other minor factors as well. Consideration is given to equal and unequal 4BBB pairs. The transitive law is seen to apply for 4BBB pairs. Thus, if pair A is better than pair B, and pair B is better than pair C, then pair A must be better than pair C. Correspondingly, if pair A is equal to pair B, and pair B is equal to pair C, then pair A is equal to pair C. Consideration is given to some strategic issues in 4BBB match-play golf. For example, the conditions under which a player should take a greater risk and have a higher probability of obtaining a bogie in order to achieve a higher probability of scoring a birdie, are determined. Also, the conditions under which a player, noting that his partner is about to have a 'bad' hole and score only a par or a bogie, should 'play safe', are determined. Thirdly, players who can interact in certain ways are seen to have an advantage over those pairs that cannot do this. Finally, one pair's optimal strategy when they see that their opponents are about to score a par or a bogie, but not a birdie, is analyzed. Key pointsA model for four-ball-best-ball match-play golf is established, and used to show that, although there can be other factors, the capacity of an individual to play birdies is a very important determinant in that player being a successful member of a four-ball-best-ball pair.Although it is not possible in general to rate play-ers individually as 4BBB players, a class of indi

  20. Split-ball resonator

    CERN Document Server

    Kuznetsov, Arseniy I; Fu, Yuan Hsing; Viswanathan, Vignesh; Rahmani, Mohsen; Valuckas, Vytautas; Kivshar, Yuri; Pickard, Daniel S; Lukiyanchuk, Boris

    2014-01-01

    We introduce a new concept of split-ball resonator and demonstrate a strong omnidirectional magnetic dipole response for both gold and silver spherical plasmonic nanoparticles with nanometer-scale cuts. Tunability of the magnetic dipole resonance throughout the visible spectral range is demonstrated by a change of the depth and width of the nanoscale cut. We realize this novel concept experimentally by employing the laser-induced transfer method to produce near-perfect spheres and helium ion beam milling to make cuts with the nanometer resolution. Due to high quality of the spherical particle shape, governed by strong surface tension forces during the laser transfer process, and the clean, straight side walls of the cut made by helium ion milling, magnetic resonance is observed at 600 nm in gold and at 565 nm in silver nanoparticles. Structuring arbitrary features on the surface of ideal spherical resonators with nanoscale dimensions provides new ways of engineering hybrid resonant modes and ultra-high near-f...

  1. Evaluation of material degradation of 1Cr-1Mo-0.25V steel using ball Indentation method

    International Nuclear Information System (INIS)

    The BI (Ball Indentation) method has the potential to assess the mechanical properties and to replace conventional fracture tests. In this study, the effect of aging on mechanical behavior of 1Cr-1Mo-0.25V steels procured by isothermal aging heat-treatment at four different aging times in the range of 0∼1820 hours at 630 .deg. C, were investigated using BI system

  2. 球磨工艺参数对醇水系纳米CeO2悬浮液稳定性的影响%Effect of process parameters of ball mill on stability of nanometer CeO2 suspension in dispersion medium of water and alcohol

    Institute of Scientific and Technical Information of China (English)

    陈刚; 黎向锋; 左敦稳; 王宏宇; 孙玉利

    2011-01-01

    使用行星式球磨机分散醇水系纳米CeO2悬浮液,引入沉淀率及其变化量评价其分散稳定性,讨论了球磨时间、球料比、球磨机转速和纳米CeO2质量分数对分散稳定性的影响.通过破碎力打开团聚体的形式来分析球磨时间的影响,从颗粒受作用次数方面来讨论球料比的影响,球磨机转速是划分研磨力和冲击力的主次地位的重要参数;理论Ce2O质量分数和球料比的选择要综合考虑分散稳定性和球磨机的能量利用率.%In this work, the planetary mill was used to disperse nanometer CeO2 particles in the dispersion medium of water and alcohol. Precipitation rate (PR) and its varied quantity (PRVQ) were introduced to evaluate the stability of CeO2 suspension. Effect of ball milling time (BMT), ball to powder ratio (BPR), milling speed (MS) and theoretic mass fraction (TMF) of CeO2 particles on stability of CeO2 suspension was discussed. In terms of the crushing force opening the agglomerates, the effect of BMT was discussed. And in the respective of crushing frequency of particles, the effect of BPR was evaluated. MS was the significant factor of the division of the milling force and the impact force. The selections of TMF and BPR need to give consideration to dispersion stabilization, energy efficiency and PR in a comprehensive way.

  3. Uranium and thorium mining and milling: material security and risk assessment

    International Nuclear Information System (INIS)

    several of the following pre-requisites in order to breach the current level of security at mining and milling facilities: covert political support; covert support by members of the security forces and/or intelligence community; adequate transport capability for bulk shipments or material by rail, road, ship, or air; corruption at the level of government officials, such as export control agencies, customs officers, and border guards. The number of illicit trafficking cases involving uranium and thorium that are known to have occurred shows that the current system of physical protection and accounting is in need of improvement. In order to reduce this risk in the future a series of practically applicable actions are recommended. (author)

  4. FOUR BALL BEST BALL 1

    Directory of Open Access Journals (Sweden)

    Geoff Pollard

    2010-03-01

    Full Text Available In this paper a four-ball-best-ball (4BBB model for pairs of golf players is set up. The 4BBB match-play scoring system is seen to satisfy a basic requirement of fairness. It is shown that it is not strictly possible to rate individual players as 4BBB players. However, a (reasonably broad class of individual players is identified such that it is possible to rate them individually as 4BBB players. The capacity of an individual to play birdies is seen to be a very important determinant in being a successful member of a 4BBB pair, but there are other minor factors as well. Consideration is given to equal and unequal 4BBB pairs. The transitive law is seen to apply for 4BBB pairs. Thus, if pair A is better than pair B, and pair B is better than pair C, then pair A must be better than pair C. Correspondingly, if pair A is equal to pair B, and pair B is equal to pair C, then pair A is equal to pair C. Consideration is given to some strategic issues in 4BBB match-play golf. For example, the conditions under which a player should take a greater risk and have a higher probability of obtaining a bogie in order to achieve a higher probability of scoring a birdie, are determined. Also, the conditions under which a player, noting that his partner is about to have a ‘bad’ hole and score only a par or a bogie, should ‘play safe’, are determined. Thirdly, players who can interact in certain ways are seen to have an advantage over those pairs that cannot do this. Finally, one pair’s optimal strategy when they see that their opponents are about to score a par or a bogie, but not a birdie, is analyzed

  5. Magnetic properties of nanocrystalline cobalt based powder soft magnetic materials and nanocomposites with silicon matrix

    International Nuclear Information System (INIS)

    The paper presents the effect of the high energy ball milling parameters and of isothermal heating of the cobalt based metallic glasses on the magnetic properties and structure of the powder material and silicon matrix nano-composites. The high energy ball milling process of the Co68Fe4Mo1Si13.5B13.5 metallic glass was carried out for various time period in the 'as quenched' state and after the isothermal heating. Heating of powder obtained by milling was also performed, to check its effect on changes of magnetic properties. The effects of the high energy ball milling and isothermal heating on the structure, grain size and magnetic properties of powder, and of the silicon base nano-composites made from them were also investigated. (author)

  6. An experimental and theoretical approach on the effect of presence of oxygen in milled graphite as lithium storage material

    International Nuclear Information System (INIS)

    The effect of milling time on the morphology of graphite is characterized by XRD, SEM, BET, FTIR and XPS and the electrochemical response of the resulting materials upon lithium-ion absorption is analyzed using different techniques. As milling time is increased, the particle size diminishes and the amount of oxygen content increases. Concomitantly, the capacity for lithium adsorption also increases because new adsorption sites become available due to more surface area and oxygen functional groups. These effects are interpreted using first-principles calculations, which show that the presence of oxygenated species promotes lithium adsorption at higher potentials. This capacity increase is probably not relevant for lithium-ion batteries since there is no intercalation process but rather an adsorption one, but may be of interest for supercapacitive applications. Diffusion coefficients of lithium for different graphite particle sizes are evaluated. The effects of diffusion, particle size and oxygen content are discussed

  7. Relación entre factores micro- estructurales e impacto repetido en aleaciones de alto cromo para bolas de molino. // Relationship among factors micro - structural and impact repeated in alloys of high chromium for mill balls.

    Directory of Open Access Journals (Sweden)

    E. Albertin

    2008-01-01

    Full Text Available Las aleaciones de alto cromo son empleadas para la fabricación de bolas de molino en industrias de procesamiento deminerales. Los usuarios y fabricantes requieren lograr mejores resultados técnicos-económicos en sus aplicaciones, por loque necesitan aumentar los conocimientos relacionados con los aspectos estructurales de estos materiales. En este trabajo serealiza una investigación con vistas a establecer relaciones entre la estructura de las aleaciones y su comportamiento ante elimpacto repetido que es un fenómeno característico en estos procesos.Se funden bolas con varias aleaciones hipo eutécticas, eutécticas, e hipereutécticas; se prueban en un equipo que simula elimpacto repetido. Los resultados permiten comprobar los buenos resultados de aleaciones hipo eutécticas con relaciones deCr/C altas y a su vez altos contenidos de Cr y de aleaciones eutécticas para menores relaciones de Cr/C y menorescontenidos de Cr, en ambos casos los carburos eutécticos son de forma simétrica, regulares y no forman redes continuas decarburos asimétricos bordeando los granos, que presentan peores comportamiento en el impacto repetido y que son el casode las hipoeutécticas con bajas relaciones Cr/C y las hipereutécticas donde aparecen también grandes carburos primariosPalabras claves: Alto-cromo, bolas de molino, impacto repetido, desgaste.____________________________________________________________________________Abstract.High Chromium alloys are used to manufacture grinding balls for the Industry of Construction Materials. Customers andusers need to improve their knowledge about the relationships between microstructure and the parts damage in these alloysto obtain better technical-economics results. In this paper the results of a research to obtain different microstructures ofeutectics, hipoeutectics and hipereutectics alloys are presented, searching for the lesser damage in these alloys. These alloysare tested in a repeated impact testing

  8. Characterization of Tool Wear in High-Speed Milling of Hardened Powder Metallurgical Steels

    Directory of Open Access Journals (Sweden)

    Fritz Klocke

    2011-01-01

    Full Text Available In this experimental study, the cutting performance of ball-end mills in high-speed dry-hard milling of powder metallurgical steels was investigated. The cutting performance of the milling tools was mainly evaluated in terms of cutting length, tool wear, and cutting forces. Two different types of hardened steels were machined, the cold working steel HS 4-2-4 PM (K490 Microclean/66 HRC and the high speed steel HS 6-5-3 PM (S790 Microclean/64 HRC. The milling tests were performed at effective cutting speeds of 225, 300, and 400 m/min with a four fluted solid carbide ball-end mill (0 = 6, TiAlN coating. It was observed that by means of analytically optimised chipping parameters and increased cutting speed, the tool life can be drastically enhanced. Further, in machining the harder material HS 4-2-4 PM, the tool life is up to three times in regard to the less harder material HS 6-5-3 PM. Thus, it can be assumed that not only the hardness of the material to be machined plays a vital role for the high-speed dry-hard cutting performance, but also the microstructure and thermal characteristics of the investigated powder metallurgical steels in their hardened state.

  9. Cryo-Milling and the Hydrogen Storage Properties of NaAlH4

    Science.gov (United States)

    Feller, Kevin; Dobbins, Tabbetha

    2013-03-01

    High energy ball milling of metal hydrides is a common way to both introduce catalysts (e.g. TiCl3) and to simultaneously increase the surface area. Both catalysis and increased surface area improve hydrogen storage capacity of the material. Nanostructuring of hydrides by depositing them into mesoporous templates (such as anodized alumina, MOFs, and SBA-15) has become a common way to increase surface area. However, the mesoporous template does not add hydrogen storage capacity--and thus, tends to decreased overall storage weight percent for the nanostructured hydride material. As with most materials, hydrides become brittle at low temperatures and will tend to fracture more readily. We will process Sodium Aluminum Hydride (NaAlH4) using cryogenic high energy ball milling using an in-house modified chamber SPEX Certiprep M8000 mixer/mill in order to gain a nanostructured hydride without mesoporous template material. Details of the modified mixer mill design will be presented. Ultimately, our planned future work is to study the resultant material using x-ray diffraction (Scherrer method for crystallite size), absorption/desorption temperature programmed desorption (TPD), and ultrasmall-angle x-ray scattering (USAXS) microstructural quantification to understand the role of cryomilling on enhancing the material's ability to store (and release) hydrogen.

  10. Material selection for the tool holder working under hard milling conditions using different multi criteria decision making methods

    International Nuclear Information System (INIS)

    Highlights: ► The material selection problem for tool holders used in hard milling was solved. ► EXPROM2, TOPSIS and VIKOR methods were used for ranking the alternative materials. ► The weighting of criteria was performed by compromised weighting method. ► The best material for the tool holder was selected as Fe–5Cr–Mo–V aircraft steel. -- Abstract: Nowadays machining of materials in their hardened state, also called hard machining, is a challenge in production of tools and molds. It has some advantages such as lower process time and lower manufacturing cost when compared to conventional machining. In machining of hard workpiece materials, however, very high stresses act on the tool holder through the cutting tool. These stresses necessitate the tool holder to have some specific properties. Especially in hard milling, the tool holder should have high stiffness and should be able to dissipate the energy generated during interrupted cutting. Material cost of the tool holder is also important since lower costs provide a competitive advantage for manufacturers. The material selection for the tool holder should be conducted considering aforementioned requirements. To tackle the difficulty of the material selection with specific properties from a large number of alternatives, multi-criteria decision-making (MCDM) methods have been used. In this paper a decision model including extended PROMETHEE II (EXPROM2) (preference ranking organization method for enrichment evaluation), TOPSIS (technique for order performance by similarity to ideal solution) and VIKOR (VIšekriterijumsko KOmpromisno Rangiranje) methods were used for the selection of the best material for the tool holder used in hard milling. The criteria weighting was performed by compromised weighting method composed of AHP (analytic hierarchy process) and Entropy methods. The candidate materials were ranked by using these methods and the results obtained by each method were compared. It was confirmed

  11. Effect of Tool Cutter Immersion on Al-Si Bi-Metallic Materials in High-Speed-Milling

    Directory of Open Access Journals (Sweden)

    J.H. Sokołowski

    2006-04-01

    Full Text Available Purpose: Aluminum-Silicon (Al-Si alloys are commonly used in the automotive industry. At high Si levels they offer good wear resistance. Abrasive wear however, has been identified as the main insert cutter damage mechanism during High-Speed-Milling (HSM. This study investigates the effect of the tool cutter immersion on Al-Si bi-metallic materials in HSM operation.Design/methodology/approach: This study considers the effects of the tool cutter immersion on the resultant cutting forces, associated machined surface roughness, and machined subsurface microstructural damage caused by the tool cutter during the Minimum Quantity Lubricant – High Speed Milling (MQL-HSM operation of Al-Si bi-metallic materials with varying amounts and morphologies of the silicon phase.Findings: Experimental results indicate that a combination of gray cast iron with the W319 microstructure yields the greatest resistance to the tool cutter rake face during the face milling operation for all investigated tool cutter radial immersions. Machined surface roughness measurements reveal that surface roughness is a function of both the silicon content and morphology, as well as the percentage of tool cutter immersion. Matrix hardness measurements indicate that machining at all immersions has the same effect on compressing the matrix structure.Research limitations/implications: This study considers the effects of the radial tooling immersion and material selection while the speed, feed, and axial depth-of-cut are kept constant. Future work should address variability in the machining parameters in an attempt to maximize tool life, while optimizing the machined surface quality.Practical implications: Material selection affects the machining conditions in HSM of Al-Si bi-metallic materials. As a result careful consideration should be given when tailoring the machining conditions to the cast microstructures.Originality/value: North American automakers rely heavily on Al-Si precision

  12. Measuring the Rebound Resilience of a Bouncing Ball

    Science.gov (United States)

    Wadhwa, Ajay

    2012-01-01

    Some balls which are made of high-quality rubber (an elastomeric) material, such as tennis or squash balls, could be used for the determination of an important property of such materials called resilience. Since a bouncing ball involves a single impact we call this property "rebound resilience" and express it as the ratio of the rebound height to…

  13. Study of radon emanation from uranium mill tailings. Relations between radon emanating power and physicochemical properties of the material

    International Nuclear Information System (INIS)

    The uranium extraction from ores leads to large amounts of mill tailings still containing radionuclides, such as thorium-230 and radium-226, which generate radon-222. Without protective action, radon exposition may be high enough to cause concern for health of populations living in the vicinity of an uranium mill tailings disposal. This exposition pathway has therefore to be taken into account in the radiological impact studies. The emanating power, i.e. the part of radon atoms which escape from the solid particles, is directly involved in the radon source term evaluation. It may be determined for a given material by laboratory measurements. Emanating powers from 0.08 to 0.33 have been obtained for mill tailings from Jouac (Limousin, France), at various moisture contents. In order to reduce the relations of dependence between some of the emanation parameters, more simple phases, kaolinite and polymeric resins, have been studied. Those experiments have led us to the selection of the mechanisms and the parameters to consider for the development of an emanation modelling. The whole of the results obtained point out the radon sorption, in various proportions depending on the materials. The moisture content influence on the emanation from materials containing fine particles have been confirmed: the emanation increases with this parameter until a continuous water film surrounding the particles have been formed, and then become constant. This 'water effect' occurs in a moisture content range, which depends on the material porosity. Elsewhere, the presence of amorphous phases may led to a high radon emanation. (author)

  14. Holy Balls!: Part Deux

    Science.gov (United States)

    Belden, Jesse; Jandron, Michael; Truscott, Tadd

    2012-11-01

    A Waboba® (WAter BOuncing BAll) demonstrates remarkable water skipping behavior, even at relatively large impact angles. The highly compliant nature of these elastic spheres results in significant deformation into a disk-like shape upon impact. The increased wetted area and force coefficient generates a large hydrodynamic force that more readily lifts the ball off the water surface. However, elasticity introduces some surprising phenomena, such as material waves that propagate on the sphere and interact with the water cavity. Depending upon impact conditions, material waves may propagate in various directions combining to create multiple modes of deformation and complicated fluid-structure interactions. Furthermore, the timescales of deformation and wave propagation depend on the material properties and impact conditions. In this talk, we will discuss skipping regimes in terms of impact parameters and material properties and relate failed skipping behavior to the structure-fluid interaction caused by deformation. The critical timescales for deformation, wave propagation and collision will be related to the relevant physical parameters of the problem.

  15. Exchange bias and anomalous vertical shift of the hysteresis loops in milled Fe/MnO2 material

    International Nuclear Information System (INIS)

    The present article reports studies on structural and magnetic properties of nanostructured Fe/MnO2 materials prepared by mechanosynthesis method, with Fe to MnO2 ratios of 20/80, 50/50 and 60/40. X-ray diffraction patterns indicate that the milled materials have crystalline grain size in the nanoscale region. Moessbauer spectra of the milled materials suggest the presence of two Fe phases for each sample: a nanocrystalline α-Fe phase with a high degree of disorder/defects and small Fe-oxide particles. The magnetic hysteresis (M(H)) loops, measured at 4.2K, after the samples were cooled from 300K in +/-10kOe fields, show unexpected large shifts in both horizontal and vertical directions for the 20/80 sample, while only horizontal shift was detected in the samples with higher Fe concentration. The anomalous vertical shift of the M(H) loop for the 20/80 sample, observed at low cooling field (10kOe), is being associated with a large contribution from non-collinear magnetic structure of the particles surface. This surface magnetic contribution is strongly influenced by the field cooling magnitude. A simple model is proposed to interpret this result

  16. Electrochemical properties of Si/(FeSiB) anode materials prepared by high-energy mechanical milling

    International Nuclear Information System (INIS)

    Highlights: • Si-embedded in less-active FeSiB nano-composite structures synthesized. • Capacity of Si anode is 540 mAh g−1 and 533 mAh g−1 after the 3rd and 50th cycle. • The nano-composite exhibited 99% efficiency until the 50th cycle. • Cracks or voids in coin cells are rarely observed during cycling. • Elastic recoverable energy range of FeSiB is 2.96 times higher than Si. -- Abstract: Nano-structured composite with overall atomic composition Si60/(FeSiB)40 has been synthesized by high-energy mechanical milling (HEMM) for Lithium-ion rechargeable batteries as anode material. Crystal structure, microstructure, electrochemical properties, elastic modulus and Vickers hardness (HV) have been observed by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), electrochemical test and nano-indentation test. With increasing milling time from 6 to 10 h, we observed a relatively homogeneous structure comprised of nano-crystalline active silicon (Si) embedded in less active FeSiB matrix phase. Electrochemical properties of 10 h milled nano-composite powder offers low capacity fade, high coulombic efficiency from 3rd cycle (540 mAh g−1) to until 102nd cycle (495 mAh g−1). The coulombic efficiencies of both 6 and 10 h milled powders are 98% and 99%, respectively. Coin cell cross sections of 6 and 10 h milled powders showed evidence for the void formation during lithiation and delithiation. Nano-indentation results exhibited that the amorphous FeSiB flakes have 2.96 times higher recoverable energy than Si. Resultant composite powders showed high irreversible capacity and stable lithiation and delithiation due to the reduced particle size, increased surface area and the highly elastic FeSiB matrix phase. Research reveals that the obtained nano-composite can be a promising candidate for lithium-ion rechargeable batteries

  17. EXPERIMENTAL RESEARCH OF THE THERMAL BALANCE OF LOOSE DISPERSE MATERIALS EXEMPLIFIED BY MILLED PEAT EXPOSED TO INFRARED HEATING

    Directory of Open Access Journals (Sweden)

    Pavlov Mikhail Vasil'evich

    2012-10-01

    Full Text Available Good knowledge of thermal balance is a prerequisite of successful mastering of the processes of heat and water transfer within a body. Given the reflective power of the substance surface under consideration, the analysis of the thermal balance of a loose disperse material was performed. A sample of milled peat served as the loose disperse material exposed to infrared heating. The practical results were compared to those available in the literature. One of the key results of the experiment represents identification of the radiation balance of the substance. Further research of the heat accumulation capacity rad will make it possible to identify the boundary conditions (energy and mass at the body boundary required to formulate and solve the boundary problem of thermal and moisture transfer. The latter will make it possible to project and to manage the thermal and moisture mode of materials in terms of timing and depth subject to thermal processes underway on their surface

  18. 高能球磨法制备的碳纳米管增强铝基复合材料的微观组织和力学性能%MICROSTRUCTURES AND MECHANICAL PROPERTIES OF CNT/Al COMPOSITES FABRICATED BY HIGH ENERGY BALL-MILLING METHOD

    Institute of Scientific and Technical Information of China (English)

    许世娇; 肖伯律; 刘振宇; 王文广; 马宗义

    2012-01-01

    采用高能球磨法制备了不同体积分数的碳纳米管(CNT)与Al粉的混合粉末,用粉末冶金工艺制备了CNT/Al复合材料.微观结构分析表明,球磨可以分散一定含量的CNT到Al基体中,并与其产生良好结合.在适当的球磨工艺下,球磨不会造成CNT的严重损伤.拉伸实验表明,CNT体积分数为1.5%时,力学性能达到了最高值,屈服强度相对于纯Al基体提高了53.6%.而CNT体积分数为3%时,形成了大量的CNT团聚,力学性能迅速下降.CNT/Al复合材料的主要强化机制为细晶强化和载荷传递.%The mixture powders of carbon nanotubes (CNTs) and aluminum were high-energy ball-milled, and then the CNT/A1 composites with different CNT contents were fabricated using a power metallurgy method. Microstructure examinations show that a certain volume of CNTs can be uniformly dispersed in the Al matrix by ball-milling and the CNTs have a close bonding with the Al matrix. By using an appropriate ball-milling process flow, the CNTs suffer no serious damage. Tensile tests indicate that the composite reinforced by 1.5% (volume fraction) CNTs exhibits the best mechanical performance, and the yield strength is improved by 53.6% compared with the Al matrix. When the CNT volume fraction reaches 3%, lots of clusters are formed in the composite, and therefore the tensile properties are significantly reduced. Both grain refinement and load transfer are proved to be the strengthening mechanisms of the CNT/A1 composites.

  19. Having a Ball with Fitness Balls

    Science.gov (United States)

    McNulty, Betty

    2011-01-01

    Fitness programs can be greatly enhanced with the addition of fitness balls. They are a fun, challenging, economical, and safe way to incorporate a cardiovascular, strength, and stretching program for all fitness levels in a physical education setting. The use of these balls has become more popular during the last decade, and their benefits and…

  20. Pitt Mill Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Oder, R.R.; Borzone, L.A.

    1990-05-01

    Results of a technical and economic evaluation of application of the Pitt Mill to fine coal grinding are presented. The Pitt Mill is a vertically oriented, batch operated, intermediate energy density (0. 025 kW/lb media), stirred ball mill. The mill grinds coal from coarse sizes (typically 3/16 inch or 4 mesh topsize) to the 10 micron to 20 micron mean particle diameter size range in a single step using a shallow grinding bed containing inexpensive, readily available, course grinding media. Size reduction is efficient because of rapid product circulation through the grinding bed caused by action of a novel circulation screw mounted on the agitator shaft. When a dispersant is employed, the grinding can be carried out to 50% to 60% solids concentration. Use of coarse grinding media offers the possibility of enhanced mineral liberation because size reduction is achieved more by impact shattering than by attrition. The batch method offers the possibility of very close control over product particle size distribution without overproduction of fines. A two- phase program was carried out. In the first phase, Grinding Studies, tests were run to determine a suitable configuration of the Pitt Mill. Machine design parameters which were studied included screw configuration, media type, agitator RPM, time, media size, and slurry chamber aspect ratio. During the last part of this phase of the program, tests were carried out to compare the results of grinding Pocahontas seam, Pittsburgh {number sign}8, and East Kentucky Mingo County coals by the Pitt Mill and by a two-stage grinding process employing a Netzsch John mill to feed a high energy density (0.05 kW/Lb media) disc mill. 22 refs., 25 tabs.

  1. Superelastic Ball Bearings: Materials and Design to Avoid Mounting and Dismounting Brinell Damage in an Inaccessible Press-fit Application-. II; Detailed Analysis

    Science.gov (United States)

    Howard, S. Adam; Dellacorte, Christopher

    2015-01-01

    Rolling element bearings utilized in precision rotating machines require proper alignment, preload, and interference fits to ensure overall optimum performance. Hence, careful attention must be given to bearing installation and disassembly procedures to ensure the above conditions are met. Usually, machines are designed in such a way that bearings can be pressed into housings or onto shafts through the races without loading the rolling elements. However, in some instances, either due to limited size or access, a bearing must be installed or removed in such a way that the load path travels through the rolling elements. This can cause high contact stresses between the rolling elements and the races and introduces the potential for Brinell denting of the races. This paper is a companion to the Part I paper by the authors that discusses material selection and the general design philosophy for the bearing. Here, a more in-depth treatment is given to the design of a dent-resistant bearing utilizing a superelastic alloy, 60NiTi, for the races. A common bearing analysis tool based on rigid body dynamics is used in combination with finite element simulations to design the superelastic bearing. The primary design constraints are prevention of denting and avoiding the balls riding over the edge of the race groove during a blind disassembly process where the load passes through the rolling elements. Through an iterative process, the resulting bearing geometry is tailored to improve axial static load capability compared to a deep-groove ball bearing of the same size. The results suggest that careful selection of materials and bearing geometry can enable blind disassembly without damage to the raceways, which is necessary in the current application (a compressor in the International Space Station Environmental Control and Life Support System), and results in potential design flexibility for other applications, especially small machines with miniature bearings.

  2. A field experimental study of lignin sand stabilizing material (LSSM) extracted from spent-liquor of straw pulping paper mills

    Institute of Scientific and Technical Information of China (English)

    WANG Han-jie; LI Jing; LU Xiao-zhen; JIN Yong-can

    2005-01-01

    A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material( LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the extracts of black-liquor issued by straw pulp paper mills. Unlike the polyvinyl acetate or foamed asphalt commonly used for dune stabilization, the new material is plant-friendly and can be used with virescence actions simultaneously. The field experimental study was conducted since 2001 in China' s Northwest Ningxia Hui Autonomous Region and has been proved that LSSM is effective in stabilizing the fugitive dunes, making the arenaceous plants survive and the bare dune vegetative. The advisable solution concentration is 2% and the optimal field spraying quantity is 2.5 L/m2. The soil nutrients of the stabilized and greened dune, such as organic matter, available phosphorous and total nitrogen are all increased compared with the control treatment, which is certainly helpful to the growth of arenaceous plants. The technique is worthwhile to be popularized because it is provided not only a new method for desertification control but also an outlet for cleaning contaminants issued from the straw paper mills.

  3. The influence of milling on the dissolution performance of simvastatin

    DEFF Research Database (Denmark)

    Zimper, Ulrike; Aaltonen, Jaakko; Krauel-Goellner, Karen;

    2012-01-01

    Particle size reduction is a simple means to enhance the dissolution rate of poorly water soluble BCS-class II and IV drugs. However, the major drawback of this process is the possible introduction of process induced disorder. Drugs with different molecular arrangements may exhibit altered......, as well as factor interactions in a dry ball milling process using simvastatin as model drug, and to optimize the milling procedure with regard to the opposing responses particle size and process induced disorder by application of a central composite face centered design. Particle size was assessed...... milling frequency, milling time and ball quantity at a set drug load, out of which milling frequency was found to be the most important factor for particle size as well as process induced disorder. Milling frequency and milling time exhibited an interaction effect on the responses. The optimum milling...

  4. Ball Screw Actuator Including a Compliant Ball Screw Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

    2015-01-01

    An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

  5. Variation cutting speed on the five axis milling

    OpenAIRE

    S. Torbaty; W. Bouzid; Moisan, A; M. Boujelbene

    2007-01-01

    Purpose: The aim of this research is to make a study of the effective cutting speed variation in milling with a ball end tool is studied. Then an experimental study of the effect of finishing strategies on surface texture, roughness is described. The material of a specific HB 300 pre-hardened mould steel Super Plast (SP 300).Design/methodology/approach: The methodology has consisted to dertemine cutting speed of each mode of tilt tool in five axes machining, and of proving a series of configu...

  6. Study of a Grey PID (Proportional,Integral and Differential) Control System for Ball Mill Load in a Thermal Power Plant%火电厂钢球磨煤机负荷的灰色PID控制系统研究

    Institute of Scientific and Technical Information of China (English)

    程启明; 闵乐聪; 李芹; 王志萍

    2009-01-01

    火电厂钢球磨煤机的负荷对象具有大滞后、慢时变、强非线性等复杂特性,采用常规控制方法难以获得满意的控制效果,提出了基于灰色预测PID控制的球磨机负荷控制方法,它融合了灰色预测与常规PID控制这两者的设计思想,将灰色预测在线预测结果代替被控对象测量值,再进行PID控制运算.Simulink仿真结果表明,灰色预测PID控制在控制的快速性、稳定性、适应性、鲁棒性、抗干扰性上均优于常规PID控制和带Simth预估PID控制.%The load of a ball mill in a thermal power plant features such complicated characteristics as a big lagging,slow time variation and strong non-linearity etc.,and it is difficult for conventional control methods to obtain a satisfactory control effectiveness.Therefore,the authors have presented a method for controlling the load of a ball mill based on a grey prediction PID(proportional,integral and differential) control,which integrates the design approach of the grey prediction with that of the conventional PID control,replaces the measured values of the controlled object with the on-line predicted results obtained from the grey prediction,and then performs a PID control operation.The Simulink simulation results show that the grey prediction-based PID control is superior to the conventional PID control and Simth-prediction-based PID one in respect of speediness,stability,adaptability,robustness and disturbance-resistant capability.

  7. Coexistence of short- and long-range ferromagnetic order in nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al (x=0.0, 0.1 and 0.3) synthesized by high-energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Thanh, Tran Dang, E-mail: thanhxraylab@yahoo.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Nanto, Dwi [Physics Education, Syarif Hidayatullah States Islamic University, Jakarta 15412 (Indonesia); Tuyen, Ngo Thi Uyen [Department of Natural Science, Nha Trang Pedagogic College, Nguyen Chanh, Nha Trang, Khanh Hoa (Viet Nam); Nan, Wen-Zhe [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Yu, YiKyung [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Tartakovsky, Daniel M., E-mail: dmt@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Yu, S.C., E-mail: scyu@cbnu.ac.kr [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi (Viet Nam)

    2015-11-15

    In this work, we prepared nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al (x=0.0, 0.1 and 0.3) powders by the high energy ball milling technique, and then studied their critical properties. Our analysis reveals that the increase of Cu-doping concentration (up to x=0.3) in these powders leads to a gradual increase of the ferromagnetic–paramagnetic transition temperature from 406 to 452 K. The Banerjee criterion suggests that all the samples considered undergo a second-order phase transition. A modified Arrott plot and scaling analysis indicate that the critical exponents (β=0.419 and 0.442, γ=1.082 and 1.116 for x=0.0 and 0.1, respectively) are located in between those expected for the 3D-Heisenberg and the mean-field models; the values of β=0.495 and γ=1.046 for x=0.3 sample are very close to those of the mean-field model. These features reveal the coexistence of the short- and long-range ferromagnetic order in the nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al powders. Particularly, as the concentration of Cu increases, values of the critical exponent shift towards those of the mean-field model. Such results prove the Cu doping favors establishing a long-range ferromagnetic order. - Highlights: • Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al nanocrystals were prepared by a high energy ball milling method. • A coexistence of the short- and long-range FM order in the nanocrystals. • Cu doping favors establishing a long-range FM order in the nanocrystals. • All the ΔS{sub m}(T, H) data are followed a universal master curve.

  8. Q-ball metamorphosis

    International Nuclear Information System (INIS)

    Flat directions in the minimal supersymmetric standard model are known to deform into nontopological solitons, Q balls, which generally possess both baryon and lepton asymmetries. We investigate how Q balls evolve if some of the constituent fields of the flat direction decay into light species. It is found that the Q balls takes a new configuration whose energy per charge slightly increases due to the decay. Specifically, we show that all the stable Q balls eventually transform into pure B balls via the decay into neutrinos

  9. Q-ball Metamorphosis

    CERN Document Server

    Kawasaki, Masahiro; Kawasaki, Masahiro; Takahashi, Fuminobu

    2004-01-01

    Flat directions in the minimal supersymmetric standard model are known to deform into non-topological solitons, Q-balls, which generally possess both baryon and lepton asymmetries. We investigate how Q-balls evolve if some of the constituent fields of the flat direction decay into light species. It is found that the Q-balls takes a new configuration whose energy per charge slightly increases due to the decay. Specifically, we show that all the stable Q-balls eventually transform into pure B-balls via the decay into neutrinos.

  10. Design and development of PCD micro straight edge end mills for micro/nano machining of hard and brittle materials

    International Nuclear Information System (INIS)

    One of the biggest challenges for mechanical micro/nano milling is the design and fabrication of high precision and high efficiency micro milling tools. Commercially available micro milling tools are either too expensive (around several hundred US dollars) or simply made from downsizing of macro milling tools, which is sometimes not appropriate for the specific micro/nano milling requirements. So the design and fabrication of custom micro milling tools are necessary. In this paper, a micro straight edge endmill (SEE) is designed. Static and dynamic FEM analyses have been done for the SEEs with different rake angles trying to identify their stiffness and natural frequencies. By wire electrical discharge machining (WEDM), the SEEs made of polycrystalline diamond (PCD) with three different rake angles have been fabricated. The evaluation milling on tungsten carbide (WC) and silicon wafer have processed on a nano milling center. Experimental results show the SEEs have a good ability to simultaneously micro/nano milling of both the side and bottom surfaces with submicron surface roughness, and the SEE has high accuracy for large aspect ratio thin wall machining. The milling experiments on silicon wafer have successfully demonstrated that ductile mode machining was achieved and the coolant played an important role in silicon wafer milling

  11. Characteristics of Cu–Al2O3 composites of various starting particle size obtained by high-energy milling

    Directory of Open Access Journals (Sweden)

    VIŠESLAVA RAJKOVIĆ

    2009-05-01

    Full Text Available The powder Cu– Al2O3 composites were produced by high-energy milling. Various combinations of particle size and mixtures and approximately constant amount of Al2O3 were used as the starting materials. These powders were separately milled in air for up to 20 h in a planetary ball mill. The copper matrix was reinforced by internal oxidation and mechanical alloying. During the milling, internal oxidation of pre-alloyed Cu-2 mass %-Al powder generated 3.7 mass % Al2O3 nano-sized particles finely dispersed in the copper matrix. The effect of different size of the starting copper and Al2O3 powder particles on the lattice parameter, lattice distortion and grain size, as well as on the size, morphology and microstructure of the Cu– Al2O3 composite powder particles was studied.

  12. Investigation of wear and tool life of coated carbide and cubic boron nitride cutting tools in high speed milling

    OpenAIRE

    Twardowski, P.; Legutko, S.; G. Krolczyk; S. Hloch

    2015-01-01

    The objective of the investigation was analysis of the wear of milling cutters made of sintered carbide and of boron nitride. The article presents the life period of the cutting edges and describes industrial conditions of the applicability of tools made of the materials under investigation. Tests have been performed on modern toroidal and ball-end mill cutters. The study has been performed within a production facility in the technology of high speed machining of 55NiCrMoV6 and X153CrMoV1...

  13. IMPROVING ENERGY EFFICIENCY VIA OPTIMIZED CHARGE MOTION AND SLURRY FLOW IN PLANT SCALE SAG MILLS

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani; Sanjeeva Latchireddi; Sravan K. Prathy; Trilokyanath Patra

    2005-12-01

    The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the cost of production of the metal. A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and others. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling

  14. Effect of the milling energy on the production and thermal stability of amorphous Mg{sub 50}Ni{sub 50}

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, D. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile)], E-mail: sordonez@usach.cl; Serafini, D. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Chile and Center for Interdisciplinary Research in Materials, CIMAT, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Rojas, P. [Instituto de Fisica, Facultad de Ciencias Basicas y Matematicas, Pontificia Universidad Catolica de Valparaiso, Av. Brasil 2950, Valparaiso (Chile); Bustos, O. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile)

    2009-03-05

    The effect of milling energy on the amorphisation process and subsequent thermal crystallization of Mg{sub 50}Ni{sub 50} was investigated. The amorphous Mg{sub 50}Ni{sub 50} was produced using a planetary mill (medium energy) with a ball to material weight ratio of 13:1, and a SPEX mill (high energy) with a ball to material weight ratio of 20:1. The results obtained by means of X-ray diffraction showed that it is possible to obtain an amorphous Mg{sub 50}Ni{sub 50} alloy, through both milling processes, starting of Ni powders and Mg turnings. However, the amorphisation process requires more time in the planetary mill (80-90 h) than in the SPEX mill (15-20 h), due to the difference in energy level and milling mechanism between these mills. The phase evolution during the amorphisation process is practically independent of the mill energy. In this way, it was observed that the mill conditions promoted an extensive refinement of the microstructure during the first hours of milling. The defects produced during this time led to the amorphisation of part of the system. This amorphous precursor suffers a mechanically induced crystallization into Mg{sub 2}Ni, which is subsequently destabilized into amorphous Mg{sub 50}Ni{sub 50}. Based on the results obtained, it is proposed that the formation of amorphous precursor during mechanical milling of Mg and Ni is a characteristic of the Mg-Ni system, over a wide composition range, rather than of a particular composition. In relation to the thermal crystallization of the amorphous produced, the results of the differential thermal analysis applied to the amorphous samples showed that the formation enthalpy for both amorphous is the same, however, the amorphous produced in a planetary mill presented higher crystallization temperatures and apparent activation energies than the amorphous produced in a SPEX mill. The last behavior would be related with iron contamination coming from the erosion of the milling media. Finally, it is

  15. Reliability of electrode wear compensation based on material removal per discharge in micro EDM milling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Tristo, G.; Hansen, Hans Nørgaard;

    2013-01-01

    This paper investigates the reliability of workpiece material removal per discharge (MRD) estimation for application in electrode wear compensation based on workpiece material removal. An experimental investigation involving discharge counting and automatic on the machine measurement of removed m...

  16. Actuated Ball Sports

    OpenAIRE

    Clerix, Ben

    2015-01-01

    Ball sports offer many physical, mental and social benefits, however they each require a different set of attributes, such as basketball hoops, volleyball nets, bowling pins, etc. Thus in order to play each of these ball sports, we need to provide and manually set up each of different attributes. Digital ball sports on the other hand virtualise these different attributes at the cost of losing physicality, however they have the possibility to create non-realistic experiences. Without physicali...

  17. Toric symplectic ball packing

    OpenAIRE

    Pelayo, Alvaro

    2007-01-01

    We define and solve the toric version of the symplectic ball packing problem, in the sense of listing all 2n-dimensional symplectic-toric manifolds which admit a perfect packing by balls embedded in a symplectic and torus equivariant fashion. In order to do this we first describe a problem in geometric-combinatorics which is equivalent to the toric symplectic ball packing problem. Then we solve this problem using arguments from Convex Geometry and Delzant theory. Applications to symplectic bl...

  18. Viscoelastic modelling of tennis ball properties

    International Nuclear Information System (INIS)

    An explicit finite element (FE) tennis ball model which illustrates the effects of the viscoelastic materials of a tennis ball on ball deformation and bounce during normal impacts is presented. A tennis ball is composed of a rubber core and a fabric cover comprised of a wool-nylon mix which exhibit non-linear strain rate properties during high velocity impacts. The rubber core model was developed and validated using low strain rate tensile tests on rubber samples as well as high velocity normal impacts of pressurised cores at velocities ranging from 15 m/s to 50 m/s. The impacts were recorded using a high speed video (HSV) camera to determine deformation, impact time and coefficient of restitution (COR). The material properties of the core model were tuned to match the HSV results. A two component anisotropic fabric model was created which included artificial Rayleigh damping to account for hysteresis effects, and the core model 'tuning' process was used to refine the cloth layer. The ball model's parameters were in good agreement with experimental data at all velocities for both cores and complete balls, and a time sequenced comparison of HSV ball motion and FE model confirmed the validity of the model.

  19. Viscoelastic modelling of tennis ball properties

    Science.gov (United States)

    Sissler, L.; Jones, R.; Leaney, P. G.; Harland, A.

    2010-06-01

    An explicit finite element (FE) tennis ball model which illustrates the effects of the viscoelastic materials of a tennis ball on ball deformation and bounce during normal impacts is presented. A tennis ball is composed of a rubber core and a fabric cover comprised of a wool-nylon mix which exhibit non-linear strain rate properties during high velocity impacts. The rubber core model was developed and validated using low strain rate tensile tests on rubber samples as well as high velocity normal impacts of pressurised cores at velocities ranging from 15 m/s to 50 m/s. The impacts were recorded using a high speed video (HSV) camera to determine deformation, impact time and coefficient of restitution (COR). The material properties of the core model were tuned to match the HSV results. A two component anisotropic fabric model was created which included artificial Rayleigh damping to account for hysteresis effects, and the core model 'tuning' process was used to refine the cloth layer. The ball model's parameters were in good agreement with experimental data at all velocities for both cores and complete balls, and a time sequenced comparison of HSV ball motion and FE model confirmed the validity of the model.

  20. Physics of ball sports

    Science.gov (United States)

    Cohen, C.; Clanet, C.

    2016-06-01

    Ball sports have been part of human history for thousands of years [1]. Nowadays, 13 of them are part of the Olympic games (badminton, basketball, beach volley, football/soccer, golf, handball, hockey, rugby, table tennis, tennis, volleyball, water polo, ice hockey). All these games differ by launcher (hand, club, racket, bat), ball (size, shape and mass), pitch size and number of players. These differences induce different ball velocities. Apart from the velocities and the way to maximize them, we discuss in this article the ball trajectories and their impact on the size of sports fields.

  1. Large gauged Q balls

    Science.gov (United States)

    Anagnostopoulos, K. N.; Axenides, M.; Floratos, E. G.; Tetradis, N.

    2001-12-01

    We study Q balls associated with local U(1) symmetries. Such Q balls are expected to become unstable for large values of their charge because of the repulsion mediated by the gauge force. We consider the possibility that the repulsion is eliminated through the presence in the interior of the Q ball of fermions with charge opposite to that of the scalar condensate. Another possibility is that two scalar condensates of opposite charge form in the interior. We demonstrate that both these scenarios can lead to the existence of classically stable, large, gauged Q balls. We present numerical solutions, as well as an analytical treatment of the ``thin-wall'' limit.

  2. Pengaruh Penambahan Ni, Cu, dan Al dan Waktu Milling pada Mechanical Alloying Terhadap Sifat Absorpsi dan Desorpsi Mg sebagai Material Penyimpan Hidrogen

    Directory of Open Access Journals (Sweden)

    Febrian Budi Pratama

    2012-09-01

    Full Text Available Mg merupakan salah satu material yang digunakan sebagai material penyimpan hidrogen dengan membentuk MgH2. Sifat absorpsi dan desorpsi hidrogen dari suatu metal hidrida salah satunya tergantung  pada bahan, unsur penambah, dan metode pembuatannya. Pada penelitian kali ini Mg sebagai material penyimpan hidrogen dihasilkan melalui metode mechanical alloying dengan unsur penambah Ni, Cu, dan Al dan variasi waktu milling 10, 20, 30 jam. Selanjutnya sampel dilakukan pengujian SEM, XRD, DSC, dan Uji hidrogenisasi. Dari data uji diperoleh bahwa meningkatnya waktu milling menurunkan ukuran partikel sehingga meningkatkan wt% hidrogen terabsorb dan menurunkan temperatur onset desorpsi. Namun efek aglomerasi dan coldwelding yang berlebih pada proses mechanical alloying mengakibatkan ukuran partikel menjadi lebih besar. Unsur pemadu Al dan Cu berfungsi sebagai katalis, sedangkan Ni berfungsi sebagai pemadu yang ikut bereaksi dengan hidrogen. Mg10wt%Al dengan waktu milling 20 jam mempunyai nilai weight percent terbaik H2 yaitu 0.38% dalam temperatur hidrogenisasi 2500C, tekanan 3 atm, dan waktu tahan 1 jam. Sedangkan Mg10wt%Al dengan waktu milling 30 jam memiliki temperatur onset paling rendah yaitu 341.490C Kata Kunci— Absorpsi, Desorpsi, Material Penyimpan Hidrogen, Mechanical Alloying, Mg

  3. Work Roll Materials For Hot Strip Milling and Casting Methods of Rolling Roll

    Directory of Open Access Journals (Sweden)

    Şadi KARAGÖZ

    2009-03-01

    Full Text Available The selection of materials for rolling, which is one of the powerful manufacturing process and the influence of these materials on the roll properties is an important factor. Also, the use of suitable material and various manufacturing technologies affect these characteristics. To understand that which roll grade is needed for which application, the rolling conditions, the roll grades and their properties should be known. In this work the evolution of roll materials from classical materials up to recently developed materials are presented and bimetallic roll technologies are investigated. Furthermore, experimentally cast pearlitic and martensitic roll microstructures were examined. The influence of microstructural phases on the roll properties were analyzed with the results of mechanical and microstructural observations.

  4. Effect of a milling surface treatment on the properties of metal hydride alloy particles

    International Nuclear Information System (INIS)

    This work reports results of studies on the electrochemical and structural properties of a Ti/Zr-based metal hydride alloy covered by Ni and LaNi4,7Sn0,3 powder additives by ball milling. The effect of this treatment is investigated for the activation time, hydrogen storage capacity and equilibrium pressure, cycling stability and the hydration/dehydration kinetics. Charge and discharge cycles show a significant decrease of the activation time due to an increase of the active area caused by the milling treatment, independent of the additive. However, other results have evidenced little effect of the milling surface treatment on the charge storage capacity, hydrogen equilibrium pressure, and hydration/dehydration kinetics, for both the Ni and LaNi4,7Sn0,3 covered materials. (author)

  5. Proposed industrial recoverd materials utilization targets for the textile mill products industry

    Energy Technology Data Exchange (ETDEWEB)

    1979-05-01

    Materials recovery targets were established to represent the maximum technically and economically feasible increase in the use of energy-saving materials by January 1, 1987. This report describes targets for the textile industry and describes how those targets were determined. (MCW)

  6. Understanding milling induced changes: Some results

    Indian Academy of Sciences (India)

    K Chattopadhyay; N Ravishankar; T A Abinandanan; Viji Varghese

    2003-10-01

    The effect of mechanical milling on materials has been studied using simple model systems. The results show that milling leads to enhancement in both thermodynamic driving force and transport kinetics. A study of some characteristic physical properties of the milled samples in comparison to the bulk shows how milling affects the properties.

  7. Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

    Science.gov (United States)

    Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

    1994-01-01

    A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

  8. Borner Ball Neutron Detector

    Science.gov (United States)

    2002-01-01

    The Bonner Ball Neutron Detector measures neutron radiation. Neutrons are uncharged atomic particles that have the ability to penetrate living tissues, harming human beings in space. The Bonner Ball Neutron Detector is one of three radiation experiments during Expedition Two. The others are the Phantom Torso and Dosimetric Mapping.

  9. Ball screw inspection setup

    Science.gov (United States)

    Janusz, Rzepka; Sambor, Slawomir; Pienkowski, Janusz; Bielenin, Marcin

    2003-05-01

    In the following paper we describe arrangements of laser interferometer for investigation of screws and for inspection of ball screws. We have constructed two of them, namely: the technological setup for investigations of screw in process of production and the ball screw inspection setup. The former one is used to measure the pitch of screws. The data gathered during measurement is used to calculate the parameters for grinding machine. The later setup is used for testing parameters of complete ball screws. The software supporting this setup makes calculation of parameters of tested ball screw and creation of reports possible. Additionally, the inspection setup is the one that the torque measuring arrangements have been integrated on. Both the arrangements and the software allow for measurements of all parameters during movement of nut in full travel length of the ball screw and make charts and reports.

  10. Characterization of Al{sub 2}O{sub 3}NP-Al{sub 2024} and Ag{sub C}NP-Al{sub 2024} composites prepared by mechanical processing in a high energy ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Carreno-Gallardo, C. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes No. 120, C.P. 31109, Chihuahua (Mexico); Universidad Autonoma Metropolitana, Departamento de Materiales, Av. San Pablo No. 180, Col Reynosa-Tamaulipas, CP 02200, D.F. (Mexico); Estrada-Guel, I. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes No. 120, C.P. 31109, Chihuahua (Mexico); Romero-Romo, M. [Universidad Autonoma Metropolitana, Departamento de Materiales, Av. San Pablo No. 180, Col Reynosa-Tamaulipas, CP 02200, D.F. (Mexico); Cruz-Garcia, R. [Universidad Autonoma de Chihuahua (UACH), Facultad de Ingenieria, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125, Chihuahua (Mexico); Lopez-Melendez, C. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes No. 120, C.P. 31109, Chihuahua (Mexico); Universidad La Salle Chihuahua, Prol. Lomas de Majalca No. 11201, C.P. 31020, Chihuahua (Mexico); Martinez-Sanchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes No. 120, C.P. 31109, Chihuahua (Mexico)

    2012-09-25

    Graphical abstract: Mechanical alloying was used to produce two kinds of metal matrix composites based on 2024 aluminum alloy, the nanocomposites were reinforced with different percentages of Al{sub 2}O{sub 3} and Ag{sub C} nanoparticles. The content of nanoparticles has a role important on the mechanical properties of the nanocomposite. 10 h of milling time are enough to former the Al{sub 2024} nanocomposites. The results obtained by differential scanning calorimeter show the temperatures of intermetallic precipitation, which were identified by X-ray diffraction. The results revealed that mechanical alloying is an excellent route to incorporate and distribute NP into Al{sub 2024}. Highlights: Black-Right-Pointing-Pointer Aluminum-based nanocomposites were synthesized bay milling process. Black-Right-Pointing-Pointer An homogeneous nanoparticles dispersion was reached and mechanical properties were enhanced. Black-Right-Pointing-Pointer Phase transformation during heating was characterized by XRD. - Abstract: Mechanical alloying was used to produce two kinds of metal matrix composites based on 2024 aluminum alloy. The nanocomposites were reinforced with different percentages of Al{sub 2}O{sub 3} and Ag{sub C} nanoparticles. The content of nanoparticles has an important role on the mechanical properties of the nanocomposites. A milling time of 10 h is enough to form the Al{sub 2024} nanocomposites. The thermograms obtained by differential scanning calorimeter show the temperatures of phase precipitation, which were identified by X-ray diffraction. The results revealed that mechanical alloying is an excellent route for the incorporation and distribution of nanoparticles into Al{sub 2024}.

  11. Happy Balls, Unhappy Balls, and Newton's Cradle

    Science.gov (United States)

    Kagan, David

    2010-01-01

    The intricacies of Newton's Cradle are well covered in the literature going as far back as the time of Newton! These discussions generally center on the highly elastic collisions of metal spheres. Thanks to the invention of happy and unhappy balls, you can build and study the interaction of less elastic systems (see Fig. 1).

  12. Structure and properties of barium ferrite powders prepared by milling and annealing

    Directory of Open Access Journals (Sweden)

    J. Wron

    2007-12-01

    Full Text Available Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatmentDesign/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The morphology of Fe2O3 and BaCO3 powders after milling was analyzed using the scanning electron microscopy (SEM method. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases and leads to increase the content of Fe2O3 phase and decrease of BaCO3 content. Milling process causes enriching of surface layer of powder particles by Fe2O3. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950°C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force for the mixture of powders annealed at 950°C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. From morphology images and distribution of powder particle size it can be concluded, that the size of tested powder particles increases with increasing time of milling process. The increase of milling time up to 20 hours leads to joining of smaller particles in bigger ones; agglomerates are formed.Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable component to produce sintered and

  13. Compact Q-balls

    CERN Document Server

    Bazeia, D; Marques, M A; Menezes, R; da Rocha, R

    2016-01-01

    In this work we deal with non-topological solutions of the Q-ball type in two space-time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  14. Spinning Q-Balls

    OpenAIRE

    Volkov, Mikhail S.; Woehnert, Erik

    2002-01-01

    We present numerical evidence for the existence of spinning generalizations for non-topological Q-ball solitons in the theory of a complex scalar field with a non-renormalizable self-interaction. To the best of our knowledge, this provides the first explicit example of spinning solitons in 3+1 dimensional Minkowski space. In addition, we find an infinite discrete family of radial excitations of non-rotating Q-balls, and construct also spinning Q-balls in 2+1 dimensions.

  15. Toward the complete utilization of rice straw: Methane fermentation and lignin recovery by a combinational process involving mechanical milling, supporting material and nanofiltration.

    Science.gov (United States)

    Sasaki, Kengo; Okamoto, Mami; Shirai, Tomokazu; Tsuge, Yota; Fujino, Ayami; Sasaki, Daisuke; Morita, Masahiko; Matsuda, Fumio; Kikuchi, Jun; Kondo, Akihiko

    2016-09-01

    Rice straw was mechanically milled using a process consuming 1.9MJ/kg-biomass, and 10g/L of unmilled or milled rice straw was used as the carbon source for methane fermentation in a digester containing carbon fiber textile as the supporting material. Milling increased methane production from 226 to 419mL/L/day at an organic loading rate of 2180mg-dichromate chemical oxygen demand/L/day, corresponding to 260mLCH4/gVS. Storage of the fermentation effluent at room temperature decreased the weight of the milled rice straw residue from 3.81 to 1.00g/L. The supernatant of the effluent was subjected to nanofiltration. The black concentrates deposited on the nanofiltration membranes contained 53.0-57.9% lignin. Solution nuclear magnetic resonance showed that lignin aromatic components such as p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) were retained primarily, and major lignin interunit structures such as the β-O-4-H/G unit were absent. This combinational process will aid the complete utilization of rice straw. PMID:27318161

  16. Investigations of mechanically alloyed nanocrystalline materials by microacoustic techniques

    Science.gov (United States)

    Dubief, P.; Hunsinger, J. J.; Gaffet, E.

    1996-09-01

    The purpose of this work is to determine whether yes or no, there is a difference between the physico-chemical properties of the nanocrystalline and the microcrystalline materials. This paper deals with the acoustical behavior of nanocrystalline materials which were prepared by ball- milling and mechanical alloying. Based on two specific techniques (acoustic microinterferometry and acoustic microechography), some of the mechanical properties (elastic ones) may be determined, related to a materials volume of about a few micrometers 3 (for the high frequency 600 MHz apparatus). Thus the mechanically alloyed powders (typically 200 micrometers in diameter), behave as massive materials in this range of frequency. The measurements are directly obtained on the grains and do not take into account the voids induced by further sinthering process. The result of such a micromechanical approach will be given for pure ball-milled elements (Fe) and for the supersaturated solid phase Fe(Si) obtained by mechanical alloying.

  17. Aerodynamics of sports balls

    Science.gov (United States)

    Mehta, R. D.

    Research data on the aerodynamic behavior of baseballs and cricket and golf balls are summarized. Cricket balls and baseballs are roughly the same size and mass but have different stitch patterns. Both are thrown to follow paths that avoid a batter's swing, paths that can curve if aerodynamic forces on the balls' surfaces are asymmetric. Smoke tracer wind tunnel tests and pressure taps have revealed that the unbalanced side forces are induced by tripping the boundary layer on the seam side and producing turbulence. More particularly, the greater pressures are perpendicular to the seam plane and only appear when the balls travel at velocities high enough so that the roughness length matches the seam heigh. The side forces, once tripped, will increase with spin velocity up to a cut-off point. The enhanced lift coefficient is produced by the Magnus effect. The more complex stitching on a baseball permits greater variations in the flight path curve and, in the case of a knuckleball, the unsteady flow effects. For golf balls, the dimples trip the boundary layer and the high spin rate produces a lift coefficient maximum of 0.5, compared to a baseball's maximum of 0.3. Thus, a golf ball travels far enough for gravitational forces to become important.

  18. 硬脂酸对高能球磨制备 Ti-48 at%Al粉体性能的影响%Effect of stearic acid on Ti-48at%Al powder properties prepared by high-energy ball milling

    Institute of Scientific and Technical Information of China (English)

    易峰; 蔡晓兰; 周蕾; 胡翠; 姜庆伟; 李铮; 余明俊

    2014-01-01

    研究了高能球磨过程中不同添加量的硬脂酸(十八烷酸)对Ti-48at%Al粉体和材料性能的影响。利用XRD、SEM、EDS、激光粒度仪、万能力学试验机、显微硬度计分别研究了粉末的物相、形貌、球磨后的成分、粒度和烧结后Ti-48at%Al的力学性能。结果表明,当硬脂酸添加量为0wt%时,有利于Ti-48at%Al机械合金化,但粉体团聚粘壁的现象严重,偏离原始设计成分;添加量为2.5wt%时,D50为16.85μm,颗粒形貌呈不规则薄片状且均匀化程度最好、成分最接近初始成分设计。硬脂酸不同添加量的粉体经过35 MPa冷压,950℃氩气保护烧结后,硬度和压缩极限强度在2wt%时达到最大值,分别为482 HV0.1和284 MPa。%Effect of different amount of stearic acid on the characteristics of Ti-48at%Al powder which prepared by high-energy ball milling was researched.The phases,particle morphology, composition and particle size of the ball milled powers were investigated by means of X-ray diffraction, scanning electron microscope, EDS and laser particle-size meter and the mechanical properties of stearic acid is Ti-48at%Al after sintering were examined by Vickers hardness tester and universal mechanical testing machine.The results indicate that when the adding amount of stearic acid is 0wt%, it benefits for mechanically alloyed of Ti-48at%Al.But the powder aggregation and stick on mill wall is serious,and it results in serious deviation of prior designed compositiion.When the stearic acid adding amount is 2.5wt%, the powder composition is nearest to the initial designed prescription,the D50 is 16.85 μm, particle appearance is irregular chip shape and uniform. When the stearic acid adding amount is 2wt%, the performances of Ti-48at%Al pieces prepared compressing at 35 MPa and sintering at 950 ℃under argon protection are that Vickers hardness can reach 482 HV0.1, the compressive strength can be 284 MPa.

  19. Synthesis and characterization of SiC and SiC/Si3N4 composite nano powders from waste material.

    Science.gov (United States)

    Zawrah, M F; Zayed, M A; Ali, Moustafa R K

    2012-08-15

    In the present work, nano silicon carbide has been prepared by pyrolysis of rice-husk ashes as starting materials. Three rice-husk ash samples having different features were used. The first was coarse-grained rice husk ash (fired husk as is), the second was fine rice husk ash (hand-ground), while the third was ball milled one. Effect of ball milling of the starting ashes for 6h on the formation of nano SiC was investigated and compared with those prepared without milling. The particle sizes of the prepared SiC materials were affected by the milling process. The particle sizes of the obtained nano SiC from ball milled staring materials were smaller than those prepared without milling. The pyrolysis conditions, i.e. the temperature and atmosphere were optimized. The optimum firing temperature to obtain well crystalline nano SiC was 1550°C. The effect of pyrolysis atmosphere, i.e. argon, vacuum and nitrogen was also demonstrated. The pyrolysis in argon exhibited lower efficiency on the formation of SiC than vacuum; while the pyrolysis in nitrogen atmosphere led to formation of SiC/Si(3)N(4) nanocomposite. PMID:22673059

  20. Demonstration of a silicon nitride attrition mill for production of fine pure Si and Si3N4 powders

    Science.gov (United States)

    Herbell, T. P.; Glasgow, T. K.; Orth, N. W.

    1984-01-01

    To avoid metallic impurities normally introduced by milling ceramic powders in conventional steel hardware, an attrition mill (high-energy stirred ball mill) was constructed with the wearing parts (mill body, stirring arms, and media) made from silicon nitride. Commercial silicon and Si3N4 powders were milled to fine uniform particles with only minimal contamination - primarily from wear of the sintered Si3N4 media.

  1. Effect of wet grinding on structural properties of ball clay

    International Nuclear Information System (INIS)

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature

  2. Research on Abrasives in the Chemical Mechanical Polishing Process for Silicon Nitride Balls

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Silicon nitride (Si 3N 4) has been the main material for balls in ceramic ball bearings, for its lower density, high strength, high hardness, fine thermal stability and anticorrosive, and is widely used in various fields, such as high speed and high temperature areojet engines, precision machine tools and chemical engineer machines. Silicon nitride ceramics is a kind of brittle and hard material that is difficult to machining. In the traditional finishing process of silicon nitride balls, balls are lapped...

  3. Solid state amorphization kinetic of alpha lactose upon mechanical milling.

    Science.gov (United States)

    Caron, Vincent; Willart, Jean-François; Lefort, Ronan; Derollez, Patrick; Danède, Florence; Descamps, Marc

    2011-11-29

    It has been previously reported that α-lactose could be totally amorphized by ball milling. In this paper we report a detailed investigation of the structural and microstructural changes by which this solid state amorphization takes place. The investigations have been performed by Powder X-ray Diffraction, Solid State Nuclear Magnetic Resonance ((13)C CP-MAS) and Differential Scanning Calorimetry. The results reveal the structural complexity of the material in the course of its amorphization so that it cannot be considered as a simple mixture made of a decreasing crystalline fraction and an increasing amorphous fraction. Heating this complexity can give rise to a fully nano-crystalline material. The results also show that chemical degradations upon heating are strongly connected to the melting process. PMID:21983262

  4. The bowling balls

    CERN Document Server

    CERN Bulletin

    2010-01-01

    10 November 1972: CERN’s Bent Stumpe places an order for 12 bowling balls for a total cost of 95 US dollars. Although not evident at first sight, he is buying the heart of some of the first tracking devices to be used in the SPS control room. Today, Bent Stumpe’s device would be called a desktop mouse…   The first order for 4 bowling balls later changed to 12 balls. The bowling balls became the heart of Bent Stumpe's mouse. Almost 40 years ago, the web, Wikipedia and Google did not exist and it was much more difficult to know whether other people in other parts of the world or even in the same laboratory were facing the same problems or developing the same tools. At that time, Bent Stumpe was an electronics engineer, newly recruited to work on developments for the SPS Central Control room. One of the things his supervisor asked him to build as soon as possible was a device to control a pointer on a screen, also called a tracker ball. The heart of the device was the...

  5. Yang-Mills and Beyond

    CERN Document Server

    Marateck, Samuel

    2011-01-01

    In their 1954 paper, Yang and Mills invented the non-Abelian field strength to satisfy certain criteria but didn't explain how it could be derived. In the penultimate section we show how the Yang-Mills field strength derives from Yang's gauge transformation. The preceding sections place Yang-Mills theory in historical perspective and cover material relating to the field strength. The final section shows how Yang-Mills theory was combined with spontaneous symmetry breaking, the Goldstone theorem and subsequent work to contribute to the Standard Model of particle physics.

  6. Dark matter balls help supernovae to explode

    Science.gov (United States)

    Froggatt, C. D.; Nielsen, H. B.

    2015-10-01

    As a solution to the well-known problem that the shock wave potentially responsible for the explosion of a supernova actually tends to stall, we propose a new energy source arising from our model for dark matter. Our earlier model proposed that dark matter should consist of cm-large white dwarf-like objects kept together by a skin separating two different sorts of vacua. These dark matter balls or pearls will collect in the middle of any star throughout its lifetime. At some stage during the development of a supernova, the balls will begin to take in neutrons and then other surrounding material. By passing into a ball nucleons fall through a potential of order 10 MeV, causing a severe production of heat — of order 10 foe for a solar mass of material eaten by the balls. The temperature in the iron core will thereby be raised, splitting up the iron into smaller nuclei. This provides a mechanism for reviving the shock wave when it arrives and making the supernova explosion really occur. The onset of the heating due to the dark matter balls would at first stop the collapse of the supernova progenitor. This opens up the possibility of there being two collapses giving two neutrino outbursts, as apparently seen in the supernova SN1987A — one in Mont Blanc and one 4 h 43 min later in both IMB and Kamiokande.

  7. High-energy milling as a method for obtaining tetragonal form of PbO

    Directory of Open Access Journals (Sweden)

    M. Staszewski

    2012-05-01

    Full Text Available Purpose: The aim of this work was to verify the usefulness of high-energy milling, using electromagnetic mill, as a method for obtaining tetragonal (red form of PbO, alternative to standard methods.Design/methodology/approach: Experiments were held to compare samples of the yellow form of PbO after milling in electromagnetic mill with the ones milled in high-energy planetary ball mill as a function of grinding medium (sticks or balls to powder mass ratio, milling duration and instrumental conditions.Findings: Quantitative X-ray diffraction and analysis of granulation of mill products were applied. The characteristics of structural transitions of studied powder depending on milling conditions were defined.Practical implications: Utilization of electromagnetic mills was found to be suitable for milling of PbO. The speed and unit price of this process assure competitiveness of the method to standard methods. Tested method of high-energy milling assures possibility to supply, in certain conditions, good product. Obtained product may be used for manufacturing of minium.Originality/value: Optimum conditions of milling process and milling limitations were determined. Suggestions regarding optimization of mill construction were presented.

  8. Mg2FeH6-based nanocomposites with high capacity of hydrogen storage processed by reactive milling

    Directory of Open Access Journals (Sweden)

    Alexandre Augusto Cesario Asselli

    2012-04-01

    Full Text Available The compound Mg2FeH6 was synthesized from a 2Mg-Fe mixture in a single process through high-energy ball milling under hydrogen atmosphere at room temperature. The complex hydride was prepared from Mg powder and granulated or powdered Fe using a planetary mill. The phase evolution during different milling times was performed by X-rays diffraction technique. The dehydrogenation behavior of the hydride was investigated through simultaneous thermal analyses of differential scanning calorimetry and thermogravimetry coupled with mass spectrometer. The use of powdered iron as starting material promoted conversion to complex hydride at shorter milling times than when granulated iron was used, nevertheless, after 24 hours of milling the 2Mg-Fe (powdered or granulated mixtures presented similar dehydrogenation behavior. The hydrogen absorption during milling was on average 3.2 wt. (%, however, changing the proportions of the reagents to 3Mg-Fe a Mg2FeH6-MgH2 based nanocomposite with higher density of hydrogen (5.2 wt. (% was obtained.

  9. Combined fundamental and experimental approach to milling

    Science.gov (United States)

    Starkey, Derek

    Air jet mills are important tools in the size reduction processing of pharmaceutical powders. The benefits of the air jet mill to the pharmaceutical industry are its sanitary design (no moving parts or media) and ability to produce narrow particle size distributions. Due to the high-value nature of active pharmaceutical ingredients, a trial-and-error approach to obtain optimal milling conditions for size reduction would lead to a needless expenditure of time and valuable resources. This work uses population balances for modeling the continuous milling of a spiral jet mill with inexpensive, readily available excipient powders, and predicts milling model parameters for high value powders with only small quantities being consumed. We have developed a multilevel model that describes the effect of material characteristics and mill operating variables on particle breakage in a specific air jet mill. This model allows us to predict product size distributions of brittle crystalline materials. The method used to develop this model can be utilized for many self-classifying mills. For a new mill, extensive initial milling with inexpensive excipient powders is required to determine mill-dependent model parameters. Subsequently, quick material characterization experiments can be made with limited powder consumption of expensive powders to determine powder-dependent milling parameters.

  10. Laboratory demonstration of ball lightning

    International Nuclear Information System (INIS)

    A common laboratory facility for creating glowing flying plasmoids akin to a natural ball lightning, allowing a number of experiments to be performed to investigate the main properties of ball lightning, is described. (methodological notes)

  11. Peculiarities of metal balls deformation by quasi-spherical shock waves

    International Nuclear Information System (INIS)

    The paper presents results of experimental studies of metal balls deformation by quasi-spherical shock waves. With use of sequential increase of explosive layer thickness characterizing level of shock wave loading for ball surface, we recorded various extents of ball from saving of material continuity to fragmentation. Results of explosive loading of metals with different strength and plastic properties are discussed

  12. A Neural Intellectual Decoupling Control Strategy for a Power Plant Ball Miller

    Institute of Scientific and Technical Information of China (English)

    Hong Zhou; Ming-Hui Zhong

    2005-01-01

    In this paper a multivariable decoupling control algorithm for the coal-pulverizing system of a ball miller is provided. It is based on a three-neuron control mechanism and solves the problem of long delay and strong coupling in ball mill coal pulverizing systems. Our system has been used for more than a year, the principle and equipment of which have been proved effective and profitable.

  13. Analysis of grease contamination influence on the internal radial clearance of ball bearings by thermographic inspection

    OpenAIRE

    Mišković Žarko Z.; Mitrović Radivoje M.; Stamenić Zoran V.

    2016-01-01

    One of the most important factors influencing ball bearings service life is its internal radial clearance. However, this parameter is also very complex because it depends on applied radial load and ball bearings dimensions, surface finish and manufacturing materials. Thermal condition of ball bearings also significantly affects internal radial clearance. Despite many researches performed in order to find out relevant facts about different aspects of ball be...

  14. Microstructure and mechanical properties of 7075 aluminum alloy nanostructured composites processed by mechanical milling and indirect hot extrusion

    International Nuclear Information System (INIS)

    Nanostructured composites of 7075 aluminum alloy and carbon coated silver nanoparticles were produced by mechanical milling and indirect hot extrusion. The milling products were obtained in a high energy SPEX ball mill, and then were compacted by uniaxial load and pressure-less sintered under argon atmosphere. Finally, the sintered product was hot extruded. Carbon coated silver nanoparticles were well distributed in the matrix of the extruded material. Tensile tests were carried out to corroborate the hypothesis that second phase particles, well dispersed in the matrix, improve the strength of the material. High resolution transmission electron microscopy was employed to locate and make sure that the silver nanoparticles were homogeneously and finely dispersed. Highlights: ► 7075 Al nanostructured composites can be produced by mechanical milling. ► Carbon coated silver nanoparticles are well dispersed into aluminum matrix. ► Ductile Ag–C NP's improve the mechanical properties of the 7075 Al-alloy. ► Ag–C NP's content has an important effect in the particle and crystallite size. ►Ag–C NP's keep their morphology after milling and conformation processes.

  15. Microstructure and mechanical properties of 7075 aluminum alloy nanostructured composites processed by mechanical milling and indirect hot extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Campos, R., E-mail: ruben.flores@itesm.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Tecnologico de Monterrey Campus Saltillo, Departamento de Ingenieria, Prol. Juan de la Barrera No. 1241 Ote., Col. Cumbres, CP 25270, Saltillo, Coah., Mexico (Mexico); Estrada-Guel, I., E-mail: ivanovich.estrada@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Martinez-Sanchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Herrera-Ramirez, J.M., E-mail: martin.herrera@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico)

    2012-01-15

    Nanostructured composites of 7075 aluminum alloy and carbon coated silver nanoparticles were produced by mechanical milling and indirect hot extrusion. The milling products were obtained in a high energy SPEX ball mill, and then were compacted by uniaxial load and pressure-less sintered under argon atmosphere. Finally, the sintered product was hot extruded. Carbon coated silver nanoparticles were well distributed in the matrix of the extruded material. Tensile tests were carried out to corroborate the hypothesis that second phase particles, well dispersed in the matrix, improve the strength of the material. High resolution transmission electron microscopy was employed to locate and make sure that the silver nanoparticles were homogeneously and finely dispersed. Highlights: Black-Right-Pointing-Pointer 7075 Al nanostructured composites can be produced by mechanical milling. Black-Right-Pointing-Pointer Carbon coated silver nanoparticles are well dispersed into aluminum matrix. Black-Right-Pointing-Pointer Ductile Ag-C NP's improve the mechanical properties of the 7075 Al-alloy. Black-Right-Pointing-Pointer Ag-C NP's content has an important effect in the particle and crystallite size. Black-Right-Pointing-Pointer Ag-C NP's keep their morphology after milling and conformation processes.

  16. The dynamic behavior of squash balls

    Science.gov (United States)

    Lewis, Gareth J.; Arnold, J. Cris; Griffiths, Iwan W.

    2011-03-01

    The behavior of a squash ball constitutes an excellent case study of the dynamic behavior of rubbery materials. It is shown that the complex viscoelastic behavior of rubber can be investigated using simple drop bounce tests and compression tests. The drop tests show that the coefficient of restitution increases as the ball temperature increases. The compression tests show that as the speed of compression increases or as the ball temperature decreases, the compressive force and the energy loss both increase. These effects are due to the viscoelastic nature of the rubber and are an excellent example of the time-temperature equivalence of polymers. Compression tests were performed on balls with small holes at the base to separate the effects of the internal air pressure from the material deformation. It was found that the internal air pressure contributed about one-third to the compressive force, but contributed little to energy loss. This behavior shows that the rubber material dominates the rebound behavior and that the normal warming up process at the start of a squash game is important to raise the temperature of the rubber rather than to increase the internal air pressure.

  17. Purification of Tronoh Silica Sand via preliminary process of mechanical milling

    Science.gov (United States)

    H, Nazratulhuda; M, Othman

    2016-02-01

    The purification of Tronoh silica sand is an important step in expanding technical applications of this silica sand. However no research on purifying of Tronoh silica sand has been reported. This study is focused on ball milling technique as a preliminary technique for Tronoh silica sand purification. The objectives are to study the effect of ball milling to the purification of the silica sand and to analyze its characteristics after the ball milling process. The samples before and after milling process were analyzed by using XRF, XRD, SEM and TEM. Results showed that the purity of SiO2 was increased, the size of the particles has been reduced and the surface area has increased. The crystalline phases for the silica before and after 4 hour milling time were remained constant.

  18. Effect of milling on the characteristics and sinterability of UO2 powders from different conversion processes

    International Nuclear Information System (INIS)

    The effect of ball-milling time on the change of powder characteristics, compaction behavior (compaction pressure range: 200-400 MPa) and sinterability (1700degC in H2 atmosphere) have been investigated for two different kinds of UO2 (ex-ADU and ex-AUC) prepared by wet processes. It is observed that, while the ex-ADU UO2 has little been affected, the ex-AUC UO2 powder has been largely affected by ball-milling treatment. This may be attributed to the characteristics of particle size formed during preparation step i.e., the former has a small average size of about 0.9 μm, while the latter has a relatively large one of about 28 μm. It appeared that the size reduction by ball-mill treatment is limited only to the particle size of larger than 1 μm, and to the extend of maximum decrease in size about 0.5 μm. In case of ex-AUC UO2, the powder particle size is observed to decrease with ball-mill time and, compact density and sintered density of ball-milled powder increased compared with those of as-received powder, under the same conditions. This may be mainly due to the fine particles formed by the ball-mill treatment. (author)

  19. GITT studies on oxide cathode LiNi1/3Co1/3Mn1/3O2 synthesized by citric acid assisted high-energy ball milling

    Indian Academy of Sciences (India)

    Weidong Zheng; Miao Shui; Jie Shu; Shan Gao; Dan Xu; Liangliang Chen; Lin Feng; Yuanlong Ren

    2013-06-01

    Layered LiNi1/3Co1/3Mn1/3O2 was synthesized by a citric acid assisted solid-state method. The structure and electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 materials were investigated. XRD analysis indicated the as-synthesized LiNi1/3Co1/3Mn1/3O2 was with the layered -NaFeO2 structure. The discharge capacity was about 154 m.Ahg-1 at 0.1 °C rate in the range of 2.0–4.5 V. The kinetics of the LiNi1/3Co1/3Mn1/3O2 materials was investigated by the galvanostatic intermittent titration technique (GITT) method. The lithium ion diffusion coefficient of the LiNi1/3Co1/3Mn1/3O2 was determined in the range of 10-8−10-9 cm2.s-1 as a function of voltage of 3.7−4.5 V.

  20. Frictional performance of ball screw

    International Nuclear Information System (INIS)

    As feed screws, ball screws have become to be adopted in place of trapezoidal threads. The structure of ball screws is complex, but those are the indispensable component of NC machine tools and machining centers, and are frequently used for industrial robots. As the problems in the operation of ball screws, there are damage, life and the performance related to friction. As to the damage and life, though there is the problem of the load distribution on balls, the results of the research on rolling bearings are applied. The friction of ball screws consists of the friction of balls and a spiral groove, the friction of a ball and a ball, the friction in a ball-circulating mechanism and the viscous friction of lubricating oil. It was decided to synthetically examine the frictional performance of ball screws, such as driving torque, the variation of driving torque, efficiency, the formation of oil film and so on, under the working condition of wide range, using the screws with different accuracy and the nuts of various circuit number. The experimental setup and the processing of the experimental data, the driving performance of ball screws and so on are reported. (Kako, I.)

  1. MECHANICAL GRINDING OF SOLID POWDER MATERIALS

    Directory of Open Access Journals (Sweden)

    Dmitrenko D. V.

    2015-10-01

    Full Text Available The article is dedicated to the determination of conditions for solid bodies’ fragmentation, providing minimal size of particles by means of their mechanical dispersion through the example of powders of titanium carbide (TiC, cubic boron nitride – borazon (CBN and boron carbide (B4C. The theoretical and practical aspects of the process of mechanical fragmentation of particles of solid powder materials in ball mill for their further utilization in furnace charge for high-speed gas-flame sputtering of wear-resistant composite materials are examined in the article. Methods of preliminary calculation of minimum allowable size of solid particles of powder materials during mechanical fragmentation, based upon Griffiths’ mechanical theory of rapture using experimental data for hardness of material and its yield are proposed and theoretically substantiated. There we have the results of experiments on mechanical fragmentation of titanium carbide in attritor, boron carbide and cubic boron nitride in centrifugal planetary mill, confirming correctness of theoretical propositions and calculations are set out. Recommendations on mechanical fragmentation of solid powder materials in ball mills are formulated as well

  2. Dark Matter Balls Help Supernovae to Explode

    CERN Document Server

    Froggatt, Colin D

    2015-01-01

    As a solution to the well-known problem that the shock wave potentially responsible for the explosion of a supernova actually tends to stall, we propose a new energy source arising from our model for dark matter. Our earlier model proposed that dark matter should consist of cm-large white dwarf-like objects kept together by a skin separating two different sorts of vacua. These dark matter balls or pearls will collect in the middle of any star throughout its lifetime. At some stage during the development of a supernova the balls will begin to take in neutrons and then other surrounding material. By passing into a ball nucleons fall through a potential of order 10 MeV, causing a severe production of heat - of order 10 foe for a solar mass of material eaten by the balls. The temperature in the iron core will thereby be raised, splitting up the iron into smaller nuclei. This provides a mechanism for reviving the shock wave when it arrives and making the supernova explosion really occur. The onset of the heating d...

  3. Effect of mechanical milling on the structural, magnetic and dielectric properties of coprecipitated ultrafine zinc ferrite

    International Nuclear Information System (INIS)

    Nanosized ZnFe2O4 particles containing traces of α-Fe2O3 by intent were produced by low temperature chemical coprecipitation methods. These particles were subjected to high-energy ball milling. These were then characterised using X-ray diffraction, magnetisation and dielectric studies. The effect of milling on zinc ferrite particles have been studied with a view to ascertaining the anomalous behaviour of these materials in the nanoregime. X-ray diffraction and magnetisation studies carried out show that these particles are associated with strains and it is the surface effects that contribute to the magnetisation. Hematite percentage, probably due to decomposition of zinc ferrite, increases with milling. Dielectric behaviour of these particles is due to interfacial polarisation as proposed by Koops. Also the defects caused by the milling produce traps in the surface layer contributes to dielectric permittivity via spin polarised electron tunnelling between grains. The ionic mechanism is enhanced in dielectrics with the rise in temperature which results in the increase of dielectric permittivity with temperature

  4. Nanocrystalline titanium characteristics obtained through cryogenic and high energy milling

    International Nuclear Information System (INIS)

    The microstructure and changes in chemical composition of Ti powders produced by cryogenic milling (modified Atritor) and by high energy milling (Spex mill) were investigated. The effect of high energy milling and cryomilling parameters, such as milling time and ball to powder ratio (BPR), on the particle size, grain size, chemistry, and structure of Ti powders were investigated using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The experimental results show that Ti powders with a grain size of approximately 20 nm (nanocrystalline) can be produced using the cryomilling technique. The average particle size increased initially with milling time from the original 55 μm to a maximum value of 125 after milling for 2 hours, and then decreased to 44μm after milling for 8 hours. Both the average particle size and the grain size decreased as the BPR increased. The results using Spex mill show that the particle size and grain size both decreased as the milling time increased. The oxygen, nitrogen and iron content of the powders increased with the milling time (au)

  5. Assessment of elemental content of milled coal, combustion residues, and stack emitted materials: Possible environmental effects for a Canadian pulverized coal-fired power plant

    International Nuclear Information System (INIS)

    Two monitoring studies were carried out at four-year intervals on a power plant that uses western Canadian subbituminous coal and generates approximately 800 Mw/h of electricity. The distributions of elements of environment concern (As, Hg, Ni, Pb, and Cd) and elements of environmental interest (B, Ba, Be, Cl, Co, Cr, Cu, Mn, Mo, Th, Se, V, U, and Zn) in milled coals, power plant ashes, and emitted materials from the stack were determined using neutron activation analysis (NAA), Inductively Coupled Plasma Emission Spectroscopy (ICPES), and Inductively Coupled Plasma-Mass spectroscopy (ICP-MS) for most elements, Graphite Furnace Atomic Absorption (GFAA) for Pb, and Cold Vapor Atomic Absorption (CVAA) for Hg. The concentrations of most of elements in milled coal are low as compared to world coals and other Canadian milled coals. For example, in both studies mercury is within the lower range of world coal. Bottom ashes from both studies have low concentrations of As, Cd, Hg, Pb, and Zn, as well as low relative enrichment factors (RE) for the same elements, indicating that they were not enriched in the bottom ash. The ESP's remove most of the elements of environmental interest as indicated by their high RE ratios of greater than >0.7. The rates of input of elements of environmental concern (As, Cd, Hg, Pb and Ni) for this station were 23.65, 1.24, 0.54, 98.2 and 95.2 kg/day, respectively, of which only 0.20, 0.02, 0.31, 0.48 and 0.36 kg/day were emitted from the stack. Thus only a small amount of these elements found in the milled coal was emitted while most were captured in the bottom and the ESP ashes. Nickel has the highest rate of emission (0.48 kg/day) within the elements of environmental concern group. However, the Ni emitted from this station does not belong to the toxic species. The element with the lowest rate of emission is Cd (0.02 kg/day). The total emission of elements of environmental concern is 1.37 kg/day, which is low as compared their ambient

  6. Milling in hardened steel - a study of tool wear in conventional- and dynamic milling

    OpenAIRE

    Ersvik, Erik; Khalid, Roj

    2015-01-01

    Milling is a commonly used machining process where a rotating cutter removes material from the workpiece. In recent years, attention has been turned towards so called dynamic milling methods which differ from the conventional way of milling. Dynamic milling normally uses, as opposed to the conventional way, more of the axial cutting edge, smaller radial depth of cut, significantly higher cutting speed and feed per tooth. The method has demonstrated potential to save both time and money under ...

  7. Texture formation in iron particles using mechanical milling with graphite as a milling aid

    International Nuclear Information System (INIS)

    Crystallographically anisotropic platelet iron particles were successfully prepared using a conventional ball mill with addition of graphite (Gp) particles. The morphological and structural changes resulting from the milling were investigated using scanning electron microscopy and X-ray diffraction. The spherical iron particles were plastically deformed into platelet shapes during the milling. Simultaneously, it is suggested that the size of the Gp particles decreased and adhered as nanoparticles on the surface of the iron particles. The adhered Gp particles affected the plastic deformation behavior of the iron particles: the (001) planes of α-iron were oriented parallel to the particle face, and no preferred in-plane orientation was observed. This study not only details the preparation of soft magnetic metal particles that crystallographically oriented to enhance their magnetic properties but also provides new insight into the activities of the well-established and extensively studied mechanical milling method

  8. BLEACHING NEPTUNE BALLS

    Directory of Open Access Journals (Sweden)

    BONET Maria Angeles

    2014-05-01

    Full Text Available Posidonia Oceanic is a seaweed from Mediterranean Sea and it is more concentrated at the Balerian SEA. This implies the Valencian Community also. It forms vaste underwater meadows in the sea and are part of the Mediterranean ecosystem. It is a sea-grass specie with fruits and flowers. Leaves are ribbon-like and they grow in winter and at the end of summer some of them are separated and arrive to some sea line. Fuit is separated and can floate, it is known as “the olive of the sea” mainly in Italy, or as the Neptune Balls. As it can be used in different fields, it is is being studied in order ro have the precitice tests. Some authors have reported the manufacturing of fully bio-based comites with a gluten matrix by hot-press molding. And it has been considered as an effective insulator for building industry or even though to determine the presence of mercure in the Mediterranean sea some years ago. As many applications can be designed from that fibers, it has been considered to be bleached in order to used them in fashionable products. Consequently, its original brown color is not the most suitable one and it should be bleached as many other cellulosic fibers. The aim of this paper is to bleache neptune balls however, the inner fibers were not accessible at all and it implied not to bleach the inner fibers in the neptune ball. Further studiesd will consider bleaching the individualized fibers.

  9. Hurwitz ball quotients

    OpenAIRE

    Stover, Matthew

    2013-01-01

    We consider the analogue of Hurwitz curves, smooth projective curves $C$ of genus $g \\ge 2$ that realize equality in the Hurwitz bound $|\\mathrm{Aut}(C)| \\le 84 (g - 1)$, to smooth compact quotients $S$ of the unit ball in $\\mathbb{C}^2$. When $S$ is arithmetic, we show that $|\\mathrm{Aut}(S)| \\le 288 e(S)$, where $e(S)$ is the (topological) Euler characteristic, and in the case of equality show that $S$ is a regular cover of a particular Deligne--Mostow orbifold. We conjecture that this ineq...

  10. Destruction of weapons-grade plutonium with pebble bed type HTGRs using burner balls and breeder balls

    International Nuclear Information System (INIS)

    As the method of disposing the plutonium coming from disassembled weapons, the method of burning the fuel in which the plutonium is mixed with a parent material in LWRs or the disposal by glass solidification is proposed. In the former method, it is desirable to do the reprocessing of spent fuel for effectively utilizing fission products. The latter method needs watch against the diversion of the plutonium. The authors devised the method of effectively annihilating plutonium by separating into the burner balls of plutonium and the breeder balls of a parent material, and burning those by mixing in a pebble bed type high temperature gas-cooled reactor, while continuously exchanging them. It was clarified from the aspect of nuclear characteristics that by using this method, 239Pu can be annihilated to the state of enabling the direct abandonment without reprocessing. The flow of burner balls and breeder balls in the reactor is shown, and multi-pass fuel exchange method was adopted to burn Pu in burner balls up. The rate of Pu annihilation was determined by the change of the amount of Pu for the burnup evaluated by lattice burning calculation. The maximum amount of Pu charge in one burner ball is limited by the maximum allowable power output of burner balls. (K.I.)

  11. High coercivity induced by mechanical milling in cobalt ferrite powders

    OpenAIRE

    Ponce, A. S.; E. F. Chagas; Prado, R. J.; Fernandes, C. H. M.; Terezo, A. J.; Baggio-Saitovitch, E.

    2013-01-01

    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500oC. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4...

  12. Evaluation of tensile properties of cast stainless steel using ball

    International Nuclear Information System (INIS)

    In this study the ball indentation tests were performed on the four unaged cast stainless steel and 316 stainless steel, which have different microstructure and strength, to examine the applicability of ball indentation test to the evaluation of thermal aging of cast stainless steel. Also, the reliability of test results were analyzed by evaluating the scattering of data tested from each material and by comparing tensile properties obtained from ball indentation test and tensile test. The results showed that the maximum standard deviation to mean value are less than 6%, and the average standard deviation to mean value are about 1.5∼2.5%, when 2 point data that show out of trend were discarded from the data set tested a single specimen. Also, the scattering increased slightly with decreasing δ-ferrite content. Additionally, the ball indentation test predicted the tensile properties of cast stainless steel within an error of ±10% for all materials

  13. Structure and magnetic properties of powder HITPERM material

    Directory of Open Access Journals (Sweden)

    J.E. Frąckowiak

    2007-03-01

    Full Text Available Purpose: The aim of the work is to investigate the structure and magnetic properties of the cobalt based HITPERM amorphous alloy Co68Fe4Mo1Si13.5B13.5 subjected high-energy ball milling and to the isothermal annealing to a combination of these two technologies.Design/methodology/approach: The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses ribbons in as state. Using the HFQS program the distributions of the magnetic hyperfine P(H fields were determined for spectra smoothed in this way, employing the Hesse-Rübartsch method. Observations of the structure of powders were made on the OPTON DSM-940 scanning electron microscope. The diffraction examinations and examinations of thin foils were made on the JEOL JEM 200CX transmission electron microscope equipped in equipped with the EDS LINK ISIS X- ray energy dispersive spectrometer made by Oxford. Graphical analyses of the obtained X-ray diffraction patterns, as well as of the HC=f(TA relationship were made using the MICROCAL ORIGIN 6.0 program.Findings: The analysis of the structure and magnetic properties test results of the HITPERM powders alloy Co68Fe4Mo1Si13.5B13.5 obtained in the high-energy ball of milling process proved that the process causes significant decrease in the magnetic properties. The magnetic properties of this material and structure and may be improved by means of a proper choice of parameters of this process as well as the final thermal treatment.Research limitations/implications: For the soft magnetic powder material, further magnetical, composition examinations and structure are planed.Practical implications: Feature an alternative to solid alloys are the amorphous and nanocrystalline metal powders obtained by milling of metallic glasses and make it possible to obtain the ferromagnetic nanocomposites, whose dimensions and shape can be freely formed.Originality/value: The paper presents results of influence of parameters

  14. Ball lightning: a realistic model

    International Nuclear Information System (INIS)

    Ball lightning is a rare and beautiful phenomenon, still lacking a scientific explanation. Here, the main ideas of a recent topological model are summarized. This model provides reasons for the stability of the ball and it is able to explain some curious contradictions in the reports of the witnesses. (Author) 3 refs

  15. Experimental research on ball lightning

    International Nuclear Information System (INIS)

    Experiments on producing ball lightning were made with discharge in flammable gas and/or aerosol. A long lifetime (2 s) ball lightning was observed in 2.7 % ethane and 100 cm3 cotton fibers, and in 1.5 % methane and 1.9 % ethane

  16. INVESTIGATION ON HARDENED STEEL MILLING WITH MICRO-END MILL

    Institute of Scientific and Technical Information of China (English)

    HUYing-ning; WANGCheng-yong; WUXue-qi; QINZhe; ZENGBao-ping

    2004-01-01

    Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiA1N coated carbide micro-end mill (Ф2 mm). The effect of cutting speed, feed per tooth and radial depth of cut on cutting force is analyzed. Cutting parameters adapting to dry machining and strategy optimized for higher rate of material removal with lower cutting force are attained. Results of SEM observation show that the main failure patterns of micro-end mill are breakage of tool tip, wear and drop-off of surface coating, micro-chipping, and breakage of flank.

  17. Eddy Current Model of Ball Lightning

    OpenAIRE

    Shelton, J. D.

    2011-01-01

    Eddy Current Model of Ball Lightning Calculations show that high-energy ball lightning may consist of a ball of plasma containing a large circular electric current arising as an eddy current generated by lightning. Synthetic ball lightning might serve as a method of plasma confinement for purposes of nuclear fusion. In this paper, three articles concerning ball lightning and the related phenomenon of large ball lightning are combined to provide insight into this rarely glimpsed occurrence.

  18. Pre-operational monitoring program of Ra-226 in biological material in uranium mining and milling areas

    International Nuclear Information System (INIS)

    The environmental licensing processes of 'Santa Quiteria' uranium mining and milling unit are being carried out nowadays. The pre-operational radiological environmental monitoring program is part of those processes, which has the objective of determining the background for further comparisons and evaluation of radiological environmental impact of the operation unit. This work shows the results of Ra-226 determination in the most consumed farm products of the region, which are black beans, corn and milk. These data are compared with data available in the literature. Measurement results of Ra-226 in black beans vary from 3.3 x 10-2 Bq/Kg to 9.1 x 10-2 Bq/Kg; in corn, the results vary from 8.0 x 10-3 Bq/Kg to 4.6 x 10-2 Bq/Kg; in milk the results vary from 1.0 x 10-3 Bq/Kg to 7.0 x 10-3 Bq/Kg that represents the smallest variation range. All of these results are in good agreement with literature reported data. (author)

  19. Efficient and Scalable Production of 2D Material Dispersions using Hexahydroxytriphenylene as a Versatile Exfoliant and Dispersant.

    Science.gov (United States)

    Liu, Gang; Komatsu, Naoki

    2016-06-01

    Thin-layer 2D materials have been attracting enormous interest, and various processes have been investigated to obtain these materials efficiently. In view of their practical applications, the most desirable source for the preparation of these thin-layer materials is the pristine bulk materials with stacked layers, such as pristine graphite. There are many options in terms of conditions for the exfoliation of thin-layer materials, and these include wet and dry processes, with or without additives, and the kind of solvent. In this context, we found that the versatile exfoliant hexahydroxytriphenylene works efficiently for the exfoliation of typical 2D materials such as graphene, MoS2 , and hexagonal boron nitride (h-BN) by both wet and dry processes by using sonication and ball milling, respectively, in aqueous and organic solvents. As for graphene, stable dispersions with relatively high concentrations (up to 0.28 mg mL(-1) ) in water and tetrahydrofuran were obtained from graphite in the presence of hexahydroxytriphenylene by a wet process with the use of bath sonication and by a dry process involving ball milling. Especially, most of the graphite was exfoliated and dispersed as thin-layer graphene in both aqueous and organic solvents through ball milling, even on a large scale (47-86 % yield). In addition, the exfoliant was easily removed from the precipitated composite by heat treatment without disturbing the graphene structure. Bulk MoS2 and h-BN were also exfoliated by both wet and dry processes. Similar to graphene, dispersions of MoS2 and h-BN of high concentrations in water and DMF were produced in high yields through ball milling. PMID:26918302

  20. Enhancement of Electrochemical Stability about Silicon/Carbon Composite Anode Materials for Lithium Ion Batteries

    OpenAIRE

    Wei Xiao; Chang Miao; Xuemin Yan; Qing Sun; Ping Mei

    2015-01-01

    Silicon/carbon (Si/C) composite anode materials are successfully synthesized by mechanical ball milling followed by pyrolysis method. The structure and morphology of the composite are characterized by X-ray diffraction and scanning electron microscopy and transmission electron microscope, respectively. The results show that the composite is composed of Si, flake graphite, and phenolic resin-pyrolyzed carbon, and Si and flake graphite are enwrapped by phenolic resin-pyrolyzed carbon, which can...