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Sample records for ball mill grinding

  1. 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.

  2. 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.

  3. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    Science.gov (United States)

    Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

    2011-01-01

    An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900° C for 60 minutes and given stepped austempering treatment at 280° C for 30 minutes and 60 minutes followed by 380° C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

  4. Kinetic study of ferronickel slag grinding at variation of ball filling and ratio of feed to grinding balls

    Science.gov (United States)

    Sanwani, Edy; Ikhwanto, Muhammad

    2017-01-01

    The objective of this paper is to investigate the effect of ball filling and ratio of feed to grinding balls on the kinetic of grinding of ferronickel slag in a laboratory scale ball mill. The experiments were started by crushing the ferronickel slag samples using a roll crusher to produce -3 mesh (-6.7 mm) product. This product, after sampling and sample dividing processes, was then used as feed for grinding process. The grinding was performed with variations of ball filling and ratio of feed to grinding balls for 150 minutes. At every certain time interval, particle size analysis was carried out on the grinding product. The results of the experiments were also used to develop linear regression model of the effect of grinding variables on the P80 of the product. Based on this study, it was shown that P80 values of the grinding products declined sharply until 70 minutes of grinding time due to the dominant mechanism of impact breakage and then decreased slowly after 70 minutes until 150 minutes of grinding time due to dominant mechanism of attrition breakage. Kinetics study of the grinding process on variations of grinding ball filling showed that the optimum rate of formation of fine particles for 20%, 30%, 40% and 50% mill volume was achieved at a particle size of 400 µm in which the best initial rate of formation occurred at 50% volume of mill. At the variations of ratio of feed to grinding balls it was shown that the optimum rate of grinding for the ratio of 1:10, 1: 8 and 1: 6 was achieved at a particle size of 400 µm and for the ratio of 1: 4 was at 841 µm in which the best initial rate of formation occurred at a 1:10 ratio. In this study, it was also produced two regression models that can predict the P80 value of the grinding product as a function of the variables of grinding time, ball filling and the ratio of the feed to grinding balls.

  5. Process engineering with planetary ball mills.

    Science.gov (United States)

    Burmeister, Christine Friederike; Kwade, Arno

    2013-09-21

    Planetary ball mills are well known and used for particle size reduction on laboratory and pilot scales for decades while during the last few years the application of planetary ball mills has extended to mechanochemical approaches. Processes inside planetary ball mills are complex and strongly depend on the processed material and synthesis and, thus, the optimum milling conditions have to be assessed for each individual system. The present review focuses on the insight into several parameters like properties of grinding balls, the filling ratio or revolution speed. It gives examples of the aspects of grinding and illustrates some general guidelines to follow for modelling processes in planetary ball mills in terms of refinement, synthesis' yield and contamination from wear. The amount of energy transferred from the milling tools to the powder is significant and hardly measurable for processes in planetary ball mills. Thus numerical simulations based on a discrete-element-method are used to describe the energy transfer to give an adequate description of the process by correlation with experiments. The simulations illustrate the effect of the geometry of planetary ball mills on the energy entry. In addition the imaging of motion patterns inside a planetary ball mill from simulations and video recordings is shown.

  6. Effect of wet grinding on structural properties of ball clay

    Science.gov (United States)

    Purohit, A.; Hameed, A.; Chander, S.; Nehra, S. P.; Singh, P.; Dhaka, M. S.

    2015-05-01

    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.

  7. 基于 PFC3D的新型球磨机数值模拟研究%Study on the movement of grinding medium in ball mill based on PFC3D

    Institute of Scientific and Technical Information of China (English)

    李笑同; 朴香兰

    2015-01-01

    In order to explore the ways to improve the fatigue life and the production efficiency of the ball mill,the paper established the discrete element model of the traditional ball mill and also the ball mill with variable structures.And this paper carried out an analysis and simulation of the motion of grinding medium with different rotational speeds and scale board heights to determine the position of the rotational board.Through the simulation experiments we found that the falling speed of the grinding ball in grinding chamber rose from 2 m/s to 5 m/s.This behavior could not only increase the impact force of grinding medium effectively but also avoid the limitation of improving the grinding efficiency of the traditional ball mill by changing the parameters of the quality of grinding grain and the diameter of the cylinder,etc.%为探索能够提高球磨机生产效率和延长球磨机研磨寿命的途径,利用 PFC3D 程序,建立了传统球磨机与变结构球磨机的离散元模型,针对不同转速、不同衬板高度,对磨介运动进行了仿真与分析,确定了辅助结构-旋转档板的位置。通过模拟实验发现,研磨腔内磨球的下落速度由原来的2m/s,增长到了5m/s 左右。有效地提高了磨介的冲击力,避免了传统球磨机需要通过改变研磨介质磨粒的质量和滚筒的直径等参数来提高研磨效率的局限性。

  8. Investigation on the Surface Coating of Grinding Balls

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The surface coating of grinding balls was investigated experimentally. The results show that a coating may form on the surface of grinding balls when Cr or Al powders are subjected to ball grinding. The plastic deformation of the ball surface plays an important role during the coating formation, and the strong binding force between the powders and the balls is a necessary pre-condition. The thickness of coating increases with the plasticity of the powders and the balls. Annealing the balls with coating will result in an obvious diffusion of the elements in the bonding zone of inter-face.

  9. An investigation of the corrosive wear of steel balls in grinding of sulphide ores

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2015-06-01

    Full Text Available Ball mills are common grinding equipment in mineral processing industries. Ball wear results from three mechanisms namely impact, abrasion and corrosion. Of these, the corrosion mechanism is the least investigated, due to its chemical-electrochemical nature. Therefore, the aims of this research were to investigate the grinding chemistry influence (slurry pH, solid percentage, water chemistry and gas purging on corrosive wear of steel balls and to determine the contribution of corrosion mechanism to total wear of steel balls. The results indicated that the mass losses of steel balls could be reduced considerably by controlling the pulp chemistry inside the mill. In addition, the results showed that 73.51% of the corrosion products are generated from the oxidation of steel balls. It was also estimated that the corrosion mechanism accounts for 26.68% of the total wear of steel balls.

  10. 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.

  11. Quenching simulation of steel grinding balls

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Hernandez, O.; Reyes, L. A.; Camurri, C.; Carrasco, C.; Garza-Monte-de-Oca, F.; Colas, R.

    2015-07-01

    The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses. (Author)

  12. Continuous grinding mill simulation using Austin's model

    Directory of Open Access Journals (Sweden)

    André Carlos Silva

    2012-01-01

    Full Text Available Comminution is a frequently-required step in mineral processing and is responsible for almost 90% of all energy consumption in a mineral processing plant. Tumbling mill design has been studied since the middle of the XIX century. There are many comminution models in the literature, with preponderance, however, of Austin’s model (2002 for mineral impact breakage. In this paper, Austin’s model was applied to tubular tumbling mills. Once Austin's model was proposed for batch processing of narrowly-distributed fraction sizes, an artifice has allowed it to be used in continuous grinding mill processes with widely-distributed fraction sizes. Interesting results were obtained with errors less than 0.005 for mills with sharp residence time distributions.

  13. Quenching simulation of steel grinding balls

    Directory of Open Access Journals (Sweden)

    Zapata-Hernández, Oscar

    2015-09-01

    Full Text Available The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses.Las transformaciones de fase en aceros de alto carbono durante su temple y un posterior periodo de estabilización fueron modelizadas por medio del uso de paquetes computacionales basados en el método del elemento finito y de la transformación cinética de los aceros. El modelo se usó para predecir los cambios de temperatura y microestructura que se presentan en bolas de dos diferentes tamaños empleadas en estaciones de molienda de minerales. Se encontró una buena correlación entre las temperaturas medidas mediante la inserción de termopares y aquellas predichas por el modelo una vez que se modificó la conductividad térmica del acero en el intervalo mixto de fases. La predicción de las transformaciones de fase se confirmó a través del análisis metalográfico.

  14. 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.

  15. Research on product size and grinding dynamics of vibration mills

    Institute of Scientific and Technical Information of China (English)

    YIN Zhong-jun; HAN Tian; CHEN Bing; ZHANG Wen-zhong

    2007-01-01

    In order to improve vibration mills grinding effect and increase productive efficiency, prime factors of vibration mills were gained much attention. The purpose of this study is to reveal product size distribution and grinding dynamics of vibration mills by orthogonal experi-ments. The metallurgical refractory materials were used as research object. In order to explore the relationships between grinding effect and primary factors, lots of milling experiments were carried out. Based on the results, the conclusions can be summarized: as time runs, the size distri-bution shows exponential trend, and range becomes more and more narrow. Also the quantitative analysis result between grinding effect and primary factors was obtained by non-linear regres-sion: high frequency, high amplitude and low fill ratio can increase grinding speed.

  16. 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.

  17. 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.

  18. Modeling on the Effect of Coal Loads on Kinetic Energy of Balls for Ball Mills

    Directory of Open Access Journals (Sweden)

    Yan Bai

    2015-07-01

    Full Text Available This paper presents a solution for the detection and control of coal loads that is more accurate and convenient than those currently used. To date, no research has addressed the use of a grinding medium as the controlled parameter. To improve the accuracy of the coal load detection based on the kinetic energy of balls in a tubular ball mill, a Discrete Element Method (DEM model for ball kinematics based on coal loads is proposed. The operating process for a ball mill and the ball motion, as influenced by the coal quality and the coal load, was analyzed carefully. The relationship between the operating efficiency of a coal pulverizing system, coal loads, and the balls’ kinetic energy was obtained. Origin and Matlab were utilized to draw the variation of parameters with increasing coal loads in the projectile and cascading motion states. The parameters include the balls’ real-time kinetic energy, the friction energy consumption, and the mill’s total work. Meanwhile, a method of balanced adjacent degree and a physical experiment were proposed to verify the considerable effect of the balls’ kinetic energy on coal loads. The model and experiment results indicate that a coal load control method based on the balls’ kinetic energy is therefore feasible for the optimized operation of a coal pulverizing system.

  19. Structural evolution of ball-milled permalloy

    Energy Technology Data Exchange (ETDEWEB)

    Brzozka, K., E-mail: kbrzozka@poczta.f [Technical University, Department of Physics (Poland); Oleksakova, D.; Kollar, P. [P.J. Safarik University, Department of Condensed Matter Physics, Institute of Physics, Faculty of Science (Slovakia); Szumiata, T.; Gorka, B.; Gawronski, M. [Technical University, Department of Physics (Poland)

    2006-02-15

    Two series of Fe{sub 19.8}Ni{sub 80.2} samples obtained by ball milling and differing in the form of starting material were investigated by Moessbauer spectroscopy. In the case of milled elemental powder, strong structural evolution was stated: both {alpha} and {gamma} phases arise and a small amount of pure iron is present as well. The annealing of as-milled powder at 490{sup o}C causes faster forming of {gamma}-(Ni-Fe) phase. Only slight changes in atomic order were stated in the series of milled polycrystalline ribbon.

  20. 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.

  1. APPLICATION OF SIMPLIFIED METHOD FOR DETERMINING THE WI TO PREDICT THE PERFORMANCE OF BALLS MILLS IN SOSSEGO PLANT

    Directory of Open Access Journals (Sweden)

    Vladmir Kronemberger Alves

    2013-12-01

    Full Text Available Over the years Vale S.A. has developed a methodology for scaling industrial comminution circuit that is being constantly improved and implemented in developing new routes and process optimization of circuits in operation. This work will be given a focus on the methodology of simplified balls mill Work Index (WI Anaconda in performance prediction of Sossego Plant ball mill. The great advantage of this methodology is to reduce the time and weight to determine the energy consumption in ball mills, whose values can be used in studies of variability, geometallurgy and design and control of industrial grinding circuits.

  2. Grinding process within vertical roller mills: experiment and simulation

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-huai; CHEN Qing-ru; KUANG Ya-li; LYNCH A J; ZHUO Jin-wu

    2009-01-01

    Based on screening analysis, laser size analysis, grindability and rigidity tests of samples collected on line from a cement and a power plant, a simulation of the grinding process in vertical roller mills was carried out. The simulation calculation used a breakage function, B. The results indicate that the breakage function, B, and the selection function, S, in the form of a matrix, can be used to express the probability of the material breaking during the grinding process. This allows the size distribution of the product to be numerically estimated. The simulation results also show that the simulated size distribution curves fit the actual ex-perimental product curves quite well. The model provides a good starting point for simulation of the grinding process. Further re-search is needed to determine the proper breakage function and the matrix value of the selection function.

  3. Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; MENG De-liang; NIE Pu-lin; LIU Jian-hua

    2004-01-01

    The preparing method, rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied. The results show that when the low chromium semi-steel bar is forged from 55 mm to 50 mm, cross-rolled into grinding ball at 1 000-1 050 ℃, air cooled and tempered at 550 ℃ for 2 h, the best mechanical properties, especially the abrasive resistance under the action of hard abrasive, can be obtained.

  4. Comparison of tungsten carbide and stainless steel ball bearings for grinding single maize kernels in a reciprocating grinder

    Science.gov (United States)

    Reciprocating grinders can grind single maize kernels by shaking the kernel in a vial with a ball bearing. This process results in a grind quality that is not satisfactory for many experiments. Tungesten carbide ball bearings are nearly twice as dense as steel, so we compared their grinding performa...

  5. Fine grinding of brittle minerals and materials by jet mill

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2008-05-01

    Full Text Available Various variables affecting grinding, such as air pressure, minerals or materials hardness, feed size were investigated.The limitations of grinding of gypsum, barite, ilmenite, quartz and ferrosilicon were also elucidated by means of particlefineness size distribution and morphology of ground products. It was found that:1 The density of particles, which are in the grinding zone affects the product fineness, i.e. higher feed rate resultsin a larger product size. The appropriate feed rate is suggested to be 0.2~0.5 g/s. Moreover, the density and hardness ofminerals or materials tend to have an effect on the product fineness. Heavy minerals, such as barite or ilmenite, exhibit afiner product size than lighter minerals, like quartz. However, for quartz, the higher hardness also results in a larger d50.2 Air pressure is the most vital variable which affects the grinding by a jet mill. The d50 seems to relate to theapplied air pressure as a power law equation expressed as following:d50 = aP b ; as P 0The a-value and b-value have been found to correlate to the feed size. The higher the air pressure applied the finerthe product size attained. Moreover, air pressure has a greater effect on hard minerals than on softer ones.3 Feed size seems to have a small effect on ground the product fineness of soft materials, such as gypsum andbarite, but a significant effect on that of hard materials, such as ferrosilicon and quartz, in particularly by milling at low airpressures of 2~3 kg/cm2.4 For the breakage behavior and morphology of ground materials, it was also found that the minerals having cleavages,such as gypsum and barite, tend to be broken along their cleavage planes. Thus, the particle size distribution of theseproducts becomes narrower. While quartz, ilmenite, and ferrosilicon have shattering and chipping breakage mechanisms,grinding results in angular shapes of the ground products and a wider size distribution. Blocks or platelets and

  6. 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

  7. 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.

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

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    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.

  9. 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.

  10. Rock Characteristics and Ball Mill Energy Requirements at ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... Goldfields Ghana Limited, Tarkwa Gold Mine (TGM), processes ores which occur in conglomerate ... effect of changes in rock characteristics on the performance of the existing ball mill. ..... feldspars, iron oxides and sulphides.

  11. Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report number 11, March 1--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Fuerstenau, D.W.

    1995-06-01

    The objective of this research is the development of improved technology for the preparation of coal-water slurries that have potential for replacing fuel oil in direct combustion. Detailed investigations of the effect of solids content and chemical additives on the rheology of coal-water slurries, prepared with fines produced by the ball milling of Pittsburgh No. 8 coal, were conducted during the first phase of the research program. These experiments were to provide a baseline against which the rheological behavior of slurries prepared with fines produced by high-pressure roll milling or hybrid high-pressure, roll mill/ball mill grinding could be compared. The viscosity of slurries with high solids content is strongly influenced by the packing density of the feed material. The packing density can be significantly altered by mixing distributions of different median sizes, and to an extent by modifying the grinding environment. The research during this quarter was, therefore, directed towards: (1) establishing the relationship between the packing characteristic of fines and the viscosity of slurries prepared with the fines; (2) investigation of the effect of mixing distribution on the rheology; and (3) study of the effect of grinding environment in the ball mill on the rheology of coal-water slurries.

  12. Structural and magnetic properties of ball milled copper ferrite

    DEFF Research Database (Denmark)

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

    1998-01-01

    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 ca...

  13. Ball milling and annealing of Co-50 at% W Powders

    CSIR Research Space (South Africa)

    Bolokang, AS

    2013-04-01

    Full Text Available annealing of unmilled compacts yielded metastable phases. Upon 10 and 20 h ball milling of Co-W powder, no alloying was obtained. Although milling did not yield significant crystal changes in W and Co ground state struc- tures, its effect is evident during...

  14. Tuning the length dispersion of multi-walled carbon nanotubes by ball milling

    Directory of Open Access Journals (Sweden)

    László Forró

    2013-09-01

    Full Text Available The statistical analysis of the length distribution of catalytic chemical vapour deposition synthesized multi-walled carbon nanotubes cut by planetary ball milling is reported. The nanotube lengths follow a log-normal distribution in a broad range of grinding time and rotational speed. We show that the scale parameter of the distribution, which equals the mean of the natural logarithm of the tube lengths, decreases linearly with the product of the duration time and the rotational speed. This relation can be used for tailoring nanotube lengths by a suitable choice of process parameters for a wide range of applications.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Nano-subgrain Strengthening in Ball-milled Iron

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-23

    The strength and deformation behavior of ball-milled, iron-base materials containing nano-scale subgrains have been evaluated. As reported by several authors, nanosubgrains form during the early stages of ball milling as a result of severe plastic deformation inherent in the ball milling process. The strength for these nano-scale subgrains are compared with the strength of larger-scale subgrains in iron and iron-base alloys produced by traditional mechanical working. The data covers over 2 orders of magnitude in subgrain size (from 30 nm to 6 {micro}m) and shows a continuous pattern of behavior. For all materials studied, the strength varied as {lambda}{sup -1}, where {lambda} is the subgrain size. Strengthening from subgrains was found to breakdown at a much smaller subgrain size than strengthening from grains. In addition, the ball-milled materials showed significant strengthening contributions from nano-scale oxide particles. Shear bands are developed during testing of ball-milled materials containing ultra-fine subgrains. A model for shear band development in nano-scale subgrains during deformation has also been developed. The model predicts a strain state of uniaxial compression in the shear band with a strain of -1.24. Subgrains are shown to offer the opportunity for high strength and good work hardening with the absence of yield point behavior.

  17. Preparation of iron sulphides by high energy ball milling

    DEFF Research Database (Denmark)

    Lin, R.; Jiang, Jianzhong; Larsen, R.K.;

    1998-01-01

    The reaction of a powder mixture consisting of 50 a.% Fe and 50 a.% S during high energy ball milling has been studied by x-ray diffraction and Mossbauer spectroscopy. After around 19 h of milling FeS2 and FeS havebeen formed. By further milling the FeS compound becomes dominating and only Fe......S with an average crystallite size of about 10 nm was observed after milling times longer than 67 h. Mossbauer spectra obtained with applied fields show that the particles are antiferromagnetic or have a strongly canted spin structure....

  18. Calculation Method for Media in Ball Mills by Layers

    Institute of Scientific and Technical Information of China (English)

    徐志强; 张荣曾; 曾鸣

    2002-01-01

    Based on analyzing the moving principle of media in ball mill, it is implicated that there is the significant difference of movement situation among each single layer. A new method to calculate each single was put forward. The results from lab experiment and actual data from 26 sets industrial mills state indicate that the new calculation method reaches the high accuracy with excellent practicab ility.

  19. Investigation of the milling capabilities of the F10 Fine Grind mill using Box-Behnken designs.

    Science.gov (United States)

    Tan, Bernice Mei Jin; Tay, Justin Yong Soon; Wong, Poh Mun; Chan, Lai Wah; Heng, Paul Wan Sia

    2015-01-01

    Size reduction or milling of the active is often the first processing step in the design of a dosage form. The ability of a mill to convert coarse crystals into the target size and size distribution efficiently is highly desirable as the quality of the final pharmaceutical product after processing is often still dependent on the dimensional attributes of its component constituents. The F10 Fine Grind mill is a mechanical impact mill designed to produce unimodal mid-size particles by utilizing a single-pass two-stage size reduction process for fine grinding of raw materials needed in secondary processing. Box-Behnken designs were used to investigate the effects of various mill variables (impeller, blower and feeder speeds and screen aperture size) on the milling of coarse crystals. Response variables included the particle size parameters (D10, D50 and D90), span and milling rate. Milled particles in the size range of 5-200 μm, with D50 ranging from 15 to 60 μm, were produced. The impeller and feeder speeds were the most critical factors influencing the particle size and milling rate, respectively. Size distributions of milled particles were better described by their goodness-of-fit to a log-normal distribution (i.e. unimodality) rather than span. Milled particles with symmetrical unimodal distributions were obtained when the screen aperture size was close to the median diameter of coarse particles employed. The capacity for high throughput milling of particles to a mid-size range, which is intermediate between conventional mechanical impact mills and air jet mills, was demonstrated in the F10 mill. Prediction models from the Box-Behnken designs will aid in providing a better guide to the milling process and milled product characteristics.

  20. 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.

  1. 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.

  2. Role of classification in grinding using the electromagnetic mill. A case study

    Directory of Open Access Journals (Sweden)

    Wolosiewicz-Glab Marta

    2016-01-01

    Full Text Available In the process of classification, one of the methods used to evaluate the effectiveness classifiers is to plot a separation curve, which determines the size of seprated particles and characterizes the process accuracy. The article presents an assessment of the impact of parameters on grinding and classification using an electromagnetic mill. The results allow a detailed assessment of the effectiveness and efficiency of the device and facilitate the optimization of the grinding process by establishing an appropriate control algorithms.

  3. 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.

  4. Properties of Cross-Rolled Low Alloy White Cast Iron Grinding Ball

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; LIU Lin; LIU Jian-hua

    2007-01-01

    The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.

  5. A Method to Determine the Ball Filling, in Miduk Copper Concentrator SAG Mill

    Directory of Open Access Journals (Sweden)

    Ali Kamali Moaveni

    2012-12-01

    Full Text Available The aim of this research work was to investigate on the ball filling estimation of Miduk semi-autogenous (SAG Mill via an utilized method. Miduk copper concentrator is located in Kerman Province, Iran, and its size reduction stage includes one gyratory crusher which feeds one SAG mill (9.75 dia.(m*3.88 length(m following two parallel ball mills (5dia.(m*7lenght(m. After SAG mill, a trommel screen produces two over and under size materials which the oversize part is circulated into SAG mill and undersize reports to hydrocyclone for further process. Ball filling identify was implemented in this work using mill`s load sampling and ball abrasion test.These methods could estimate ball filling variation with easy, undeniable, and useful tests. Also, these tests have shown the digression of operating ball filling amount and its manual designed. To make more homogenous load, mill load samplings were carried out from 6 points after whirling the mill via inching motor. Acquired load sampling results were compared with ball abrasion tests. Ball abrasion tests were calculated for 3 different conditions include maximum, average, and minimum ball abrasion. However, the calculated maximum and minimum conditions never occurred. However, these are just for obtaining to ball filling variation in the mill. The results obtained from this work show, the ball filling percentage variation is between 1.2– 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%. In addition, acquired load samplings result for mill ball filling was 1.3%.

  6. ALSTOM Schusselmuhle fur die feinvermahlung von anhydrit ALSTOM bowl mill for anhydrite fine grinding

    CERN Document Server

    Angleys, M

    2003-01-01

    After the ALSTOM bowl mill had proved a success during numerous laboratory tests using different industrial minerals, for the first time a mill, type SM 20/12 was commissioned for ATLAS s.c. at Lodz /Poland for anhydrite grinding. Based on corresponding laboratory tests with anhydrite, it was possible to adapt the equipment to the requirements of the material with modified properties. Due to the project preparation together with the customer, the mill could be installed and commissioned according to schedule by a joint team of engineers for erection and commissioning.

  7. the quality of locally-manufactured corn- mill grinding plates

    African Journals Online (AJOL)

    User

    nate the milled maize, which when consumed could have health ... tions of consuming metal particles with the ..... roding environment increases with time. This ... menopausal women for whom iron defi- ... media in wet grinding”, Miner. Metall.

  8. Application of multi regressive linear model and neural network for wear prediction of grinding mill liners

    Directory of Open Access Journals (Sweden)

    Farzaneh Ahmadzadeh

    2013-06-01

    Full Text Available The liner of an ore grinding mill is a critical component in the grinding process, necessary for both high metal recovery and shell protection. From an economic point of view, it is important to keep mill liners in operation as long as possible, minimising the downtime for maintenance or repair. Therefore, predicting their wear is crucial. This paper tests different methods of predicting wear in the context of remaining height and remaining life of the liners. The key concern is to make decisions on replacement and maintenance without stopping the mill for extra inspection as this leads to financial savings. The paper applies linear multiple regression and artificial neural networks (ANN techniques to determine the most suitable methodology for predicting wear. The advantages of the ANN model over the traditional approach of multiple regression analysis include its high accuracy.

  9. DESIGN OF INTELLIGENT CONTROL SYSTEM USING ACOUSTIC PARAMETERS FOR GRINDING MILL OPERATION

    Directory of Open Access Journals (Sweden)

    Sonali Sen

    2013-02-01

    Full Text Available This paper utilizes acoustic parameters such as FS,NC, N, P, INC, FL, FH, W for acoustic signals S of different running conditions of a ballmill to deriveout the acoustic signatures and hence control signals, which is to be used for designing the control systems of the mill. The parameters FS, NC, N, P, INC, FL, FH and W are represented by sample rate in Hz, number of cepstral coefficients, length of frame in samples, number of filters in filter bank, frame increment, low end of the lowest filter, high end of highest filter and the window over which the analysis is to be performed respectively. The work establishes an appropriate theoretical background that helps to predict dynamic breakage characteristics with respect to particle size distribution of materials, adequately supported by experimental data. The signatures of different running conditions of grinding mill have been extracted from the captured signal in time frame these have been used as feedback signal to monitor the grinding operation. Condenser based microphones have been used for capturing acoustic signals in time domain directly in computers and stored for further analysis. Matlab R2010b has been used for different analysis of the experiment. On analyzing the signatures, it has been observed whether the fines are produced progressively to attain the desired size range or the mill producing undesired products. Thus, the approach has been used in this paper has the ability to arrive in the stage of optimum grinding by tuning parameters of the mill in real time, and also it can prevent the mill to enter into an erroneous state. Moreover, on study it has found that the present scheme can be used more accurately in comparison to the earlier work of the author. This paper presents an implementation scheme to use acoustic signal as the control signal to regulate the operation of a grinding mill.

  10. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Directory of Open Access Journals (Sweden)

    Anthony ANDREWS

    2010-12-01

    Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

  11. SAXS study of nanocrystalline materials produced by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez van Raap, M.; Socolovky, L.; Mendoza Zelis, L.; Sanchez, F.H. [La Plata Univ. Nacional (Argentina). Dept. de Fisica; Kellermann, Guinther; Torriani, Iris [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    1997-12-31

    Full text. SAXS characterization of nanocrystalline materials produced by ball milling was performed at the Brazilian National Synchrotron Light-SAXS beam line. Two kind of sample were used: pure metals (Fe and Pd) milled in Ar atmosphere in a vibratory horizontal mill Resc MM2 for 12, 25 and 48 h. And Fe y Cu 1-y(05,0.10,0.14,0.18,0.20,0.35 and 0.45) alloys subjected to 75 milling hours in a low energy mill. SAXS data was collected with (formula) corresponding to a photon energy just below Fe absorption edge to avoid fluorescence, and with two camera length to be able to see Guinier and Porod regions. Mechanical work performed on any materials produces simultaneously reduction in particles sizes and in grain sizes up to the nanometer scale, increase in micro strain storage and defects. Broadening of the XRD reflection lines with milling time gives an estimation of grain sizes and volume deformation (micro strain), but no information is obtained on the nature of the defects, which due to the high milling intensity could be clustered as voids. On the other hand, for a mixture of two elements, besides the facts listed above, alloying in different metastable states (amorphous, extended solid solution, granular materials, etc.) can be obtained depending on the system and on composition. For the Fe y Cu 1-y alloys studied here, previous results indicates: the alloys are fcc, a dependence of the magneto resistivity on Fe concentration can be recorded (maximum at 0.20) and from HREM the existence of inclusion of 7.3 nm size was proposed. Our preliminary data analysis of the recorded SAXS patterns shows that for the metals no clear dependence with milling time can be established, a distribution of sizes can be predicted from the Guinier region behavior and a Porod region can be fitted indicating a fairly sharp density contrast. Patterns recorded Fe y Cu 1-y are similar of those recorded for milled metals, the possibility of distinguish from voids or from composition

  12. Homogeneity of ball milled ceramic powders: Effect of jar shape and milling conditions

    Directory of Open Access Journals (Sweden)

    M. Broseghini

    2017-02-01

    Full Text Available This paper contains data and supporting information of and complementary to the research article entitled “Effect of jar shape on high-energy planetary ball milling efficiency: simulations and experiments” (Broseghini et al., [1]. Calcium fluoride (CaF2 was ground using two jars of different shape (cylindrical and half-moon installed on a planetary ball-mill, exploring different operating conditions (jar-to-plate angular velocity ratio and milling time. Scanning Electron Microscopy (SEM images and X-Ray Powder Diffraction data (XRPD were collected to assess the effect of milling conditions on the end-product crystallite size. Due to the inhomogeneity of the end product, the Whole Powder Pattern Model (WPPM, (Scardi, 2008 [2] analysis of XRPD data required the hypothesis of a bimodal distribution of sizes – respectively ground (fine fraction and less-to-not ground (coarse fraction – confirmed by SEM images and suggested by the previous literature (Abdellatief et al., 2013 [3,4]. Predominance of fine fraction clearly indicates optimal milling conditions.

  13. The Tool Life of Ball Nose end Mill Depending on the Different Types of Ramping

    Directory of Open Access Journals (Sweden)

    Vopát Tomáš

    2014-12-01

    Full Text Available The article deals with the cutting tool wear measurement process and tool life of ball nose end mill depending on upward ramping and downward ramping. The aim was to determine and compare the wear (tool life of ball nose end mill for different types of copy milling operations, as well as to specify particular steps of the measurement process. In addition, we examined and observed cutter contact areas of ball nose end mill with machined material. For tool life test, DMG DMU 85 monoBLOCK 5-axis CNC milling machine was used. In the experiment, cutting speed, feed rate, axial depth of cut and radial depth of cut were not changed. The cutting tool wear was measured on Zoller Genius 3s universal measuring machine. The results show different tool life of ball nose end mills depending on the copy milling strategy.

  14. Experimental Study of Machinability in Mill-grinding of SiCp/Al Composites

    Institute of Scientific and Technical Information of China (English)

    LI Jianguang; DU Jinguang; YAO Yingxue; HAO Zhaopeng; LIU Xiao

    2014-01-01

    An attempt was made to investigate the machinability of SiCp/Al composites based on the experimental study using mill-grinding processing method. The experiments were carried out on a high-speed CNC machining center using integrated abrasive cutting tool. The effects of combined machining parameters, e g, cutting speed (vs), feed rate (vf), and depth of cut (ap), with the same change of material removal rate (MRR) on the mill-grinding force and surface roughness (Ra) were investigated. The formation mechanism of typical machined surface defects was analyzed by SEM. The experimental results reveal that with the same change of material removal rate, lower mill-grinding force values can be gained by increasing depth of cut and feed rate simultaneously at higher cutting speed. With the same change of MRR value, lower surface roughness values can be gained by increasing the feed rate at higher cutting speed, rather than just increasing the depth of cut, or increasing the feed rate and depth of cut simultaneously. The machined surface of SiCp/Al composites reveals typical defects which can influence surface integrity.

  15. Preparation of lithium ferrite nanoparticles by high energy ball milling and characterizations

    Directory of Open Access Journals (Sweden)

    J. Touthang

    2016-11-01

    Full Text Available Ferrites are ferrimagnetic ceramic materials with inherent useful electromagnetic properties. Of them, spinelstructured ferrites are promising materials for microwave device applications; stress/torsion sensors and energy storage applications like anode materials in lithium batteries, fuel cells, solar cells etc. Nanostructured spinels further have high and wide scope of potential applications. In the present study, two different types of varied sized ferrimagnetic lithium ferrite spinel nanoparticles prepared using chemical sol-gel auto-combustion method were chosen. The prepared spinel particles were heated at 300°C for 1h. After heating the powders were milled using a High Energy Ball Mill for 30 minutes to further grind the particles and then subjected to various characterizations. Structural characterization was done using X-Ray Diffraction Method (XRD. The study revealed the spinel structure of these samples. Structural parameter such as lattice constant was determined using XRD data and found that the lattice parameter agrees with the standard data. DLS study found the agglomerations of the nanoparticles. The synthesized nanospinel particles were also characterized by the UVVis Spectroscopy, the Fourier Transform Infrared Spectroscopy (FTIR. Finally the magnetic hysteresis properties were studied using a Vibrating Sample Magnetometer (VSM.

  16. Hydriding-dehydriding properties of Mg2Ni alloy modified by ball-milling in tetrahydrofuran

    Institute of Scientific and Technical Information of China (English)

    CHEN Changpin; WANG Wei; CHEN Yun; CHEN Lixin; WANG Qidong

    2004-01-01

    A new approach of ball-milled Mg2Ni in tetrahydrofuran (THF) to improve the hydriding kinetics of Mg2Ni alloy is suggested and studied. It is found that the modified alloy displayed the improved activity for hydriding even at relatively low temperature (e.g., 323-373 K). In the case of the sample milled in THF for 20 h, the hydrogen content (mass fraction)reaches 1.6 % at 323 K, 2.1% at 348 K and 3.4% at 448 K, respectively. The use of THF during grinding led to the change of the structure, which is reflected by the broadening and weakening of the diffraction peaks in the XRD spectra. The XPS analysis shows that Mg (2s) binding energy peak of Mg2Ni after modification shifted from a lower binding energy to a higher one, indicating the charge transference between Mg and THF and the formation of catalytically active electron donor-acceptor (EDA) complexes on the surface of modified Mg2Ni alloy.

  17. Ammonia synthesis over multi-promoted iron catalysts obtained by high-energy ball-milling

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Jiang, Jianzhong; Mørup, Steen

    1999-01-01

    The feasibility of producing ammonia synthesis catalysts from high-energy ball-milling of a simple mixture of the constituent oxides has been investigated. The effect of ball-milling the fused oxidic precursor of the industrial KM1 ammonia synthesis catalyst has also been studied. The results show...

  18. 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 rad...

  19. Influence of milling time on fineness of Centella Asiatica particle size produced using planetary ball mill

    Science.gov (United States)

    Borhan, M. Z.; Ahmad, R.; Rusop, M.; Abdullah, S.

    2012-11-01

    Centella Asiatica (C. Asiatica)contains asiaticoside as bioactive constituent which can be potentially used in skin healing process. Unfortunately, the normal powders are difficult to be absorbed by the body effectively. In order to improve the value of use, nano C. Asiatica powder was prepared. The influence of milling time was carried out at 0.5, 2, 4, 6, 8 hours and 10 hours. The effect of ball milling at different times was characterized using particles size analysis and FTIR Spectroscopy. The fineness of ground product was evaluated by recording the z-Average (nm), undersize distribution and polydispersity index (PdI). The results show that the smallest size particles by mean is 233 nm while FTIR spectra shows that there is no changing in the major component in the C. Asiatica powders with milling time.

  20. Remediation of oil-contaminated sand by coal agglomeration using ball milling.

    Science.gov (United States)

    Shin, Yu-Jen; Shen, Yun-Hwei

    2011-10-01

    The mechanical shear force provided by a less energy intensive device (usually operating at 20-200 rpm), a ball mill, was used toperform coal agglomeration and its effects on remediation of a model fuel oil-contaminated sand were evaluated. Important process parameters such as the amount of coal added, milling time, milling speed and the size of milling elements are discussed. The results suggested that highly hydrophobic oil-coal agglomerates, formed by adding suitable amounts of coal into the oil-contaminated sand, could be mechanically liberated from cleaned sand during ball milling and recovered as a surface coating on the steel balls. Over 90% removal of oil from oil-contaminated sand was achieved with 6 wt% of coal addition and an optimum ball milling time of 20 min and speed of 200 rpm. This novel process has considerable potential for cleaning oil-contaminated sands.

  1. Application of Ultra-Small Micro Grinding and Micro Milling Tools: Possibilities and Limitations

    Directory of Open Access Journals (Sweden)

    Benjamin Kirsch

    2017-08-01

    Full Text Available Current demands for flexible, individual microstructures in high quality result in high requirements for micro tools. As the tool size defines the minimum structure size, ultra-small tools are needed. To achieve tool diameters of 50 µm and lower, we investigate the complete manufacturing chain of micro machining. From the development of the machine tools and components needed to produce and apply the micro tools, the micro tools themselves, as well as the micro machining processes. Machine tools are developed with the possibility of producing the micro geometry (cutting edge design of micro tools as well as plating processes to produce super abrasive micro grinding tools. Applying these setups, we are able to produce ultra-small micro grinding and micro milling tools with typical diameters of 50 µm and down to 4 µm. However, the application of such tools is very challenging. The article presents possibilities and limitations in manufacturing the micro tools themselves as well as microstructures made with these tools. A special emphasis will be on the influence of the tool substrate in micro milling and grain sizes in micro grinding.

  2. Surface modification of titanium hydride with epoxy resin via microwave-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Ning, Rong [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Ding, E-mail: ma97chen@hotmail.com [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Zhang, Qianxia [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Bian, Zhibing; Dai, Haixiong; Zhang, Chi [Jiangsu Jinling Special Paint Co., Ltd., Yangzhou 225212 (China)

    2014-10-15

    Highlights: • TiH{sub 2} was modified with epoxy resin by microwave-assisted ball milling. • The epoxy ring was opened under the coupling effect of microwave and ball milling. • Microwave-assisted ball milling improved the compatibility of TiH{sub 2} with epoxy. - Abstract: Surface modification of titanium hydride with epoxy resin was carried out via microwave-assisted ball milling and the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR). A sedimentation test was performed to investigate the compatibility of the modified nano titanium hydride with the epoxy resin. The results show that the epoxy resin molecules were grafted on the surface of nano titanium hydride particles during the microwave-assisted ball milling process, which led to the improvement of compatibility between the nanoparticles and epoxy resin. According to the FT-IR, the grafting site was likely to be located around the epoxy group due to the fact that the epoxy ring was opened. However, compared with microwave-assisted ball milling, the conventional ball milling could not realize the surface modification, indicating that the coupling effect of mechanical force and microwave played a key role during the process.

  3. Properties of high-energy ball-milled Fe-Se based superconductors.

    Science.gov (United States)

    Ahn, Jung-Ho; Sangjun-Oh

    2012-02-01

    We have synthesized FeSe0.5Te0.5 superconductors by high-energy ball-milling and subsequent annealing. High-energy ball-milling of elemental powder mixtures resulted in the formation of metastable and/or nanocrystalline phases. Both XRD and DSC results show that the ball-milled powers were completely transformed to FeSe0.5Te0.5 with the grain size of a few nanometers during sintering at low temperatures. The resulting materials exhibited superconducting transition at 14 K. The enhancement of critical current density was observed for the high-energy ball-milled powder, compared with the un-milled powders.

  4. Optimize Operating Conditions on Fine Particle Grinding Process with Vertically Stirred Media Mill

    Science.gov (United States)

    Yang, Yang; Rowson, Neil; Ingram, Andy

    2016-11-01

    Stirred media mill recently is commonly utilized among mining process due to its high stressing intensity and efficiency. However, the relationship between size reduction and flow pattern within the mixing pot is still not fully understand. Thus, this work investigates fine particle grinding process within vertically stirred media mills by altering stirrer geometry, tip speed and solids loading. Positron Emitting Particle Tracking (PEPT) technology is utilized to plot routine of particles velocity map. By tacking trajectory of a single particle movement within the mixing vessel, the overall flow pattern is possible to be plotted. Ground calcium carbonate, a main product of Imerys, is chosen as feeding material (feed size D80 30um) mixed with water to form high viscous suspension. To obtain fine size product (normally D80 approximately 2um), large amount of energy is drawn by grinding mill to break particles through impact, shear attrition or compression or a combination of them. The results indicate higher energy efficient is obtained with more dilute suspension. The optimized stirrer proves more energy-saving performance by altering the slurry circulate. Imerys Minerals Limited.

  5. 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.

  6. 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.

  7. Synthesis of Fe3O4 nanoparticles by wet milling iron powder in a planetary ball mill

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fe3O4 nanoparticles with sizes ranging from 30 to 80nm were synthesized by wet milling iron powders in a planetary ball mill. The phase composition and the morphologies of the as-synthesized products were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Nanosized Fe3O4 particles were prepared by wet milling metallic iron powder (-200 mesh, 99%)rotation speed of 300 rpm. The use of the iron balls in this method played a key role in Fe3O4 formation. The present technique is simple and the process is easy to carry out.

  8. Effect of process variables on synthesis of MgB2 by a high energy ball mill

    Directory of Open Access Journals (Sweden)

    Kurama Haldun

    2016-01-01

    Full Text Available The discovery of superconductivity of MgB2 in 2001, with a critical temperature of 39 K, offered the promise of important large-scale applications at around 20 K. Except than the other featured synthesis methods, mechanical activation performed by high energy ball mills, as bulk form synthesis or as a first step of wire and thin film productions, has considered as an effective alternative production route in recent years. The process of mechanical activation (MA starts with mixing the powders in the right proportion and loading the powder mixture into the mill with the grinding media. The milled powder is then consolidated into a bulk shape and heat-treated to obtain desired microstructure and properties. Thus, the important components of the MA process are the raw materials, mill type and process variables. During the MA process, heavy deformation of particles occure. This is manifested by the presence of a variety of crystal defects such as dislocations, vacancies, stacking faults and increased number of particle boundaries. The presence of this defect structure enhances the diffusivity of solute hence the critical currents and magnetic flux pinning ability of MgB2 are improved. The aim of the present study is to determine the effects of process variables such as ball-to-powder mass ratio, size of balls, milling time, annealing temperature and contribution of process control agent (toluene on the product size, morphology and conversion level of precursor powders to MgB2 after subsequent heat treatment. The morphological analyses of the samples were performed by a high vacuum electron microscope ZEISS SUPRA VP 50. The phase compositions of the samples were performed with an Rigaku-Rint 2200 diffractometer, with nickel filtered Cu Kα radiation and conversion level. The MgB2 phase wt % was calculated by the Rietveld refinement method. The obtained results were discussed according to the process variables to find out their affect on the structure

  9. 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℃.

  10. 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.

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

    DEFF Research Database (Denmark)

    Linderoth, Søren; Jiang, Jianzhong; Mørup, Steen

    1997-01-01

    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 hi...... 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.......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...

  12. Efficiency of ball milled South African bentonite clay for remediation of acid mine drainage

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2015-12-01

    Full Text Available The feasibility of using vibratory ball milled South African bentonite clay for neutralization and attenuation of inorganic contaminants from acidic and metalliferous mine effluents has been evaluated. Treatment of acid mine drainage (AMD...

  13. Finite size effects and spin transition in ball-milled γ-(FeMn) 30Cu 70 nanostructured alloys

    Science.gov (United States)

    Restrepo, J.; Greneche, J. M.; González, J. M.

    2004-12-01

    Fe 15Mn 15Cu 70 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 Mössbauer 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 Å 3 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.

  14. Structural and magnetic stability of high energy ball milled Co{sub 2}MnSi

    Energy Technology Data Exchange (ETDEWEB)

    Vinesh, A., E-mail: attatappa85@gmail.com [Department of Physics, Amity School of Applied Sciences, Amity University Haryana, Gurgaon 122413 (India); Sudheesh, V.D. [Department of Physics, MohanlalSukhadia University Udaipur, Rajasthan 313001 (India); Sebastian, Varkey [Department of Physics, Nimalagiri College, Nirmalagiri, Kannur, Kerala 670701 (India); Lakshmi, N.; Venugopalan, K. [Department of Physics, MohanlalSukhadia University Udaipur, Rajasthan 313001 (India)

    2015-07-15

    Structural and magnetic properties of ball milled Co{sub 2}MnSi 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 µ{sub B} per formula unit at room temperature and is in agreement with the prediction of Slater Pauling curve. On milling it reduces to ~3 µ{sub B} 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 Co{sub 2}MnSi. • Structural disordering is minimal even at 36 nm. • Constant value of T{sub C} 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.

  15. 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%.

  16. PREPARING NANO-CRYSTALLINE La DOPED WC/Co POWDER BY HIGH ENERGY BALL MILLING

    Institute of Scientific and Technical Information of China (English)

    S. Liu; D.Q. Yi; Y.X. Li; D. Zou

    2002-01-01

    The La doped WC/Co powder was prepared by high energy ball milling. The changesof crystal structure, micrograph and defect of the powder were investigated by means ofXRD (X-ray diffraction), SEM (scanning electron microscope) and DTA (differentialthermal analysis). The results show that adding trace La element into carbides iseffective to minish the grain size of WC/Co powder. The La doped carbides powderwith grain size of 30nm can be obtained after 1Oh ball milling. The XRD peak of Cophase disappeared after 20h ball milling, which indicated solid solution (or secondarysolid solution) of Co phase in WC phase. The La doped powder with grain size of1Ohm is obtained after 30h ball milling. A peak of heat release at the temperatureof 470℃ was emerged in DTA curve within the range of heating temperature, whichshowed that the crystal structure relaxation of the powder appeared in the process ofhigh energy ball milling. After consolidated the La doped WC/Co alloy by high energyball milling exhibits ultra-fine grain Sizes and better mechanical properties.

  17. Reseach on Mill-grinding Experiment of Grinding Wheel with Phyllotactic Pattern%磨粒族叶序排布砂轮的铣磨实验研究

    Institute of Scientific and Technical Information of China (English)

    王军; 赵良兵; 赵成义; 吕玉山

    2013-01-01

    In order to realize the ordering of the grinding wheel abrasive surface assignment, this paper combined with phyllotaxis theory and grinding mechanism, and manufactured phyllotactic pattern grinding wheel by UV lithography method and electroplating technology. The mill-grinding experiment results show that; the grinding performance of phyllotactic pattern grinding wheel is superior to what of disordered arrangement grinding wheel.%为了实现砂轮表面磨料排布的有序化,本文将仿生学叶序理论与磨削机理相结合,利用光刻技术和复合电镀技术制备出了磨粒族叶序排布砂轮.铣磨实验结果表明:磨粒族叶序排布砂轮的磨削性能优于普通无序排布砂轮.

  18. Catalytic Effect of Nb2O5 in MgH2-Nb2O5 Ball-Milled Composites

    Directory of Open Access Journals (Sweden)

    Somei Ohnuki

    2012-09-01

    Full Text Available We report a study on the desorption properties, crystallography and chemical state of MgH2 and 1 mol% Nb2O5 ball-milled composites. Desorption temperatures of the composites decreased with increase of ball-milling time. Size of MgH2 crystallites decreased during ball-milling. Reduction of Nb2O5 after ball-milling was confirmed by tracing the chemical state of Nb and was further supported by TEM observation. The reduced phases may act as more effective catalysts improving the desorption properties.

  19. 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.

  20. Effect of ball milling process on the microstructure of titanium-nanohydroxyapatite composite powder

    Institute of Scientific and Technical Information of China (English)

    PANG Pengsha; LI Wei; LIU Ying

    2007-01-01

    Titanium-nanohydroxyapatite (Ti-nHA) composite powders, composed of titanium with 10 vol.% and 20 vol.%of nano-hydroxyapatite, were milled in a planetary ball mill using alcohol media to avoid excessive heat. XRD and SEM were performed for characterization of the microstructure, and the homogeneity of Ti/HA nanocomposite powder was evaluated by EPMA with prolonged ball milling time. The results show that under the condition of wet milling, the grain size of Ti-nHA composite powders is decreased with the increase in ball milling time and the amount of the addition of nHA.While for milling of 30 h, the nanocomposite powder with fine structure, which consists of the nano-hydroxyapatite (nHA)particles and titanium (Ti) phase, is obtained. Three stages of milling can be observed from the element mapping of Ti, Ca,and P by EPMA; meanwhile, it is found that the nHA would be more homogenously distributed after milling for 30 h.

  1. Preparation and Characterization of Stainless Steel/TiC Nanocomposite Particles by Ball-milling Method

    Institute of Scientific and Technical Information of China (English)

    CHEN Wenyi; ZHOU Jian

    2009-01-01

    A stainless steel/10wt%TiC nanocomposite particles were prepared by high-energy ball-milling method using stainless steel, carbon and titanium as raw materials. The evolution of phase composition, microstructure and specific surface area of the stainless steel/TiC nanocomposite particles with increasing ball-milling time in the range of 0-100 h were investigated by XRD, SEM, TEM and BET techniques. The results showed that the stainless steel/TiC nano-composite particles were fabricated when the ball-milling time was longer than 20 h. However, the nanocomposite particles were soldered and agglomerated again when the ball-milling time was longer than 60 h. The microstructure of the composite particles transformed from lamellar structure to nanostructure during the repeated process of the cold welding and cracking. TEM image reveals clearly that the in-situ TiC nanoparticles with grain size of 3-8 nm are in the interior of the stainless steel/TiC nanocomposite particles obtained by ball-milling 100 h.

  2. Effect of ball milling and heat treatment process on MnBi powders magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wei; Polikarpov, Evgueni; Choi, Jung-Pyung; Bowden, Mark E.; Sun, Kewei; Cui, Jun

    2016-09-01

    The metallic compound MnBi has high intrinsic coercivity with large positive temperature coefficient. The coercivity of MnBi exceeds 12 kOe and 26 kOe at 300 K and 523 K, respectively. Hence MnBi is a good candidate for the hard phase in exchange coupled nanocomposite magnets. In order to maximize the loading of the soft phase, the size of the MnBi particle has to be close to 500 nm, the size of single magnetic domain. Low energy milling is the common method to reduce MnBi particle size. However, only 3-7 mu m size particle can be achieved without significant decomposition. Here, we report our effort on preparing submicron MnBi powders using traditional powder metallurgy methods. Mn55Bi45 magnetic powders were prepared using arc melting method, followed by a series of thermal-mechanical treatment to improve purity, and finished with low energy ball milling at cryogenic temperature to achieve submicron particle size. The Mn55Bi45 powders were decomposed during ball milling process and recovered during 24 h 290 degrees C annealing process. With increasing ball-milling time, the saturation magnetization of MnBi decreases, while the coercivity increases. Annealing after ball milling recovers some of the magnetization, indicating the decomposition occurred during the ball-milling process can be reversed. The coercivity of Mn55Bi45 powders are also improved as a result of the heat treatment at 290 degrees C for 24 h. The world record magnetization 71.2 emu/g measured applying a field of 23 kOe has been achieved via low energy ball mill at room temperature

  3. 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.

  4. Study on the Method for Collecting Vibration Signals from Mill Shell Based on Measuring the Fill Level of Ball Mill

    Directory of Open Access Journals (Sweden)

    Peng Huang

    2014-01-01

    Full Text Available At present the method for measuring the fill level which used the vibration signal of mill shell shows its advantage compared with other methods. However, this method is developed late, and the technique for collecting the vibration signal from mill shell is immature. In this paper, a novel method for collecting the vibration data from mill shell is proposed. Firstly, the layout scheme of vibration sensors on mill shell is given by analyzing the axial and circumferential movement of coal powder in roller. And a special data acquisition system is developed, which can acquire vibration data from different axial and circumferential positions on mill shell. Then the sampling frequency is obtained based on impact model and hierarchical model of steel balls. At the same time, the impact region on mill shell caused by steel balls is considered as the collecting region of vibration signals. Experimental result shows that vibration signals collected by the method proposed in this paper present a high sensitivity to the changes on fill level compared with vibration data of mill bearing, which provides a reliable basis for accurate measurement of the fill level.

  5. The effect of cryogenic grinding and hammer milling on the flavour quality of ground pepper (Piper nigrum L.).

    Science.gov (United States)

    Liu, Hong; Zeng, Fankui; Wang, Qinghuang; Ou, Shiyi; Tan, Lehe; Gu, Fenglin

    2013-12-15

    In this study, we compared the effects of cryogenic grinding and hammer milling on the flavour attributes of black, white, and green pepper. The flavour attributes were analysed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS), sensory evaluation and electronic nose (e-nose) analysis. Cryogenic grinding resulted in minimal damage to the colour, flavour, and sensory attributes of the spices. Cryogenic grinding was also better than hammer milling at preserving the main potent aroma constituents, but the concentrations of the main aroma constituents were dramatically reduced after storing the samples at 4 °C for 6 months. Pattern matching performed by the e-nose further supported our sensory and instrumental findings. Overall, cryogenic grinding was superior to hammer milling for preserving the sensory properties and flavour attributes of pepper without significantly affecting its quality. However, we found that the flavour quality of ground pepper was reduced during storage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Use of high energy ball milling on the sintering optimization of alumina ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Simoni, Helio R.; Saito, Eduardo; Santos, Claudinei dos; Santos, Felipe Antunes, E-mail: heliorss@ppgem.eel.usp.br, E-mail: claudinei@demar.eel.usp.br, E-mail: felipeantunes@usp.br [Universidade de Sao Paulo (EEL/USP) Lorena, SP (Brazil). Escola de Engenharia; Ramos, Alfeu Saraiva, E-mail: alfeuramos@uol.com.br [Unersidade Estadual Paulista Julio de Mesquista Filho (UNESP/FEG), Guaratingueta, SP (Brazil). Faculdade de Engenharia; Silva, Oliverio Moreira M., E-mail: silvaoliva@bol.com.br [Instituto de Aeronautica e Espacao (CTA/IAE/AMR), Sao Jose dos Campos, SP (Brazil). Centro Tecnico Aeroespacial

    2009-07-01

    In this work, the effect of the milling time on the densification of the alumina ceramics with or without 5wt.%Y{sub 2}O{sub 3}, is evaluated, using high-energy ball milling. The milling was performed with different times of 0, 2, 5 or 10 hours. All powders, milled at different times, were characterized by X-Ray Diffraction presenting a reduction of the crystalline degree and crystallite size as function of the milling time increasing. The powders were compacted by cold uniaxial pressing and sintered at 1550°C-60min. Green density of the compacts presented an increasing as function of the milling time and sintered samples presented evolution on the densification as function of the reduction of the crystallite size of the milled powders. (author)

  7. Influence of cation disorder on the magnetic properties of ball-milled ilmenite (FeTiO{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Morup, Steen; Rasmussen, Helge K. [Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Brok, Erik [Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Keller, Lukas [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Frandsen, Cathrine, E-mail: fraca@fysik.dtu.dk [Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark)

    2012-09-14

    We have investigated the evolution of crystal structure, cation disorder and magnetic properties of ilmenite (FeTiO{sub 3}) after increasing time of high-energy ball-milling in an inert atmosphere. Refinement of X-ray diffraction data show that the hexagonal crystal structure of ilmenite is maintained after high-energy ball-milling of up to 128 h, but neutron diffraction studies reveal significant cation redistribution of Fe{sup 2+} and Ti{sup 4+} ions in the ball-milled samples. Moessbauer spectroscopy studies show that the magnetic hyperfine field of Fe{sup 2+}, which is around 5 T before ball-milling, increases, and after milling times longer than 4 h a broad distribution of hyperfine fields with values up to around 40 T for Fe{sup 2+} is seen. This can be explained by the cation disorder induced by the ball-milling which affects the orbital contribution to the magnetic hyperfine field. In contrast to some ball-milled spinel ferrites, the Neel temperature of ilmenite is not significantly affected by the cation disorder. -- Highlights: Black-Right-Pointing-Pointer High-energy ball-milling of FeTiO{sub 3} results in cation disorder. Black-Right-Pointing-Pointer The magnetic hyperfine field of {sup 57}Fe is strongly affected by the ball-milling. Black-Right-Pointing-Pointer The Neel temperature of FeTiO{sub 3} is not significantly affected by cation disorder.

  8. Effects of Wheel Wear on the Manufacturing Errors of Ball-Nose End Milling Cutter%砂轮磨损对球头立铣刀制造误差的影响研究

    Institute of Scientific and Technical Information of China (English)

    夏文胜; 周兆锋; 成岗; 何林

    2013-01-01

    The ball-nose end milling cutter is an important cutting tool which is used to cut the complicated high-precision curved surface. In the manufacturing process of grinding ball-nose end milling cutter, as the grinding time increased, the wheel will be wear, the edge curve of ball-nose end milling cutter will also change. In the paper, the grinding simulation system and parameters analysis system of rake face of ball-nose end milling cutter was established, the means of Visual Basic, based on SolidWorks software platform. Effects of grinding wheel wear on the edge strip width and edge curve of ball-nose end milling cutter was investigated. The obtained results can provide theoretical guides to the manufacturing process of ball-nose end milling cutter, and provide the guidance for the follow-up to develop the correct error compensation strategy.%球头立铣刀是加工复杂高精度曲面的重要刀具.在磨削加工球头立铣刀的制造过程中,随着磨削时间的增加,砂轮会出现磨损,球头立铣刀的刃形曲线会随之发生变化.文章以SolidWorks为开发平台,基于球头立铣刀前刀面的磨削加工运动关系,利用Visual Basic语言进行二次开发,开发出球头立铣刀前刀面的磨削仿真加工系统和刀具参数分析系统,分析了砂轮磨损对球头立铣刀刃带宽度和刃形曲线的影响.分析结果可为实际加工过程提供理论指导,有助于制定正确的磨削制造工艺,并为后续制定正确误差补偿策略提供重要指导.

  9. 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.

  10. 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.

  11. The Key Role of Ball Milling Time in the Microstructure and Mechanical Property of Ni-TiCNP Composites

    Science.gov (United States)

    Zhou, Xiaoling; Huang, Hefei; Xie, Ruobing; Yang, Chao; Li, Zhijun; Jiang, Li; Ye, Xiangxi; Xu, Hongjie

    2016-12-01

    Titanium carbide nanoparticle-reinforced nickel-based alloys (Ni-TiCNP composites) with ball milling time ranging from 8 to 72 h were prepared by ball milling and spark plasma sintering. Transmission electron microscopy (TEM) and scanning electron microscopy equipped with electron backscatter diffraction were used to characterize the microstructures. Their hardness and tensile properties were measured using the Vickers pyramid method and tensile tests. TEM results showed that a slight coarsening of TiCNP occurred during the ball milling process. The grain sizes of the Ni-TiCNP composites with various ball milling times were different, but they were all much smaller than those of the pure Ni. In all cases, the Ni-TiCNP composites showed higher strengths and hardness values than the unreinforced pure nickel. Furthermore, the strength of the Ni-TiCNP composites increased initially and then decreased as a function of ball milling time. The maximum strengths occurred in the 24-h ball milling sample, which presented the lowest average grain size. The Hall-Petch strengthening was suggested to be the main reason responsible for such variations in mechanical properties. Additionally, the elongation percentage of the Ni-TiCNP composites decreased gradually with ball milling time. This may be caused by the change of microvoids in the composite as the ball milling time varies, which is also related to their fracture behavior.

  12. Amorphous solid dispersions of sulfonamide/soluplus® and sulfonamide/PVP prepared by ball milling

    OpenAIRE

    Healy, Anne,

    2013-01-01

    PUBLISHED The aim of this paper is to investigate the physicochemical properties of binary amorphous dispersions of poorly soluble sulfonamide/polymeric excipient prepared by ball milling. The sulfonamides selected were sulfathiazole (STZ), sulfadimidine (SDM), sulfamerazine (SMZ) and sulfadiazine (SDZ). The excipients were polyvinylpyrrolidone (PVP) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co-polymer, commercially known as Soluplus®. Co-milled systems were cha...

  13. 磨球残余应力的数值模拟及分析%Simulation and Analysis of Residual Stress of Grinding Balls

    Institute of Scientific and Technical Information of China (English)

    袁允社; 张小博

    2009-01-01

    The distribution of residual stress of grinding balls in casting condition was simulated based on the software ProCAST. The stress distribution after heat treating was determined by X-ray diffraction instrument. The results indicate that grinding balls in the metal mould solidify first and then in the sand mould, and the interior structures of grinding balls are compact; there is mass of residual stress in the grinding ball in cast condition,although a definite residual stress can be eliminated after heat treating, an amount of stress still exists.%通过铸造数值模拟软件ProCAST模拟了磨球铸态下的残余应力分布情况,同时通过X射线衍射仪,测定了热处理后磨球试样上应力分布状态.结果表明,磨球金属型部位先凝固,砂型部位后凝固,磨球内部组织致密、无缺陷;铸态下在磨球内有大量的残余应力,热处理后可以消除一定的铸造残余应力,但仍有大量残余应力存在.

  14. Effect of Grinding Methods on Structural, Physicochemical, and Functional Properties of Insoluble Dietary Fiber from Orange Peel

    Directory of Open Access Journals (Sweden)

    Yanlong Liu

    2016-01-01

    Full Text Available This study evaluated the effect of grinding methods (regular laboratory milling, ultra centrifugal rotor milling, and ball milling on structural, physicochemical, and functional properties of insoluble dietary fiber (IDF fraction from orange peel. The results demonstrated that both ultra centrifugal milling and ball milling could effectively decrease average particle size of IDF fraction (81.40 μm and 19.63 μm, resp.. The matrix structure of IDF fraction was destroyed but FTIR structure had no major change after grinding. As particle size decreased, the bulk density and lightness of IDF fraction increased and a redistribution of fiber components from insoluble to soluble fractions was observed. Furthermore, ball milled IDF fraction exhibited significantly higher capacity to retard glucose diffusion and inhibit α-amylase activity (35.09%. This work would give useful insight into effect of grinding methods on properties and functions of orange peel IDF in food industry.

  15. Electrochemical Properties of CeMg12+x%Ni Composites (x=0~200) Prepared by Ball-Milling

    Institute of Scientific and Technical Information of China (English)

    Wang Li; Wang Xinhua; Chen Changpin; Xiao Xuezhang

    2005-01-01

    The electrochemical properties of the as-cast and ball-milled CeMg12+x%(mass fraction) Ni (vs. CeMg12) (x=0, 50, 100 and 200) composites were investigated. The microstructure and discharge capacity of the ball-milled CeMg12+x%Ni composites differ greatly depending on the amount of Ni introduced during ball-milling. The more nickel powder added, the more advantageous for the formation of the amorphous structure. And the discharge capacities of the ball-milled composites increase with increasing amount of nickel added. After 90 h ball-milling, the CeMg12+200% Ni composite exhibits a high discharge capacity of 1170 mAh·g-1(CeMg12)-1 at 303 K. The improvement of electrochemical capacity is attributed to the formation of a homogeneous amorphous structure as well as the modification of the surface state after Ni addition.

  16. 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.

  17. 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.

  18. Synthesis of FeTi hydrogen storage material via ball milling: effect of milling energy and atmosphere.

    OpenAIRE

    Livramento, Vanessa; Rangel, C. M.; Correia, J. Brito; Shohoji, Nobumitsu; R.A. Silva

    2008-01-01

    Attempts were made earlier to synthesize and activate the FeTi intermetallic during ball milling (BM), for H2 storage using sodium boron tetra-hydride (NaBH4) additive as a process controlling agent. Simple reactive milling starting from Fe and Ti powders resulted in heavy agglomeration of powders, due to the self sustaining nature of the reaction following an incubation period. When NaBH4 was used as the process control agent to avoid agglomeration, this resulted in the production of titaniu...

  19. Design of Ball-Milling Experiments on Bi2Te3 Thermoelectric Material

    Science.gov (United States)

    Kanatzia, A.; Papageorgiou, Ch.; Lioutas, Ch.; Kyratsi, Th.

    2013-07-01

    In this work, factorial ball-milling experiments have been applied to Bi2Te3 material, for the first time, aiming to investigate the effect of the main process parameters on the structural features and thermoelectric properties of the ball-milled materials. The selected main parameters were the duration of milling, the speed, and the ball-to-material ratio. Analysis suggests a strong effect of the speed and duration of processing, whereas the ball-to-material ratio is of minor importance. This approach is advantageous for better understanding of the milling mechanism and the importance of the role of each independent parameter as well as their interaction. All experiments led to nanocrystalline Bi2Te3, whose structural features were studied. The nanocrystalline size was estimated based on x-ray diffraction analysis, while transmission electron microscopy (TEM) studies were also performed to confirm the presence of nanoscale crystals. A mathematical model was developed based on statistical analysis for prediction of the crystalline size and the Seebeck coefficient of the nanopowders. The thermoelectric properties were also investigated on selected, highly dense pellets fabricated via hot-pressing of the nanopowders.

  20. 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 mag...

  1. 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...

  2. 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.

  3. A vertical ball mill as a new reactor design for biomass hydrolysis and fermentation process

    DEFF Research Database (Denmark)

    de Assis Castro, Rafael Cunha; Mussatto, Solange I.; Conceicao Roberto, Inês

    2017-01-01

    A vertical ball mill (VBM) reactor was evaluated for use in biomass conversion processes. The effects of agitation speed (100–200 rpm), number of glass spheres (0–30 units) and temperature (40–46 °C) on enzymatic hydrolysis of rice straw and on glucose fermentation by a thermotolerant Kluyveromyces...

  4. Effect of ball milling on hydrogen storage of Mg3La alloy

    Institute of Scientific and Technical Information of China (English)

    DONG Hanwu; OUYANG Liuzhang; SUN Tai; ZHU Min

    2008-01-01

    Hydrogen storage and microstructure of ball milled Mg3La alloy were investigated by X-ray diffraction and pressure-composition-isotherm measurement. The ball milled Mg3La alloy could absorb hydrogen up to 4wt.% at 300 °C for the first time, along with a decomposing course. Following tests showed that the average reversible hydrogen storage capacity was 2.7wt.%. The enthalpy and entropy of dehydrogenation reaction of the decomposed ball milled Mg3La and hydrogen were calculated. XRD patterns indicated the existence of MgH2 and LaH3 in the decomposed hydride and the formation of Mg when hydrogen was desorbed. After the first hydrogenation, all the latter hydrogenation/dehydrogenation reactions could be taken place between Mg and MgH2. The ball milled Mg3La alloy exhibited better hydriding kinetics than that of the as-cast Mg3La alloy at room temperature. The kinetic curve could be well fitted by Avrami-Erofeev equation.

  5. 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.

  6. Structural transition and softening in Al–Fe intermetallic compounds induced by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Basariya, M. Raviathul, E-mail: ravia80@gmail.com [CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India); Roy, Rajat K.; Pramanick, A.K.; Srivastava, V.C. [CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Mukhopadhyay, N.K. [Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India)

    2015-06-25

    In the present investigation, powders of as-cast ingots of Al–25 at%Fe and Al–34.5 at%Fe alloys close to Al{sub 3}Fe and Al{sub 2}Fe intermetallic phases are subjected to high energy ball milling to understand the possibility of formation of amorphous and/or nanocrystalline phases or any other metastable phases. The development of microstructure, evolution of various metastable phases and their stability are investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Mechanical milling of the alloys, up to 50 h, was carried out in high energy planetary ball mill. It resulted in phase transformation from monoclinic and triclinic structures of Al{sub 3}Fe and Al{sub 2}Fe, respectively, to orthorhombic structure pertaining to Al{sub 5}Fe{sub 2} phase and structural transformation from crystalline to amorphous phase. Hardness measurements revealed a transition from hardening to softening behavior in these mechanically milled alloys undergoing prolonged milling. The softening effect in the milled powders, having a composite structure involving nanocrystalline and amorphous phases, is attributed to the competing phenomenon of grain size reduction and amorphous phase formation with increasing milling time.

  7. Effect of ball milling energy on rheological and thermal properties of amaranth flour.

    Science.gov (United States)

    Roa, Diego F; Baeza, Rosa I; Tolaba, Marcela P

    2015-12-01

    Pearled amaranth grains obtained by abrasive milling were processed by planetary ball milling to produce amaranth flours. The influence of milling energy on rheological and thermal behavior of amaranth flour dispersions and stability during 24 h storage at 4 °C were investigated based on a factorial design. The rheological behavior of flour dispersions (4 % and 8 % w/v) was determined using a rotational viscometer, while gelatinization degree was determined by differential scanning calorimetry as a measure of structural changes.The power law model was found to be suitable in expressing the relationship between shear stress and shear rate. Flour dispersions showed a pseudoplastic behavior. However this character decreased with the storage being dependent on flour concentration and milling energy. A decrease of the consistency index and an increase of the flow behavior index were observed as a result of the increasing milling energy. Gelatinization enthalpy decrease showed the loss of crystalline structure due to ball milling. Amaranth flour dispersions presented increasing stability during storage. It was observed, that the stability changed with the concentration of amaranth flours.Thus, more stable dispersions were obtained as the flour concentration increased. The highly milled sample was the most stable sample during the storage.

  8. Defect induced electronic states and magnetism in ball-milled graphite.

    Science.gov (United States)

    Milev, Adriyan; Dissanayake, D M A S; Kannangara, G S K; Kumarasinghe, A R

    2013-10-14

    The electronic structure and magnetism of nanocrystalline graphite prepared by ball milling of graphite in an inert atmosphere have been investigated using valence band spectroscopy (VB), core level near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and magnetic measurements as a function of the milling time. The NEXAFS spectroscopy of graphite milled for 30 hours shows simultaneous evolution of new states at ~284.0 eV and at ~290.5 eV superimposed upon the characteristic transitions at 285.4 eV and 291.6 eV, respectively. The modulation of the density of states is explained by evolution of discontinuities within the sheets and along the fracture lines in the milled graphite. The magnetic measurements in the temperature interval 2-300-2 K at constant magnetic field strength show a correlation between magnetic properties and evolution of the new electronic states. With the reduction of the crystallite sizes of the graphite fragments, the milled material progressively changes its magnetic properties from diamagnetic to paramagnetic with contributions from both Pauli and Curie paramagnetism due to the evolution of new states at ~284 and ~290.5 eV, respectively. These results indicate that the magnetic behaviour of ball-milled graphite can be manipulated by changing the milling conditions.

  9. Onset of chaotic dynamics in a ball mill: Attractors merging and crisis induced intermittency

    Science.gov (United States)

    Manai, G.; Delogu, F.; Rustici, M.

    2002-09-01

    In mechanical treatment carried out by ball milling, powder particles are subjected to repeated high-energy mechanical loads which induce heavy plastic deformations together with fracturing and cold-welding events. Owing to the continuous defect accumulation and interface renewal, both structural and chemical transformations occur. The nature and the rate of such transformations have been shown to depend on variables, such as impact velocity and collision frequency that depend, in turn, on the whole dynamics of the system. The characterization of the ball dynamics under different impact conditions is then to be considered a necessary step in order to gain a satisfactory control of the experimental set up. In this paper we investigate the motion of a ball in a milling device. Since the ball motion is governed by impulsive forces acting during each collision, no analytical expression for the complete ball trajectory can be obtained. In addition, mechanical systems exhibiting impacts are strongly nonlinear due to sudden changes of velocities at the instant of impact. Many different types of periodic and chaotic impact motions exist indeed even for simple systems with external periodic excitation forces. We present results of the analysis on the ball trajectory, obtained from a suitable numerical model, under growing degree of impact elasticity. A route to high dimensional chaos is obtained. Crisis and attractors merging are also found.

  10. Magnetoresistivity and microstructure of YBa2Cu3Oy prepared using planetary ball milling

    Science.gov (United States)

    Hamrita, A.; Ben Azzouz, F.; Madani, A.; Ben Salem, M.

    2012-01-01

    We have studied the microstructure and the magnetoresistivity of polycrystalline YBa2Cu3Oy (YBCO or Y-123 for brevity) embedded with nanoparticles of Y-deficient YBCO, generated by the planetary ball milling technique. Bulk samples were synthesized from a precursor YBCO powder, which was prepared from commercial high purity Y2O3, Ba2CO3 and CuO via a one-step annealing process in air at 950 °C. After planetary ball milling of the precursor, the powder was uniaxially pressed and subsequently annealed at 950 °C in air. Phase analysis by X-ray diffraction (XRD), granular structure examination by scanning electron microscopy (SEM), microstructure investigation by transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDXS) were carried out. TEM analyses show that nanoparticles of Y-deficient YBCO, generated by ball milling, are embedded in the superconducting matrix. Electrical resistance as a function of temperature, ρ(T), revealed that the zero resistance temperature, Tco, is 84.5 and 90 K for the milled and unmilled samples respectively. The milled ceramics exhibit a large magnetoresistance in weak magnetic fields at liquid nitrogen temperature. This attractive effect is of high significance as it makes these materials promising candidates for practical application in magnetic field sensor devices.

  11. 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.

  12. 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.

  13. Modeling High-Energy Ball Milling in the Alumina-Yttria System

    Science.gov (United States)

    Alkebro, J.; Bégin-Colin, S.; Mocellin, A.; Warren, R.

    2002-02-01

    Experimental results from high-energy ball milling of alumina-yttria powder mixtures have been analyzed with models collected from the literature. Depending on the milling conditions, either there is formation of an intermediate phase in the alumina-yttria system (yttrium aluminum perovskite, YAP), or the sample becomes mostly amorphous. Variations due to milling tool material can be accounted for by local models based on the Hertzian theory of elastic bodies, but the effects of changing mills are poorly accounted for by published models. Therefore, the concept of an impact frequency distribution over the energy spectrum is introduced as a tool for studying the characteristics of the mills. The pressure on the powder trapped between two colliding bodies has been found to be the factor deciding the outcome of the process. The threshold behavior of the system yields an amorphous structure for low pressures, and formation of YAP when impact pressures exceed the threshold value.

  14. 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.

  15. Magnesium-based nanocomposites synthesized by high-energy ball milling for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, H.; Nakatomi, S.; Tanaka, K.; Hashimoto, Y.; Sakata, Y. [Yamaguchi Univ., Tokiwadai (Japan)

    2010-07-01

    Nanocrystalline MgH{sub 2} obtained by ball milling with cyclohexane or benzene showed excellent properties for hydrogen storage. 1 at% Al-added nanocrystalline magnesium samples obtained by milling of MgH{sub 2} with solutions of Al(C{sub 2}H{sub 5}){sub 3} in benzene showed the reversible hydrogen absorption/desorption cycles even at 0.1 MPa of hydrogen. Moreover, the hydrogen storage properties of magnesium hydride were markedly improved upon nanocomposite formation by ball milling of MgH{sub 2} with Sn or SiC. For MgH{sub 2}/Sn and MgH{sub 2}/SiC nanocomposites, the dissociation temperature at 0.1 MPa of hydrogen was raised, compared to that for MgH{sub 2}. (orig.)

  16. Electromagnetic properties of Co flaky particles prepared via ball-milling method

    Science.gov (United States)

    Liu, Chao; Jiang, Jian-Tang; Yuan, Yong; Gong, Yuan-Xun; Zhen, Liang

    2016-10-01

    Flaky cobalt particles with different aspect ratio were produced with ball-milling method. The phase structure and morphology of the particles were identified by XRD analysis and SEM observation. The static magnetic and electromagnetic properties of the particles were measured and effects of shape, microstructure and filling fraction were investigated. Phase transition from fcc lattice to hcp lattice occur due to the drive of ball-milling is responsible for the largely increased coercivity. Particles with high aspect ratio are found to possess high permittivity and permeability, compelling the frequency of absorption peak to shift to low frequency. Coatings using cobalt particles milled for 20 h as fillers present a RL peak of -33 dB at 8 GHz at the thickness of 2.5 mm together with a broad effective absorbing (RL below -10 dB) bandwidth covering 6-10 GHz.

  17. Microstructural Evolution, Thermodynamics, and Kinetics of Mo-Tm2O3 Powder Mixtures during Ball Milling

    Directory of Open Access Journals (Sweden)

    Yong Luo

    2016-10-01

    Full Text Available The microstructural evolution, thermodynamics, and kinetics of Mo (21 wt % Tm2O3 powder mixtures during ball milling were investigated using X-ray diffraction and transmission electron microscopy. Ball milling induced Tm2O3 to be decomposed and then dissolved into Mo crystal. After 96 h of ball milling, Tm2O3 was dissolved completely and the supersaturated nanocrystalline solid solution of Mo (Tm, O was obtained. The Mo lattice parameter increased with increasing ball-milling time, opposite for the Mo grain size. The size and lattice parameter of Mo grains was about 8 nm and 0.31564 nm after 96 h of ball milling, respectively. Ball milling induced the elements of Mo, Tm, and O to be distributed uniformly in the ball-milled particles. Based on the semi-experimental theory of Miedema, a thermodynamic model was developed to calculate the driving force of phase evolution. There was no chemical driving force to form a crystal solid solution of Tm atoms in Mo crystal or an amorphous phase because the Gibbs free energy for both processes was higher than zero. For Mo (21 wt % Tm2O3, it was mechanical work, not the negative heat of mixing, which provided the driving force to form a supersaturated nanocrystalline Mo (Tm, O solid solution.

  18. Optimization of the Chemical Composition of Cast Iron Used for Casting Ball Bearing Grinding Disks

    Institute of Scientific and Technical Information of China (English)

    Aurel Crisan; Sorin Ion; Munteanu; Ioan Ciobanu; Iulian Riposan

    2008-01-01

    The chemical composition of cast iron used for casting ball bearing machining disks was varied to optimize the properties such as castability, hardenability, and durability in ball machining. The cast iron characteristics were most strongly dependent on the Ni content and the carbon saturation degree, So. This paper describes the types of test specimens, the working conditions, and the experimental results. The in-crease of the degree of carbon saturation reduces the tendency to form shrinkholes in the castings. The de-crease in the Ni content negatively affects the final hardening treatment. A way to control solidification de-fects in cast iron, by reducing the Ni content, has been verified on cast disks.

  19. 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.

  20. 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.

  1. Ball Mill Synthesis of Bulk Quaternary Cu2ZnSnSe4 and Thermoelectric Studies

    Science.gov (United States)

    Tiwari, Kunal J.; Prem Kumar, D. S.; Mallik, Ramesh Chandra; Malar, P.

    2017-01-01

    In this work, quaternary chalcogenide Cu2ZnSnSe4 (CZTSe) was synthesized using a mechanochemical ball milling process and its thermoelectric properties were studied by electrical resistivity, Seebeck coefficient, and thermal conductivity measurements. The synthesis process comprises three steps viz., wet ball milling of the elemental precursors, vacuum annealing, and densification by hot pressing. The purpose of this is to evaluate the feasibility of introducing wet milling in place of vacuum melting in solid state synthesis for the reaction of starting elements. We report the structural characterization and thermoelectric studies conducted on samples that were milled at 300 rpm and 500 rpm. X-ray diffraction (XRD) analysis showed the existence of multiple phases in the as-milled samples, indicating the requirement for heat treatment. Therefore, the ball milled powders were cold pressed and vacuum annealed to eliminate the secondary phases. Annealed samples were hot pressed and made into dense pellets for further investigations. In addition to XRD, energy dispersive spectroscopy (EDS) studies were performed on hot pressed samples to study the composition. XRD and EDS studies confirm CZTSe phase formation along with ZnSe secondary phase. Electrical resistivity and Seebeck coefficient measurements were done on the hot pressed samples in the temperature range 340-670 K to understand the thermoelectric behaviour. Thermal conductivity was calculated from the specific heat capacity and thermal diffusivity values. The thermoelectric figure of merit zT values for samples milled at 300 rpm and 500 rpm are ˜0.15 and ˜0.16, respectively, at 630 K, which is in good agreement with the values reported for solid state synthesized compounds.

  2. Atomic scale study of ball milled Ni-Fe{sub 2}O{sub 3} using Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Ravi Kumar; Govindaraj, R., E-mail: govind@igcar.gov.in; Vinod, K.; Kumar, P. A. Manoj; Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2016-05-23

    Evolution of hyperfine fields at Fe atoms has been studied in a detailed manner in a mixture of Ni and α-Fe{sub 2}O{sub 3} subjected to high energy ball milling using Mossbauer spectroscopy. Mossbauer results indicate the dispersion of α-Fe{sub 2}O{sub 3} particles in Ni matrix in the as ball milled condition. Evolution of α-Fe{sub 2}O{sub 3} due to ball milling, reduction of the valence of associated Fe and possible interaction between the oxide particles with Ni in the matrix due to annealing treatments has been elucidated in the present study.

  3. Magnetic property and microstructure of single crystalline Nd2Fe14B ultrafine particles ball milled from HDDR powders

    Energy Technology Data Exchange (ETDEWEB)

    Li, WF; Hu, XC; Cui, BZ; Yang, JB; Han, JZ; Hadjipanayis, GC

    2013-08-01

    In this work we report the microstructure and magnetic property of single crystalline Nd2Fe14B ultrafine particles ball milled from HDDR Nd-Fe-B alloys. The average size of the particles is 283 nm, and TEM observation reveals that these particles are single crystalline. The coercivity of these particles is 6.0 kOe, which is much higher than that of the particles ball milled from sintered and hot pressed Nd-Fe-B magnets. Micromagnetic analysis shows that the coercivity degradation is caused by surface damage during ball milling. (C) 2013 Elsevier B.V. All rights reserved.

  4. Atomic scale study of ball milled Ni-Fe2O3 using Mössbauer spectroscopy

    Science.gov (United States)

    Yadav, Ravi Kumar; Govindaraj, R.; Vinod, K.; Kumar, P. A. Manoj; Amarendra, G.

    2016-05-01

    Evolution of hyperfine fields at Fe atoms has been studied in a detailed manner in a mixture of Ni and α-Fe2O3 subjected to high energy ball milling using Mossbauer spectroscopy. Mossbauer results indicate the dispersion of α-Fe2O3 particles in Ni matrix in the as ball milled condition. Evolution of α-Fe2O3 due to ball milling, reduction of the valence of associated Fe and possible interaction between the oxide particles with Ni in the matrix due to annealing treatments has been elucidated in the present study.

  5. Discrete element method based scale-up model for material synthesis using ball milling

    Science.gov (United States)

    Santhanam, Priya Radhi

    Mechanical milling is a widely used technique for powder processing in various areas. In this work, a scale-up model for describing this ball milling process is developed. The thesis is a combination of experimental and modeling efforts. Initially, Discrete Element Model (DEM) is used to describe energy transfer from milling tools to the milled powder for shaker, planetary, and attritor mills. The rolling and static friction coefficients are determined experimentally. Computations predict a quasisteady rate of energy dissipation, E d, for each experimental configuration. It is proposed that the milling dose defined as a product of Ed and milling time, t, divided by the mass of milled powder, mp characterizes the milling progress independently of the milling device or milling conditions used. Once the milling dose is determined for one experimental configuration, it can be used to predict the milling time required to prepare the same material in any milling configuration, for which Ed is calculated. The concept is validated experimentally for DEM describing planetary and shaker mills. For attritor, the predicted Ed includes substantial contribution from milling tool interaction events with abnormally high forces (>103 N). The energy in such events is likely dissipated to heat or plastically deform milling tools rather than refine material. Indeed, DEM predictions for the attritor correlate with experiments when such events are ignored in the analysis. With an objective of obtaining real-time indicators of milling progress, power, torque, and rotation speed of the impeller of an attritor mill are measured during preparation of metal matrix composite powders in the subsequent portion of this thesis. Two material systems are selected and comparisons made between in-situ parameters and experimental milling progress indicators. It is established that real-time measurements can certainly be used to describe milling progress. However, they need to be interpreted carefully

  6. Influence of ball milling on the particle size and antimicrobial properties of Tridax procumbens leaf nanoparticles.

    Science.gov (United States)

    Karthik, Subramani; Suriyaprabha, Rangaraj; Balu, Kolathupalayam Shanmugam; Manivasakan, Palanisamy; Rajendran, Venkatachalam

    2017-02-01

    The herbal nanoparticles were prepared from shade dried Tridax procumbens plant leaves employing ball milling technique using different process parameters, like ball ratio/size and milling time. The obtained nanoparticles were comprehensively characterised using X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible spectroscopy, dynamic light scattering, scanning electron microscopy and antimicrobial analysis techniques. The crystallinity of the nanoparticles was retained without altering even though the particle size changes due to milling periods. The antibacterial activities of the prepared herbal nanoparticles against Staphylococcus aureus and Escherichia coli were explored to understand the influence of particle size on antimicrobial activities and their functional properties. The increase in ball ratio and milling time periods leads to a decrease in nanoparticle size from 114 to 45 nm which in turn increases the antimicrobial activities. The above study confirms that antimicrobial activity relies on nanoparticle size. The observed knowledge on influence of particle size on antimicrobial activities will help to optimise the production of potential herbal nanoparticles for different biomedical applications.

  7. Effect of ball-milling on the physicochemical properties of maize starch

    Directory of Open Access Journals (Sweden)

    Shenghua He

    2014-09-01

    Full Text Available The effect of ball-milling on physicochemical properties of maize starch was evaluated. Results found that the cold water solubility (CWS of maize starch was positively correlated with the time of milling up to 3 h. There was no significant influence of using a ceramic pot versus a stainless steel pot on CWS. However, following 5 h of ball-milling CWS increased quite dramatically in the ceramic pot (72.6% and in the stainless steel pot (70.7%, as compared to the untreated maize starches (2.9%. In addition, as CWS increased, the regions of amorphism enlarged at the expense of the crystalline regions, resulting in a change from the native starch state (oval with a smooth surface to having more of a rough, abrasive surface. Finally, the transparency of the starch increased as CWS increased and that the syneresis of freeze–thawed ball-milled maize starch also increased with an increase in the number of freeze–thaw cycles.

  8. 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}).

  9. 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

    2016-10-01

    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.

  10. Evaluation of different pulverisation methods for RNA extraction in squash fruit: lyophilisation, cryogenic mill and mortar grinding.

    Science.gov (United States)

    Román, Belén; González-Verdejo, Clara I; Peña, Francisco; Nadal, Salvador; Gómez, Pedro

    2012-01-01

    Quality and integrity of RNA are critical for transcription studies in plant molecular biology. In squash fruit and other high water content crops, the grinding of tissue with mortar and pestle in liquid nitrogen fails to produce a homogeneous and fine powered sample desirable to ensure a good penetration of the extraction reagent. To develop an improved pulverisation method to facilitate the homogenisation process of squash fruit tissue prior to RNA extraction without reducing quality and yield of the extracted RNA. Three methods of pulverisation, each followed by the same extraction protocol, were compared. The first approach consisted of the lyophilisation of the sample in order to remove the excess of water before grinding, the second one used a cryogenic mill and the control one a mortar grinding of frozen tissue. The quality of the isolated RNA was tested by carrying out a quantitative real time downstream amplification. In the three situations considered, mean values for A(260) /A(280) indicated minimal interference by proteins and RNA quality indicator (RQI) values were considered appropriate for quantitative real-time polymerase chain reaction (qRT-PCR) amplification. Successful qRT-PCR amplifications were obtained with cDNA isolated with the three protocols. Both apparatus can improve and facilitate the grinding step in the RNA extraction process in zucchini, resulting in isolated RNA of high quality and integrity as revealed by qRT-PCR downstream application. This is apparently the first time that a cryogenic mill has been used to prepare fruit samples for RNA extraction, thereby improving the sampling strategy because the fine powder obtained represents a homogeneous mix of the organ tissue. Copyright © 2012 John Wiley & Sons, Ltd.

  11. 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.

  12. Excess lithium storage in LiFePO4-Carbon interface by ball-milling

    Science.gov (United States)

    Guo, Hua; Song, Xiaohe; Zheng, Jiaxin; Pan, Feng

    2016-07-01

    As one of the most popular cathode materials for high power lithium ion batteries (LIBs) of the electrical-vehicle (EV), lithium iron phosphate (LiFePO4 (LFP)) is limited to its relatively lower theoretical specific capacity of 170mAh g-1. To break the limits and further improve the capacity of LFP is promising but challenging. In this study, the ball-milling method is applied to the mixture of LFP and carbon, and the effective capacity larger than the theoretical one by 30mAh g-1 is achieved. It is demonstrated that ball-milling leads to the LFP-Carbon interface to store the excess Li-ions.

  13. Fe-Al2O3 nanocomposites prepared by high-energy ball milling

    DEFF Research Database (Denmark)

    Linderoth, Søren; Pedersen, M.S.

    1994-01-01

    Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x(upsilon) alm......Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x......(upsilon) almost-equal-to 0.25. The effect is ascribed to the production of single-domain magnetic grains. Mossbauer spectroscopy reveals the presence of iron oxide phases which could not be seen by x-ray and electron diffraction measurements....

  14. 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.

  15. 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.

  16. 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.

  17. Preparation of MgTiO3 Ceramics by High Energy Ball Milling

    Institute of Scientific and Technical Information of China (English)

    TAO Zhendong; ZHANG Ying; YANG Zhongxi; WANG Yingzi; MENG Shanshan; TENG Tieli

    2006-01-01

    MgTiO3 precursor was mechanochemically synthesized by high-energy ball milling of MgO and TiO2. The sintering characteristic of the resulted MgTiO3 precursor was investigated. The experimental results indicate that particles of both MgO and TiO2 powders become smaller rapidly, and then the crystalline structures of MgO and TiO2 change significantly. MgTiO3 was observed by XRD after 30 hours of ball milling. Strong diffraction peaks of MgTiO3 were observed after 50 hours of ball milling. HRTEM observation proves that dense MgTiO3 ceramics with a compact crystalline structure can be sintered from mechanochemically activated MgTiO3 precursor, the volume density of the resulting ceramic is as high as 95% of the theoretical density, the porosity and average pore diameter of the ceramic are measured as 4.95% and 50 nm respectively, and the transverse strength exceeded 500 MPa.

  18. High-performance ball-milled SiOx anodes for lithium ion batteries

    Science.gov (United States)

    Zhang, Junying; Zhang, Chunqian; Liu, Zhi; Zheng, Jun; Zuo, Yuhua; Xue, Chunlai; Li, Chuanbo; Cheng, Buwen

    2017-01-01

    High-performance SiOx was scalable synthesized by means of simple high-energy ball-milling method, and used as anode materials for lithium ion batteries. The electrochemical performance of SiOx electrode after high-energy ball-milling is improved effectively compared to raw SiOx. That is benefit for the reduced size of SiOx powder. By changing the species of conductive agents, improved cyclic performance and excellent rate capability were achieved. Under galvanostatic mode with current density of 0.3 A/g, SiOx electrode after high-energy ball-milling with optimized conductive agents delivers a reversible capacity of 1416.8 mAh/g with coulombic efficiency as high as 99.8% and capacity retention of 83.6% (1184.8 mAh/g) even after 100 cycles. The approach is simple and can be adopted for large scale production of high performance SiOx anode materials.

  19. Characteristics and oil absorption in deep-fat fried batter prepared from ball-milled wheat flour.

    Science.gov (United States)

    Thanatuksorn, Pariya; Kajiwara, Kazuhito; Suzuki, Toru

    2010-01-15

    The porous structure generated during frying influences oil absorption and textural qualities. The alteration in physical properties of wheat flour is suspected to affect the structure formation. The present study investigated the effect of physicochemical changes in wheat flour by the ball-milling process on structure formation and consequently oil absorption of a fried wheat flour batter model. Batter models containing 600 g kg(-1) moisture were made of 0-10 h ball-milled wheat flour and then fried in frying oil at 150 degrees C for 1-7 min. The samples made of milled flour possess larger pores and exhibit lower oil absorption than sample made of 0 h milled flour. The fracture force of a fried sample prepared from 5 and 10 h milled flour is lower than that of a sample prepared from 0 h milled flour. The decrease in glass transition temperature (T(g)) and melting temperature (T(m)) of milled flour affect the microstructure formation in the fried wheat flour batter. The microstructure is responsible for oil absorption and fracturability in fried food. The samples made of flour of longer ball-milling time have lower oil absorption and higher crispness. Ball-milling may be a tool to produce mechanically modified wheat flour which can reduce oil absorption for fried batter. Copyright (c) 2009 Society of Chemical Industry.

  20. 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.

  1. Finite size effects and spin transition in ball-milled {gamma}-(FeMn){sub 30}Cu{sub 70} nanostructured alloys

    Energy Technology Data Exchange (ETDEWEB)

    Restrepo, J. [Grupo de Estado Solido, Instituto de Fisica, Universidad de Antioquia, A. A. 1226, Medellin (Colombia)]. E-mail: jrestre@fisica.udea.edu.co; Greneche, J.M. [Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, 72085 Le Mans, Cedex 9 (France); Gonzalez, J.M. [Instituto de Magnetismo Aplicado, P.O. Box 155. 28230 Las Rozas, Madrid (Spain)

    2004-12-31

    Fe{sub 15}Mn{sub 15}Cu{sub 70} 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 A{sup 3} 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.

  2. Rheology of coal-water slurries prepared by the high-pressure roll mill grinding of coal. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fuerstenau, D.W.; De, A.

    1996-08-01

    The preparation of coal water slurries to replace fuel oil for direct combustion has become an important field in modem coal technology. The U.S. Department of Energy has planned or has underway several demonstration projects to burn coal-water slurries to replace fuel oil is attractive not only because there is an assured domestic supply of coal, but also on various technoeconomic grounds. Coal-water slurries combine the handling flexibility of fuel oil in power plants and various other industrial applications. This report discusses the rheology of coal-water slurries and the correlation to the coal preparation by grinding with a choke-fed high pressure roll mill. Performance of the roll mills and energy consumption are described.

  3. Synthesis of hydroxyapatite from eggshell powders through ball milling and heat treatment

    Directory of Open Access Journals (Sweden)

    Shih-Ching Wu

    2016-03-01

    Full Text Available Every day, several million tons of eggshells are being generated as bio-waste across the world. This study demonstrates the synthesis of HA powder using dicalcium phosphate dehydrate (CaHPO4·2H2O, DCPD and eggshell powders via ball milling and subsequent heat treatment. The formation of HA phase can be initiated by sintering the 1 h milled sample at 1000 °C for 1 h, while pure HA phase can be obtained upon sintering the 10 h milled sample. Additionally, the final products composed of biphasic calcium phosphate (HA + β-TCP crystals can easily be prepared by ball milling for 5 h followed by heat treatment at 1000 °C for 1 h. The carbonate peaks observed in the FTIR analysis of the as-prepared HA closely matched those of A- and B-type carbonates, which is typical of the biological apatite. The elemental composition of the as-synthesized HA showed the presence of Ca, P, Mg, and Sr.

  4. 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.

  5. Transformation of Goethite to Hematite Nanocrystallines by High Energy Ball Milling

    Directory of Open Access Journals (Sweden)

    O. M. Lemine

    2014-01-01

    Full Text Available α-Fe2O3 nanocrystallines were prepared by direct transformation via high energy ball milling treatment for α-FeOOH powder. X-ray diffraction, Rietveld analysis, TEM, and vibrating sample magnetometer (VSM are used to characterize the samples obtained after several milling times. Phase identification using Rietveld analysis showed that the goethite is transformed to hematite nanocrystalline after 40 hours of milling. HRTEM confirm that the obtained phase is mostly a single-crystal structure. This result suggested that the mechanochemical reaction is an efficient way to prepare some iron oxides nanocrystallines from raw materials which are abundant in the nature. The mechanism of the formation of hematite is discussed in text.

  6. Structural, microstructural and magnetocaloric investigations in high-energy ball milled NiMnGa powders

    Science.gov (United States)

    de Santanna, Y. V. B.; de Melo, M. A. C.; Santos, I. A.; Coelho, A. A.; Gama, S.; Cótica, L. F.

    2008-11-01

    In this paper, structural, microstrucutural and magnetocaloric properties of Ni 2.18Mn 0.82Ga alloys submitted to high-energy ball milling are reported. A 7-layered orthorhombic martensitic ( Pnnm) phase was detected in post-milling annealed samples, which reached a microstrucuture composed predominantly by nanograins. The magnetocaloric effect is strongly weakened in comparison with as-cast samples of similar composition. This effect can be attributed to the absence of the mesoscale twin-related martensitic variants in the nanostructurated powders. However, post-milled samples annealed at 1123 K for 4 h present relative cooling powers as high as those observed for manganites. Therefore, these materials can be considered as potential candidates for use as regenerators in prototypal magnetic refrigerators.

  7. Improvement of Center -driven Overflow Ball Mill with Double -wall Partition%中心传动双仓溢流型球磨机改进

    Institute of Scientific and Technical Information of China (English)

    李兴

    2015-01-01

    磨机广泛应用于选矿、冶金、水泥厂、化工、电力等工矿企业粉磨各种矿石及其它可磨性物料。中心传动双仓溢流型球磨机应用于拜耳法生产氧化铝,在生产中用于对原矿浆的细磨,对于中心传动双仓溢流型球磨机在全国的使用没有几例。针对目前出现的问题,结合球磨机、管磨机在该行业成熟的使用经验进行了分析处理,找到合理的改进措施,取得了一定的社会和经济效益。%Mill is widely used in mineral processing,metallurgy,cement plant,chemical industry,electric pow-er and other industrial and mining enterprises to smash all kinds of ores and other materials.Center -driven over-flow ball mill with double -wall partition is used in alumina production by Bayer process,but few were applied in the grinding of original pulp.Aiming at these problems,the service experience of ball mill and tube mill in this industry was analyzed and then rational improvement measures were found,thus achieving some social and economic benefits.

  8. HRTEM and Nanoindentation Studies of Bulk WC Nanocrystalline Materials Prepared by Spark Plasma Sintering of Ball-Milled Powders

    Science.gov (United States)

    Sherif El-Eskandarany, M.; Al-Hazza, Abdulsalam; Al-Hajji, L. A.

    2017-01-01

    In the present work, mechanical milling technique using a high-energy ball mill was employed for preparing of nanoscaled WC grains powders with an average grain size of 7 nm in diameters of WC. The present study demonstrates a successful consolidation process achieved at 1250 °C for sintering of ball-milled WC powders into full dense bulk buttons (above 99.6%), using SPS technique. The as-consolidated WC bulk nanocrystalline buttons revealed high hardness value ( 24 GPa) with low elastic modulus ( 332 GPa). Moreover, they possessed a high fracture toughness (15 MPa m1/2) that has never been reported for pure WC.

  9. 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...... time of 122 h. This demonstrates that the high-energy ball milling technique is able to prepare metastable solid solutions with an extended range of compositions in ceramic/ceramic systems with a positive hear of mixing....

  10. Magnetic and Magnetocaloric Properties of High-Energy Ball-Milled Nanocrystalline CeMn2Ge2 Compound

    Science.gov (United States)

    Kaya, Melike; Dincer, Ilker; Akturk, Selcuk; Elerman, Yalcin

    2016-10-01

    CeMn2Ge2 nanopowders have been obtained by high-energy ball milling for 5 and 10 hours from bulk compound to investigate the effect of milling time on magnetic and magnetocaloric properties. CeMn2Ge2 nanopowders have been characterized by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, and magnetization measurements. The average grain size of the nanoparticles from XRD measurements is about 12.2 and 8 nm for 5-hour and 10-hour ball-milled samples, respectively. The investigations reveal that magnetic entropy change (∆ S m) can be altered by changing the particle size of the compound. Maximum ∆ S m is -2.45 and -1.30 J kg-1 K-1 for the 5- and 10-hour ball-milled nanopowders, respectively.

  11. 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.

  12. Influences of speed of impact grinding mill and speed of classifying impeller on grinding efficiency%冲击式磨机转速和分级叶轮转速对研磨效率的影响

    Institute of Scientific and Technical Information of China (English)

    王珊; 董为民; 陈国鼎

    2013-01-01

    Taking the impact grinding mill as the study objective,the paper theoretically deduced the calculation formula of maximum crushing energy and cut size of the impact grinding mill.Based on the formula of the maximum crushing energy,it analyzed the influence of the mill speed on the grinding efficiency.Meanwhile,based on the calculation formula of the cut size,it analyzed the influence of the speed of the classifying impeller on the grinding efficiency.At last,tests were conducted to verify the above influences.%以冲击式磨机为研究对象,理论推导了冲击式磨机的最大破碎能公式和切割粒径的计算公式.根据最大破碎能公式分析了冲击式磨机转速对研磨效率的影响;根据切割粒径公式分析了分级叶轮转速对研磨效率的影响,并通过试验进行了验证.

  13. One step conversion of wheat straw to sugars by simultaneous ball milling, mild acid, and fungus Penicillium simplicissimum treatment.

    Science.gov (United States)

    Yuan, Li; Chen, Zhenhua; Zhu, Yonghua; Liu, Xuanming; Liao, Hongdong; Chen, Ding

    2012-05-01

    Wheat straw is one of the major lignocellulosic plant residues in many countries including China. An attractive alternative is the utilization of wheat straw for bioethanol production. This article mainly studies a simple one-step wet milling with Penicillium simplicissimum and weak acid to hydrolysis of wheat straw. The optimal condition for hydrolysis was ball milling 48 h in citrate solvent (pH = 4) with P. simplicissimum H5 at the speed of 500 rpm and the yield of sugar increased with increased milling time. Corresponding structure transformations before and after milling analyzed by X-ray diffraction, transmission Fourier transform infrared spectroscopy, and environmental scanning electron microscopy clearly indicated that this combined treatment could be attributed to the crystalline and chemical structure changes of cellulose in wheat straw during ball milling. This combined treatment of ball milling, mild acid, and fungus hydrolysis enabled the conversion of the wheat straw. Compared with traditional method of ball milling, this work showed a more simple, novel, and environmentally friendly way in mechanochemical treatment of wheat straw.

  14. Synthesis and Characterizations of Nanocrystalline WC-Co Composite Powders by a Unique Ball Milling Process

    Institute of Scientific and Technical Information of China (English)

    Jun SHEN; Jianfei SUN; Faming ZHANG

    2004-01-01

    In order to explore the high efficiency of fabricating nanocrystalline WC-Co composite powders, this paper presented a unique high energy ball milling process with variable rotation rate and repeatious circulation, by which nanocrystalline WC-10Co0.8VC-0.2Cr3C2 (wt pct) composite powders with mean grain size of 25 nm were prepared in 32 min, and the quantity of the powders for a batch was as much as 800 grams. The as-prepared powders were analyzed and characterized by chemical analysis,X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential thermal analysis (DTA). The results show that high energy ball milling with variable rotation rates and repeatious circulation could be used to produce nanocrystalline WC-Co powder composites with high efficiency. The compositions of the powders meet its specifications with low impurity content. The mean grain size decreases, lattice distortion and system energy increase with increasing the milling time. The morphology of nanocrystalline WC-Co particles displays dominantly sphere shape and their particle sizes are all lower than 80nm. The eutectic temperature of the nanocrystalline WC-10Co-0.8VC-0.2Cr3C2 composites is about 1280℃.

  15. Improvement on ball-milling composite process of metal matrix micro-nanometer powder using nanosuspension as the precursor

    Science.gov (United States)

    Wang, Hongyu; Zhou, Jianzhong; Li, Xiangfeng; Shen, Qing; Cheng, Man

    2014-12-01

    The wet ball-milling preparation of metal matrix micro-nanometer powder using nanosuspension as the precursor can well solve the agglomeration of nanoscale component, but the micro-nanometer powder prepared by the method can hardly meet the requirement of powder feeding in laser cladding process and its composite effect is still not desirable enough. Aiming at the problem, the ball-milling composite process of metal matrix micro-nanometer powder using nanosuspension as the precursor was analyzed. It has been found that the morphological diversity of original micron powder is the main influencing factor of the deliverability and the composite effect of micro-nanometer powder. In addition, the deposition of the compounding powder in the bottom of ball-milling tank also has some negative influences on the composite effect. Accordingly, two improving measures namely the micron powder pretreatment with Ball Mill Reshaping + Screening and the additional stirring during ball-milling process are proposed and experimented. Results show that the micron powder pretreatment could significantly improve the composite effect and the deliverability of micro-nanometer powder, and the additional stirring could further improve the composite effect of micro-nanometer powder.

  16. 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.

  17. 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.

  18. Metastable phase transitions in Mo-Si and V-Si systems activated by high energy ball milling

    Institute of Scientific and Technical Information of China (English)

    柳林

    2002-01-01

    Mechanical alloying of Mo-Si (Mo33Si67) and V-Si (V75Si25) powder mixtures was activated by high energy ball milling at ambient temperature. The metastable phase transitions in both systems during milling were investigated by X-ray diffraction, scanning and transmission electron microscopy. It is found that the alloying processes are closely related to the milling conditions. As far as the Mo-Si system is concerned, ball milling leads to the formation of both α-MoSi2 (room temperature phase) and β-MoSi2 (high temperature phase), but lower energy milling favors the formation of β phase, while higher energy milling promotes the formation of α phase. In addition, if the milling energy is high enough, the Mo/Si reaction is governed by a self-propagating high temperature process. On the other hand, two different pathways of phase transition in the V-Si system were also identified depending on the milling intensity, i.e. weak milling leads to amorphous transition, whereas intensive milling causes the formation of V3Si and V5Si3 intermetallic compounds. Finally, the thermodynamics and kinetics related to the different phase transitions in the two systems were discussed.

  19. 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)

  20. 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.

  1. 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.

  2. 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)

  3. 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.

  4. Characterization and Magnetic Properties of Nickel Ferrite Nanoparticles Prepared by Ball Milling Technique

    Institute of Scientific and Technical Information of China (English)

    G.Nabiyouni; M.Jafari Fesharaki; M.Mozafari; J.Amighian

    2010-01-01

    @@ Nickel ferrite nanoparicles with various grain sizes are synthesized using annealing treatment followed by ball milling of its bulk component materials.Commercially available nickel and iron oxide powders are first mixed,and then annealed at 1100℃ in an oxygen environment furnace and for 3h.The samples are then milled for different times in an SPEX mill.X-ray diffraction pattern indicates that in this stage the sample is single phase.The average grain size is estimated by scanning electron microscopy(SEM)and x-ray diffraction techniques.Magnetic behavior of the sample at room temperature is studied using a superconducting quantum interference device(SQUID).The Curie temperature of the powders is measured by an LCR meter unit.The x-ray diffraction patterns clearly indicate that increasing the milling time leads to a decrease in the grain size and consequently leads to a decrease in the saturation magnetization as well as the Curie temperatures.This result is attributed to the spin-glass-like surface layer on the nanocrystalline nickel ferrite with a ferrimagnetically aligned core.

  5. TEM and HRTEM studies of ball milled 6061 aluminium alloy powder with Zr addition.

    Science.gov (United States)

    Lityńska-Dobrzyńska, L; Dutkiewicz, J; Maziarz, W; Rogal, Ł

    2010-03-01

    The effect of mechanical alloying on the microstructure of atomized 6061 aluminium alloy powder and 6061 powder with a zirconium addition was studied in the work. The atomized 6061 aluminium alloy powder and 6061 powder with addition of 2 wt.% Zr were milled in a planetary ball mill and investigated using X-ray diffraction measurements, conventional and high-resolution electron microscopy (TEM/HRTEM) and high-angle annular dark field scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis. An increase of stresses was observed in milled powders after the refinement of crystallites beyond 100 nm. In the powder with zirconium addition, some part of the Zr atoms diffused in aluminium forming a solid solution containing up to 0.5 wt.% Zr. The remaining was found to form Zr-rich particles containing up to 88 wt.% Zr and were identified as face centred cubic (fcc) phase with lattice constant a= 0.48 nm. That fcc phase partially transformed into the L1(2) ordered phase. Eighty-hour milling brought an increase of microhardness (measured with Vickers method) from about 50 HV (168 MPa) for the initial 6061 powder to about 170 HV (552 MPa). The addition of zirconium had no influence on the microhardness.

  6. Structural Investigations of Nanocrystalline Cu-Cr-Mo Alloy Prepared by High-Energy Ball Milling

    Science.gov (United States)

    Kumar, Avanish; Pradhan, Sunil Kumar; Jayasankar, Kalidoss; Debata, Mayadhar; Sharma, Rajendra Kumar; Mandal, Animesh

    2017-02-01

    Cu-Cr-Mo alloy could be a suitable candidate material for collector electrodes in high-power microwave tube devices. An attempt has been made to synthesize ternary Cu-Cr-Mo alloys by mechanical alloying of elemental Cu, Cr, and Mo powders, to extend the solid solubility of Cr and Mo in Cu, using a commercial planetary ball mill. For the first ternary alloy, a mixture of 80 wt.% Cu, 10 wt.% Cr, and 10 wt.% Mo was mechanically milled for 50 h. For the second ternary alloy, a mixture of 50 wt.% Cr and 50 wt.% Mo was mechanically milled for 50 h to obtain nanocrystalline Cr(Mo) alloy, which was later added to Cu powder and milled for 40 h to obtain Cu-20 wt.%Cr(Mo) alloy. Both nanocrystalline Cu-Cr-Mo ternary alloys exhibited crystallite size below 20 nm. It was concluded that, with addition of nanocrystalline Cr(Mo) to Cu, it was possible to extend the solid solubility of Cr and Mo in Cu, which otherwise was not possible by mechanical alloying of elemental powders. The resulting microstructure of the Cu-20 wt.%Cr(Mo) alloy comprised a homogeneous distribution of fine and hard (Cr, Mo) particles in a copper matrix. Furthermore, Cu-20 wt.%Cr(Mo) alloy showed better densification compared with Cu-10 wt.%Cr-10 wt.%Mo alloy.

  7. 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.

  8. Online SAG Mill Pluse Measurement and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2007-06-30

    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment. An instrumented load cell package that can measure the force of impacts inside the grinding chamber of a mill is developed here. The signal from the instrumented load cell package is interpreted in terms of a histogram termed as an impact spectrum which is a plot of the number of impacts at a specific energy level against the energy. It reflects on the average force regime of the mill. The instrumented load cell package was calibrated against the ultra fast load cell which has been unanimously accepted as a standard to measure single breakage events. The load cell package was successfully used to produce impact spectra in an 8.5 inch lab scale mill. The mill speed and the ball size were varied to

  9. 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)

  10. Experimental Investigation into the Effect of Ball End Milling Parameters on Surface Integrity of Inconel 718

    Science.gov (United States)

    Bhopale, Nandkumar N.; Joshi, Suhas S.; Pawade, Raju S.

    2015-02-01

    In machining of Inconel 718, various difficulties such as increased tool wear and poor machined surface quality are frequently encountered due to its high temperature strength and poor thermal properties. This work considers the effect of number of passes and the machining environment on the machined surface quality in ball end milling of Inconel 718, which hitherto has not been adequately understood. To this effect, extensive experimentation has been carried out to analyze machined surface quality and integrity in terms of surface roughness, surface damage, and microhardness variation in the machined surfaces. The machined surfaces show formation of distinct bands as a function of instantaneous machining parameters along the periphery of cutting tool edge. A distinct variation is also observed in the measured values of surface roughness and microhardness in these regions. The minimum surface roughness is obtained in the stable cutting zone and it increases toward the periphery of the cutter on band #2 and band #3. Microhardness of depth beneath the machined surface shows that the machining affected zone varies from 60 to 100 µm in ball end milling under various machining conditions.

  11. Electrochemical properties of LiFePO{sub 4} prepared via ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Fey, George Ting-Kuo; Chen, Yun Geng [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 Taiwan (China); Kao, Hsien-Ming [Department of Chemistry, National Central University, Chung-Li 32054 Taiwan (China)

    2009-04-01

    LiFePO{sub 4} cathode materials with distinct particle sizes were prepared by a planetary ball-milling method. The effects of particle size on the morphology, thermal stability and electrochemical performance of LiFePO{sub 4} cathode materials were investigated. The ball-milling method decreased particle size, thereby reducing the length of diffusion and improving the reversibility of the lithium ion intercalation/deintercalation. It is worth noting that the small particle sample prepared using malonic acid as a carbon source achieved a high capacity of 161 mAh g{sup -1} at a 0.1 C rate and had a very flat capacity curve during the early 50 cycles. However, the big particle samples ({proportional_to}400 nm) decayed more dramatically in capacity than the small particle size samples ({proportional_to}200 nm) at high current densities. The improvement in electrode performance was mainly due to the fine particles, the small size distribution, and the increase in electronic conductivity as a result of carbon coating. The structure and morphology of the ground LiFePO{sub 4} samples were characterized with XRD, FE-SEM, TEM, EDS, and DSC techniques. (author)

  12. Hydrogen generation by the hydrolysis reaction of ball-milled aluminium-lithium alloys

    Science.gov (United States)

    Chen, Xingyu; Zhao, Zhongwei; Liu, Xuheng; Hao, Mingming; Chen, Ailiang; Tang, Zhongyang

    2014-05-01

    The addition of Li can prevent an inert alumina film from forming on the surface of Al alloy particles, allowing the rapid hydrogen generation of Al alloys to be achieved. However, because the Li content is less than 10%, the hydrogen generation rate and hydrogen yield of Al-Li alloys are significantly decreased. In this work, NaCl is introduced to prepare Al-Li alloys with low Li contents by ball milling. The research results show that by increasing the amount of NaCl added, the ball milling time and Li content can effectively improve the hydrogen generation of the alloys. Under optimal preparation conditions, the ultimate hydrogen yield of Al-Li alloys can reach 100%. The initial water temperature has almost no effect on the generation of hydrogen, even at 0 °C. Ca2+ and Mg2+ can combine with OH- to form the insoluble compounds Ca(OH)2 and Mg(OH)2, which can prevent hydrogen generation. NO3- reacts with Al to form ammonia and reduce the hydrogen yield of the alloys. Therefore, Al-Li alloys should be prevented from reacting with water containing Ca2+, Mg2+ and NO3-. Al-Li alloys must be stored in isolation from air to maintain good hydrogen-generation performances.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Jiang, Jian-Tang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Wang, Zeng-Quan [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Gong, Yuan-Xun [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Aerospace Research Institute of Special Material and Processing Technology, Beijing 100074 (China); Liu, Chao [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (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)

    2014-11-15

    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.

  14. 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

    2016-06-03

    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.

  15. Effect of ball to powder ratio on the ZrO{sub 2} phase transformations during milling

    Energy Technology Data Exchange (ETDEWEB)

    Zakeri, M.; Razavi, M., E-mail: m-razavi@merc.ac.ir; Rahimipour, M.R.; Jamal Abbasi, B.

    2014-07-01

    Effect of milling time and ball to powder weight ratio (BPR) were investigated on the phase transformation of monoclinic zirconia during high energy ball milling. Degree of phase transformation was studied by X-ray diffraction (XRD) and quantitative phase analysis (Rietveld refinement). Morphology and microstructure were monitored by scanning and transmission electron microscopy, respectively. Higher milling time and BPR led to the more transformation, smaller mean grain size and larger strain. There was approximately 80% tetragonal zirconia in the 80 h milled powder with the BPR 25:1. A nanostructure powder with the mean grain size less than 10 nm was obtained in both BPRs that were in consistence with TEM images. Stress and strain inducing in the lattice of m-ZrO{sub 2} was proposed as the main mechanism of its transformation.

  16. Solid State Reaction Mechanism and Microstructure Evolution of Ni-Al Powders during High Energy Ball Milling Revisited by TEM.

    Science.gov (United States)

    Fan, Guohua; Geng, Lin; Feng, Yicheng; Cui, Xiping; Yan, Xudong

    2015-08-01

    Microstructure evolution during the formation of B2-NiAl by high energy ball milling of equiatomic elemental mixtures was studied by X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy (TEM). The crystallite size, lattice defects and ordering of the B2-NiAl were monitored via TEM as function of milling time. The diffusion reaction, Ni+Al→NiAl3 or/and Ni2Al3, occurred during high energy ball milling, and to a certain extent offered the stored energy for the explosive exothermic reaction, Ni+Al→B2-NiAl. The fine microstructure of newly formed B2-NiAl after 5 h milling involved high density defects, e.g. antiphase boundary, long range ordering domains, vacancies, and dislocations.

  17. Surfactant Removal Study for Nano-Scale SmCo5 Powder Prepared by High Energy Ball Milling (Postprint)

    Science.gov (United States)

    2014-04-01

    DD-MM-YY) 2. REPORT TYPE 3. DATES COVERED (From - To) April 2014 Interim 19 March 2014 – 31 March 2014 4. TITLE AND SUBTITLE SURFACTANT ...thickness of 300 nm were prepared by high energy ball milling using valeric acid as a surfactant . In order to remove the surfactant the as-milled...investigated. Partial (58%) and nearly complete (96%) surfactant removal was observed by DSC after treatments at 200°C and 400°C, respectively, without oxide

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

    OpenAIRE

    Pajin Biljana; Zarić Danica; Dokić Ljubica; Šereš Zita; Šoronja-Simović Dragana; Omorjan Radovan; Lončarević Ivana

    2011-01-01

    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 chocolat...

  19. Monitoring and Analyzing of Vibration Signal from Grinding of Precision Balls Based on Virtual Instrument%基于虚拟仪器的精密球研磨加工的振动信号检测与分析

    Institute of Scientific and Technical Information of China (English)

    夏其表; 王洁; 许凤亚

    2011-01-01

    振动信号是反映精密球体研磨状态的重要途径.利用加速度计传感器、数据采集卡和LabVIEW,设计一套基于虚拟仪器的振动信号检测设备,对精密球在研磨加工过程中的振动信号进行测试,从时域、频域等多个角度进行分析.结果表明:利用精密球体研磨加工的振动信号能有效地监控整个研磨过程,实时反映球体研磨的状态和精度.%Vibration signal is one important approach which can reflect the state of ball lapping. The grinding vibration signals in the process of precision balls grinding were tested by one detection device built by data acquisition kard, accelerometer sensor and virtual instrument software. These signals were analyzed from time domain and frequency domain. The results indicate that grinding vibration signals can be used to monitor the process of ball grinding. The grinding state and precision of precision balls can be reflected realtime.

  20. Niobium Carbide-Reinforced Al Matrix Composites Produced by High-Energy Ball Milling

    Science.gov (United States)

    Travessa, Dilermando Nagle; Silva, Marina Judice; Cardoso, Kátia Regina

    2017-06-01

    Aluminum and its alloys are key materials for the transportation industry as they contribute to the development of lightweight structures. The dispersion of hard ceramic particles in the Al soft matrix can lead to a substantial strengthening effect, resulting in composite materials exhibiting interesting mechanical properties and inspiring their technological use in sectors like the automotive and aerospace industries. Powder metallurgy techniques are attractive to design metal matrix composites, achieving a homogeneous distribution of the reinforcement into the metal matrix. In this work, pure aluminum has been reinforced with particles of niobium carbide (NbC), an extremely hard and stable refractory ceramic. Its use as a reinforcing phase in metal matrix composites has not been deeply explored. Composite powders produced after different milling times, with 10 and 20 vol pct of NbC were produced by high-energy ball milling and characterized by scanning electron microscopy and by X-ray diffraction to establish a relationship between the milling time and size, morphology, and distribution of the particles in the composite powder. Subsequently, an Al/10 pct NbC composite powder was hot extruded into cylindrical bars. The strength of the obtained composite bars is comparable to the commercial high-strength, aeronautical-grade aluminum alloys.

  1. Crystal Structure and Hydrogen Storage Behaviors of Mg/MoS2 Composites from Ball Milling

    Institute of Scientific and Technical Information of China (English)

    HAN Zongying; ZHOU Shixue; WANG Naifei; ZHANG Qianqian; ZHANG Tonghuan; RAN Weixian

    2016-01-01

    The Mg/MoS2 composites were prepared by ball milling under argon atmosphere, and the effect of MoS2 on the crystal structure and hydrogen storage properties of Mg was investigated. It is found that 10 wt% of MoS2 is sufifcient to prevent particle aggregation and cold welding during the milling process. The crystallite size of Mg will remain constant at slightly less than 38.8 nm with the milling process due to the size conifnement effect of MoS2. The dehydrogenation temperature of MgH2 is reduced to 390.4-429.4℃ due to the crystallite size reduction. Through iftting by Johnson-Mehl-Avrami model, it is found that Mg crystal grows by three dimension controlled by interface transformation during the process of MgH2 decomposition. MoS2 has a weak catalyst effect on the decomposition of MgH2 and activation energy of 148.9 kJ/mol is needed for the dehydrogenation process calculated by the Arrhenius equation.

  2. 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.

  3. Reactive Ball Milling to Fabricate Nanocrystalline Titanium Nitride Powders and Their Subsequent Consolidation Using SPS

    Science.gov (United States)

    El-Eskandarany, M. Sherif

    2017-05-01

    The room-temperature reactive ball milling (RBM) approach was employed to synthesize nanostructured fcc-titanium nitride (TiN) powders, starting from milling hcp-titanium (Ti) powders under 10 bar of a nitrogen gas atmosphere, using a roller mill. During the first and intermediate stage of milling, the agglomerated Ti powders were continuously disintegrated into smaller particles with fresh surfaces. Increasing the RBM time led to an increase in the active-fresh surfaces of Ti, resulting increasing of the mole fraction of TiN against unreacted hcp-Ti. Toward the end of the RBM time (20 h), ultrafine spherical powder (with particles 0.5 μm in diameter) of the fcc-TiN phase was obtained, composed of nanocrystalline grains with an average diameter of 8 nm. The samples obtained after different stages of RBM time were consolidated under vacuum at 1600 °C into cylindrical bulk compacts of 20 mm diameter, using spark plasma sintering technique. These compacts that maintained their nanocrystalline characteristics with an average grain size of 56 nm in diameter, possessed high relative density (above 99% of the theoretical density). The Vickers hardness of the as-consolidated TiN was measured and found to be 22.9 GPa. The modulus of elasticity and shear modulus of bulk TiN were measured by a nondestructive test and found to be 384 and 189 GPa, respectively. In addition, the coefficient of friction of the end-product TiN bulk sample was measured and found to be 0.35.

  4. Fabrication of lanthanum-doped thorium dioxide by high-energy ball milling and spark plasma sintering

    Science.gov (United States)

    Scott, Spencer M.; Yao, Tiankai; Lu, Fengyuan; Xin, Guoqing; Zhu, Weiguang; Lian, Jie

    2017-03-01

    High-energy ball milling was used to synthesize Th1-xLaxO2-0.5x (x = 0.09, 0.23) solid solutions, as well as improve the sinterability of ThO2 powders. Dense La-doped ThO2 pellets with theoretical density above 94% were consolidated by spark plasma sintering at temperatures above 1400 °C for 20 min, and the densification behavior and the non-equilibrium effects on phase and structure were investigated. A lattice contraction of the SPS-densified pellets occurred with increasing ball milling duration, and a secondary phase with increased La-content was observed in La-doped pellets. A dependence on the La-content and sintering duration for the onset of localized phase segregation has been proposed. The effects of high-energy ball milling, La-content, and phase formation on the thermal diffusivity were also studied for La-doped ThO2 pellets by laser flash measurement. Increasing La-content and high energy ball milling time decreases thermal diffusivity; while the sintering peak temperature and holding time beyond 1600 °C dramatically altered the temperature dependence of the thermal diffusivity beyond 600 °C.

  5. Influence of cation disorder on the magnetic properties of ball-milled ilmenite (FeTiO3)

    DEFF Research Database (Denmark)

    Mørup, Steen; Rasmussen, Helge Kildahl; Brok, Erik;

    2012-01-01

    We have investigated the evolution of crystal structure, cation disorder and magnetic properties of ilmenite (FeTiO3) after increasing time of high-energy ball-milling in an inert atmosphere. Refinement of X-ray diffraction data show that the hexagonal crystal structure of ilmenite is maintained ...

  6. 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.

  7. Enhancement of the initial hydrogenation of Mg by ball milling with alkali metal amides MNH2 (M = Li or Na).

    Science.gov (United States)

    Chu, Hailiang; Qiu, Shujun; Sun, Lixian; Huot, Jacques

    2015-10-14

    The introduction of 4 wt% of MNH2 (M = Li, Na) and other additives (Li, MgH2, NaCl, and NaBr) into pure Mg by ball milling greatly enhances the first hydrogenation (activation). Under 2 MPa of H2 at 608 K, the best activation performance is achieved with the NaNH2 additive.

  8. Reaction between LiBH4 and MgH2 induced by high-energy ball milling

    Science.gov (United States)

    Ding, Zhao; Zhao, Xuzhe; Shaw, Leon L.

    2015-10-01

    Previous studies of ab initio density functional theory (DFT) calculations have predicted that reactions between LiBH4 and MgH2 can take place at temperature near 200 °C. However, such predictions have been shown to be inconsistent with many experiments. Herein, we have designed a novel process termed as ball milling with aerosol spraying (BMAS) to prove, for the first time, that the reaction between LiBH4 and MgH2 can indeed occur during ball milling at room temperature. Through this BMAS process we have demonstrated unambiguously the formation of MgB2 and LiH during ball milling of MgH2 while aerosol spraying of the LiBH4/THF solution. In this BMAS process, aerosol spraying of the LiBH4/THF solution leads to the formation of LiBH4 nanoparticles which decompose to form Li2B12H12. The Li2B12H12 formed then reacts with MgH2 in situ during ball milling to form MgB2 and LiH. The discovery made in this study has significant implications in making LiBH4 + MgH2 as a viable system for reversible hydrogen storage applications near ambient temperature in the future.

  9. Comparative Study by MS and XRD of Fe{sub 50}Al{sub 50} Alloys Produced by Mechanical Alloying, Using Different Ball Mills

    Energy Technology Data Exchange (ETDEWEB)

    Rojas Martinez, Y., E-mail: yarojas@ut.edu.co [University of Tolima, Department of Physics (Colombia); Perez Alcazar, G. A. [University of Valle, Department of Physics (Colombia); Bustos Rodriguez, H.; Oyola Lozano, D., E-mail: doyolalozano@yahoo.com.mx [University of Tolima, Department of Physics (Colombia)

    2005-02-15

    In this work we report a comparative study of the magnetic and structural properties of Fe{sub 50}Al{sub 50} alloys produced by mechanical alloying using two different planetary ball mills with the same ball mass to powder mass relation. The Fe{sub 50}Al{sub 50} sample milled during 48 h using the Fritsch planetary ball mill pulverisette 5 and balls of 20 mm, presents only a bcc alloy phase with a majority of paramagnetic sites, whereas that sample milled during the same time using the Fritsch planetary ball mill pulverisette 7 with balls of 15 mm, presents a bcc alloy phase with paramagnetic site (doublet) and a majority of ferromagnetic sites which include pure Fe. However for 72 h of milling this sample presents a bcc paramagnetic phase, very similar to that prepared with the first system during 48 h. These results show that the conditions used in the first ball mill equipment make more efficient the milling process.

  10. 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.

  11. 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.

  12. ELECTROMAGNETIC MICROWAVE PROPERTIES OF Fe82B17Cu1 BALL MILLED ALLOY

    Science.gov (United States)

    Tian, N.; Fan, X. D.; Wang, J. W.; You, C. Y.; Lu, Z. X.; Ge, L. L.

    2013-07-01

    High saturation magnetization and magnetic anisotropy are helpful for getting a high frequency electromagnetic microwave absorption performance. The α-Fe possesses a high saturation magnetization. Fe-B phases exhibit a relatively higher magnetic anisotropy and higher resistivity than α-Fe simultaneously. In this work, we made nanocrystalline powders of Fe82B17Cu1, mainly consisting of α-Fe and Fe2B phases, by ball milling and post-annealing. Electromagnetic microwave characterization shows that Fe82B17Cu1 powders possess a relative high permeability and considerable permittivity. Due to a good electromagnetic impedance matching, a good electromagnetic microwave absorption property (RL < -35 dB) has been achieved at 3.6 GHz. The experimental frequency and the matching thickness are coincident with the quarter wavelength matching condition.

  13. Hydrogen storage materials discovery via high throughput ball milling and gas sorption.

    Science.gov (United States)

    Li, Bin; Kaye, Steven S; Riley, Conor; Greenberg, Doron; Galang, Daniel; Bailey, Mark S

    2012-06-11

    The lack of a high capacity hydrogen storage material is a major barrier to the implementation of the hydrogen economy. To accelerate discovery of such materials, we have developed a high-throughput workflow for screening of hydrogen storage materials in which candidate materials are synthesized and characterized via highly parallel ball mills and volumetric gas sorption instruments, respectively. The workflow was used to identify mixed imides with significantly enhanced absorption rates relative to Li2Mg(NH)2. The most promising material, 2LiNH2:MgH2 + 5 atom % LiBH4 + 0.5 atom % La, exhibits the best balance of absorption rate, capacity, and cycle-life, absorbing >4 wt % H2 in 1 h at 120 °C after 11 absorption-desorption cycles.

  14. Solvent-free ball-milling subcomponent synthesis of metallosupramolecular complexes.

    Science.gov (United States)

    Giri, Chandan; Sahoo, Prasit Kumar; Puttreddy, Rakesh; Rissanen, Kari; Mal, Prasenjit

    2015-04-20

    Subcomponent self-assembly from components A, B, C, D, and Fe(2+) under solvent-free conditions by self-sorting leads to the construction of three structurally different metallosupramolecular iron(II) complexes. Under carefully selected ball-milling conditions, tetranuclear [Fe4 (AD2 )6 ](4-) 22-component cage 1, dinuclear [Fe2 (BD2 )3 ](2-) 11-component helicate 2, and 5-component mononuclear [Fe(CD3 )](2+) complex 3 were prepared simultaneously in a one-pot reaction from 38 components. Through subcomponent substitution reaction by adding subcomponent B, the [Fe4 (AD2 )6 ](4-) cage converts quantitatively to the [Fe2 (BD2 )3 ](2-) helicate, which, in turn, upon addition of subcomponent C, transforms to [Fe(CD3 )](2+) , following the hierarchical preference based on the thermodynamic stability of the complexes.

  15. Comparison on structural modification of industrial lignin by wet ball milling and ionic liquid pretreatment

    Directory of Open Access Journals (Sweden)

    Yongshui Qu

    2015-06-01

    Full Text Available As the most abundant aromatic compounds, lignin is still underutilized due to its relatively low quality. In order to improve its quality, two pretreatment technologies, wet ball milling (WBM and ionic liquid pretreatment (ILP were tested on the industrial lignin and evaluated on the average molecular weight and polydispersity, surface morphology, and functional groups changes. The results showed that the lignin pretreated by the WBM with phosphoric acid presented dramatic decrease of polydipersity (23% and increase of phenolic hydroxyl content (9%. While, the ILP treated samples exhibited the significant reduction of the average molecular weight and polydispersity. The decrease on the particle size and the emergence of the porous structure were found when treated with [Emim][OAc]. In addition, the remarkable reduction of the methoxy groups were observed to be 50% and 45% after treated with [Bmim]Cl and [Emim][OAc], respectively.

  16. Structural study of ball-milled sodium alanate under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Selva Vennila, R. [Center for Study of Matter at Extreme Conditions, Florida International University, Miami, FL 33199 (United States)], E-mail: selva.raju@fiu.edu; Drozd, Vadym; George, Lyci; Saxena, Surendra K. [Center for Study of Matter at Extreme Conditions, Florida International University, Miami, FL 33199 (United States); Liermann, Hanns-Peter [High Pressure Collaboration Access Team (HPCAT) and Geophysical Laboratory, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Liu, H.Z. [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Building 434E, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Stowe, Ashley C.; Berseth, Polly; Anton, Donald; Zidan, Ragaiy [Savannah River National Laboratory, Energy Security Department, Aiken, SC 29808 (United States)

    2009-04-03

    Ball-milled NaAlH{sub 4} was studied up to 15 GPa in a diamond anvil cell (DAC) by X-ray diffraction using a synchrotron radiation source. Lattice parameters were determined from the X-ray diffraction data at various pressures up to 6.5 GPa. Intensity of the powder diffraction patterns decreased with increasing pressure. Amorphisation started at a pressure of {approx}6.5 GPa and completed at 13.5 GPa. Reversible phase transformation from amorphous phase to the tetragonal phase was observed. A fit to the pressure-volume data equation of state was obtained using the Birch-Murnaghan equation of state and the bulk modulus was found to be 52.16 {+-} 0.9 GPa which is twice higher than the unmilled NaAlH{sub 4}.

  17. Microwave Absorption Properties of Iron Nanoparticles Prepared by Ball-Milling

    Science.gov (United States)

    Chu, Xuan T. A.; Ta, Bach N.; Ngo, Le T. H.; Do, Manh H.; Nguyen, Phuc X.; Nam, Dao N. H.

    2016-05-01

    A nanopowder of iron was prepared using a high-energy ball milling method, which is capable of producing nanoparticles at a reasonably larger scale compared to conventional chemical methods. Analyses using x-ray diffraction and magnetic measurements indicate that the iron nanoparticles are a single phase of a body-centered cubic structure and have quite stable magnetic characteristics in the air. The iron nanoparticles were then mixed with paraffin and pressed into flat square plates for free-space microwave transmission and reflection measurements in the 4-8 GHz range. Without an Al backing plate, the Fe nanoparticles seem to only weakly absorb microwave radiation. The reflected signal S 11 drops to zero and a very large negative value of reflection loss ( RL) are observed for Al-backed samples, suggesting the existence of a phase matching resonance near frequency f ˜ 6 GHz.

  18. 球磨法微细化马铃薯淀粉工艺优化%Optimization of micronization technology for potato starch with a ball-grinding method

    Institute of Scientific and Technical Information of China (English)

    杨宏志; 刘凤亮

    2014-01-01

    Objective To investigate the influence of various conditions on the effect of micro-miniaturization of potato starch after food-grade potato starch was micronized with a ball-grinder. Methods With the par-ticle size of potato starch as experimental indexes, the quadratic orthogonal regression experiments were de-signed, and the regressive equations concerning the experimental indexes and experimental parameters were obtained for grinding process. According to the influence of experimental parameters on the particle size of potato starch, the order of parameters is, milling time>rotary speed>mass concentration. The most appropri-ate conditions for the process of micronization of potato starch were obtained according to the results of a series of grinding experiments carried out with ball-grinder. Results The conditions mentioned above were milling time 24 h, rotary speed 350 r/min and mass concentration 0.35 g/mL, respectively. Conclusion Quadratic regression orthogonal rotation combination test results showed that the main impact of the order of potato starch miniaturization process factors were: the milling time, ball speed and starch concentration; starch grain size under optimal conditions for 11.019μm, return model predicted deviation was 2.7%with a higher prediction accuracy.%目的:利用球磨设备对普通食用级马铃薯淀粉进行微细化加工,研究不同微细化条件对马铃薯淀粉微细化效果的影响。方法采用二次正交旋转回归试验对微细化工艺进行优化,通过得到的二次正交旋转回归方程,确定影响微细化结果的各因素的主次顺序依次为:球磨时间、球磨机转速、淀粉液浓度。结果经试验最后确定马铃薯淀粉微细化的最适宜条件为以无水乙醇为球磨介质,球磨时间24 h,球磨机转速350 r/min,淀粉液浓度0.35 g/mL。结论二次正交回归旋转组合试验结果表明,影响马铃薯淀粉微细化工艺的各因素的主次顺序依次为:球

  19. 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.

  20. 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...... of 15 nm have formed and no reaction between alpha-Fe2O3 and SiO2 is found in the two types of milling containers. This demonstrates that the high energy mechanical milling technique is able to prepare a dispersion of ultrafine alpha-Fe2O3 particles. After extended milling in the open container all iron...

  1. Role of carbon order in structural transformations and hydrogen evolution induced by reactive ball milling in cyclohexene

    Energy Technology Data Exchange (ETDEWEB)

    Sakti, A.; Wonderling, N.M.; Clifford, C.E.B.; Badding, J.V.; Lueking, A.D. [Penn State University, University Park, PA (United States). Dept. of Energy and Mineral Engineering

    2008-11-15

    Demineralized Summit (DS) anthracite, DS annealed at 1673 K, and graphite are used to explore the effect of precursor order on structural transformations and H{sub 2} evolution that result during reactive ball milling. Carbon structure was assessed before and after milling with temperature-programmed oxidation, X-ray diffraction (XRD), ultraviolet Raman spectroscopy, N{sub 2} adsorption, He density, and solvent swelling. Graphite milled in cyclohexene is primarily nanocrystalline graphite, with 8 wt % amorphous content leading to low-temperature oxidation, swelling, increased surface area, and mesoporosity. Milling the disordered DS leads to signs of increased sp{sup 2} clustering, increased cross-linking, a significant ultramicroporosity with pores less than 8 angstrom, and low-temperature H{sub 2} evolution. The carbon fraction of annealed DS behaves similarly to graphite in the mill.

  2. Effect of High-energy Ball Milling on Synthetic Reaction in Al- TiO2- C System

    Institute of Scientific and Technical Information of China (English)

    KOU Shengzhong; XU Guangji; DING Yutian

    2005-01-01

    High-energy ball milling has a great influence on the temperature characters of synthetic reaction in Al-TiO2- C system by changing the size, distribution state and wet ability of reactants. Reaction temperature characters ( reaction ignition time, ignition temperature tine , the maximum temperature and temperature rising rate ) were changed by different milling time. The longer the milling time, the earlier the reaction, the quicker the temperature rise and the higher the maximum temperature. When the milling time exceeded 10 hours, the reactivity of reactants was so high that the synthetic reaction could take place at 850℃ directly without a long time pretreatment at 670℃ . The microstructure of synthetic composites became uniform and the reinforced particles ( TiC and α-Al2 O3 ) became fine with milling time increasing.

  3. Preparation of natural pyrite nanoparticles by high energy planetary ball milling as a nanocatalyst for heterogeneous Fenton process

    Energy Technology Data Exchange (ETDEWEB)

    Fathinia, Siavash [Department of Mining Engineering, Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of); Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of); Fathinia, Mehrangiz [Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of); Rahmani, Ali Akbar [Department of Mining Engineering, Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of); Khataee, Alireza, E-mail: a_khataee@tabrizu.ac.ir [Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2015-02-01

    Graphical abstract: - Highlights: • Pyrite nanoparticles were successfully produced by planetary ball milling process. • The physical and chemical properties of pyrite nanoparticles were fully examined. • The degradation of AO7 was notably enhanced by pyrite nanoparticles Fenton system. • The influences of basic operational parameters were investigated using CCD. - Abstract: In the present study pyrite nanoparticles were prepared by high energy mechanical ball milling utilizing a planetary ball mill. Various pyrite samples were produced by changing the milling time from 2 h to 6 h, in the constant milling speed of 320 rpm. X-ray diffraction (XRD), scanning electron microscopy (SEM) linked with energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR) analysis and Brunauer–Emmett–Teller (BET) were performed to explain the characteristics of primary (unmilled) and milled pyrite samples. The average particle size distribution of the produced pyrite during 6 h milling was found to be between 20 nm and 100 nm. The catalytic performance of the different pyrite samples was examined in the heterogeneous Fenton process for degradation of C.I. Acid Orange 7 (AO7) solution. Results showed that the decolorization efficiency of AO7 in the presence of 6 h-milled pyrite sample was the highest. The impact of key parameters on the degradation efficiency of AO7 by pyrite nanoparticles catalyzed Fenton process was modeled using central composite design (CCD). Accordingly, the maximum removal efficiency of 96.30% was achieved at initial AO7 concentration of 16 mg/L, H{sub 2}O{sub 2} concentration of 5 mmol/L, catalyst amount of 0.5 g/L and reaction time of 25 min.

  4. Easily recycled Bi2O3 photocatalyst coatings prepared via ball milling followed by calcination

    Science.gov (United States)

    Cheng, Lijun; Hu, Xumin; Hao, Liang

    2017-06-01

    Bi2O3 photocatalyst coatings derived from Bi coatings were first prepared by a two-step method, namely ball milling followed by the calcination process. The as-prepared samples were characterized by XRD, SEM, XPS and UV-Vis spectra, respectively. The results showed that monoclinic Bi2O3 coatings were obtained after sintering Bi coatings at 673 or 773 K, while monoclinic and triclinic mixed phase Bi2O3 coatings were obtained at 873 or 973 K. The topographies of the samples were observably different, which varied from flower-like, irregular, polygonal to nanosized particles with the increase in calcination temperature. Photodegradation of malachite green under simulated solar irradiation for 180 min showed that the largest degradation efficiency of 86.2% was achieved over Bi2O3 photocatalyst coatings sintered at 873 K. The Bi2O3 photocatalyst coatings, encapsulated with Al2O3 ball with an average diameter around 1 mm, are quite easily recycled, which provides an alternative visible light-driven photocatalyst suitable for practical water treatment application.

  5. 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.

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

    Science.gov (United States)

    Chen, Daming; Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew

    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 (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.

  7. [Radical formation by grinding of commercial tablets according to hospital and pharmacy prescription].

    Science.gov (United States)

    Kuzuya, Masayuki; Kondo, Shin-ichi; Ishikawa, Takaaki; Furuta, Youji; Aramaki, Hideki; Sasai, Yasushi; Yamauchi, Yukinori

    2005-04-01

    We examined mechanoradical formation in the grinding process of commercial tablets using electron spin resonance (ESR). Mechanoradicals were detected in all tested samples (23 types of commercial tablets) when the ball-milling of tablets was conducted under anaerobic conditions and some were fairly stable even in air. Thus the grinding may cause changes in the physicochemical properties of ingredients included in commercial tablets. Because high quality is demanded in pharmaceuticals, these results suggest more caution should be taken in the grinding of commercial tablets in hospitals and pharmacies.

  8. Comparison of pretreating pyrite cinder by high pressure roller grinding with damp milling to improve pelletization%高压辊磨和润磨预处理强化硫酸渣球团对比研究

    Institute of Scientific and Technical Information of China (English)

    朱德庆; 陈栋; 潘建

    2011-01-01

    The pretreatment of pyrite cinder was studied using high pressure roll grinding (HPRG), which aims to improve the quality of green pellets and reinforce roasting performance of pyrite cinder pellets, and HPRG was compared with damp milling was made. The results show that both HPRG and damp milling can significantly improve green ball quality while bentonite consumption is dramatically reduced, the drop number of green balls increases from 9.0 times without pretreatment to more than 30.0 times from 0.5 m height by pretreating the pyrite cinder using HPRG and 27.4 times from 0.5 m height by using damp milling, the compressive strength increases from 7.2 N per pellet without pretreatment to 10.6 N per pellet by using HPGR to pretreat cinder and 13.7 N per pellet by using damp milling, respectively. Thermal shock temperature of green balls is above 540 ℃ and the moisture of green pellets drops by 6.5%. After the pyrite cider is pretreated by HPRG and damp milling, the preheating and roasting temperatures of the pyrite cinder pellets are decreased by 150 ℃ and 80 ℃, respectively, and the roasting time is shortened by 6 mines. Therefore, the roasting performance of pyrite cinder pellets is reinforced greatly by HPRG and damp milling. The mechanisms of HPRG and damp milling show that specific surface areas and surface energy and activity are improved, and that solid diffusion reactions are enhanced, resulting in strong bonding inside fired pellets. However, productivity of HPRG is much higher than that of damp milling, and unit energy consumption is lower than that of damp milling.%采用高压辊磨技术预处理硫酸渣改善生球质量和强化球团焙烧,并且与传统的润磨技术进行对比.研究结果表明:高压辊磨和润磨预处理硫酸渣均可大幅度提高生球质量,在膨润土用量大幅降低的同时,生球落下强度从9 0次/(0.5 m)分别增加到大于30.0次/(0.5 m)和27.4次/(0.5 m),抗压强度从7.2 N/个分别增加到10

  9. 静压轴承在球磨机改造中的应用%Application of Hydrostatic Bearing in Renovation of Ball-Grinding Equipment Device

    Institute of Scientific and Technical Information of China (English)

    徐广普; 吴晓元; 陈忠基; 王安清

    2001-01-01

    By analysing 3231 case about ball-grinding equipment of Anshanmine corportion and discussing about hydrostatic bearing design and the implement of renovation. It is showed that the hydrostatic bearings have wide application in the low speed and heavy loads, meanwhile the considerable profit for enterprises can be brought.%通过对东烧厂3231球磨机的工况分析、静压轴承设计方案讨论和实施球磨机静压轴承改造的总结,表明静压轴承在低速重载设备上的应用前景广阔,可为企业带来十分可观的经济效益.

  10. Highly anisotropic SmCo{sub 5} nanoflakes by surfactant-assisted ball milling at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lidong; Zhang, Songlin [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhang, Jian, E-mail: zhangj@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Ping Liu, J. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Xia, Weixing; Du, Juan; Yan, Aru [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Yi, Jianhong [Institute of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Li, Wei; Guo, Zhaohui [Division of Functional Materials, Central Iron and Steel Research Institute, Beijing 100081 (China)

    2015-01-15

    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 SmCo{sub 5} 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 SmCo{sub 5} nanoflakes were investigated systematically. Comparing with the samples milled at room temperature, the SmCo{sub 5} 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 SmCo{sub 5} 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 SmCo{sub 5} 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.

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

    Institute of Scientific and Technical Information of China (English)

    SUN Jin-Feng; LI Xiao-Pu; LIANG Bao-Yan; ZHAO Yu-Cheng; WANG Ming-Zhi

    2009-01-01

    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 tem-perature 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 correspond-ing to the content ratio between Ti and urea increasing from 2:1 to 4:1. Ammonia gas (NHa) 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.

  12. 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.

  13. Electrochemical properties of CeMg11 Ni+ x % Ni composites (x=0, 50, 100 and 200) prepared by ball-milling

    Institute of Scientific and Technical Information of China (English)

    WANG Li; WANG Xin-hua; CHEN Li-xin; CHEN Chang-pin

    2005-01-01

    The electrochemical properties of the as-cast CeMg11 Ni and ball-milled CeMg11 Ni+ x% Ni(x = 0, 50,100 and 200, mass fraction) composites were investigated. The results show that homogeneous amorphous phase of CeMg11 Ni+x% Ni composite can be obtained by ball-milling, and discharge capacity of the ball-milled CeMg11 Ni+x% Ni composites differs greatly depending on the amount of Ni introduced during milling. The CeMg11 Ni+200% Ni composite after 90 h ball-milling was found to exhibit a large discharge capacity of about 1 012 mAh/g at 303 K,and it also shows better charge-discharge cycling stability than those with lower Ni content. This remarkable improvement in electrochemical properties of the ball-milled composites seems to be attributed to the formation of an amorphous composite as well as the improvement of the surface state of the ball-milled particles.

  14. 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.

  15. Phase transformation in magnesium hydride induced by ball milling; Changement de phase induit par broyage mecanique dans l'hydrure de magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Huot, J. [Universite du Quebec a Trois-Rivieres, Institut de Recherche sur l' Hydrogene, Quebec (Canada); Swainson, I. [Canadian Neutron Beam Centre, National Research Council Canada, Chalk River Lab. (Canada); Schulz, R. [Institut de Recherche d' Hydro-Quebec, Expertise Chimie et Materiaux, Quebec (Canada)

    2006-01-15

    The synthesis of magnesium hydride by reactive ball milling leads to the formation of a metastable orthorhombic {gamma}-MgH{sub 2} phase along with tetragonal {beta}-MgH{sub 2}. The structures of the {beta}-MgD{sub 2} and {gamma}-MgD{sub 2} phases of ball milled nanocrystalline MgD{sub 2} were studied by neutron powder diffraction. The ball-milled {beta}-MgD{sub 2} and {gamma}-MgD{sub 2} structures are distorted compared to the same phases synthesized by high-pressure and high temperature. Two Mg-D bond lengths are significantly distorted in {beta}-MgD{sub 2} while in the {gamma}-MgD{sub 2} phase, only one bond length is largely affected. The micro-stress associated with the strain fields and deformations caused by the ball milling is most likely the driving force of this phase transformation. (authors)

  16. A study on the surface shape and roughness of aluminum alloy for heat exchanger using ball end milling

    Science.gov (United States)

    Lee, E.; Kim, Y.; jeong, H.; Chung, H.

    2015-09-01

    Aluminum alloy is a material with a high strength-weight ratio and excellent thermal conductivity. It neither readily corrodes nor quickly weakens at low temperatures, but can be easily recycled. Because of these features, aluminum heat exchangers are widely used in aluminum alloy. In addition, the aluminum alloy used in other areas is expected to gradually increase. As a result, researchers have been continuously studying the cutting patterns of aluminium alloy. However, such studies are fewer than those on the cutting patterns of ordinary steel. Moreover, the research on ball end milling with aluminium alloys has not received much attention. Therefore, in this study, an attempt was made to find the optimal cutting pattern among the seven cutting patterns for the machining of the commonly used aluminum alloy using ball end milling for a heat exchanger. The optimal pattern was found by comparing the different shapes and surface roughness values produced by the seven patterns.

  17. 基于正交设计的SiCp/Al复合材料铣磨力实验%Study on mill-grinding force of SiCp/Al composites by orthogonal experiment design

    Institute of Scientific and Technical Information of China (English)

    都金光; 李建广; 姚英学

    2013-01-01

    To solve the problems in machining of SiCp/Al composites, experiments were carried out using electroplated diamond tool with spiral grooves for mill-grinding of SiCp/Al composites. Through the orthogonal experiments, the effects of different mill-grinding tools and processing parameters on the milling force were investigated, and the mill-grinding force was analyzed through the main effect and the variance analysis. Results showed that when mill-grinding SiCp/Al composite material, the optimal parameters combination was T2,v4, f1 and a1 , which was to say, at the processing helix angle 50°, the mill-grinding tool with three spiral grooves could get the smallest mill-grinding force in the case of processing parameters v = 314 m/min, f= 100 mm/min, a =0.01 mm. Both the normal mill-grinding force Fn and tangential mill-grinding force Ft decreased with the increase of mill-grinding speed, while increased with the increase of feed rate and mill-grinding depth. The feed rate and mill-grinding depth were found to be the highly significant factors of the normal milling force. Milling speed, feed rate and mill-grinding depth were all found to be the most effective factors of the tangential milling force. The significance of various factors on the milling force was in an order of a >f >v> Tool.%针对SiCp/Al复合材料加工中存在的问题,使用电镀金刚石螺旋槽铣磨工具对SiCp/Al复合材料进行了实验研究.通过正交实验设计,研究了不同的铣磨工具和加工参数对铣磨力的影响规律,并对实验结果进行了主效应和方差分析.结果表明:铣磨加工SiCp/Al复合材料时,最佳的参数组合为T2ν4f1a1,即使用螺旋角为50°,螺旋槽数为3的铣磨工具,在加工参数为ν=314 m/min,f=100 mm/min,a=0.01 mm下能得到较小的铣磨力;法向铣磨力Fn和切向力铣磨力Ft均随着铣磨速度的增加而减小,随着进给速度和铣磨深度的增加而增大;进给速度和铣磨深度对法向铣磨力

  18. Analysis of Failure and Solving Measures of Grinding Ball in the Permanent Mold Casting%金属型铸造磨球失圆失效的分析与解决措施

    Institute of Scientific and Technical Information of China (English)

    史正兴; 王志熙; 刘彦民; 杨永福; 秦俊敏

    2013-01-01

    Out-of-round is one of the failure types of grinding ball in the metal mold casting besides of abrasion and fragmentation failure,which has two types of the shape of steamed bread and pear.Microstructure defects,appearance defects during casting and grinding during working process are responsible for the failure.Through refining molten iron,changing geometric shape of grinding ball and standard specification of polishing,the out-of-round defects of the grinding ball can be eliminated.%失圆是金属型铸造磨球除研磨失效、破碎失效外的另一种失效形式,常表现为两种形状:馒头状和鸭梨状.失圆主要原因包括铸造组织缺陷、外形缺陷和后期修磨等,可以通过铁水精炼、改变磨球几何外形和规范修磨工艺等措施解决.

  19. 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.

  20. Significantly improved dehydrogenation of ball-milled MgH2 doped with CoFe2O4 nanoparticles

    OpenAIRE

    Shan, Jiawei; LI, Ping; Wan, Qi; Zhai, Fuqiang; Zhang, Jun-Ying; Li, Ziliang; Liu, Zhaojiang; Alex A. Volinsky; Qu, Xuanhui

    2014-01-01

    CoFe2O4 nanoparticles are added to magnesium hydride (MgH2) by high-energy ball milling in order to improve its hydriding properties. The hydrogen storage properties and catalytic mechanism are investigated by pressure-composition-temperature (PCT), differential thermal analysis (DTA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The nonisothermal desorption results show that the onset desorption temperature of the Mg...

  1. 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)....

  2. Galvanic Interaction between Chalcopyrite and Pyrite with Low Alloy and High Carbon Chromium Steel Ball

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2013-01-01

    Full Text Available This study was aimed to investigate the galvanic interaction between pyrite and chalcopyrite with two types of grinding media (low alloy and high carbon chromium steel ball in grinding of a porphyry copper sulphide ore. Results indicated that injection of different gases into mill altered the oxidation-reduction environment during grinding. High carbon chromium steel ball under nitrogen gas has the lowest galvanic current, and low alloy steel ball under oxygen gas had the highest galvanic current. Also, results showed that the media is anodic relative to pyrite and chalcopyrite, and therefore pyrite or chalcopyrite with a higher rest potential acted as the cathode, whilst the grinding media with a lower rest potential acted as the anode, when they are electrochemically contacted. It was also found that low alloy steel under oxygen produced the highest amount of EDTA extractable iron in the slurry, whilst high carbon chromium steel under nitrogen atmosphere led to the lowest amount.

  3. Catalytic hydrodechlorination of monochloroacetic acid in wastewater using Ni-Fe bimetal prepared by ball milling.

    Science.gov (United States)

    Zhu, Hong; Xu, Fuyuan; Zhao, Jianzhuang; Jia, Linfang; Wu, Kunming

    2015-09-01

    Monochloroacetic acid (MCA) is a chemically stable and biologically toxic pollutant. It is often generated during the production of the pesticide dimethoate. Conventional wastewater treatment processes have difficulty degrading it. In this work, the dechlorination effects of Ni-Fe bimetal prepared using ball milling (BM) technology for the high concentrations of MCA in wastewater were examined. The MCA in aqueous solution was found to be degraded efficiently by the Ni-Fe bimetal. However, S-(methoxycarbonyl) methyl O, O-dimethyl phosphorodithioate (SMOPD) in wastewater, a by-product of the dimethoate production process, significantly inhibited the reductive dechlorination activity of Ni-Fe bimetal. Increasing the reaction temperature in the MCA wastewater enhanced the reduction activity of the Ni-Fe bimetal effectively. Oxygen was found to be unfavorable to dechlorination. Sealing the reaction to prevent oxidation was found to render the degradation process more efficient. The process retained over 88% efficiency after 10 treatment cycles with 50 g/L of Ni-Fe bimetal under field conditions.

  4. 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). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 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.

  6. Evaluation of hydrogenation properties on MgHx-transition metal fluoride composites by planetary ball milling

    Science.gov (United States)

    Jang, Min-Hyuk; Park, So-Hyun; Kim, Whan-Gi; Hong, Tae-Whan

    2015-11-01

    To improve the disadvantages of Mg hydrides, a few studies were conducted for MgHx intermixed with transition metal fluorides. MgF2 formed from the MgHx-transition metal fluoride system can be replaces the initial surface oxide layer and provides a reactive and protective fluorinated surface for for hydrogen uptake. Thus, the absorption/desorption kinetics will be enhanced. In this research, MgHx-transition metal fluoride composites mixture has been prepared by hydrogen induced planetary ball milling. The synthesized powders were characterized by X-ray diffraction analysis, scanning electron microscopy and simultaneous thermogravimetric, differential scanning calorimetric analysis. The hydrogenation behaviors were evaluated by using a sievert's type automatic pressure-composition-temperature apparatus without any activation treatment. From the characteristics of the absorption kinetics and curves observed, the role of transition metal fluoride was catalyst in hydrogen absorption. The results of Pressure-Composition Isotherm curve, available hydrogen storage amount for MgHx-5 vol% CoF2 composites were 4.85 wt%, for MgHx-5 vol%TiF3 composites were 4.88 wt%. at 623K in the 5th cycle.

  7. Vertical mill simulation applied to iron ores

    Directory of Open Access Journals (Sweden)

    Douglas Batista Mazzinghy

    2015-04-01

    Full Text Available The application of vertical mills in regrind circuits is consolidated. This type of mill is now attracting interest in primary grinding applications, due to its higher efficiency when compared to ball mills, which are usually used at this stage. In this study, a coarse sample of iron ore was tested in a pilot scale grinding circuit with a vertical mill. Other three samples of pellet feed had already been tested with the methodology used in this study. The sample of coarse iron ore was characterized in laboratory tests carried out in a small batch ball mill. Selection and breakage function parameters were determined from the laboratory tests. The parameters were then used for simulating the pilot scale tests using Modsim™ software. The model previously implemented in Modsim™ has been successfully applied to represent the vertical mill operated with different ores. The simulations produced particle size distributions that were very close to the actual size distributions, and the predictions were accomplished only by imputing the calibrated parameters from the batch tests, the power draw and the feed size distribution of the pilot tests. The methodology is therefore useful for scale-up and simulation of vertical mills, only requiring laboratory tests that can be carried out in standard laboratory batch ball mills with small amounts of samples.

  8. Effects of grinding processes on enzymatic degradation of wheat straw.

    Science.gov (United States)

    Silva, Gabriela Ghizzi D; Couturier, Marie; Berrin, Jean-Guy; Buléon, Alain; Rouau, Xavier

    2012-01-01

    The effectiveness of wheat straw fine to ultra-fine grindings at pilot scale was studied. The produced powders were characterised by their particle-size distribution (laser diffraction), crystallinity (WAXS) and enzymatic degradability (Trichoderma reesei enzymatic cocktail). A large range of wheat-straw powders was produced: from coarse (median particle size ∼800 μm) to fine particles (∼50 μm) using sieve-based grindings, then ultra-fine particles ∼20 μm by jet milling and ∼10 μm by ball milling. The wheat straw degradability was enhanced by the decrease of particle size until a limit: ∼100 μm, up to 36% total carbohydrate and 40% glucose hydrolysis yields. Ball milling samples overcame this limit up to 46% total carbohydrate and 72% glucose yields as a consequence of cellulose crystallinity reduction (from 22% to 13%). Ball milling appeared to be an effective pretreatment with similar glucose yield and superior carbohydrate yield compared to steam explosion pretreatment.

  9. Microstructure characterization of ball-milled Ni{sub 50}Co{sub 50} alloy by Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Loudjani, Nadia; Bensebaa, Nadia; Alleg, Safia; Djebbari, Chaffia [Laboratoire de Magnetisme et de Spectroscopie des Solides, Departement de Physique, Faculte des Sciences, Universite Badji Mokhtar, Annaba (Algeria); Greneche, Jean Marc [Laboratoire de Physique de l' Etat Condense - UMR 6087, Universite du Maine, Faculte des Sciences, Le Mans (France)

    2011-09-15

    A nanostructured Ni{sub 50}Co{sub 50} mixture was prepared by high-energy ball milling in a planetary ball mill (Frisch P7) under an argon atmosphere. Scanning electron microscopy and X-ray diffraction (XRD) have been used to study the morphology of the powder particles, microstructure, and structure evolution. Detailed analysis of the XRD patterns was performed by the MAUD program, which is based on the Rietveld method. It reveals the complete vanishing of the Co peaks after 3 h of milling, indicating the allotropic transformation of Co from hcp to fcc structure. The reciprocal dissolution of the elemental Ni and Co powders leads to the formation of a heterogeneous solid solution with two structures: fcc-Ni(Co) and fcc-Co(Ni) with relative fractions of about 76 and 20%, respectively, after 24 h of milling. Microstructural parameters such as lattice parameter, crystallite size, microstrains, dislocation density, and stacking faults have been deduced from the best Rietveld refinements. The formation kinetics of nanostructured Ni{sub 50}Co{sub 50} mixture can be described by a lower Avrami parameter, n, close to 0.34. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. 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.

  11. 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.

  12. Preparation of an additive-free sample with a MgH2 phase by planetary ball milling of Mg with10 wt% MgH2

    Science.gov (United States)

    Hong, Seong-Hyeon; Song, Myoung Youp

    2016-11-01

    In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named Mg-10MgH2) was milled under hydrogen atmosphere in a planetary ball mill for different durations (2 h, 5 h, and 10 h). The hydrogen absorption and release properties of the prepared samples were investigated and compared with those of purchased pure MgH2 samples. Mg-10MgH2 milled for 5 h had the largest quantity of hydrogen released at 648 K for 100 min of 5.96 wt%. Mg-10MgH2 milled for 5 h released 0.11 wt% H for 10 min, 4.85 wt% H for 30 min, and 5.83 wt% H for 60 min at 648 K at the first cycle. Mg-10MgH2 milled for 5 h absorbed 5.39 wt% H for 5 min and 5.92 wt% H for 60 min at 648 K at the second cycle. Dehydriding curves were also obtained at the first cycle of Mg-10MgH2 samples milled for 5 h using Mg powder with or without sieving (200 mesh). The dehydriding curve at 648 K of a Mg-10MgH2 sample milled for 5 h in the planetary ball mill was compared with that of the sample milled for 24 h in a horizontal ball mill.

  13. 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.

  14. Grinding analysis of Indian coal using response surface methodology

    Institute of Scientific and Technical Information of China (English)

    Twinkle Singh; Aishwarya Awasthi; Pranjal Tripathi; Shina Gautam; Alok Gautam

    2016-01-01

    The present work discusses a systematic approach to model grinding parameters of coal in a ball mill.A three level Box-Behnken design combined with response surface methodology using second order model was applied to the experiments done according to the model requirement.Three parameters ball charge (numbers 10-20),coal content (100-200 g) and the grinding time (4-8 min) were chosen for the experiments as well as for the modeling work.Coal fineness is defined as the d80 (80 % passing size).A quadratic model was developed to show the effect of parameters and their interaction with fineness of the product.Three different sizes (4,1 and 0.65 mm) of Indian coal were used.The model equations for each fraction were developed and different sets of experiments were performed.The predicted values of the fineness of coal were in good agreement with the experimental results (R2 values of d80 varies between 0.97 and 0.99).Fine size of three different coal sizes were obtained with larger ball charge with less grinding time and less solid content.This work represents the efficient use of response surface methodology and the Box-Behnken design use for grinding of Indian coal.

  15. Quantification of residual crystallinity in ball milled commercially sourced lactose monohydrate by thermo-analytical techniques and terahertz spectroscopy.

    Science.gov (United States)

    Smith, Geoff; Hussain, Amjad; Bukhari, Nadeem Irfan; Ermolina, Irina

    2015-05-01

    The quantification of crystallinity is necessary in order to be able to control the milling process. The use of thermal analysis for this assessment presents certain challenges, particularly in the case of crystal hydrates. In this study, the residual crystallinity on ball milling of lactose monohydrate (LMH), for periods up to 90min, was evaluated by thermo-analytical techniques (TGA, DSC) and terahertz spectroscopy (THz). In general, the results from one of the DSC analysis and the THz measurements agree showing a monotonous decrease in relative residual crystallinity with milling time (∼80% reduction after 60min milling) and a slight increase at the 90min time point. However, the estimates from TGA and two other methods of analyzing DSC curve do not agree with the former techniques and show variability with significantly higher estimates for crystallinity. It was concluded that, the thermal techniques require more complex treatment of the data in the evaluation of changes in crystallinity of a milled material (in particular to account for the de-vitrification and mutarotation of the material that inevitably occurs during the measurement cycle) while the analysis of THz data is more straightforward, with the measurement having no impact on the native state of the material. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. 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.

    2017-01-01

    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 2 hours 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 1 hour. The biochar/Fe3O4 had a maximum adsorption capacity of 62.7 mg/g for CBZ and 94.2 mg/g for TC, while values obtained for AC/Fe3O4 were 135.1 mg/g for CBZ and 45.3 mg/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 3 hours 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 0.3 g 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

  17. 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.

  18. Analysis and correction of the machining errors of small plastic helical gears by ball-end milling

    Institute of Scientific and Technical Information of China (English)

    Gao Sande; Huang Loulin; and Han Baoling

    2012-01-01

    Many small-size precise plastic helical involutes gears are used in electrical appliances to transmit rotary movements con- tinuously and smoothly. Ball-end milling is an effective method for trial manufacture or small batch production of this type of gear, but the precision of the gear is usually low. In this research, the main sources of the errors of the gear, machining errors of the tooth profile and trace of the gear obtained were analyzed. The correction amounts for these errors are then determined by using a CNC gear tester. They are used to generate a new 3D-CAD model for gear machining with better nrecision.

  19. Improved critical current densities in bulk FeSe superconductor using ball milled powders and high temperature sintering

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M.; Furutani, K.; Murakami, M. [Graduate School of Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Kumar, Dinesh; Rao, M.S. Ramachandra [Department of Physics, Nano Functional Materials Technology Centre and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai (India); Koblischka, M.R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany)

    2016-12-15

    The present study is investigating the effect of high temperature sintering combined with ball milled powders for the preparation of FeSe material via solid state sintering technique. The commercial powders of Fe (99.9% purity) and Se (99.9% purity) were mixed in a nominal ratio Fe:Se = 1:1 and thoroughly ground and ball-milled in a glove box during 6 h. Then, the powder mixture was pressed into pellets of 5 mm in diameter and 2 mm thickness using an uniaxial pressure of 100 MPa. The samples were sealed in quartz tubes and sintered at 600 C for 24 h. Then, the pellets were again thoroughly ground and ball-milled in the glove box and pressed into pellets, and the final sintering was performed at two different temperatures, namely at 900 C for 24 h and at 950 C for 24 h. X-ray diffraction results confirmed that both samples showed mainly of the β-FeSe with tetragonal structure. The temperature dependence of magnetization (M-T) curves revealed a sharp superconducting transition T{sub c,} {sub onset} = 8.16 K for the sample sintered at 900 C. Further, scanning electron microscopy observations proved that samples sintered at 900 C show a platelike grain structure with high density. As a result, improved irreversibility fields around 5 T and the critical current density (J{sub c}) values of 6252 A cm{sup -2} at 5 K and self-field are obtained. Furthermore, the normalized volume pinning force versus the reduced field plots indicated a peak position at 0.4 for the sample sintered at 900 C. Improved flux pinning and the high J{sub c} values are attributed to the textured microstructure of the material, produced by a combination of high temperature sintering and ball milling. (copyright 2016 The Authors. Phys. Status Solidi A published by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Effect of Surfactant Molecular Weight on Particle Morphology of SmCo5 Prepared by High Energy Ball Milling

    Science.gov (United States)

    2014-04-01

    palmitic acid (Aldrich), undecanoic acid (Aldrich), and valeric acid (Aldrich) were used as received at a concen- tration equivalent to 30% by... Acid 296 3 420 16.2 Oleic Acid 246 4 456 15.3 Palmitic Acid 236 3 418 16.6 Myristic Acid 216 3 398 15.7 Undecanoic Acid 246 5 376 16.6 Octanoic Acid ...ball milling (HEBM) is a widely used technique for producing nanostructured magnetic materials with oleic acid (OA) being the most commonly utilized

  1. Enzymatic hydrolysis of rice straw and glucose fermentation using a Vertical Ball Mill Bioreactor (VBMB): Impact of operational conditions

    DEFF Research Database (Denmark)

    Castro, Rafael C.A.; Mussatto, Solange I.; Roberto, Inês C.

    The effects of agitation speed (100-200 rpm), number of glass spheres (0-30 units) and temperature (40-46 °C) on both enzymatic hydrolysis of rice straw (8% w/v) and glucose fermentation (50 g/L) by Kluyveromyces marxianus NRRL Y-6860 were evaluated using a Vertical Ball Mill Bioreactor (VBMB....... By applying the needed adjustments on the levels of the variables for each process (hydrolysis and fermentation), the VBMB can be efficiently used for rice straw bioconversion into ethanol. In addition, the design of this bioreactor would allow its use in different processes, such as simultaneous...

  2. Nanostructured MgH2 Obtained by Cold Rolling Combined with Short-time High-energy Ball Milling

    OpenAIRE

    Ricardo Floriano; Daniel Rodrigo Leiva; Stefano Deledda; Bjørn Christian Hauback; Walter José Botta

    2013-01-01

    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 depen...

  3. Effective Route to Graphitic carbon Nitride from Ball-Milled Amorphous carbon in NH3 Atmosphere Under Annealing

    Institute of Scientific and Technical Information of China (English)

    费振义; 刘玉先

    2003-01-01

    Graphitic carbon nitride (g-C3N4) powders were successfully synthesized from ball-milled amorphous carbon under NHs atmosphere at high temperature, for the first time to the best of our knowledge. The combined characteristic data obtained by x-ray diffraction, high-resolution transmission-electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, energy dispersive spectroscopic analysis, and Fourier transformation infrared spectroscopy provide substantial evidence for the graphite-like sp2-bonded structure with C3N4 stoichiometry.

  4. Prediction of cutting forces in ball-end milling of 2.5D C/C composites

    Directory of Open Access Journals (Sweden)

    Shan Chenwei

    2016-06-01

    Full Text Available Machining of carbon/carbon (C/C composite materials is difficult to carry out due to its high specific stiffness, brittleness, anisotropic, non-homogeneous and low thermal conductivity, which can result in tear, burr, poor surface quality and rapid wear of cutters. Accurate and fast prediction of cutting forces is important for milling C/C composite materials with high quality. This paper presents an alternative cutting force model involving the influences of the directions of fiber. Based on the calculated and experimental results, the cutting forces’ coefficients of 2.5D C/C composites are evaluated using multiple linear regression method. Verification experiment has been carried out through a group of orthogonal tests. Results indicate that the proposed model is reliable and can be used to predict the cutting forces in ball-end milling of 2.5D C/C composites.

  5. 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.

  6. Determining cement ball mill dosage by artificial intelligence tools aimed at reducing energy consumption and environmental impact

    Directory of Open Access Journals (Sweden)

    Julio R. Gómez Sarduy

    2012-10-01

    Full Text Available Energy management systems can be improved by using artificial intelligence techniques such as neural networks and genetic algorithms for modelling and optimising equipment and system energy consumption. This paper proposes modelling ball mill consumption as used in the cement industry from field variables. The regression model was based on artificial neural networks for predicting the electricity consumption of the mill’s main drive and evaluating established consumption rate performance. This research showed the influence of the amount of pozzolanic ash, gypsum and clinker on a mill’s power consumption; the dose determined according to the model ensured minimum energy consumption using a simple genetic algorithm. The estimated savings potential from the proposed dose was 36 600 kWh / year for mill number 1, representing $5,793.78 / year and a 33,708 kg CO2 / year reduction in the environmental impact of gas left to escape.

  7. Magnetic hardening of high-energy ball-milled nanocrystalline LaMn{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Elmali, Ayhan [Department of Physics Engineering, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara (Turkey)], E-mail: elmali@eng.ankara.edu.tr; Tekerek, Simsek; Dincer, Ilker; Elerman, Yalcin [Department of Physics Engineering, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara (Turkey); Theissmann, Ralf [Institute for Materials Science, Darmstadt Technology University, Petersenstr. 23, 64287 Darmstadt (Germany); Institute for NanoTechnology, Forschungszentrum Karlsruhe (Germany); Ehrenberg, Helmut [Institute for Materials Science, Darmstadt Technology University, Petersenstr. 23, 64287 Darmstadt (Germany); Institute for Solid State and Materials Research, Institute for Complex Materials, Helmholtzstr. 20, D-01069 Dresden (Germany); Fuess, Hartmut [Institute for Materials Science, Darmstadt Technology University, Petersenstr. 23, 64287 Darmstadt (Germany)

    2008-02-15

    Nanocrystalline LaMn{sub 2}Si{sub 2} powders have been obtained by high-energy ball milling for 30 min from bulk alloys. After milling a high coercivity about 6 kOe is observed at 10 K in contrast to neglectable coercivity for the bulk LaMn{sub 2}Si{sub 2} at 5 K. The average grain size of the optimum particles which is obtained from X-ray diffraction pattern and HRTEM picture is about 20 nm. The magnetic hardening is observed for the nanocrystalline LaMn{sub 2}Si{sub 2,} reflected in the coercivity field strength of 6 kOe at 10 K.

  8. Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

    Science.gov (United States)

    Dellinger, Timothy Michael

    Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

  9. XRD and Moessbauer characterization of iron-doped SnO{sub 2} powders obtained by ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Brito, A.D.B. de; Alves, H.W.L.; Raposo, M.T. [Universidade Federal de Sao Joao del-Rei (UFSJ), MG (Brazil); Ardisson, J.D. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2012-07-01

    Full text: Rutile SnO{sub 2} (or cassiterite) is a semiconductor oxide, with many industrial applications, mainly as spin source for spintronics because of the relevant electronic and magnetic properties changes when doped with transition elements (TE) like Fe, Co, Ni and Co. Therefore, it is meaningful for the materials science research to study the properties of SnO{sub 2} nanomaterials doped by a TE ion. In this work, mechanical alloying process has been used to produce SnO{sub 2} doped with iron. The samples were characterized by X-Ray and Moessbauer spectroscopy. The crystalline alloy were obtained by milling in a planetary ball mill with a zirconia milling assembly for up to 24 hours in air, at room temperature. The mill rotation speed was 250 rpm and two different powder-to-ball weight ratios, 1:20 and 1:10, were used. X-ray diffraction analyses of SnO{sub 2} powders indicate only the formation of the cassiterite phase. X-Ray diffraction results of SnO{sub 2} doped with 10% of iron show some peaks quite wider when compared with diffraction peaks of the undoped samples, suggesting the absorption of iron probably in a new phase with tin. However, this phase cannot be identified by X-Ray diffraction. Moessbauer spectroscopy analyses (table below) indicate the presence of 85% of {alpha}-Fe and two new phases, both related to Fe-Sn phase magnetically disordered. On the other hand, {sup 119}Sn-Moessbauer spectroscopy measurements show the presence of tetrahedral tin (IV), chemical environment of the tin species. Based on the obtained results, thermal annealing and new measurements with both XRD and Moessbauer spectroscopies will be performed and compared with them. (author)

  10. Structure of composites consolidated from ball milled 7475 aluminum alloy and ZrO{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Dutkiewicz, Jan; Litynska-Dobrzynska, Lidia [Polish Academy of Sciences, Krakow (Poland). Inst. of Metallurgy and Materials Science; Matsuda, Kenji [Toyama Univ., Gofuku (Japan). Graduate School of Science and Engineering

    2013-02-15

    Nanocomposites were prepared from 7475 alloy powder ball milled for 40h with additions of 2% Zr and 10 or 20wt.% of ZrO{sub 2}, Y{sub 2}O{sub 3} stabilized powders. Two types of ZrO{sub 2} powder additions of size near 30nm and 0.3-0.5 {mu}m were used. Transmission electron microscopy studies confirmed the refinement of the aluminum solid solution grain size after milling, down to about 40nm. The milled powders were consolidated using uniaxial hot pressing in vacuum at 380 C and at a pressure of 600 MPa. The hardness of consolidated samples was higher for the 20% ZrO{sub 2} nanocrystalline ceramic powder addition than for 20% ZrO{sub 2} coarser powder, at 320 and 280 HV, respectively. Transmission electron microscopy studies allowed the determination of the grain size of aluminum solid solution to be near 100nm after hot pressing and homogeneous distribution of ZrO{sub 2} particles. The fractions of monoclinic ZrO{sub 2} were similar in the milled powder and in the hot pressed samples. ZrO{sub 2} nanoparticles did not retard the grain growth, contrary to 2% of Zr which prevented grain growth during hot pressing. The compression tests showed 1000 MPa of ultimate compression strength of samples with ZrO{sub 2} nanoparticles, slightly higher than those with ZrO{sub 2} larger particle additions. (orig.)

  11. 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.

  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. High-temperature large diamagnetism in ball-milled Sr0.6Ca0.4CuO2

    Science.gov (United States)

    Hernando, A.; Herrero, E.; Vázquez, M.; Alonso, J.; González, A.; Rivero, G.; Rojo, J. M.; Vallet-Regi, M.; González Calbet, J.

    1997-10-01

    The observation of a large effective diamagnetic susceptibility of -3.4×10-6 emu g-1 Oe-1 up to temperatures above 1000 K in highly deformed ball-milled Sr0.6Ca0.4CuO2 is reported. These samples do not exhibit superconductivity at low temperature. This anomalously strong diamagnetism increases with milling time and reaches a maximum value after 500 h of milling. A model is proposed in which excess holes, introduced during milling, have wave functions that are extended over the CuO2 planes of the crystallites, resulting in large values of the diamagnetic susceptibility.

  14. Agile Thermal Management STT-RX. Catalytic Influence of Ni-based Additives on the Dehydrogentation Properties of Ball Milled MgH2 (PREPRINT)

    Science.gov (United States)

    2011-12-01

    milled MgH2 (PREPRINT) Patrick J. Shamberger, Jonathan E. Spowart, and Andrey A. Voevodin Thermal Sciences & Materials Branch Placidus B...the dehydrogentation properties of ball milled MgH2 (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F...LaNi5 on the dehydrogenation properties of milled MgH2 , was investigated. MgH2 milled in the presence of Ni (5wt%) and Zr2Ni5 (5wt%) catalysts for 2 h

  15. Effects of ball-milled graphite in the synthesis of SnO2/graphite as an active material in lithium ion batteries

    Science.gov (United States)

    Jung, Dong-Won; Jeong, Jae-Hun; Cha, Byung-Chul; Kim, Jun-Bom; Kong, Byung-Seon; Lee, Jung Kyoo; Oh, Eun-Suok

    2011-12-01

    Nano-sized SnO2 particles supported on ball-milled graphite were manufactured by the in situ NaBH4 reduction method and were used as an anode active material in lithium-ion batteries. Their physical and electrochemical characteristics were investigated using various characterization techniques: Raman spectroscopy, x-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). From coin half-cell tests, the SnO2 particles supported on graphite that was ball-milled for 24 hr showed a reversible capacity better than that of commercial graphite and other SnO2/graphite materials for which the graphite was ball-milled for longer lengths of time.

  16. Facile and Cost-Effective Synthesis and Deposition of a YBCO Superconductor on Copper Substrates by High-Energy Ball Milling

    Science.gov (United States)

    Alami, Abdul Hai; Assad, Mhd Adel; Aokal, Camilia

    2016-09-01

    The article investigates the synthesis and deposition of YBCO on a copper substrate for various functional purposes. The superconductor is first prepared by mechanically alloying elemental components (yttrium, barium, and copper) for 50 hours in a high-energy ball mill with subsequent protocol of heat treatment in an oxygen-rich atmosphere to arrive at stoichiometric ratios of YBa2Cu3O7. The material is then deposited on a thin copper substrate also by ball milling under various parameters of rotational speed and deposition time to select the best and most homogenous substrate coverage. Atomic force microscopy has confirmed the desired results, and other microstructural, thermal, and electrical techniques are used to characterize the obtained material. High-energy ball milling proved to be a versatile means to synthesize and deposit the material in a straightforward manner and controllable parameters for different deposit thicknesses and coverages.

  17. Facile and Cost-Effective Synthesis and Deposition of a YBCO Superconductor on Copper Substrates by High-Energy Ball Milling

    Science.gov (United States)

    Alami, Abdul Hai; Assad, Mhd Adel; Aokal, Camilia

    2016-12-01

    The article investigates the synthesis and deposition of YBCO on a copper substrate for various functional purposes. The superconductor is first prepared by mechanically alloying elemental components (yttrium, barium, and copper) for 50 hours in a high-energy ball mill with subsequent protocol of heat treatment in an oxygen-rich atmosphere to arrive at stoichiometric ratios of YBa2Cu3O7. The material is then deposited on a thin copper substrate also by ball milling under various parameters of rotational speed and deposition time to select the best and most homogenous substrate coverage. Atomic force microscopy has confirmed the desired results, and other microstructural, thermal, and electrical techniques are used to characterize the obtained material. High-energy ball milling proved to be a versatile means to synthesize and deposit the material in a straightforward manner and controllable parameters for different deposit thicknesses and coverages.

  18. Chemical reactions of metal powders with organic and inorganic liquids during ball milling

    Science.gov (United States)

    Arias, A.

    1975-01-01

    Chromium and/or nickel powders were milled in metal chlorides and in organic liquids representative of various functional groups. The powders always reacted with the liquid and became contaminated with elements from them. The milled powders had specific surface areas ranging from 0.14 to 37 sq m/g, and the total contamination with elements from the milling liquid ranged from 0.01 to 56 weight percent. Compounds resulting from substitution, addition, or elimination reactions formed in or from the milling liquid.

  19. Synthesis and hydrogen storage properties of mechanically ball-milled SiC/MgH{sub 2} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, H., E-mail: hi-khm@yamaguchi-u.ac.j [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611 (Japan); Nakatomi, S.; Hashimoto, Y.; Kitazawa, I.; Sakata, Y. [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611 (Japan); Mae, H.; Fujimoto, M. [Yamaguchi Prefectural Industrial Technology Institute, 4-1-1 Asutopia, Ube 755-0195 (Japan)

    2009-11-20

    The hydrogen storage characteristics of SiC/MgH{sub 2} nanocomposites which are prepared by mechanical ball milling of MgH{sub 2} and SiC with cyclohexane have been studied. MgH{sub 2} as a starting material exhibited a desorption peak of hydrogen at 705 K in thermal desorption spectrometry (TDS), while the ball-milled SiC/MgH{sub 2} nanocomposites showed much lower desorption temperatures near 437 K. The hydrogen storage properties of SiC/MgH{sub 2} were significantly improved as a result of nanocomposite formation. In addition, the nanocomposites were characterized by X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimeter (DSC) and pressure-composition isotherm (PCT) measurements. For the SiC/MgH{sub 2} nanocomposites, the reversibility of hydrogen absorption/desorption was observed, but heating above 573 K led to the irreversible breakdown of nanocomposites into MgH{sub 2} and SiC.

  20. Synthesis of magnetically exchange coupled SrFe12O19/FeCo composites through cryogenic ball milling

    Science.gov (United States)

    Pang, Ning; Ye, Feng; Jiang, Ying

    2017-07-01

    SrFe12O19/FeCo composite particles with different mass ratios of SrFe12O19 to FeCo were synthesized through a cryogenic ball milling process. The corresponding products were characterized with scanning electron microscopy (SED), transmission electron microscopy (TEM), x-ray diffraction (XRD) and vibrating sample magnetometer (VSM) for crystal morphology, elemental distribution, crystal phases, and magnetic properties. The results showed that when the mass percentage of FeCo was less than 15%, smooth magnetic hysteresis loops could be obtained from SrFe12O19/FeCo composite particles, indicating effective magnetic exchange coupling between the SrFe12O19 and FeCo particles. A further FeCo mass increase resulted in kinks in the magnetic hysteresis loop and destroyed the magnetic exchange coupling. As a comparison, room temperature ball milling of SrFe12O19/FeCo (95/5 wt%) cannot achieve magnetic exchange coupling between SrFe12O19 and FeCo due to FeCo nanoparticle agglomeration.

  1. 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.

  2. 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 (0.176 mg/g), tanshinone I (0.181 mg/g), and tanshinone II A (0.421 mg/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 5-8 ng/mL, were respectively obtained. Application of ball mill-assisted deep eutectic solvent-based extraction may fundamentally shape the future development of extraction methods.

  3. Effects of supercritical water and mechanochemical grinding treatments on physicochemical properties of chitin.

    Science.gov (United States)

    Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide

    2013-02-15

    This study examined the effects of a combined pretreatment with supercritical water and mechanochemical grinding with a ball mill on the physicochemical properties of chitin and its enzymatic degradation. Following pretreatment with a combination of supercritical water and grinding, chitin had a lower mean molecular weight, a lower crystallinity index, a lower crystallite size, greater d-spacing, weaker hydrogen bonds, and the amide group was more exposed compared with untreated chitin. These properties increased the hydrophilicity of the chitin and enhanced its enzymatic degradation. The N,N'-diacetylchitobiose (GlcNAc)(2) yield after enzymatic degradation of chitin following pretreatment with supercritical water (400 °C, 1 min) and grinding (800 rpm, 10 min) was 93%, compared with 5% without any treatment, 37% with supercritical water pretreatment alone (400 °C, 1 min), and 60% with grinding alone (800 rpm, 30 min).

  4. Spin-glass-like behaviour in ball milled Fe{sub 30}Cr{sub 70} alloy studied by ac magnetic susceptibility

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Blanco, D.; Gorria, P. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Fernandez-Martinez, Alejandro [Lawrence Livermore National Laboratory 7000 East Avenue, Livermore, CA 9455 (United States); Perez, M.J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Cuello, Gabriel J. [Institut Laue-Langevin, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Blanco, J.A., E-mail: jabr@uniovi.es [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)

    2011-06-15

    Research highlights: > Spin-glass-like behaviour o owing an re-entrant spin-glass transition. > No critical divergence observed in the maxima of the real and magnetic susceptibility on ball milled Fe{sub 30}Cr{sub 70}. > High temperature Curie-Weiss behavior of the magnetic susceptibility on ball milled Fe{sub 30}Cr{sub 70}. > Moderate shift of the freezing temperature per frequency in ball milled Fe{sub 30}Cr{sub 70} obtained from the temperature dependence of the real magnetic susceptibility - Abstract: Nominal nanostructured Fe{sub 30}Cr{sub 70} obtained from ball milling during 110 h has been investigated from dc magnetization and ac magnetic susceptibility. The as-milled sample is not monophasic and is formed of two phases, Fe{sub 20{+-}2}Cr{sub 80{+-}2} ({approx}86 {+-} 2%) and iron ({approx}14 {+-} 2%). The ac susceptibility measurements show evidence of a re-entrant spin-glass-like transition for the Fe{sub 20}Cr{sub 80} phase below 30 K. The shift of the freezing temperature per frequency decade is moderate when compared to that found in conventional spin-glass alloys. A Vogel-Fulcher activation process can be used to explain the frequency variation. The results are also analyzed in terms of Cole-Cole formalism for extracting information of relaxation time ({tau} {approx} 10{sup -5} to 10{sup -4} s).

  5. Nanoscale characterisation and clustering mechanism in an Fe-Y{sub 2}O{sub 3} model ODS alloy processed by reactive ball milling and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Brocq, M., E-mail: mathilde.brocq@cea.fr [CEA, DEN, DMN, Service de Recherches de Metallurgie Physique, F-91191 Gif-sur-Yvette (France); Radiguet, B.; Le Breton, J.-M.; Cuvilly, F.; Pareige, P. [Universite et INSA de Rouen, Groupe de Physique des Materiaux - UMR 6634 CNRS, 76801 Saint Etienne du Rouvray (France); Legendre, F. [CEA, DEN, DMN, Service de Recherches de Metallurgie Physique, F-91191 Gif-sur-Yvette (France)

    2010-03-15

    Reactive ball milling and annealing is proposed as a new production method for oxide dispersion strengthened (ODS) steels. A highly concentrated Fe-38 atm.% Y{sub 2}O{sub 3} ODS model alloy was processed by reactive ball milling and annealing of YFe{sub 3} and Fe{sub 2}O{sub 3} powders so as to induce the chemical reaction 2YFe{sub 3} + Fe{sub 2}O{sub 3} {yields} 8Fe + Y{sub 2}O{sub 3}. The model alloy was characterised after milling and annealing by complementary techniques, including atom probe tomography. Ball milling up to the stationary state results in the formation of two metastable nanometric interconnected phases: super-saturated {alpha}-iron and an yttrium and oxygen rich phase. Annealing leads the system towards equilibrium through: (i) a chemical evolution of each phase to nearly pure {alpha}-Fe and Y{sub 2}O{sub 3} oxide slightly sub-stoichiometric in oxygen; and (ii) growth of the phases. A pure iron matrix reinforced by nanometric Y{sub 2}O{sub 3} particles was successfully synthesised by reactive ball milling and annealing.

  6. Characteristics of the Ti1.27Fe + 11 wt.% Ni Composite Obtained by Arc Melting and Ball Milling

    Directory of Open Access Journals (Sweden)

    J. Bonifacio-Martínez

    2013-01-01

    Full Text Available The Ti1.27Fe + 11 wt.% Ni composite synthesized by arc melting and ball milling and its possible use in hydrogen storage were studied. First the intermetallic Ti1.27Fe was obtained from elemental powders of Ti and Fe by using the arc melting in argon atmosphere and was cracked in a reactor, after that nickel powder was added to the Ti1.27Fe alloy before the milling. The mixture was subjected to high-energy ball milling to produce the Ti1.27Fe/Ni composite. Nanocrystalline phases Ti1.27Fe + Ni were observed after 5 h of milling. Hydrogenation results indicated that in the first cycle of hydriding the maximum amount of hydrogen release was 2.10 wt.% for the composite at 100∘C, under hydrogen pressure of 0.8 MPa and without prior activation.

  7. 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.

  8. Reactive-inspired ball-milling synthesis of an ODS steel: study of the influence of ball-milling and annealing; Synthese et caracterisation d'un acier ODS prepare par un procede inspiredu broyage reactif: etude de l'influence des conditions de broyage et recuit

    Energy Technology Data Exchange (ETDEWEB)

    Brocq, M.

    2010-10-15

    In the context of the development of new ODS (Oxide Dispersion Strengthened) steels as core materials in future nuclear reactors, we investigated a new process inspired by reactive ball-milling which consists in using YFe{sub 3} andFe{sub 2}O{sub 3} as starting reactants instead of Y{sub 2}O{sub 3} to produce a dispersion of nano-oxides in a steel matrix and the influence of synthesis conditions on the nano-oxide characteristics were studied. For that aim, ODS steels were prepared by ball-milling and then annealed. Multi-scale characterizations were performed after each synthesis step, using notably atom probe tomography and small angle neutron scattering. The process inspired by reactive ball-milling was shown to be efficient for ODS steel synthesis, but it does not modify the nano-oxide characteristics as compared to those of oxides directly incorporated in the matrix by ball-milling. Broadly speaking, the nature of the starting oxygen bearing reactants has no influence on nano-oxide formation. Moreover, we showed that the nucleation of nano-oxides nucleation can start during milling and continues during annealing with a very fast kinetic. The final characteristics of nano-oxides formed in this way can be monitored through ball-milling parameters (intensity, temperature and atmosphere) and annealing parameters (duration and temperature). (author)

  9. 斜轧中铬半钢磨球的冲击疲劳和磨损性%Impact Fatigue Resistance and Abrasiveness of Cross Rolled Medium Chromium Semi-Steel for Grinding Ball

    Institute of Scientific and Technical Information of China (English)

    李慧

    2001-01-01

    The repeated low-energy impact fatigue resistance and abrasiveness of cross rolled 1.85%C - 5.86%Cr medium chromium semi-steel have been studied. The results indicated that the impact fatigue life of cross rolled medium chromium semi-steel grinding ball is higher than that of casting grinding ball, and the higher impact fatigue resistance and abrasiveness of ball could be got by adequate rolled residual heat treated.%通过落球和冲击磨损试验,研究了斜轧1.85%C、5.86%Cr中铬半钢磨球的抗小能量多冲击破坏能力和耐磨性。结果表明:斜轧中铬半钢磨球的冲击疲劳寿命高于铸造半钢磨球。该球经适当的热轧余热热处理,可获得较高的抗多冲击破坏能力与耐磨性能。

  10. Spark plasma sintered Sm(2)Co(17)-FeCo nanocomposite permanent magnets synthesized by high energy ball milling.

    Science.gov (United States)

    Sreenivasulu, G; Gopalan, R; Chandrasekaran, V; Markandeyulu, G; Suresh, K G; Murty, B S

    2008-08-20

    Nanocomposite Sm(2)Co(17)-5 wt% FeCo magnets were synthesized by high energy ball milling followed by consolidation into bulk shape by the spark plasma sintering technique. The evolution of magnetic properties was systematically investigated in milled powders as well as in spark plasma sintered samples. A high energy product of 10.2 MGOe and the other magnetic properties of M(s) = 107 emu g(-1), M(r) = 59 emu g(-1), M(r)/M(s) = 0.55 and H(c) = 6.4 kOe were achieved in a 5 h milled and spark plasma sintered Sm(2)Co(17)-5 wt% FeCo nanocomposite magnet. The spark plasma sintering was carried out at 700 °C for 5 min with a pressure of 70 MPa. The nanocomposite showed a higher Curie temperature of 955 °C for the Sm(2)Co(17) phase in comparison to its bulk Curie temperature for the Sm(2)Co(17) phase (920 °C). This higher Curie temperature can improve the performance of the magnet at higher temperatures.

  11. 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.

  12. 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.

  13. Effects of high energy ball milling on synthesis and characteristics of Ti-Mg alloys

    CSIR Research Space (South Africa)

    Chikwanda, HK

    2008-01-01

    Full Text Available The synthesis of Ti-Mg alloys using mechanical alloying method has been investigated. Effects of the mechanical alloying parameters on the resultant microstructural features have been studied. This work presents the effects of milling speed...

  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. 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.

  16. Orange-red light emitting europium-doped calcium molybdate phosphor prepared by high-energy ball milling

    Science.gov (United States)

    Hong, Woo Tae; Lee, Joo Hyun; Park, Jin Young; Yang, Hyun Kyoung; Jeong, Jung Hyun; Moon, Byung Kee

    2016-09-01

    Europium-doped calcium molybdates (CaMoO4:Eu3+) were successfully synthesized by a high-energy ball milling method. The x-ray diffraction patterns confirmed their powellite structure, and the field emission scanning electron microscope image exhibited the spherical particles with submicron size. The photoluminescence (PL) properties of Eu3+ in these phosphors were also studied by analyzing the excitation and emission spectra for the effect of europium concentration. The CaMoO4:Eu3+ PL excitation and PL spectra show charge transfer band and several transition peaks correlated with host lattice band gap and f-f transitions of Eu3+, respectively. By sintering Ca0.95MoO4:0.05Eu3+ phosphor at 1200°C, PL intensity has a maximum value at 618 nm with Commision Internationale de I'Eclairage 1931 (CIE 1931) chromaticity coordinates (0.609, 0.343).

  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. Influence of Process Control Agent on Characterization and Structure of Micron Chitosan Powders Prepared by Ball Milling Method

    Directory of Open Access Journals (Sweden)

    ZHANG Chuan-jie

    2016-12-01

    Full Text Available With ethyl alcohol or distilled water as process control agent (PCA, micron chitosan powder was prepared by ball milling method. The yield rate, particle size distribution, micro morphology, viscosity average molecular mass, chemical and crystal structures, and thermal properties of these different micron chitosan powders were measured. The results indicate that the yield rate of micron chitosan powders prepared with ethyl alcohol as PCA increases significantly, and improves to 94.7% from 25% while the amount of ethyl alcohol is 0.75mL/g. The particle size distribution of micron chitosan powder prepared with ethyl alcohol as PCA is concentrated, while the D50 and D90 in size are 824nm and 1629nm respectively. Chitosan do not react with ethyl alcohol used as PCA, but the viscosity average molecular mass of prepared micron chitosan powder decreases by 23%, the crystal structures are destroyed slightly, and its thermal stability is slightly weakened.

  19. 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

  20. Sulfur-graphene nanostructured cathodes via ball-milling for high-performance lithium-sulfur batteries.

    Science.gov (United States)

    Xu, Jiantie; Shui, Jianglan; Wang, Jianli; Wang, Min; Liu, Hua-Kun; Dou, Shi Xue; Jeon, In-Yup; Seo, Jeong-Min; Baek, Jong-Beom; Dai, Liming

    2014-10-28

    Although much progress has been made to develop high-performance lithium-sulfur batteries (LSBs), the reported physical or chemical routes to sulfur cathode materials are often multistep/complex and even involve environmentally hazardous reagents, and hence are infeasible for mass production. Here, we report a simple ball-milling technique to combine both the physical and chemical routes into a one-step process for low-cost, scalable, and eco-friendly production of graphene nanoplatelets (GnPs) edge-functionalized with sulfur (S-GnPs) as highly efficient LSB cathode materials of practical significance. LSBs based on the S-GnP cathode materials, produced by ball-milling 70 wt % sulfur and 30 wt % graphite, delivered a high initial reversible capacity of 1265.3 mAh g(-1) at 0.1 C in the voltage range of 1.5-3.0 V with an excellent rate capability, followed by a high reversible capacity of 966.1 mAh g(-1) at 2 C with a low capacity decay rate of 0.099% per cycle over 500 cycles, outperformed the current state-of-the-art cathode materials for LSBs. The observed excellent electrochemical performance can be attributed to a 3D "sandwich-like" structure of S-GnPs with an enhanced ionic conductivity and lithium insertion/extraction capacity during the discharge-charge process. Furthermore, a low-cost porous carbon paper pyrolyzed from common filter paper was inserted between the 0.7S-0.3GnP electrode and porous polypropylene film separator to reduce/eliminate the dissolution of physically adsorbed polysulfide into the electrolyte and subsequent cross-deposition on the anode, leading to further improved capacity and cycling stability.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Huimei; Xu, Lingyun; Chen, Guijie; Peng, Chuanyi [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); Ke, Fei [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); School of Science, Anhui Agricultural University, Hefei 230036 (China); Liu, Zhengquan; Li, Daxiang; Zhang, Zhengzhu [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); Wan, Xiaochun, E-mail: xcwan@ahau.edu.cn [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China)

    2016-07-01

    Highlights: • Ultrafine tea powder (UTP) was prepared by ball-milling. • A novel and high efficient biosorbent from ultrafine tea powder (UTP) for the removal of fluoride from drinking water was prepared. • Loaded ultrafine tea powder adsorbed more fluoride adsorption than loaded tea waste. • UTP-Zr performed well over a considerably wide pH range, from 3.0 to 10.0. • UTP-Zr retains Zr metal ion during defluoridation, limiting secondary pollution. - Abstract: 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.

  2. Dielectric and photocatalytic properties of sulfur doped TiO{sub 2} nanoparticles prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Jalalah, Mohammed [Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Electrical Engineering Department, College of Engineering, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Faisal, M. [Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Bouzid, Houcine [Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Department of Physics, Faculty of Sciences and Arts, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Ismail, Adel A., E-mail: adelali141@yahoo.com [Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Nanostructured and Nanotechnology Materials Division, Central Metallurgical R and D Institute, CMRDI, P.O. Box 87, Helwan, 11421, Cairo (Egypt); Chemistry Department, Science and Art at Sharurah, Najran University (Saudi Arabia); Al-Sayari, Saleh A. [Promising Centre for Sensors and Electronic Devices (PCSED), Advanced Materials and Nano-Research Centre, Najran University, P.O. Box 1988, Najran, 11001 (Saudi Arabia); Chemistry Department, Science and Art at Sharurah, Najran University (Saudi Arabia)

    2013-09-01

    Graphical abstract: - Highlights: • Designing of visible light responsive photocatalyst utilizing ball milling. • Sulphur used as dopant in commercial TiO{sub 2} 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 TiO{sub 2} shows 3-times higher activity than that of TiO{sub 2} P25. - Abstract: Sulfur (S) doped commercial TiO{sub 2} 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 TiO{sub 2}. The optical absorption edge of S-doped TiO{sub 2} was red shifted with indirect bandgap energy of 2.8 eV. The dielectric studies confirm that the dielectric constant of TiO{sub 2} increases after doping, however it becomes more conductive. Newly designed S-doped TiO{sub 2} 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 TiO{sub 2} was significantly 3-times higher than that of commercial TiO{sub 2} 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 TiO{sub 2}.

  3. 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.

  4. Significantly improved dehydrogenation of ball-milled MgH2 doped with CoFe2O4 nanoparticles

    Science.gov (United States)

    Shan, Jiawei; Li, Ping; Wan, Qi; Zhai, Fuqiang; Zhang, Jun; Li, Ziliang; Liu, Zhaojiang; Volinsky, Alex A.; Qu, Xuanhui

    2014-12-01

    CoFe2O4 nanoparticles are added to magnesium hydride (MgH2) by high-energy ball milling in order to improve its hydriding properties. The hydrogen storage properties and catalytic mechanism are investigated by pressure-composition-temperature (PCT), differential thermal analysis (DTA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The nonisothermal desorption results show that the onset desorption temperature of the MgH2 + 7 mol% CoFe2O4 is 160 °C, which is 200 °C lower than of the as-received MgH2. The dehydrogenation process of the MgH2 doped with the CoFe2O4 nanoparticles includes two steps. DTA curves and XRD patterns reveal that a chemical reaction happens between MgH2 and CoFe2O4, forming the final products of the ternary combination, corresponding to Co3Fe7, MgO and Co. The onset desorption temperature of the ball-milled MgH2 doped with Co3Fe7, MgO and Co is about 260 °C, approximately 100 °C lower than the un-doped MgH2, demonstrating that the ternary combination (Co3Fe7, MgO, and Co) also has a great catalytic effect on the MgH2 hydrogen storage properties. It is also confirmed that the various methods of adding the ternary combination have different effects on the MgH2 hydriding-dehydriding process.

  5. Hydroamination reactions of alkynes with ortho-substituted anilines in ball mills: synthesis of benzannulated N-heterocycles by a cascade reaction.

    Science.gov (United States)

    Weiße, Maik; Zille, Markus; Jacob, Katharina; Schmidt, Robert; Stolle, Achim

    2015-04-20

    It was demonstrated that ortho-substituted anilines are prone to undergo hydroamination reactions with diethyl acetylenedicarboxylate in a planetary ball mill. A sequential coupling of the intermolecular hydroamination reaction with intramolecular ring closure was utilized for the syntheses of benzooxazines, quinoxalines, and benzothiazines from readily available building blocks, that is, electrophilic alkynes and anilines with OH, NH, or SH groups in the ortho position. For the heterocycle formation, it was shown that several stress conditions were able to initiate the reaction in the solid state. Processing in a ball mill seemed to be advantageous over comminution with mortar and pestle with respect to process control. In the latter case, significant postreaction modification occurred during solid-state analysis. Cryogenic milling proved to have an adverse effect on the molecular transformation of the reagents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. 金属矿磨矿设备研究与应用新进展%The Research in the Research & Application of Metal Mine Grinding Equipment

    Institute of Scientific and Technical Information of China (English)

    刘琨

    2014-01-01

    阐述了近年来国内外金属矿山磨矿设备的研究和应用进展,涉及自磨(半自磨)机、球磨机和搅拌磨机等,主要综述了磨矿设备在大型化方面的研究与发展,介绍了国内外典型的应用情况。%This article elaborates the progress in the application and research of metal mine grinding equipment at home and abroad in recent years. The involved equipments are (semi) autogeneous mill, ball mill, agitating mill, vertical mill and Isa mill. We mainly talk about the achievement of grinding attachment in large-scale and introduce the typical examples at home and abroad.

  7. Synthesis, characterization and performance of high energy ball milled meso-scale zero valent iron in Fenton reaction.

    Science.gov (United States)

    Ambika, Selvaraj; Devasena, M; Nambi, Indumathi Manivannan

    2016-10-01

    Understanding contaminant degradation by different sized zero valent iron (ZVI) particles is one important aspect in addressing the long-term stability of these particles in field studies. In this study, meso zero valent iron (mZVI) particles were synthesised in a milling time of 10 h using ball milling technique. The efficacy of mZVI particles for removal of phenol was quantitatively evaluated in comparison with coarse zero valent iron (cZVI) and nano zero valent iron (nZVI) particles. Phenol degradation experiments were carried out in sacrificial batch mode at room temperature independently with cZVI, nZVI and mZVI under varied pH conditions of 3, 4, 6, 7, 8 and 10. Batch experiments substantiating the reactivity of mZVI under unbuffered pH system were also carried out and compared with buffered and poorly buffered pH systems. mZVI particles showed consistent phenol degradation at circum-neutral pH with efficiency of 44%, 67%, and 89% in a span of 5, 10 and 20 min respectively. The dissolved iron species and residual iron formation were also measured as a function of pH. Unbuffered systems at circum-neutral pH produced less residual iron when compared to buffered and poorly buffered systems. At this pH, oxidation of Fe(2+) produced a different oxidant Ferryl ion, which was found to effectively participate in phenol degradation.

  8. Textured PrCo{sub 5} nanoflakes with large coercivity prepared by low power surfactant-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Wen-Liang, E-mail: wlzuo@iphy.ac.cn; Liu, Rong-Ming; Zheng, Xin-Qi; Wu, Rong-Rong; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen, E-mail: shenbg@aphy.iphy.ac.cn [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-05-07

    The effect of the milling time on the structure, morphology, coercivity, and remanence ratio of textured PrCo{sub 5} nanoflakes produced by low power surfactant-assisted ball milling (SABM) was investigated. The X-ray powder diffraction (XRD) patterns indicate that the SABM PrCo{sub 5} samples are all CaCu{sub 5}-type hexagonal structure. The average grain size is smaller than 10 nm when the SABM time is equal to or longer than 5.5 h. The thickness of nanoflakes is mainly in the range of 50−100 nm while the length is 0.5−5 μm when the SABM time reaches 8 h. For the field-aligned PrCo{sub 5} nanoflakes, the out-of-plane texture is indicated from the increasing (0 0 l) peaks in the XRD patterns, and the easy magnetization direction is perpendicular to the flake surface. The strong texture of PrCo{sub 5} nanoflakes leads to a large coercivity H{sub c} (7.8 kOe) and obvious anisotropic magnetic behaviors for the aligned samples.

  9. Preparation of Mg-MgH2 flakes by planetary ball milling with stearic acid and their hydrogen storage properties

    Science.gov (United States)

    Hong, Seong-Hyeon; Song, Myoung Youp

    2016-05-01

    Many studies preparing magnesium hydride using catalyst addition were performed, resulting in the preparation of additive-containing magnesium hydride. Preparation of a sample with a MgH2 phase without additives requires high pressure and high temperature and is time-demanding. In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named 90Mg+10MgH2) was milled under a hydrogen atmosphere with 6 wt% stearic acid as a process-controlling agent, which led to a formation of Mg-MgH2 flakes. The hydrogen storing and releasing properties of the prepared flakes were investigated and compared with those of purchased MgH2. A sample with a majority fraction of MgH2 phase was prepared by planetary ball milling of 90 Mg+10 MgH2 with 6 wt% stearic acid. The resultant particles of 90 Mg+10 MgH2 obtained after hydridingdehydriding cycling were much smaller and had significantly more cracks and defects than those of MgH2 after hydriding-dehydriding cycling. 90 Mg+10 MgH2 released 0.12 wt% hydrogen for 4 min, 3.70 wt% for 20 min, and 5.30 wt% for 60 min at 648 K at the first cycle.

  10. 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, ...

  11. Studies on hydrogen generation characteristics of hydrolysis of the ball milling Al-based materials in pure water

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Mei-Qiang [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian (China). Materials and Thermochemistry Laboratory; Graduate School of the Chinese Academy of Sciences, Beijing (China); Xu, Fen; Sun, Li-Xian [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian (China). Materials and Thermochemistry Laboratory

    2007-09-15

    In this paper, a series of Al-based materials were prepared by ball milling and/or melting. The XRD, SEM and TG-DTA techniques were used for sample analyses. Effects of different metals such as Zn, Ca, Ga, Bi, Mg, In and Sn on the hydrogen generation through hydrolysis of the Al alloy were evaluated in pure water. The results showed that mechanical milling was more favorable than the melting method to synthesize the Al alloys containing some metals with lower melting point and easier vaporization in the melting process. Addition of Bi and Sn could more significantly enhance Al reactivity with water in Al alloy than other metals such as Zn, Ca and Ga. Especially Al-Bi alloy had a faster hydrolysis rate than Al-Sn alloy at room temperature. For Al-Bi alloy, the addition of Zn and Ga accelerated the alloy hydrolysis while the effect of addition of other metals (Sn, In, Mg) on the hydrolysis of the alloy was reverse. Furthermore, the effect of some compounds (NaCl, MgCl{sub 2}, CaH{sub 2}) on the hydrolysis of the Al-Bi alloy was explored. It showed that the milling Al-Bi alloy together with the compounds could accelerate the formation of its mico-galvanic cell between the anode (Al) and cathode (Bi). The alloy composition was therefore optimized to be Bi, Zn, Ga, CaH{sub 2} and Al. The optimized Al alloy demonstrated a high hydrogen generation rate and theoretic hydrogen yields. (author)

  12. Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acid-assisted mechanical ball-milling process

    Science.gov (United States)

    Phoohinkong, Weerachon; Pavasupree, Sorapong; Wannagon, Anucha; Sanguanpak, Samunya; Boonyarattanakalin, Kanokthip; Mekprasart, Wanichaya; Pecharapa, Wisanu

    2017-09-01

    In this work activated ilmenite nanoparticles were prepared by chemical-assisted in mechanical ball-milling process from ilmenite ore as starting raw material. The effect of milling process on their phase composition, particle size, surface morphology and local structure were investigated. Phase identification and crystalline structure of ilmenite mineral, milled samples and subsequent leached residues were characterized by x-ray diffraction (XRD). Meanwhile, the distorted octahedral structure and the oxidation state of relevant elements in ilmenite ore and activated ilmenite obtained by different process conditions were analyzed by x-ray absorption spectroscopy (XAS). Particle size and morphologies of the samples were monitored by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Three dominant peaks of TiO2 rutile, FeTiO3, and Fe2TiO4 are obviously adulterated in XRD patterns after mechanical milling with water and acid solution when comparing to precursor mineral. However, the contaminated phase of FeTiO3 and Fe2TiO4 was readily decreased by acid-assisted mechanical ball-milling. The enhancement in leaching process of ilmenite residue after milling can be obtained with sulfuric acid. This result suggests that iron contaminated phase could be leached from the sample resulting to the decrease in Fe environment around Ti atom. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  13. 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.

  14. Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun; Jensen, Peter Arendt

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size......, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed...... of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (mass loss of 10–56 wt % and size reduction of 20–60%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle morphology...

  15. Investigation and characterization of ball-milled magnesium-based hydrides for hydrogen storage materials

    Science.gov (United States)

    Yang, Jing

    2011-12-01

    Three alloys are prepared through mechanical alloying and the hydrogen storage properties have been investigated systematically. In Mg-Ni and Mg-Ni-Fe alloys, the main binary alloy phase is Mg2Ni, while in Mg-Ni-Fe-Ti alloys, NiTi, FeTi are also found as the main binary phases beside Mg 2Ni. The hydrogen absorption capacities of the three alloys are 2.9wt%, 2.2wt% and 2.3wt% respectively. Absorption content increases with the increasing of milling time, which also increases the amorphous degree of the alloys. The amorphous degree increasing is unfavorable to improve hydrogen storage capacity. Longer milling time will contribute to a higher hydriding/dehydriding rate at a constant temperature. The alloys exhibit a different hydriding behavior when temperature was increased from 473K to 673K. The alloys particles became finer after long time milling, which led to a decrease in the different distance of the hydrogen atoms.

  16. 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.

  17. 卧式搅拌磨搅拌叶轮形状对粉碎效果的影响%Effect of Blade Shape of Horizontal Stirred Mill on Grinding Efficiency

    Institute of Scientific and Technical Information of China (English)

    李茂林; 杨鑫; 崔瑞

    2012-01-01

    The effects of blade shape of horizontal stirred mill on grinding efficiency were studied. Three type of impellers were designed. The particle size and grinding capacity in same power was inspected in different stirring speed Comparing the test date, the impeller with circular holes gives the best performance on ultrafine grinding. It is the best shape of this three stirrer impellers for horizontal stirred mill on ultrafine grinding. In the energy input nearly the same circumstances,the impeller with circular holes gives the best energy utilization and yield in particle size of 1-15 u.m.%研究卧式搅拌磨的搅拌叶轮形状对磨矿效果的影响,设计3种搅拌叶轮,在不同搅拌速度的条件下,考察磨矿产品的粒度与能量新生能力.通过对比发现,3种叶轮中圆形孔叶轮的细磨效果最好,磨矿性能最优,是比较适合卧式搅拌磨机进行超细磨的搅拌叶轮形状;在能量输入基本一致的情况下,圆形孔叶轮在1~15 μm粒级能量利用率最高,产率最大.

  18. 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.

  19. Thermoelectric properties of polythiophene/MWNT composites prepared by ball-milling

    Science.gov (United States)

    Wang, Dagang; Wang, Lei; Wang, Wenxin; Bai, Xiaojun; Li, Junqin

    2012-04-01

    Polythiophene /multi-wall carbon nanotubes (MWNT) composites were prepared by ball-mailing. The morphology and internal structure of the composites were evaluated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD). Their thermoelectric properties, i.e., the electrical conductivity, the Seebeck coefficient and the thermal conductivity, were investigated in detail. The remarkably increased electrical conductivity, the slightly increased Seebeck coefficient and the relatively insensitive thermal conductivity with increasing MWNT content led to an obvious enhancement in the thermoelectric figure of merit. The results showed that the MWNT were uniformly dispersed in the polymer matrix, and that increasing the electrical conductivity is the key factor for enhancing the thermoelectric figure of merit. This study suggested a simple way to improve the thermoelectric performances of conducting polymers.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kotan, Hasan, E-mail: hkotan@ncsu.edu [Department of Materials Science and Engineering, NC State University, 911 Partners Way, Room 3078, Raleigh, NC 27606-7907 (United States); Darling, Kris A. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, RDRL-WMM-F, Aberdeen Proving Ground, MD 21005-5069 (United States); Saber, Mostafa; Koch, Carl C.; Scattergood, Ronald O. [Department of Materials Science and Engineering, NC State University, 911 Partners Way, Room 3078, Raleigh, NC 27606-7907 (United States)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer Pure Fe, Fe{sub 92}Ni{sub 8}, and Fe{sub 91}Ni{sub 8}Zr{sub 1} powders were hardened up to 10 GPa by ball milling. Black-Right-Pointing-Pointer Annealing of Fe and Fe{sub 92}Ni{sub 8} leads to reduced hardness and extensive grain growth. Black-Right-Pointing-Pointer The addition of Zr to Fe{sub 92}Ni{sub 8} increases its stability and strength by second phases. Black-Right-Pointing-Pointer The second phases are found to promote the stability of Fe{sub 91}Ni{sub 8}Zr{sub 1} by Zener pinning. Black-Right-Pointing-Pointer The Zr-containing precipitates contribute to the overall strength of the material. - Abstract: Grain growth of ball-milled pure Fe, Fe{sub 92}Ni{sub 8}, and Fe{sub 91}Ni{sub 8}Zr{sub 1} 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 Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy to be much less than that of pure Fe and the Fe{sub 92}Ni{sub 8} alloy at elevated temperatures. The microstructure of the ternary Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy remains nanoscale up to 700 Degree-Sign C where only a few grains grow abnormally whereas annealing of pure iron and the Fe{sub 92}Ni{sub 8} alloy leads to extensive grain growth. The grain growth of the ternary alloy at high annealing temperatures is coupled with precipitation of Fe{sub 2}Zr. 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 Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy drastically when the grain size is above nanoscale.

  1. 基于LABVIEW的球磨机筒体应力测试系统%Stress measuring system for barrels of ball mills based on LABVIEW

    Institute of Scientific and Technical Information of China (English)

    李斌; 董为民

    2011-01-01

    研究开发了基于LABVIEW平台的球磨机测试系统,结合有限元分析结果,在球磨机筒体关键处进行了应力测量与分析,为提高筒体设计效率和寿命提供了试验依据.%The paper develops a measuring system for ball mills based on LABVIEW, and carries out stress measurement and analysis at key points of the barrel of a ball mill in combination with the finite element analysis results, which offers experimental data for improving the designing efficiency and the lifespan of the barrel.

  2. 大型塔式磨机在金精矿氰化细磨中的应用%Application of Large Tower Mill in Cyanide Fine Grinding of Gold Concentrate

    Institute of Scientific and Technical Information of China (English)

    姚福善

    2014-01-01

    Tower mill is a type of fine grinding equipment with vertical fixed installation,cylinder fixed and helical mixing device.Because gold and silver particles is fine in gold concentrate,and most of gold and silver minerals with even had body and inclusions form coexist with pyrite,fully grinding of gold concentrate is necessary in order to improve grinding fineness,make gold and silver particles fully naked,and achieve the effect of monomer dissociation.During the process of cyanide gold concentrate,due to the large increase in degree of dissociation,gold and silver are leached thoroughly,thus cyanide recovery.Tower grinding machine has the advantage of low energy consumption,grinding fine granularity,low noise,occupies less space,easy maintenance, easy installation and high grinding efficiency,therefore,it is ideal fine grinding mill in cyanide fine grinding.%塔式磨机是一种垂直安装、筒体固定及内带螺旋搅拌装置的搅拌型细磨设备。由于金精矿中金、银颗粒比较细,金、银矿物大多以连生体和包裹体形式与黄铁矿共存,需要对金精矿进行充分研磨,提高磨矿细度,使金、银颗粒充分裸露,达到单体解离的效果。在金精矿氰化过程中,解离度的大幅提高,可使金、银浸出彻底,氰化回收率随之提高。塔式磨机具有能耗低、磨矿粒度细、噪音低、占用空间少、易维护、便于安装及磨矿效率高等优点,因此是金精矿氰化细磨的理想磨机。

  3. On the Design of QM3500X6000P Large Ball Mill%浅谈QM3500X6000P大型球磨机的设计

    Institute of Scientific and Technical Information of China (English)

    崔向东; 赵红美

    2012-01-01

    介绍了QM3500X6000P大型球磨机的工作原理、主要参数的确定、起动特点及其起动力矩校核的新方法。%This thesis introduces the working principle of QM3500X6000P large ball mill, the confirmation of main parameter, starting characteristics and a new method of checking starting torque.

  4. 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.

  5. 溢流型球磨机物料检测方法的研究%Detection Method of Materials in the Overflow Ball Mill

    Institute of Scientific and Technical Information of China (English)

    高莹

    2014-01-01

    对溢流型球磨机工作过程中出现给料过多的情况进行原因分析,针对这些原因给出可能解决问题的方案,再根据实际情况分析方案的合理性,并在实际设计和现场调试过程中采用相应的方案,使溢流型球磨机与物料输送系统之间建立联锁关系,实现必要的联锁控制,给出联锁控制的流程图和PLC程序梯形图。最后给出了现场实际应用的效果。%As a crushing equipment , ball mill has been widely applied in the mining and chemical industries . Overflow ball mill is one of the equipments w hich have been used earlier and commonly . During the practi-cal application in the mines , due to over feeding , the ball mills are overloaded , broken and even broken dow n . T he thesis has analyzed the reasons of over feeding , and brought up the solutions accordingly . Then , based on the actual situation on site , the most reasonable and effective solution will be selected . During the designing and commissioning , the solution will be applied and established interlocking relation-ships between the overflow ball mill and the material transfer system . Control flow diagram and PLC pro-gram diagram will be provided as well .

  6. Comparison of particle sizes between 238PuO2 before aqueous processing, after aqueous processing, and after ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta Nancy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    Particle sizes determined for a single lot of incoming Russian fuel and for a lot of fuel after aqueous processing are compared with particle sizes measured on fuel after ball-milling. The single samples of each type are believed to have particle size distributions typical of oxide from similar lots, as the processing of fuel lots is fairly uniform. Variation between lots is, as yet, uncharacterized. Sampling and particle size measurement methods are discussed elsewhere.

  7. Correlation of gas sensitivite properties with microstructure of Fe2O3-SnO2 ceramics prepared by high energy ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lu, S.W.; Zhou, Y.X.;

    1997-01-01

    A remarkable gas sensitivity to ethnaol gas has been observed in nanostructured Fe2O3-SnO2 materials with a composition of 6.4 mol% SnO2 prepared by high energy ball milling. The microstructure of the materials has been examined by x-ray diffraction (XRD) and Mossbauer spectroscopy. It was found...... that tin in the hematite phase plays an important role in high gas sensitivity....

  8. The influence of CNC milling and ball burnishing on shaping complex 3D surfaces

    Science.gov (United States)

    Bachtiak-Radka, Emilia; Dudzińska, Sara; Grochała, Daniel; Berczyński, Stefan; Olszak, Wiesław

    2017-03-01

    Hybrid techniques for surface treatment should ensure compliance with exterior layer state and stress requirements. The more factors which influence final treatment effects, the more difficult it is to conduct a technological process combining different treatment methods. A combination of shaping milling with finishing burnishing can provide very good smoothness and satisfactory stress conditions. However, implementation of predefined geometric surface specifications (GPS) is very difficult. This article presents the results of the effect of technological parameters of both treatments combined into a single operation on surface topography. A new surface geometry evaluation approach, combining both relative and absolute changes of isotropy and surface roughness, enabling an objective efficiency comparison of machining operations combined in a single operation, is presented.

  9. Stacking faults and phase transformations study in ball milled Co{sub 100-x}Cr{sub x} (x = 0, 20, 50) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Louidi, S., E-mail: louidisof@yahoo.fr [Laboratoire de Magnetisme et de Spectroscopie des Solides (LM2S), Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, 23000 Annaba (Algeria); Departement des Sciences de la Matiere, Faculte des Sciences, Universite 20 Aout de Skikda (Algeria); Bentayeb, F.-Z.; Tebib, W. [Laboratoire de Magnetisme et de Spectroscopie des Solides (LM2S), Departement de Physique, Faculte des Sciences, Universite de Annaba, B.P. 12, 23000 Annaba (Algeria); Sunol, J.J.; Escoda, L. [Dep. Fisica, Universitat Girona, Campus Montilivi, 17071 Girona (Spain); Mercier, A.M. [Laboratoire des Fluorures, UMR CNRS 6010, Universite du Maine, F-72085 Le Mans Cedex 9 (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We investigate the induced phase transformations fcc {r_reversible} hcp in Co{sub 100-x}Cr{sub x} (x = 0, 20, 50) alloys during milling. Black-Right-Pointing-Pointer The investigation is carried out by the Rietveld refinement of the XRD patterns. Black-Right-Pointing-Pointer The structural parameters of different phases are determined. Black-Right-Pointing-Pointer Ball milling induces fcc {yields} hcp and hcp {yields} fcc phase transformations in the first and the last stage of milling, respectively Black-Right-Pointing-Pointer The induced phase transformations are correlated with the stacking faults accumulation in fcc and hcp structures. - Abstract: The structural evolution and the phase transformations occurred during milling process of Co{sub 100-x}Cr{sub x} (x = 0, 20, 50) alloys are investigated by X-ray diffraction. Microstructural parameters such as the crystallites size, the microstrains, the stacking faults, the dislocation density and the phase fraction were determined from the Rietveld refinement of the X-ray diffraction patterns. The results show the formation of nanostructured alloys which depend on the initial composition of the mixture. In addition, X-ray diffraction indicates that the ball milling induces the fcc to hcp phase transformation in the first stage of milling and the reverse hcp to fcc phase transformation at the end of milling. On the basis of Warren's model, these allotropic transformations were explained by the presence of dislocations and the accumulation of stacking faults in the hcp and the fcc structures.

  10. 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.

  11. Optimization of Process Parameters for in High-Energy Ball Milling of CNTs/Al2024 Composites Through Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    Li Guo; Xiaolan Cai; Lei Zhou; Cui Hu; Changjiang Yang; Ziyang Wang; Wenzhong Zhang; Gang Peng

    2016-01-01

    The mathematical models are developed to evaluate the ultimate tensile strength( UTS) and hardness of CNTs/Al2024 composites fabricated by high⁃energy ball milling. The effects of the preparation variables which are milling time, rotational speed, mass fraction of CNTs and ball to powder ratio on UST and hardness of CNTs/Al2024 composites are investigated. Based on the central composite design( CCD) , a quadratic model is developed to correlate the fabrication variables to the UST and hardness. From the analysis of variance ( ANOVA) , the most influential factor on each experimental design response is identified. The optimum conditions for preparing CNTs/Al2024 composites are found as follows: 1. 53 h milling time, 900 r/min rotational speed, mass fraction of CNTs 2. 87% and Ball to powder ratio 25 ∶ 1. The predicted maximum UST and hardness are 273.30 MPa and 261.36 HV, respectively. And the experimental values are 283.25 MPa and 256.8 HV, respectively. It is indicated that the predicted UST and hardness after process optimization are found to agree satisfactory with the experimental values.

  12. Band gap-engineered ZnO and Ag/ZnO by ball-milling method and their photocatalytic and Fenton-like photocatalytic activities

    Science.gov (United States)

    Choi, Young In; Jung, Hye Jin; Shin, Weon Gyu; Sohn, Youngku

    2015-11-01

    The hybridization of ZnO with Ag has been performed extensively to increase the efficiency of ZnO in various applications, including catalysis. In this study, a wet (w) and dry (d) ball-milling method was used to hybridize Ag with ZnO nanoparticles, and their physicochemical properties were examined. Visible light absorption was enhanced and the band gap was engineered by ball-milling and Ag hybridization. Their photocatalytic activities were tested with rhodamine B (RhB) and a mixed dye (methyl orange + RhB + methylene blue) under visible light irradiation. For pure RhB, the photocatalytic activity was decreased by ball-milling and was observed in the order of ZnO(d) degradation of RhB and methylene blue (MB) in the mixed dye (or the simulated real contaminated water), the photocatalytic activity was observed in the order of Ag/ZnO(d) degradation of RhB and methylene blue (MB). In the mixed dye over all the catalysts, methyl orange (MO) was degraded most rapidly. The relative degradation rates of RhB and MB were found to be dependent on the catalyst and reaction conditions.

  13. DEM modeling of ball mills with experimental validation: influence of contact parameters on charge motion and power draw

    Science.gov (United States)

    Boemer, Dominik; Ponthot, Jean-Philippe

    2017-01-01

    Discrete element method simulations of a 1:5-scale laboratory ball mill are presented in this paper to study the influence of the contact parameters on the charge motion and the power draw. The position density limit is introduced as an efficient mathematical tool to describe and to compare the macroscopic charge motion in different scenarios, i.a. with different values of the contact parameters. While the charge motion and the power draw are relatively insensitive to the stiffness and the damping coefficient of the linear spring-slider-damper contact law, the coefficient of friction has a strong influence since it controls the sliding propensity of the charge. Based on the experimental calibration and validation by charge motion photographs and power draw measurements, the descriptive and predictive capabilities of the position density limit and the discrete element method are demonstrated, i.e. the real position of the charge is precisely delimited by the respective position density limit and the power draw can be predicted with an accuracy of about 5 %.

  14. 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.

  15. A comparison between different X-ray diffraction line broadening analysis methods for nanocrystalline ball-milled FCC powders

    Energy Technology Data Exchange (ETDEWEB)

    Soleimanian, V. [Shahrekord University, Department of Physics, Faculty of Sciences, P.O. Box 115, Shahrekord (Iran, Islamic Republic of); Shahrekord University, Nanotechnology Research Center, Shahrekord (Iran, Islamic Republic of); Mojtahedi, M. [Pooya Gharb Branch of University of Applied Science and Technology, Department of Materials Engineering, Kermanshah (Iran, Islamic Republic of)

    2015-06-15

    The microstructural characteristics of aluminum, copper and nickel powders are investigated using different X-ray diffraction line broadening analysis approaches. Prior to analysis, the powders were ball-milled to produce a nanocrystalline structure with high density of probable types of lattice defects. A variety of methods, including Scherrer, Williamson-Smallman, Williamson-Hall, Warren-Averbach, modified Williamson-Hall, modified Warren-Averbach, Rietveld refinement and whole powder pattern modeling (WPPM) approaches are applied. In this way, microstructural characteristics such as crystallite size, microstrain, dislocation density, effective outer cut-off radius of dislocations and the probability of twining and stacking faults are calculated. On the other hand, the results of conventional and advanced line broadening analysis methods are compared. It is revealed that the density of linear and planar defects in the mechanically deformed aluminum powder is significantly smaller than that of copper and nickel, as well as the level of anisotropic strain broadening. Moreover, the WPPM procedure provided a better profile fitting with more accurate results. (orig.)

  16. 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.

  17. 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.

  18. 泡沫铝层合结构钢球磨煤机隔声罩降噪性能研究%Study on reduction noise properties of foamed aluminum laminated structure acoustical enclosure for ball mill

    Institute of Scientific and Technical Information of China (English)

    于英华; 余国军

    2012-01-01

    In order to explore a new way for reduction noise of ball mill,the view point of using foamed aluminum laminated structure in ball mill acoustical enclosures was put forward based noise properties of ball mill.The laminated structure plate used to ball mills acoustical enclosures was designed,reduction noise properties of it were studied by theoretical analysis and test.The results show that the new ball mill acoustical enclosures can improve the reduction noise and environmental protection capabilities of the ball mill acoustical enclosure.%为探索钢球磨煤机的降噪新途径,针对钢球磨煤机噪声的特点,提出将泡沫铝层合结构应用于钢球磨煤机隔声罩中的观点。设计了泡沫铝钢球磨煤机隔声罩板的层合结构,并运用理论分析和实验分析的方法对其降噪性能进行研究。结果表明,用泡沫铝层合结构制造钢球磨煤机隔声罩,可提高隔声罩的降噪性能,并可提高隔声罩环保性能。

  19. The phase analysis of spark plasma sintered MgB2 after ball milling.

    Science.gov (United States)

    Kang, Deuk-Kyun; Kim, Dong-Woong; Kim, Cheol-Jin; Ahn, In-Shup

    2010-01-01

    Mg and amorphous B powders below 10 and 3 micro meter were used as raw materials, and mixed by planetary-mill for 9 hours at argon atmosphere. MgB2 bulk was fabricated at the various temperatures by Spark Plasma Sintering. In the sintering process, mixed powders were sintered in graphite mold, at the pressure of 55 Mpa. The fabricated MgB2 samples were evaluated with XRD, EDS, FE-SEM, PPMS. MgB2, MgO and Fe phases were observed from XRD result. In the results, MgO and Fe were impurity which may affect superconducting properties of MgB2 samples, and it's distribution could be confirmed from EDS mapping result. In order to confirm the formation of MgB2 phase, DTA was used as heating rate of 10 degrees C/min at Ar atmosphere from room temperature to 1200 degrees C. In the PPMS result, the Tc (critical temperature) was about 21 K, and the density of spark plasma sintered samples increased to 1.87 g/cm3 by increasing sintering temperature.

  20. Improved critical current density in ex situ processed MgB2 tapes by the size reduction of grains and crystallites by high-energy ball milling

    Science.gov (United States)

    Fujii, Hiroki; Ishitoya, Akira; Itoh, Shinji; Ozawa, Kiyoshi; Kitaguchi, Hitoshi

    2017-03-01

    We have fabricated Fe-sheathed MgB2 tapes through an ex situ process in a powder-in-tube (PIT) technique using powders ball milled under various conditions. Although the ex situ processed wires and tapes using the high-energy ball milled MgB2 powders have been studied and the decrease of grain and crystallite sizes of MgB2 and the critical current density (Jc) improvement of those conductors were reported so far, the use of filling powders milled at a higher rotation speed than previously reported further decreases the crystallite size and improves the Jc properties. The improved Jc values at 4.2 K and 10 T were nearly twice as large as those previously reported. Those milled powders and hence as-rolled tapes easily receive contamination in air. Thus, the transport Jc properties are easily deteriorated and scattered unless the samples are handled with care. The optimized heat treatment temperature (Topt) of those tape samples at which best performance in the Jc property is obtained decreases by more than 100 °C, compared with that of tapes using the as-received MgB2 powder.

  1. Soft Sensor for Ball Mill Fill Level Based on CART-LSSVM Model%基于CART-LSSVM的球磨机料位软测量方法研究

    Institute of Scientific and Technical Information of China (English)

    张兴; 李伟; 阎高伟; 庞宇松

    2015-01-01

    Ball mill is a high energy consumption equipment used in electricity,grinding and metallurgical indus-tries.Accurate measurement of its fill level(FL)can improve operational efficiency and safety performance. Howev-er,The real-time measurement of FL is difficult to realize,and the components of bearing vibration of ball mill are complex and redundant. Aiming at these problems,a new soft sensor approach of FL based on Classification and Re-gression Tree(CART)and Least Squares Support Vector Machine(LSSVM)is proposed. Firstly,the Power Spectrum density(PSD)of bearing vibration is obtained by welch method,essential features are achieved by partition subse-quently. Secondly,these features are adopted to build CART,and branch nodes of the best model is selected as fea-tures. Finally,the LSSVM are used to implement the non-linear mapping between features and FL. The comparative experiments verifies that this model is feasible and practical with high prediction accuracy.%球磨机是用于电力、磨矿和冶金等行业的高能耗设备,准确测量其滚筒料位能够提高运行效率和安全性能.针对其滚筒内料位难以实时检测,球磨机的轴承振动信号中存在较多的冗余特征,提出了一种基于分类回归树和最小二乘支持向量机的软测量方法,首先用Welch法获得振动信号的功率谱密度,并分割得到基本特征,然后建立分类回归树模型,根据最优树模型的分支节点进行特征选择,最后利用最小二乘支持向量机实现特征变量与料位间的非线性映射.通过实验结果的对比分析,验证了该模型的有效性和实用性,以及良好的预测精度.

  2. Mechanochemical Ring-Opening Polymerization of Lactide: Liquid-Assisted Grinding for the Green Synthesis of Poly(lactic acid) with High Molecular Weight.

    Science.gov (United States)

    Ohn, Nuri; Shin, Jihoon; Kim, Sung Sik; Kim, Jeung Gon

    2017-09-22

    Mechanochemical polymerization of lactide is carried out by using ball milling. Mechanical energy from collisions between the balls and the vessel efficiently promotes an organic-base-mediated metal- and solvent-free solid-state polymerization. Investigation of the parameters of the ball-milling synthesis revealed that the degree of lactide ring-opening polymerization could be modulated by the ball-milling time, vibration frequency, mass of the ball media, and liquid-assisted grinding. Liquid-assisted grinding was found to be an especially important factor for achieving a high degree of mechanochemical polymerization. Although polymer-chain scission from the strong collision energy prevented mechanical-force-driven high-molecular-weight polymer synthesis, the addition of only a small amount of liquid enabled sufficient energy dissipation and poly(lactic acid) was thereby obtained with a molecular weight of over 1×10(5)  g mol(-1) . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 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.

  4. Mechanical ball-milling preparation of fullerene/cobalt core/shell nanocomposites with high electrochemical hydrogen storage ability.

    Science.gov (United States)

    Bao, Di; Gao, Peng; Shen, Xiande; Chang, Cheng; Wang, Longqiang; Wang, Ying; Chen, Yujin; Zhou, Xiaoming; Sun, Shuchao; Li, Guobao; Yang, Piaoping

    2014-02-26

    The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

  5. 钢坯试样铣磨床总体方案的创新设计%Innovative design for overall Scheme of milling-grinding machine for billet steel sample

    Institute of Scientific and Technical Information of China (English)

    薛会民; 欧阳晶晖

    2011-01-01

    It expounds the innovative design for overall scheme of the milling-grinding machineAc-cording to the processing requirements of high efficiency and high surface quality for billet test sample,the principle scheme of machine tool was proposed based on combined innovation, which achieves a composite process of milling and grindingJn addition the grinding adopts modern belt grinding.The motion scheme of the machine tool was designed through analyzing movement functionsAs for general structure of the machine tool fixed beam gantry frame structure is adopted based on structural variation.The result indicates that the overall scheme innovation realizes the uniqueness design of the machine tool,which has good performance and can well satisfy the processing requirements of billet steel sample.%阐述了铣磨床总体方案的创新设计,针对钢坯检测试样高效率、高表面质量的加工要求,采用组合创新的方法,提出了在同一机床上实现铣削、磨削复合加工的工艺原理方案,并且机床的磨削加工采用了现代砂带磨削.通过分析机床的各种运动功能,设计了机床的运动方案.对于机床的总体结构布局,采用结构变异的方法,确定其为定梁龙门式框架结构.结果表明,通过总体方案的创新,实现了机床的独特性设计,所设计机床性能优良,很好地满足了钢坯检测试样的加工要求.

  6. Facile synthesis and regeneration of Mg(BH4)2 by high energy reactive ball milling of MgB2.

    Science.gov (United States)

    Gupta, Shalabh; Hlova, Ihor Z; Kobayashi, Takeshi; Denys, Roman V; Chen, Fu; Zavaliy, Ihor Y; Pruski, Marek; Pecharsky, Vitalij K

    2013-01-28

    We report direct hydrogenation of MgB(2) in a planetary ball mill. Magnesium borohydride, Mg(BH(4))(2), and various polyhedral borane anion salts have been synthesized at pressures between 50 and 350 bar H(2) without the need for subsequent isothermal hydrogenation at elevated temperature and pressure. The obtained products release ∼4 wt% H(2) below 390 °C, and a major portion of Mg(BH(4))(2) transforms back to MgB(2) at around 300 °C, demonstrating the possibility of reversible hydrogen storage in an Mg(BH(4))(2)-MgB(2) system.

  7. 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)

  8. 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.

  9. 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.

  10. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  11. 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

  12. Improved electrode characteristics of olivine-LiCoPO 4 processed by high energy milling

    Science.gov (United States)

    Rabanal, M. E.; Gutierrez, M. C.; Garcia-Alvarado, F.; Gonzalo, E. C.; Arroyo-de Dompablo, M. E.

    Olivine-LiCoPO 4 powders have been processed by mechanical grinding for time periods ranging from 0.5 to 10 h with conductive carbon contents of 0, 8 and 20% (w/w). In all cases the grinding process produces an amorphization of the crystalline materials and decreases both the crystallite and particle sizes. Secondary phases are detected by scanning electron microscopy and X-ray diffraction in the materials milled for times greater than 2 h without carbon. The addition of conductive carbon during the milling process decelerates the degradation of the material and secondary phases are not detected even after 10 h of grinding. The electrochemical performance of olivine-LiCoPO 4 is improved in all the materials milled for 0.5 h; a lower cell polarization and a larger reversible specific capacity are observed. These characteristics are enhanced in the materials grinded with conductive carbon, which also display a capacity retention with cycling clearly superior to that of the fresh LiCoPO 4. Ball milling LiCoPO 4 for times greater than 1 h is detrimental for the response of the electrode, independently on the amount of conductive carbon in the grinding media.

  13. Lignocellulose fermentation and residual solids characterization for senescent switchgrass fermentation by Clostridium thermocellum in the presence and absence of continuous in situ ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Balch, Michael L.; Holwerda, Evert K.; Davis, Mark F.; Sykes, Robert W.; Happs, Renee M.; Kumar, Rajeev; Wyman, Charles E.; Lynd, Lee R.

    2017-04-12

    Milling during lignocellulosic fermentation, henceforth referred to as cotreatment, is investigated as an alternative to thermochemical pretreatment as a means of enhancing biological solubilization of lignocellulose. We investigate the impact of milling on soluble substrate fermentation by Clostridium thermocellum with comparison to yeast, document solubilization for fermentation of senescent switchgrass with and without ball milling, and characterize residual solids. Soluble substrate fermentation by C. thermocellum proceeded readily in the presence of continuous ball milling but was completely arrested for yeast. Total fractional carbohydrate solubilization achieved after fermentation of senescent switchgrass by C. thermocellum for 5 days was 0.45 without cotreatment or pretreatment, 0.81 with hydrothermal pretreatment (200 degrees C, 15 minutes, severity 4.2), and 0.88 with cotreatment. Acetate and ethanol were the main fermentation products, and were produced at similar ratios with and without cotreatment. Analysis of solid residues was undertaken using molecular beam mass spectrometry (PyMBMS) and solid-state nuclear magnetic resonance spectroscopy (NMR) in order to provide insight into changes in plant cell walls during processing via various modes. The structure of lignin present in residual solids remaining after fermentation with cotreatment appeared to change little, with substantially greater changes observed for hydrothermal pretreatment - particularly with respect to formation of C-C bonds. The observation of high solubilization with little apparent modification of the residue is consistent with cotreatment enhancing solubilization primarily by increasing the access of saccharolytic enzymes to the feedstock, and C. thermocellum being able to attack all the major linkages in cellulosic biomass provided that these linkages are accessible.

  14. Heterogeneous sono-Fenton-like process using martite nanocatalyst prepared by high energy planetary ball milling for treatment of a textile dye.

    Science.gov (United States)

    Dindarsafa, Mahsa; Khataee, Alireza; Kaymak, Baris; Vahid, Behrouz; Karimi, Atefeh; Rahmani, Amir

    2017-01-01

    High energy planetary ball milling was applied to prepare sono-Fenton nanocatalyst from natural martite (NM). The NM samples were milled for 2-6h at the speed of 320rpm for production of various ball milled martite (BMM) samples. The catalytic performance of the BMMs was greater than the NM for treatment of Acid Blue 92 (AB92) in heterogeneous sono-Fenton-like process. The NM and the BMM samples were characterized by XRD, FT-IR, SEM, EDX and BET analyses. The particle size distribution of the 6h-milled martite (BMM3) was in the range of 10-90nm, which had the highest surface area compared to the other samples. Then, the impact of main operational parameters was investigated on the process. Complete removal of the dye was obtained at the desired conditions including initial pH 7, 2.5g/L BMM3 dosage, 10mg/L AB92 concentration, and 150W ultrasonic power after 30min of treatment. The treatment process followed pseudo-first order kinetic. Environmentally-friendly modification of the NM, low leached iron amount and repeated application at milder pH were the significant benefits of the BMM3. The GC-MS was successfully used to identify the generated intermediates. Eventually, an artificial neural network (ANN) was applied to predict the AB92 removal efficiency based upon the experimental data with a proper correlation coefficient (R(2)=0.9836). Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    El-Eskandarany, M Sherif; Shaban, Ehab

    2015-10-10

    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.

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

    Science.gov (United States)

    El-Eskandarany, M. Sherif; Shaban, Ehab

    2015-01-01

    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 (∆H) and entropy (∆S) 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 ΔH and ΔS 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. PMID:28793606

  17. 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.

  18. CORN-MILL GRINDING PLATES

    African Journals Online (AJOL)

    hardness and wear resistance of the samples are explained in terms of chemical composition and/ .... Chromium 0.69 0.4 0.25. Molybdenum 0.03 01 50.010. Nickel 0.18 0.07 0.05. Copper 0.35 .... hard and brittle with good wear resistance.

  19. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Science.gov (United States)

    Padhan, Aneeta Manjari; Ravikumar, P.; Saravanan, P.; Alagarsamy, Perumal

    2016-11-01

    We report the effect of mechanical activation on NiO-Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO-Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO-Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO-Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al2O3. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO-Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO-Al is encouraging for the applications in catalysis and process of ore reduction.

  20. Process parameter dependent growth phenomena of naproxen nanosuspension manufactured by wet media milling.

    Science.gov (United States)

    Bitterlich, A; Laabs, C; Krautstrunk, I; Dengler, M; Juhnke, M; Grandeury, A; Bunjes, H; Kwade, A

    2015-05-01

    The production of nanosuspensions has proved to be an effective method for overcoming bioavailability challenges of poorly water soluble drugs. Wet milling in stirred media mills and planetary ball mills has become an established top-down-method for producing such drug nanosuspensions. The quality of the resulting nanosuspension is determined by the stability against agglomeration on the one hand, and the process parameters of the mill on the other hand. In order to understand the occurring dependencies, a detailed screening study, not only on adequate stabilizers, but also on their optimum concentration was carried out for the active pharmaceutical ingredient (API) naproxen in a planetary ball mill. The type and concentration of the stabilizer had a pronounced influence on the minimum particle size obtained. With the best formulation the influence of the relevant process parameters on product quality was investigated to determine the grinding limit of naproxen. Besides the well known phenomenon of particle agglomeration, actual naproxen crystal growth and morphology alterations occurred during the process which has not been observed before. It was shown that, by adjusting the process parameters, those effects could be reduced or eliminated. Thus, besides real grinding and agglomeration a process parameter dependent ripening of the naproxen particles was identified to be a concurrent effect during the naproxen fine grinding process.

  1. 圆弧头立铣刀端刃CNC磨削仿真技术研究%Research on CNC grinding simulation technology of torus end milling cutter's end edges

    Institute of Scientific and Technical Information of China (English)

    刘建军; 黎荣; 程雪锋; 金晓波; 丁国富

    2012-01-01

    A technology on universal end edges model and CNC grinding simulation of torus end milling cutters is introduced. With the theory of space vector rotation,the universal mathematic model of end edges above center or not was builded. Based on the accurate cutting - edge model, the grinding processes of the end milling cutter end - edge rake & flank faces were researched, and also the wheel' s moving path and tool axis vector were calculated. Meanwhile, the post processing program of five-axis NC grinder and the virtual simulation environment based on VERICUT software were developed, and three kinds of end-edge models with different tooth number were geted through grinding simulation,which validated acquired cutter location data. Taking four edges end milling cutter with two edges above center as example, the grinding simulation technology proposed was verified by measuring the structure parameters of simulation model and physical model,and comparing them with design parameters.%介绍一种圆弧头立铣刀端刃的通用建模及CNC磨削仿真技术.运用空间矢量旋转原理,对过中心和不过中心端齿刃线建立通用数学模型.基于所建立的精确刃线数模,研究了立铣刀端刃前、后刀面的磨削加工工艺并计算出砂轮的运动轨迹和刀轴矢量.开发了五轴数控磨床的后置处理程序和基于VERICUT软件的虚拟仿真环境,加工出三类不同齿数的立铣刀端齿模型,对获得的刀位数据正确性进行了验证.以两齿过中心的四齿平底立铣刀为例,通过测量仿真模型和加工实物的结构参数并与设计参数进行对比,验证了提出的磨削仿真技术的可行性.

  2. Nitrogen-doped graphene by all-solid-state ball-milling graphite with urea as a high-power lithium ion battery anode

    Science.gov (United States)

    Liu, Chao; Liu, Xingang; Tan, Jiang; Wang, Qingfu; Wen, Hao; Zhang, Chuhong

    2017-02-01

    Nitrogen-doped graphene nanosheets (NGNS) are prepared by a novel mechanochemical method via all-solid-state ball-milling graphite with urea. The ball-milling process does not only successfully exfoliate the graphite into multi-layer (low cost and good water solubility that can simplify the fabrication process. The as-prepared NGNS are investigated in detail by XRD, SEM, HRTEM, TGA, XPS and Raman spectroscopy. The doping nitrogens are around 3.15% and dominated (>94%) by pyrindic-N and pyrrolic-N which facilitates the NGNS with enhanced electronic conductivity and Li-ion storage capability. For the first time, we demonstrate that the all-solid-state prepared NGNS exhibits, especially at high currents, enhanced cycling stability and rate capability as Lithium ion battery (LIB) anode active material when compared to pristine graphite and undoped graphene in half-cell configuration. The method presented in this article may provide a simple, clean, economical and scalable strategy for preparation of NGNS as a feasible and promising anode material for LIBs.

  3. Synthesis of stoichiometric Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, B.F.; Morales, M.A.; Bohn, F.; Carriço, A.S. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Medeiros, S.N. de, E-mail: sndemedeiros@gmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Dantas, A.L. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210 Mossoró, RN (Brazil)

    2016-05-01

    We report the synthesis of Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing from α-Fe{sub 2}O{sub 3} and CaCO{sub 3}. 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 Ca{sub 2}Fe{sub 2}O{sub 5}. Samples annealed at lower temperatures show departure from stoichiometry, with a higher occupancy of Fe{sup 3+} 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 Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles.

  4. Investigation of physical properties and stability of indomethacin-cimetidine and naproxen-cimetidine co-amorphous systems prepared by quench cooling, coprecipitation and ball milling

    DEFF Research Database (Denmark)

    Lim, Ai Wei; Löbmann, Korbinian; Grohganz, Holger;

    2016-01-01

    OBJECTIVES: The objective was to characterize the structural behaviour of indomethacin-cimetidine and naproxen-cimetidine co-amorphous systems (1 : 1 molar ratio) prepared by quench cooling, co-evaporation and ball milling. METHODS: Powder X-ray diffraction (PXRD) and DSC were used to characterise...... the samples. Structural relaxation (i.e. molecular mobility) behaviour was obtained from the Kohlrausch-Williams-Watts (KWW) relationship. KEY FINDINGS: A glass transition temperature (Tg ), on average 20 °C higher than the predicted Tg (calculated from the Fox equation), was observed in all samples...... by quench cooling (ln τ(β) = 2.4) and co-evaporation (ln τ(β) = 2.5). In contrast, molecular mobility of the naproxen-cimetidine samples followed the order co-evaporation (ln τ(β) = 0.8), quench cooling (ln τ(β) = 1.6) and ball milling (ln τ(β) = 1.8). CONCLUSION: The estimated relaxation times by the DSC...

  5. One Step Ball-Milling Synthesis of LiFePO4 Nanoparticles as the Cathode Material of Li-lon Batteries

    Institute of Scientific and Technical Information of China (English)

    AI Xinping; LI Hai; LI Xiaoyan; LIAO Qinlin; LIU Bingdong; YANG Hanxi

    2006-01-01

    A one-step synthetic method was used to synthesize Olivline LiFePO4 powders by direct ball milling the stoichiometric mixture of Fe, Li3 PO4, and FePO4 powders.XRD and TEM measurements revealed that the as-prepared LiFePO4 powder have a homogeneous Olivine structure and a uniform size distribution of ca. 50 nm. Based on this material,a LiFePO4/C composite was prepared and used for the cathode material of Li-ion batteries. The charge-discharge experiments demonstrated that the LiFePO4/C composite material has a high capacity of 132 mAh/g at 0.1 C and a quite highrate capability of 95 mAh/g at 1 C. This new ball-milling method may provide a completely green synthetic route for preparing the materials of this type cost-effectively and in large volume.

  6. Research on Ball Best Gradation Technology of Coal Mill%磨煤机钢球最佳级配技术应用研究

    Institute of Scientific and Technical Information of China (English)

    宋绍伟

    2012-01-01

    The steady - state abrasion model and a lot of engineering tests are conducted to determine the optimal ball grade and reasonable loading; by changing the high chrome steel balls carbon chrome ration, adding manganese, tungsten and other alloying elements and the use of special oil quenching process, a diverse high - chromium alloy wear - resistant ball is successfully developed, improving the stability of the best grading, effectively reducing the mill current energy efficiency significantly. Practice shows that: using the technology,thermal power plant reduced 37% ball mill load,achieving 23% less power consumption and 61% less steel consumption, which is a substantial energy saving; with the mill load decreases , the failure rate of the gears, bearings and transmissions and other equipment was significantly reduced , extending equipment life, and also saving a lot of maintenance costs, which has broad prospects for promotion.%应用钢球磨损稳态模型计算和工程试验确定钢球最佳级配和合理的钢球装载量;通过改变高铬钢球的铬碳比,增添锰、钨等合金元素以及采用特殊的油淬火热处理工艺,研制成功了多元高铬合金耐磨钢球,提高了最佳级配的稳定性,有效地降低了磨煤机电流,节能效益显著.实践表明:火电厂使用该技术后,磨煤机钢球装载量减少37%、电耗降低23%、钢耗降低61%,实现了火电厂磨煤机的大幅度节能降耗;随着磨煤机负载的减小,大小齿轮、轴瓦和变速箱等设备的故障率明显降低,设备寿命得到延长,同时也节省了大量的维护成本,具有广阔的推广前景.

  7. An X-Ray Absorption Spectroscopy Study of Ball-Milled Lithium Tantalate and Lithium Titanate Nanocrystals

    Science.gov (United States)

    Chadwick, A. V.; Pickup, D. M.; Ramos, S.; Cibin, G.; Tapia-Ruiz, N.; Breuer, S.; Wohlmuth, D.; Wilkening, M.

    2017-02-01

    Previous work has shown that nanocrystalline samples of lithium tantalate and titanate prepared by high-energy milling show unusually high lithium ion conductivity. Here, we report an X-ray absorption spectroscopy (XAS) study at the Ti K-edge and the Ta L3 edge of samples that have been milled for various lengths of time. For both systems the results show that milling creates amorphous material whose quantity increases with the milling time. The more extensive data for the tantalate shows that milling for only 30 minutes generates ∼25% amorphous content in the sample. The content rises to ∼60% after 16 hours. It is suggested that it is the motion of the lithium ions through the amorphous content that provides the mechanism for the high ionic conductivity.

  8. Design of pressure control system for grinding machine of precision ball%精密球体研磨机压力控制系统设计

    Institute of Scientific and Technical Information of China (English)

    赵文宏; 楼一兵; 赵蓉; 杨碧波

    2011-01-01

    In order to solve the problems that based on the traditional adaptive pressure control system and PID theory in eccentric and dualrotation lapping machine for precision ball, such as long response time, low control accuracy, large system vibration, etc. , the fuzzy control strategy was investigated. After the analysis of blurring input variables (E, EC)and output variable (SV), the relationship of three variables was established. A method of fuzzy pressure control system was presented based on DSP chip. The fuzzy control system was evaluated on the Simulink platform of Matlab, the lapping machine for precision ball with fuzzy control system was tested. The experimental results show that the design can shorten response time, reduce system vibration and improve control accuracy and machine efficiency.%为解决传统自适应压力控制和PID压力控制下精密磨球机在磨球时出现的诸如响应时间长,控制精度不够高、机械振动过大等问题,将模糊控制技术应用到磨球机的压力控制中.开展了系统输入变量E,EC和输出变量SV模糊化分析,建立了3个模糊变量之间的关系,提出了基于DSP芯片的压力模糊控制方法,在Matlab软件的Simulink平台上对模糊控制系统性能进行了评价,并进行了在该模糊系统控制下的偏心和双自转式球体研磨加工试验.试验结果表明,该系统实现了快速响应,并且减少了系统振动,提高了压力控制的精度和球体研磨的效率.

  9. Synthesis of Vanadium-Vanadium Carbide in-situ nanocomposites by high energy ball milling and spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Krishnan Vinoadh Kumar

    2016-01-01

    Full Text Available In the present work, Vanadium-Vanadium Carbide (V-V2C in-situ nanocomposites were synthesized by mechanically milling vanadium powders with 0.5 wt.% stearic acid. Milled powders were consolidated using spark plasma sintering at 1150, 1250 and 1350°C for 10 min. Phase and morphology of the milled powders were studied using X-ray diffraction and scanning electron microscopy. X-ray diffraction analysis of 10 h milled powder shows the evolution of amorphous phase. Energy dispersive X-ray spectroscopy studies on milled powder shows the presence of carbon, which could be due to the decomposition of stearic acid during milling. Degree of crystallinity of milled powder was confirmed using the selective area electron diffraction pattern. X-ray diffraction analysis of sintered samples indicate sharp peaks from vanadium and vanadium carbide (V2C, endorsing amorphous to nanocrystalline transformation. Micro-hardness value of sintered samples increases with increasing sintering temperature.

  10. Nanocrystalline Nd{sub 2}Fe{sub 17} synthesized by high-energy ball milling: crystal structure, microstructure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Pablo; Gorria, Pedro; Perez, Maria J; Sanchez Llamazares, Jose L; Blanco, Jesus A [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Franco, Victorino [Departamento Fisica de la Materia Condensada, ICMSE-CSIC, Universidad de Sevilla, PO Box 1065, 41080 Sevilla (Spain); Sanchez Marcos, Jorge [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Puente Orench, Ines, E-mail: alvarezpablo.uo@uniovi.e [Institute Laue-Langevin, BP 156, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2010-06-02

    Nanocrystalline Nd{sub 2}Fe{sub 17} powders have been obtained by means of high-energy ball milling from nearly single-phase bulk alloys produced by arc melting and high temperature homogenization annealing. The rhombohedral Th{sub 2}Zn{sub 17}-type crystal structure of the bulk alloy remains unaltered after the milling process, with almost unchanged values for the cell parameters. However, the severe mechanical processing induces drastic microstructural changes. A decrease of the mean crystalline size down to around 10 nm is observed, giving rise to a considerable augmentation of the disordered inter-grain boundaries. This modification of the microstructure affects the magnetic behaviour of the milled powders, although the magnetic structure remains collinear ferromagnetic. While a unique ferro-to-paramagnetic transition temperature, T{sub C} = 339 {+-} 2 K, is observed in the bulk alloy, the nanocrystalline samples exhibit a more likely distribution of T{sub C} values. The latter seems to be responsible for the significant broadening of the temperature range in which magneto-caloric effect is observed, and the lowering of the maximum value of the magnetic entropy change.

  11. Market Demand and Application About Mill Ball and Rod%耐磨球段的市场需求及应用

    Institute of Scientific and Technical Information of China (English)

    徐佩芬; 吴海平

    2012-01-01

    The market demand and application status of wear resisting ball and rod, which is widely applied in industrial production of material grinding, for example metallurgical mines, building and cement, thermal power generation, coal processing and magnetic materials, was analyzed, and the market demand and the development trend in the next few years in China were predicted. The results show that the specification of wear resisting ball and rod products is complete in China, their properties have already been caught up with the foreign similar products. The market demand of wear resisting ball and rod products in 2012 is 172.82 million ton and that in 2015 will be up to 208.74 million ton, compared with that in 2010, it is increased by 44.34%. From the point of optimizing resource allocation and establishing the benign market, enterprise merger and integration is a developing trend of wear resisting ball and rod in the future.%对广泛用于冶金矿山、建材水泥、火力发电、煤炭加工、磁性材料等物料研磨生产过程中的耐磨球段的市场需求及应用现状进行了分析,并对未来几年的市场需求进行了预测.结果表明:中国耐磨球段产品规格齐全,产品性能已经赶上国外同类产品.2012年中国耐磨球段产品预计需求量为172.82万t,至2015年将达到208.74万t,较2010年增长44.34%.从优化资源配置,建立良性市场角度分析,产业兼并整合是耐磨球段行业未来发展方向.

  12. 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.

  13. Preparation of Capsaicin Powders by Balling Milling%球磨法制备天然辣椒素粉体工艺研究

    Institute of Scientific and Technical Information of China (English)

    黄永鹏; 钟辉; 陈博; 焦剑岚

    2012-01-01

    Capsaicin powders were prepared by ball milling with the materials of capsaicin and silica gel. The mass ratio of steel balls to capsaicin and silica gel, the mass ratio of capsaicin to silica gel, the milling time and the velocity of revolution were changed according to orthogonal design of the experiments. The results of the orthogonal experiments show that the optimum parameters in the preparation of capsaicin are as follows: the mass ratio of steel balls to capsaicin and silica gel is 5 M, the mass ratio of capsaicin to silica gel is 4:6, the milling time is 20 min and the velocity of revolution is 300 r/min. 94.98% volume fraction of capsaicin particles small than 10 (xm in size are obtained under the optimum parameters.%以天然辣椒素和硅胶为原料和辅料,采用球磨法制备天然辣椒素粉体,采用正交实验法,对球料质量比、天然辣椒素与硅胶的质量比、球磨时间、球磨机转速等参数进行4因素3水平的正交实验设计,研究这些工艺参数对球磨法制备天然辣椒素粉体的影响.结果表明,制备天然辣椒素粉体的最佳工艺为球料质量比为5∶1,天然辣椒素与硅胶的质量比为4∶6,球磨时间为20 min,转速为300 r/min,在此条件下,制备的天然辣椒素粉体中粒径小于10 μm的颗粒的体积分数为94.98%.

  14. Progress in high-energy ball milling for the preparation of absorbing materials%吸波材料的高能球磨工艺研究进展

    Institute of Scientific and Technical Information of China (English)

    王锰刚; 谌静; 谢国治; 陈文俊; 李艳; 张泽敖; 王嘉波; 沈杨; 孙康; 周倜

    2016-01-01

    High-energy ball milling method has become a important way to prepare various absorbing materials, because of simple control, environmental production, low cost and high efficiency. This paper summarizes the recent research progress of high-energy ball milling process in absorbing materials,indicating that high-energy ball milling process in absorbing materials, especially in flaky absorbing materials with shape anisotropy, which has very broad application prospects. Then we look forward to the development prospects of high-energy ball milling process in absorbing materials.%高能球磨法由于其便于控制、生产环保、成本低、效率高等优点成为制备吸波材料的一种重要方法。总结了近期高能球磨工艺在吸波材料领域的应用研究进展,表明高能球磨工艺在吸波领域,尤其是在制备具有形状各向异性的片状吸波材料领域,具有十分广阔的应用前景,展望了高能球磨工艺在未来吸波材料领域的发展前景。

  15. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Energy Technology Data Exchange (ETDEWEB)

    Padhan, Aneeta Manjari; Ravikumar, P. [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Advanced Magnetic Lab, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Alagarsamy, Perumal, E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2016-11-15

    We report the effect of mechanical activation on NiO–Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO–Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO–Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO–Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al{sub 2}O{sub 3}. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO–Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO–Al is encouraging for the applications in catalysis and process of ore reduction. - Highlights: • Preparation of Ni/Al{sub 2}O{sub 3} nanocomposite by mechanical activation of NiO–Al reduction. • Study the effect of Al addition on the reduction reaction of NiO–Al powders. • Understand the change in the structural and microstructural properties of NiO–Al. • Investigate role of reduction of NiO by Al on resulting magnetic property of NiO–Al. • Study the magnetic phase

  16. Effect of ball milling and thermal treatment on exchange bias and magnetocaloric properties of Ni48Mn39.5Sn10.5Al2 ribbons

    Science.gov (United States)

    Czaja, P.; Przewoźnik, J.; Fitta, M.; Bałanda, M.; Chrobak, A.; Kania, B.; Zackiewicz, P.; Wójcik, A.; Szlezynger, M.; Maziarz, W.

    2016-03-01

    The combined effect of ball milling and subsequent heat treatment on microstructure, magnetic, magnetocaloric and exchange bias properties of Ni48Mn39.5Sn10.5Al2 ribbons is reported. The annealing treatment results in the increase of the critical martensitic transformation temperature. The magnetic entropy change ΔSM of the order of 7.9 and -2.3 J kg K-1 for the annealed 50-32 μm powder fraction is determined. This is less than in the as melt spun ribbon but appears at a considerably higher temperature. At the same time EB is decreased due to annealing treatment. This decrease is attributed to the strengthened ferromagnetic exchange coupling due heat induced stress and structural relaxation.

  17. Use of cellobiohydrolase-free cellulase blends for the hydrolysis of microcrystalline cellulose and sugarcane bagasse pretreated by either ball milling or ionic liquid [Emim][Ac].

    Science.gov (United States)

    Teixeira, Ricardo Sposina Sobral; da Silva, Ayla Sant'Ana; Kim, Han-Woo; Ishikawa, Kazuhiko; Endo, Takashi; Lee, Seung-Hwan; Bon, Elba P S

    2013-12-01

    This study investigated the requirement of cellobiohydrolases (CBH) for saccharification of microcrystalline cellulose and sugarcane bagasse pretreated either by ball milling (BM) or by ionic liquid (IL) [Emim][Ac]. Hydrolysis was done using CBH-free blends of Pyrococcus horikoshii endoglucanase (EG) plus Pyrococcus furiosus β-glucosidase (EGPh/BGPf) or Optimash™ BG while Acremonium Cellulase was used as control. IL-pretreated substrates were hydrolyzed more effectively by CBH-free enzymes than were the BM-pretreated substrates. IL-treatment decreased the crystallinity and increased the specific surface area (SSA), whereas BM-treatment decreased the crystallinity without increasing the SSA. The hydrolysis of IL-treated cellulose by EGPh/BGPf showed a saccharification rate of 3.92 g/Lh and a glucose yield of 81% within 9h. These results indicate the efficiency of CBH-free enzymes for the hydrolysis of IL-treated substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Microstructure and Electrical Properties of Er2O3-Doped ZnO-Based Varistor Ceramics Prepared by High-Energy Ball Milling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microstructure, electrical properties and density of ZnO-based varistor ceramics with different Er2O3 content prepared by high-energy ball milling (HEBM) and sintered at 800 ℃ were investigated. With increasing Er2O3 content, the ZnO grain size decreases due to the Er-rich phases inhibiting grain growth;and nonlinear coefficient (α) decreases because of the decrease of barrier height (φB). The breakdown voltage (Eb) and density increase, whereas leakage current (IL) decreases with increasing Er2O3 content. The barrier height (φB), donor concentration (Nd), density of interface states (Ns) decrease and barrier width (ω) increases with increasing Er2O3 content due to acceptor effect of Er2O3 in varistor ceramics.

  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

    2016-05-01

    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.

  20. The Structure and Mechanical Properties of High-Strength Bulk Ultrafine-Grained Cobalt Prepared Using High-Energy Ball Milling in Combination with Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Ivo Marek

    2016-05-01

    Full Text Available In this study, bulk ultrafine-grained and micro-crystalline cobalt was prepared using a combination of high-energy ball milling and subsequent spark plasma sintering. The average grain sizes of the ultrafine-grained and micro-crystalline materials were 200 nm and 1 μm, respectively. Mechanical properties such as the compressive yield strength, the ultimate compressive strength, the maximum compressive deformation and the Vickers hardness were studied and compared with those of a coarse-grained as-cast cobalt reference sample. The bulk ultrafine-grained sample showed an ultra-high compressive yield strength that was greater than 1 GPa, which is discussed with respect to the preparation technique and a structural investigation.

  1. DRY AND WET GRINDING KINETICS OF CHROMIUM ORE AND EFFECT OF PULP DENSITY

    Directory of Open Access Journals (Sweden)

    Alper ÖZKAN

    2006-01-01

    Full Text Available In this study, the kinetics of dry and wet grinding of various feed sizes of chromium ore has been determined using a laboratory scale ceramic ball mill. In addition, the effect of pulp density on the spesific rate of breakage (Si and net production rate to finer than specified size were investigated. The dry and wet grinding of all the size intervals of chromium ore followed the first-order breakage law, and the Si values increased as the feed sizes became coarser. Moreover, the wet grinding of these various feed sizes gave higher Si values by a factor of 2.0 to 2.6 comparing to the dry Si values. From the experimental studies performed on the effect of pulp density on the grinding process, the highest Si value was obtained at a pulp density of 45 % solids by volume. At the same pulp density value, the rate of net production of -75 µm particle size also reached the highest value.

  2. 交流异步伺服系统在龙门刨铣磨中的应用%Application of AC asynchronous servo system in grinding-milling-planing

    Institute of Scientific and Technical Information of China (English)

    张莉军; 杜宏祺

    2012-01-01

    Using time servo control system for AC induction electric planer system technology upgrade, the use of the system within the integrated PLC, pulse, encoders, digital I/O, analog I/O, communications and other interface functions, without the configuration of PC to achieve closed-loop control. In the planer on the basis of a simplified mechanical structure to achieve a grinding-milling-planing integrated. Electronic hand wheel is applied to the non-CNC machine tool feed control, to achieve precision aligning cutter during milling and grinding. Applying specific servo position control system to achieve change without switching to improve system reliability and performance of non-NC machine tools.%使用时光交流异步伺服控制系统对龙门刨电气系统进行技术升级,利用系统内部集成的PLC、脉冲、编码器、数字I/0、模拟I/O、通讯等接口功能,不需配置上位机,实现闭环控制.在对龙门刨机械结构简化的基础上,实现了刨铣磨一体.并将电子手轮应用到非数控机床的进给控制中,达到了铣、磨加工时精确对刀的要求.应用伺服系统特有的位置控制方式,实现了无开关换向,提高了系统的可靠性和非数控机床的操控性能.

  3. 酶解-球磨法制备微细化淀粉的性质研究%Properties of micronized starch prepared by amylase hydrolysis and ball milling

    Institute of Scientific and Technical Information of China (English)

    吴国利; 扶雄; 黄强; 刘莎

    2011-01-01

    Native starch mashing with the traditional ball milling method takes much time and energy consumption,and the product is easily being gelatinized. In this paper, micronized starch was prepared by partially hydrolysis with amylase and then micronized with ball milling. The properties of the micronized starch were compared with native corn starch and ball milling starch. The results showed that the particle size of ball milling starch was slightly larger than that of native corn starch (12. 90 pm) ;While the particle size of amylase hydrolysis and ball milling pretreated starch was reduced significantly,and the crystalline structure was partially destroyed,part of the maltese cross lost, the intensity of birefringence weakened and crystal-linity reduced significantly.%传统微细化小颗粒淀粉的制备采用原淀粉直接球磨的方法,耗时长,能耗高,产物易糊化.采用先酶解再球磨的新工艺制备微细化小颗粒淀粉,并与玉米原淀粉、原淀粉球磨淀粉的性质进行比较.结果表明:玉米原淀粉的表面积平均粒径为12.90 μm,原淀粉球磨淀粉的表面积平均粒径略有增大,而酶解-球磨淀粉的表面积平均粒径显著降低;酶解-球磨淀粉的结晶结构受到一定程度的破坏,部分偏光十字消失,双折射强度减弱,结晶度显著降低.

  4. Research on Smooth Connection for Edge Curves of Conical Ball End Mill%锥形球头立铣刀刀刃曲线光滑过渡研究

    Institute of Scientific and Technical Information of China (English)

    乔小峰; 刘志兵; 庞思勤; 王西彬; 何理论

    2013-01-01

    针对锥形球头立铣刀的几何特征,应用广义螺旋运动概念建立了刀刃螺旋线的通用数学模型.利用微分几何的基本原理,研究了锥形球头立铣刀的刀刃曲线建模方法,设计了一种新的锥形球头立铣刀复合型刀刃曲线,解决了复合型刀刃曲线的光滑过渡问题,并应用Matlab软件对所设计的刀刃曲线进行了建模和验证.为锥形球头类刀具的进一步设计提供了理论方法和依据.%According to the geometrical characteristics of conical ball end mills,the general mathematical model of helical edge curves was established by using the concept of generalized helical movement.With the basic principles of differential geometry,the modelling method for edge curves of conical ball end mill was studied and a novel edge curve of conical ball end mill was designed,and the problem on the smooth connection of composite edge curves of conical ball end mill was also studied.Beside,the smooth connection of composite edge curves was modeled and verified by using Matlab.As a result,a theoretical method and basis for the further design of conical ball end mills was provided.

  5. Study on design of thrust blocks of large-scale ball mills with seismic loadings%地震载荷作用下大型球磨机止推块的抗震设计研究

    Institute of Scientific and Technical Information of China (English)

    刘普林; 郭勤涛; 姬建刚; 陈剑

    2011-01-01

    In order to study the anti-seismic performance of large-scale ball mills, the paper firstly establishes a finite element model of overall system composed of the ball mill barrel and the foundation. Then it finds the most dangerous conditions of earthquake, and respectively uses current national anti-seismic design code and Australian anti-seismic standards as the input stimulus to obtain the acceleration peak response of ball mills with seismic loadings in the finite element analysis software Nastran. In addition, the paper uses the peak response as the input loadings, establishes the finite element sub-model of the most dangerous parts of the ball mill, and further analyzes the contact strength of the dangerous parts. The analysis provides a theoretical basis for the anti-seismic structural design of large-scale ball mills and the overall anti-seismic design.%为了研究大型球磨机的抗震性能,首先建立了球磨机回转体和地基基础的整体系统有限元模型;寻找地震作用最危险工况,分别以我国现行抗震设计规范和澳大利亚抗震标准作为输入激励,在有限元分析软件Nastran中得到球磨机地震加速度峰值响应;然后,以该峰值响应作为输入载荷,建立了球磨机最危险部位的有限元子模型,进一步分析该危险部位的接触强度.该分析为大型球磨机抗震结构设计及整体抗震设计提供了理论依据.

  6. Study on Comminution Process and Micronization Efficiency of Potato Starch by Ball Milling%马铃薯淀粉的球磨破碎方式和微细化效果研究

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    采用机械球磨方法对马铃薯淀粉进行微粉碎,研究了球磨过程中淀粉颗粒的形貌、粒度分布及比表面积的变化特征,探讨了淀粉颗粒的破碎方式和粉碎模型,并考察了马铃薯淀粉微细化的效果。%Potato starch is mechanically ground by ball milling.The granular appearance,granule size distribution and specific surface of the starch are studied before and after milling.The comminution process and micronization effciency of the starch are discussed based on ultra-micronization model.The results show that potato starch can be effectively micronized by ball milling.

  7. Improving milling and production of a dust-producing unit equipped with hammer mills

    Energy Technology Data Exchange (ETDEWEB)

    Vorotnikov, Ye.G.; Nikiforov, A.A.; Rasputin, O.V.; Sukhunin, V.I.

    1982-01-01

    This paper presents generalized experience for deriving coarse ground coal dust in hammer mills by providing comparison data on improving efficiency of operation of the unit when switching to a coarser-type grind of the fuel. Need to have more precise formulas to calculate grinding potential of hammer mills when using a coarser grind is shown.

  8. Microstructure-Property Correlation in Magnesium-based Hydrogen Storage Systems: The Case for Ball-milled Magnesium Hydride Powder and Magnesium-based Multilayered Composites

    Science.gov (United States)

    Danaie, Mohsen

    The main focus of this thesis is the characterization of defects and microstructure in high-energy ball milled magnesium hydride powder and magnesium-based multilayered composites. Enhancement in kinetics of hydrogen cycling in magnesium can be achieved by applying severe plastic deformation. A literature survey reveals that, due to extreme instability of alpha-MgH 2 in transmission electron microscope (TEM), the physical parameters that researchers have studied are limited to particle size and grain size. By utilizing a cryogenic TEM sample holder, we extended the stability time of the hydride phase during TEM characterization. Milling for only 30 minutes resulted in a significant enhancement in desorption kinetics. A subsequent annealing cycle under pressurized hydrogen reverted the kinetics to its initial sluggish state. Cryo-TEM analysis of the milled hydride revealed that mechanical milling induces deformation twinning in the hydride microstructure. Milling did not alter the thermodynamics of desorption. Twins can enhance the kinetics by acting as preferential locations for the heterogeneous nucleation of metallic magnesium. We also looked at the phase transformation characteristics of desorption in MgH2. By using energy-filtered TEM, we investigated the morphology of the phases in a partially desorbed state. Our observations prove that desorption phase transformation in MgH2 is of "nucleation and growth" type, with a substantial energy barrier for nucleation. This is contrary to the generally assumed "core-shell" structure in most of the simulation models for this system. We also tested the hydrogen storage cycling behavior of bulk centimeter-scale Mg-Ti and Mg-SS multilayer composites synthesized by accumulative roll-bonding. Addition of either phase (Ti or SS) allows the reversible hydrogen sorption at 350°C, whereas identically roll-bonded pure magnesium cannot be absorbed. In the composites the first cycle of absorption (also called "activation

  9. Phase evolution during early stages of mechanical alloying of Cu–13 wt.% Al powder mixtures in a high-energy ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Dudina, Dina V.; Lomovsky, Oleg I. [Institute of Solid State Chemistry and Mechanochemistry SB RAS, Kutateladze str. 18, Novosibirsk 630128 (Russian Federation); Valeev, Konstantin R.; Tikhov, Serguey F.; Boldyreva, Natalya N. [Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Salanov, Aleksey N.; Cherepanova, Svetlana V.; Zaikovskii, Vladimir I. [Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Novosibirsk State University (NSU), Pirogova str. 2, Novosibirsk 630090 (Russian Federation); Andreev, Andrey S. [Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Novosibirsk State University (NSU), Pirogova str. 2, Novosibirsk 630090 (Russian Federation); Soft Matter Sciences and Engineering Laboratory, UMR 7615 CNRS UPMC, ESPCI ParisTech, 10 rue Vauquelin, Paris 75005 (France); Lapina, Olga B.; Sadykov, Vladislav A. [Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Novosibirsk State University (NSU), Pirogova str. 2, Novosibirsk 630090 (Russian Federation)

    2015-04-25

    Highlights: • Phase formation during early stages of Cu–Al mechanical alloying was studied. • The products of mechanical alloying are of highly non-equilibrium character. • X-ray amorphous phases are present in the products of mechanical alloying. • An Al-rich X-ray amorphous phase is distributed between the crystallites. - Abstract: We report the phase and microstructure evolution of the Cu–13 wt.% Al mixture during treatment in a high-energy planetary ball mill with a particular focus on the early stages of mechanical alloying. Several characterization techniques, including X-ray diffraction phase analysis, nuclear magnetic resonance spectroscopy, differential dissolution, thermal analysis, and electron microscopy/elemental analysis, have been combined to study the evolution of the phase composition of the mechanically alloyed powders and describe the microstructure of the multi-phase products of mechanical alloying at different length scales. The following reaction sequence has been confirmed: Cu + Al → CuAl{sub 2}(+Cu) → Cu{sub 9}Al{sub 4} + (Cu) → Cu(Al). The phase evolution was accompanied by the microstructure changes, the layered structure of the powder agglomerates disappearing with milling time. This scheme is further complicated by the processes of copper oxidation, reduction of copper oxides by metallic aluminum, and by variation of the stoichiometry of Cu(Al) solid solutions with milling time. Substantial amounts of X-ray amorphous phases were detected as well. Differential dissolution technique has revealed that a high content of aluminum in the Cu(Al) solid solution-based powders is due to the presence of Al-rich phases distributed between the Cu(Al) crystallites.

  10. Preparation of a sample with a single MgH2 phase by horizontal ball milling and the first hydriding reaction of 90 wt% Mg-10 wt% MgH2

    Science.gov (United States)

    Hong, Seong-Hyeon; Song, Myoung Youp

    2015-03-01

    In order to prepare an additive-free sample with a single MgH2 phase, 90 wt% Mg-10 wt% MgH2 (named 90Mg-10MgH2) was milled under a hydrogen atmosphere in a horizontal ball mill, and then hydrided. The hydrogen absorption and desorption properties of the prepared samples were investigated, and compared with those of milled pure Mg and purchased MgH2. X-ray diffraction analysis, measurement of specific BET surface areas, and observation of the prepared samples by scanning electron microscope were performed. The 90Mg-10MgH2 sample after hydriding-dehydriding cycling had small and large particles with fine particles on their surfaces, and had much finer particles and more defects than the milled pure Mg sample after hydridingdehydriding cycling. The specific BET surface areas of the milled Mg and 90Mg-10MgH2 were measured as 7.81 and 99.81 m2/g, respectively. A sample that had almost a single MgH2 phase could be prepared by horizontal ball milling and the first hydriding reaction of 90Mg-10MgH2. 90Mg-10MgH2 released 5.82 wt% H for about 70 min, while unmilled MgH2 (Aldrich) released 6.04 wt% H for about 100 min, at 648 K.

  11. 黄金矿山大型球磨机综合节能研究及应用%Study on comprehensive energy saving of large-scale ball mills in gold mines and its application

    Institute of Scientific and Technical Information of China (English)

    谢敏雄; 梅治福

    2014-01-01

    球磨机是岩金矿山选矿厂的重要设备,同时也是能耗大户。以三山岛金矿8000 t/d新立选矿厂MQY5.5 m ×8.5 m大型球磨机为工程实例,简要介绍了球磨机磨矿效能的影响因数,着重分析研究了大型球磨机磨矿效能影响因素优化节能、大型球磨机设计及参数优化节能、磨矿自动化及磨矿系统最大临界负荷节能。综合节能研究及生产应用取得了磨矿能耗降低17.24%的显著效果。%Ball mills are important equipment in ore-dressing plant of rock gold mines and they are also quite en-ergy-consuming.The paper,with MQY5.5 m ×8.5 m large-scale ball mills in 8 000 t/d Xinli ore-dressing plant as an example,briefly introduces influence parameters of ball mill efficiency and focuses on energy saving through optimiza-tion of influence parameters,design of large-scale ball mills and energy saving through its parameter optimization,mill-ing automation and energy saving through maximum critical load.A significant reslut of 17.24 %energy saving is a-chieved in the study and production application.

  12. Thermal behaviour of Cu-Ti and Cu-Ti-H amorphous powders prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Baricco, M. (Ist. Elettrotecnico Nazionale Galileo Ferraris and INFM/GNSM, Research Unity, Turin (Italy)); Battezzati, L. (Dipt. di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Turin Univ. (Italy)); Soletta, I.; Schiffini, L. (Dipt. di Chimica, Univ. di Sassari (Italy)); Cowlam, N. (Dept. of Physics, Univ. of Sheffield (UK))

    1991-03-25

    Solid state amorphization reactions in Cu-Ti have been studied by means of DSC and structural techniques. The influence of hydrogen from the parent titanium powder on the amorphization and crystallization processes has been investigated. For Cu-Ti a diffusion-controlled process can be inferred for solid state amorphization from the parabolic trend of the heat of crystallization, as a function of the milling time. The presence of hydrogen in the alloys is found to modify the crystallization behaviour of the amorphous phase. A DSC method for the determination of the amount of hydrogen present in the alloys is given. (orig.).

  13. Magnetocaloric effect in high-energy ball-milled Gd{sub 5}Si{sub 2}Ge{sub 2} and Gd{sub 5}Si{sub 2}Ge{sub 2}/Fe nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, D.M.; Manivel Raja, M. [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India); Gopalan, R. [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India)], E-mail: rg_gopy@yahoo.com; Chandrasekaran, V. [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India)

    2008-04-15

    Evolution of structure and magnetocaloric properties in ball-milled Gd{sub 5}Si{sub 2}Ge{sub 2} and Gd{sub 5}Si{sub 2}Ge{sub 2}/0.1 wt% Fe nanostructured powders were investigated. The high-energy ball-milled powders were composed of very fine grains (70-80 nm). Magnetization decreased with milling time due to decrease in the grain size and randomization of the magnetic moments at the surface. The magnetic entropy change ({delta}S{sub M}) was calculated from the isothermal magnetization curves and a maximum value of 0.45 J/kg K was obtained for 32 h milled Gd{sub 5}Si{sub 2}Ge{sub 2} alloy powder for a magnetic field change of 2 T while it was still low in Fe-contained alloy powders. The thermo-magnetic measurements revealed that the milled powders display distribution of magnetic transitions, which is desirable for practical magnetic refrigerant to cover a wide temperature span.

  14. 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.

  15. 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.

  16. Hydrogen storage properties of MgH2-diatomite composites obtained by high-energy ball milling.

    Science.gov (United States)

    Milovanović, S; Matović, L; Drvendzija, M; Novaković, J G

    2008-12-01

    To investigate the effects of specific porous microstructure of diatomite on the hydrogen storage properties of MgH(2), a two-step preparation was carried out. The first step was decrepitation of MgH(2) particle size during 10 h of milling. The second step was additional 1 h of milling with diatomite. The microstructure and phase composition of materials was characterized by X-ray diffraction, whereas the powder morphology and degree of additive dispersion were analyzed by scanning electron microscopy. The hydrogen desorption behaviour of nanocomposites was investigated by differential scanning calorimetry. The results show that addition of porous diatomite structure leads to decrease in desorption temperature, since there was no other effect that can have an influence on kinetics, such as formation of the metastable gamma-phase, reduction of oxides to the native metal and/or homogeneous dispersion of the catalyst. This indicates that the microstructure of added material plays the main role in the enhancement of desorption properties of composites.

  17. 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}.

  18. 酒钢选烧厂新型磨矿介质工业试验研究%In-situ Performance Evaluation for New-type Grinding Media in JISCO

    Institute of Scientific and Technical Information of China (English)

    张志荣; 叶传勇; 司胜

    2016-01-01

    对酒钢选烧厂的磨矿介质进行了工业试验研究。结果表明,低铬铸球单耗为0.316 kg/t,高铬铸球单耗为0.214 kg/t,热轧钢球单耗为0.185 kg/t。采用热轧钢球作球磨机介质,碎球率极低,钢球经过一个阶段使用后,钢球硬度内外均匀,性能稳定,外形尺寸圆度好。%Commercial tests were carried out to evaluate the performance of grinding media used in Concentration and Sintering Plant of JISCO. The results show that, unit consumption of low⁃chrome cast iron ball, high⁃chrome cast iron ball and hot⁃rolled steel ball is 0.316, 0.214 and 0.185 kg/t, respectively. The hot⁃rolled steel ball, as grinding medium in ball mills, can have an extremely low breakage ratio, and remain stable performance after running for a certain period of time, with the uniform ball hardness for the inner and outer parts, roundness in boundary dimension remaining unchanged.

  19. 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.

  20. 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.

  1. Ultra-fine grinding and mechanical activation of mine waste rock using a high-speed stirred mill for mineral carbonation

    Institute of Scientific and Technical Information of China (English)

    Jia-jie Li; Michael Hitch

    2015-01-01

    CO2 sequestration by mineral carbonation can permanently store CO2 and mitigate climate change. However, the cost and reaction rate of mineral carbonation must be balanced to be viable for industrial applications. In this study, it was attempted to reduce the carbonation costs by using mine waste rock as a feed stock and to enhance the reaction rate using wet mechanical activation as a pre-treatment method. Slurry rheological properties, particle size distribution, specific surface area, crystallinity, and CO2 sequestration reaction efficiency of the initial and mechanically activated mine waste rock and olivine were characterized. The results show that serpentine acts as a catalyst, in-creasing the slurry yield stress, assisting new surface formation, and hindering the size reduction and structure amorphization. Mechanically activated mine waste rock exhibits a higher carbonation conversion than olivine with equal specific milling energy input. The use of a high-speed stirred mill may render the mineral carbonation suitable for mining industrial practice.

  2. Development of MQY6095 ball mill and FEA of key structures%MQY6095型球磨机开发与关键结构有限元分析

    Institute of Scientific and Technical Information of China (English)

    马振刚; 李建明; 刘楠楠; 唐威; 田磊

    2011-01-01

    To adapt to the large-scale development trend of ball mills, MQY6095 ball mill has been developed.In the paper, based on the structural characteristics of the ball mill, stress and distortion of the rotary body are computed using FEM, and then the stress at the round comer of the end cover and the quill shaft are calculated by applying radial force to the quill shaft. Lastly the pressure distribution and the velocity distribution of the oil film of the bearing are calculated with computing fluid dynamics method. The field application shows that the analysis results is coincident well with the measured data, which indicates that the design ensures the reliability of the ball mill.%为了适应球磨机大型化的发展趋势,开发了MQY6095型球磨机.针对该球磨机的结构特点,用有限元方法计算得到了回转部的整体应力和变形,然后在中空轴处施加支撑力,计算中空轴和端盖圆角处的应力,最后用计算流体动力学方法计算得到了轴承油膜的压力分布和速度分布.现场应用表明,分析结果与实际观测值吻合得很好,说明该设计方法有效地保证了球磨机设计的可靠性.

  3. Effect of ball-milling and Fe-/Al-doping on the structural aspect and visible light photocatalytic activity of TiO2 towards Escherichia coli bacteria abatement.

    Science.gov (United States)

    Schlur, Laurent; Begin-Colin, Sylvie; Gilliot, Pierre; Gallart, Mathieu; Carré, Gaëlle; Zafeiratos, Spiros; Keller, Nicolas; Keller, Valérie; André, Philippe; Greneche, Jean-Marc; Hezard, Bernard; Desmonts, Marie-Hélène; Pourroy, Geneviève

    2014-05-01

    Escherichia coli abatement was studied in liquid phase under visible light in the presence of two commercial titania photocatalysts, and of Fe- and Al-doped titania samples prepared by high energy ball-milling. The two commercial titania photocatalysts, Aeroxide P25 (Evonik industries) exhibiting both rutile and anatase structures and MPT625 (Ishihara Sangyo Kaisha), a Fe-, Al-, P- and S-doped titania exhibiting only the rutile phase, are active suggesting that neither the structure nor the doping is the driving parameter. Although the MPT625 UV-visible spectrum is shifted towards the visible domain with respect to the P25 one, the effect on bacteria is not increased. On the other hand, the ball milled iron-doped P25 samples exhibit low activities in bacteria abatement under visible light due to charge recombinations unfavorable to catalysis as shown by photoluminescence measurements. While doping elements are in interstitial positions within the rutile structure in MPT625 sample, they are located at the surface in ball milled samples and in isolated octahedral units according to (57)Fe Mössbauer spectrometry. The location of doping elements at the surface is suggested to be responsible for the sample cytotoxicity observed in the dark.

  4. 浅谈球磨机在金川选矿厂的应用现状和发展趋势%Current application status and development tendency of ball mills in Jinchuan concentrator

    Institute of Scientific and Technical Information of China (English)

    鲁培兴

    2012-01-01

    简要介绍球磨机的发展状况以及金川选矿厂球磨机的应用现状,根据目前金川选矿厂技术改造或扩建中采用球磨机的性能特点,归纳出金川选矿厂今后将采用大型化、高可靠性的球磨机,并实现球磨机的计算机自动控制。%The paper briefl y introduced the development status of the ball mill as well as its current application in the concentrator of Jinchuan Group Co.,Ltd.(abbreviated as Jinchuan concentrator).According to the performance of the ball mills applied in technical innovation or scale expansion in Jinchuan concentrator,it indicated that the large-scale and high-reliability ball mills should be used,and automatic control by computers should be realized in Jinchuan concentrator.

  5. 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.

  6. Preparation of Nylon Ball-stirring Mill Lining Modified by Polyurethane%聚氨酯改性尼龙球磨机内衬的研制

    Institute of Scientific and Technical Information of China (English)

    赵伟; 杨洁; 赵彩荣; 周刚

    2013-01-01

    A polyurethane prepolymer w as synthesized to modify the monomer casting nylon. The result showed that when the prepolymer prepared at the NCO content of 4% with PTMG molecular weight of 2000 and the prepolymer dosage was 15% mass fraction of copolymer,copolymer had maximum impact strength. The modified material used in ball-stirring mill lining had better temperature-resistance property than polyurethane lining.%采用相对分子质量为2000的聚四亚甲基醚二醇(PTMG)合成NCO质量分数为4.0%的聚氨酯预聚体,用于增韧改性铸型(MC)尼龙.结果表明,当预聚体的用量为共聚物质量分数的15%,共聚产品显示出最大的冲击强度,将此改性材料应用于球磨机内衬,显示出比聚氨酯内衬更好的耐温性能.

  7. 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.

  8. Electric modulus formalism and electrical transport property of ball mill synthesized nanocrystalline Mn doped ZrO{sub 2} solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Saha, S. [Department of Physics, National Institute of Technology, Durgapur, Burdwan 713209, West Bengal (India); Nandy, A. [Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India); Meikap, A.K., E-mail: meikapnitd@yahoo.com [Department of Physics, National Institute of Technology, Durgapur, Burdwan 713209, West Bengal (India); Pradhan, S.K. [Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

    2015-12-15

    Here we report the formation of Mn doped nanocrystalline ZrO{sub 2} solid solution synthesized by high energy ball-milling method and the transport mechanism in the temperature range 298 K

  9. 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

  10. Grinding Characteristic of Multi-walled Carbon Nanotubes-alumina Composite Particle

    Institute of Scientific and Technical Information of China (English)

    B MUNKHBAYAR; Nasan BAYARAA; Hafizur REHMAN; Junhyo KIM; Hanshik CHUNG; Hyomin JEONG

    2012-01-01

    The synthesis of new materials containing multi-walled carbon nanotubes (MWCNTs) and the microstructure of alumina particles were investigated and characterized.The MWCNTs and alumina particles were ground under both the dry and wet conditions with various rotation speeds (200-400 r/min) in planetary ball milling machine,and their combination characteristics were described.The experimental results were examined by scanning electron microscopy (SEM),X-ray diff action (XRD),transmission electron microscopy (TEM) and particle sizing analysis (PSA).SEM result revealed that the combination of MWCNTs -Alumina particles mixed quite well under both the dry and wet grinding with rotation speed of 400 r/min.XRD characterization indicated the better result could get in ground samples at a rotation speed of 400 r/min.PSA result showed the particle size decreased with increase the grinding speeds.From the overall results,we observed that the grinding method can be used to synthesize new material with high efficiency.

  11. Design of Universal Grinding Device Using in Vertical Turning and Milling Center%应用于立式车铣中心的万能磨削装置的设计

    Institute of Scientific and Technical Information of China (English)

    喻鹏; 刘兴卓; 洪寿福

    2013-01-01

    The universal grinding device that using in the Vertical Turning and Milling Center was included with electric spindle and manual universal mechanism.The power supply and cooling liquid circulating system was integrated in the machine tool,with which the integrated multi-processing could be realized when the workpiece was clamped in one time.By using this device,working accuracy of machine tool is improved,and the working efficiency is improved greatly.%应用于立式车铣中心的万能磨削装置,包括电主轴及手动万能机构,其电源与冷却液循环系统集成在立式车铣中心机床上,可实现工件一次装卡,多种工序集成加工.使用该装置,提高了机床工作精度,同时大大提高了工作效率.

  12. 膨润土的有机改性与球磨细小化及其助留性能研究%Organic modification and ball milling of bentonite and its retention properties

    Institute of Scientific and Technical Information of China (English)

    陈威; 李友明; 万小芳

    2011-01-01

    采用十八烷基三甲基溴化铵(STAB)对膨润土进行了有机改性并对改性膨润土球磨细小化。对制得的改性膨润土进行了扫描电镜(SEM)、傅里叶红外光谱(FT-IR)、X射线衍射(XRD)实验分析。结果表明,有机表面活性剂STAB已经进入膨润土的片层间,层间距由1.256nm增大到2.694nm;晶面间距增大的最佳实验条件为:STAB用量为40%,反应时间为4h,反应温度为75℃。通过对球磨后的改性膨润土进行SEM观察发现,球磨时间2h能使其颗粒基本达到亚微米至纳米级,粒度分布范围为100~500nm。对球磨改性膨%Stearyltrimethyl ammonium bromide was used for organic modification of bentonite and then ball milled the modified bentonite.The organically modified bentonite was analyzed by SEM,FT-IR and XRD.The results show that the stearyltrimethyl ammonium bromide has been interalated into the layers of bentonite.The layer distance of the bentonite is increased from 1.256nm to 2.694nm.The appropriate experimental conditions of interplanar spacing increasing were the dosage of STAB 40%,reaction time 4h,temperature 75℃.The ball milled organically modified bentonite was analyzed by SEM.The results show that the particle mainly reach submicron to nanometer when ball mill 2h.The particle size distribution range is from 100 to 500nm.Ball milled organically modified bentonite/CPAM can improve retention rate of OCC pulp obviously than organically modified bentonite/CPAM because of smaller grains and better unigormity of ball milled bentonite.

  13. Influence of Ball Milling on Boron Carbide's Particle Size and Content of Free C%球磨对碳化硼粒度及游离碳的影响

    Institute of Scientific and Technical Information of China (English)

    王慧华; 孙树臣; 王德永; 涂赣峰; 马伟民; 郭卓; 曹大力; 马雷

    2012-01-01

    Boron carbide powders show wide application advantages in the fields of wear-resistant materials and high-hardness ceramics.The ball milling technologies have strong effect on the particle size of boron carbide.The influence of milling factors on particle size distribution of boron carbide and the content of free C with increasing milling time were investigated in this paper.The results show that the particle size distribution curve of boron carbide shifted to small size direction with increasing milling time;the refinement slowed down when after milling for 60 h and the concentration of ultrafine particles could be improved with further milling.The different ball-to-powder mass ratio had slight effect on particle size distribution curve of boron carbide when the milling time reached a certain level.The content of free C increased significantly in the range of 20~40 h and became marginally after further milling.The morphologies of the starting material and milled powder were observed by scanning electronic microscopy.X-ray diffraction showed that some strong diffractions of free C were detected after milling for 60 h.%主要研究球磨因素对碳化硼粒度分布的影响,并考察游离碳含量随球磨时间的变化规律.实验结果表明:随着球磨时间增加,碳化硼粒径分布曲线向粒径小的方向移动,当球磨时间达到60 h,粉体粒径细化程度减缓,继续球磨可进一步提高超细颗粒含量;当球磨时间达到一定程度,不同的球料比对粉体粒径分布曲线影响较小;游离碳含量随着球磨时间增加而提高,在20~40 h碳含量增加显著,之后增加缓慢;SEM电镜显示球磨前后粉体显微形貌发生显著变化;XRD分析显示球磨60 h后粉体中出现很强的游离碳衍射峰.

  14. Optimization of operating variables for production of ultra-fine talc in a stirred mill. Specific surface area investigations

    Directory of Open Access Journals (Sweden)

    Toraman Oner Yusuf

    2016-01-01

    Full Text Available Due to its properties such as chemical inertness, softness, whiteness, high thermal conductivity, low electrical conductivity and adsorption properties talc has wide industrial applications in paper, cosmetics, paints, polymer, ceramics, refractory materials and pharmaceutical. The demand for ultra-fine talc is emerging which drives the mineral industry to produce value added products. In this study, it was investigated how certain grinding parameters such as mill speed, ball filling ratio, powder filling ratio and grinding time of dry stirred mill affect grindability of talc ore (d97=127 μm. A series of laboratory experiments using a 24 full factorial design was conducted to determine the optimal operational parameters of a stirred mill in order to minimize the specific surface area. The main and interaction effects on the volume specific surface area (SV, m2.cm−3 of the ground product were evaluated using the Yates analysis. Under the optimal conditions at the stirrer speed of 600 rpm, grinding time of 20 min, sample mass of 5% and ball ratio of 70%, the resulting talc powder had larger volume specific surface area (i.e., 3.48 m2.cm−3 than the starting material (i.e., 1.84 m2.cm−3.

  15. A New Shaping Model for Green Ceramic Balls

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The shaping quality of green ceramic balls is directly related to the efficiency and cost of later machining for the ceramic balls. Until now the shaping for green ceramic balls is still conducted by handwork. In this paper, a new shaping model for green ceramic balls was designed. In the new model, two grinding wheels with the same generator line as circular arc are mounted on symmetry, and their axes are parallel. The green ball can be put in the enveloping space formed by the two grinding wheels. The rad...

  16. Synthesis, structural and hydrogenation properties of Mg-rich MgH2-TiH2 nanocomposites prepared by reactive ball milling under hydrogen gas.

    Science.gov (United States)

    Cuevas, Fermin; Korablov, Dmytro; Latroche, Michel

    2012-01-21

    MgH(2)-TiH(2) nanocomposites have been obtained by reactive ball milling of elemental powders under 8 MPa of hydrogen pressure. The composites consist of a mixture of β-rutile MgH(2), γ-orthorhombic high pressure MgH(2) and ε-tetragonal TiH(2) phases with nanosized crystallites ranging from 4 to 12 nm. In situ hydrogen absorption curves on milling reveal that nanocomposite formation occurs in less than 50 min through the consecutive synthesis of the TiH(2) and MgH(2) phases. The abrasive and catalytic properties of TiH(2) speed up the formation of the MgH(2) phase. Thermodynamic, kinetic and cycling hydrogenation properties have been determined for the 0.7MgH(2)-0.3TiH(2) composite and compared to nanometric MgH(2). Only the MgH(2) phase desorbs hydrogen reversibly at moderate temperature (523 to 598 K) and pressure (10(-3) to 1 MPa). The presence of TiH(2) does not modify the thermodynamic properties of the Mg/MgH(2) system. However, the MgH(2)-TiH(2) nanocomposite exhibits outstanding kinetic properties and cycling stability. At 573 K, H-sorption takes place in less than 100 s. This is 20 times faster than for a pure nanometric MgH(2) powder. We demonstrate that the TiH(2) phase inhibits grain coarsening of Mg, which allows extended nucleation of the MgH(2) phase in Mg nanoparticles before a continuous and blocking MgH(2) hydride layer is formed. The low crystallinity of the TiH(2) phase and its hydrogenation properties are also compatible with a gateway mechanism for hydrogen transfer from the gas phase to Mg. Mg-rich MgH(2)-TiH(2) nanocomposites are an excellent media for hydrogen storage at moderate temperatures.

  17. GRINDING OF DOUBLE DISC GRINDING MACHINE

    Institute of Scientific and Technical Information of China (English)

    Hu Huiqing

    2005-01-01

    The grinding of two parallel sides of a component is accomplished with the accuracy and higher productivity by passing a blank through the truncated cone shape grinders, which are turned angles. The machine is designated by the name of double disc grinding machine (DDGM). Usually, it is used in the mass production. The relationship between these angles, the accuracy, productivity,allowance and parameters of the machine and technology is explained in detail by math, such as vector analysis, transformation of 3D space coordinates, etc. Therefore, in the aspects of qualitative and quantitative analyses, the grinding potential of DDGM is enormous increased and superior to conventional methods. Furthermore, the theoretical foundation of DDGM grinding design and technology is provided to improve, to expand and to create for future. The established machine design and practical experience of grinding technology will get great benefit by them.

  18. Obtention of hydroxyapatite submicrometric of bovine origin by vibratory grinding for rapid prototyping; Obtencao de hidroxiapatita submicrometrica de origem bovina por moagem vibratoria visando prototipagem rapida

    Energy Technology Data Exchange (ETDEWEB)

    Meira, C.R.; Purquerio, B.M.; Fortulan, C.A., E-mail: camilameira@sc.usp.br [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia; Braga, F.J.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Submicron bovine hydroxyapatite was obtained for rapid prototyping. Hydroxyapatite structure originated from bovine mineral bone has great importance among the biomaterials and biocompatibility due to its great similarity with the human bone structure. This study aims to obtain powder for manufacture by rapid prototyping of scaffolds. This technique manufacture requires highly reactive powders to compensate for the absence of pressure forming. Hydroxyapatite was milled in a ball mill and vibratory mill, and analyzed for their average equivalent spherical diameter and surface area. Test specimens were isostatically pressed at 100 MPa and machined into cylindrical test specimens. These specimens were sintered at several temperatures to determine the optimal sintering temperature based on densification and chemistry stability. In grinding ball mill was obtained particles of equivalent diameter of 0.74 micron in vibratory mill of 0.46 micrometers. An average flexural strength of 100 MPa and 99,8% of real density was attained for the sample sintered at 1300 deg C/2h, signaling potential for use in rapid prototyping. (author)

  19. Ball-milled nano-colloids of rare-earth compounds as liquid gain media for capillary optical amplifiers and lasers

    Science.gov (United States)

    Patel, Darayas; Blockmon, Avery; Ochieng, Vanesa; Lewis, Ashley; Wright, Donald M.; Lewis, Danielle; Valentine, Rueben; Valentine, Maucus; Wesley, Dennis; Sarkisov, Sergey S.; Darwish, Abdalla M.; Sarkisov, Avedik S.

    2017-02-01

    Nano-colloids and nano-crystals doped with ions of rare-earth elements have recently attracted a lot of attention in the scientific community due to their potential applications as biomarkers, fluorescent inks, gain media for lasers and optical amplifiers. Many rare-earth doped materials of different compositions, shapes and size distribution have been prepared by different synthetic methods, such as chemical vapor deposition, sol-gel process, micro-emulsion techniques, gas phase condensation methods, hydrothermal methods and laser ablation. In this paper micro-crystalline powder of the rare-earthdoped compound NaYF4:Yb3+, Er3+ was synthesized using a simple wet process followed by baking in open air. Under 980 nm diode laser excitation strong fluorescence in the 100 nm band around 1531-nm peak was observed from the synthesized micro-powder. The micro-powder was pulverized using a ball mill and prepared in the form of nano-colloids in different liquids. The particle size of the obtained nano-colloids was measured using an atomic force microscope and a dynamic light scatterometer. The size of the nano-particles was close to 100-nm. The nano-colloids were utilized as a filling media in capillary optical amplifiers and lasers. The gain of a 7-cm-long capillary optical amplifier (150-micron inner diameter) was as high as 6 dB at 200 mW pump power. The synthesized nano-colloids and the active optical components using them can be potentially used in optical communication, signal processing, optical computing, and other applications.

  20. STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL

    Directory of Open Access Journals (Sweden)

    S.K. GARG

    2010-06-01

    Full Text Available Grinding is a unit operation to break big solid material into smaller pieces. As far as process of grinding is concerned, power consumption, specific energy consumption and particle size distribution and mill capacity are main considerations from engineering point of view. The experiments were conducted to study the effect of speed of mill, sieve size, feed rate and time of grinding on power consumption and average particle diameter of water chestnut in continuous grinding process. Power consumption was measured for a constant feed rate of 1 and 2 kg/h at different speed of the mill varied from 800 to 1200 rpm for the sieve openings of 0.5 mm, 1.0 mm and 2.0 mm. For all the sieve sizes and feed rates, it was observed that as the speed of the mill increases, there is an increase in power consumption and found significantly low for higher sieve size and lower feed rate. The size distribution of the water chestnut kernel for different speeds and sieve sizes at constant feed rate were obtained by sieve analysis. The milling speed has no significant effect on particle size distribution of ground product and mass fraction was minimum at lower feed rate and higher sieve size. Harris model was found best suitable to describe the size distribution in continuous grinding process. Fineness modulus decreases with increase of milling speed for experimental sieve size and feed rate.

  1. 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.

  2. 基于复制测量法的球头立铣刀磨损预测研究%Study on Prediction of Ball End Mill Wear Based on Copy Measurement

    Institute of Scientific and Technical Information of China (English)

    孙博; 陈锦江; 王芳; 孙占伟; 田广伟

    2016-01-01

    论文提出一种测量球头立铣刀磨损量的复制测量方法并分析该方法的误差。以铣刀径向磨损量为研究对象进行刀具磨损试验,找出铣削参数对刀具磨损的影响规律,得出径向磨损量增量与铣削参数的铣刀磨损模型和刀具寿命经验公式,并通过试验验证磨损模型具有较高精度,可用于磨损量预测。%This paper proposes a copy measurement of ball end mill wear and analyzes the error of this meth-od. The radial mill wear quantity as the research object for the tool wear test, find out the influence law of milling parameters on tool wear. It is concluded that the radial wear increment and the milling parameters of milling cutter tool wear model and tool life experience formula can be obtained, and through the test the wear model has higher accuracy and is useful to predict the amount of wear.

  3. In situ Fabrication of Fe-TiB{sub 2} Nanocomposite Powder by Planetary Ball Milling and Subsequent Heat-treatment of FeB and TiH{sub 2} Powder Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Xuan-Khoa [Hanoi Uneversity of Science and Technology, Hanoi (Viet Nam); Bae, Sun-Woo; Kim, Ji Soon [University of Ulsan, Ulsan (Korea, Republic of)

    2017-01-15

    Fe-TiB{sub 2} powder was synthesized in-situ by the planetary ball milling and subsequent heat-treatment of an iron boride (FeB) and titanium hydride (TiH{sub 2}) powder mixture. Mechanical activation of the (FeB+TiH{sub 2}) powder mixtures was observed after a milling time of 3 hours at 700 rpm of rotation speed, but activation was not the same after 1 hour milling time. The particle size of the (FeB+ TiH{sub 2}) powder mixture was reduced to the nanometer scale, and each constituent was homogeneously distributed. A sharp exothermic peak was observed at a lower temperature (749 ℃) on the DSC curves for the (FeB+TiH{sub 2}) powder mixture milled for 3 hours, compared to the one milled for 1 hour (774 ℃). These peaks were confirmed to have resulted from the formation reaction of the TiB{sub 2} phase, from Ti and B elements in the FeB. The Fe-TiB{sub 2} composite powder fabricated in situ exhibited only two phases of Fe and TiB{sub 2} with homogeneous distribution. The size of the TiB{sub 2} particulates in the Fe matrix was less than 5 nm.

  4. CZKQ5263龙门式车铣钻磨加工中心结构设计和优化%Structure Design and Optimization for CZKQ5263 Gantry-typed Machining Center of Turning, Milling, Drilling and Grinding

    Institute of Scientific and Technical Information of China (English)

    韩玉坤; 张运真; 张传生

    2012-01-01

    To process large plate covered parts, based on the structure of vertical lathe, a modular machine tool with a movable gantry and a traditional vertical lathe worktable was designed. In the case of a fixture, the turning, milling, grinding of cylindrical surface, end surface and ring groove and the drilling, reaming of holes on the large plate covered parts were completed, reducing clamping times, saving time of handling, lifting and clamping part. A three-dimensional model of the whole modular machine tool was built and the multi-body kinematic analysis was made. Aiming at the key component, finite element analysis was carried out to optimize its structure.%针对大型盘盖类零件的加工要求,参照立式车床的结构,设计一种由可动式龙门框架和传统立车工作台组合而成的机床.在一次装夹的情况下,能够完成大型盘盖类零件的外圆、端面和环槽的车、铣、磨以及钻、铰孔等工作,可减少装夹次数,节约搬运、吊装、装夹的时间.建立了整机的三维模型并进行了多体运动学分析,针对关键零件进行了有限元分析和仿真设计,改善了产品的结构.

  5. 酸解-球磨法制备小颗粒淀粉及形成机理研究%Form Mechanism of Micronized Starch Prepared by Acid Hydrolysis and Ball Milling

    Institute of Scientific and Technical Information of China (English)

    刘莎; 扶雄; 黄强

    2011-01-01

    传统微细化小颗粒淀粉的制备采用原淀粉直接球磨的方法,耗时长,能耗高,产物易糊化.采用先酸解再球磨的新工艺制备了微细化小颗粒淀粉,并与玉米原淀粉、酸处理淀粉的物化性质进行了比较.结果表明,玉米原淀粉的表面积平均粒径为12.9μm,酸处理后淀粉的表面积平均粒径没有明显变化,而微细化淀粉的表面积平均粒径有显著降低;酸处理淀粉的结晶度较原淀粉有所增加,而酸水解后球磨淀粉结晶结构减弱,部分偏光十字消失,双折射强度减弱.%Starch mashing with the traditional ball milling method takes much time and energy consumption, and the product is easily being gelatinized. In this work, micronized starch was prepared by partially hydrolysis with inorganic acid and then micronized with ball milling. The physicochemical properties of the micronized starch were compared with native corn starch and acid modified starch. Results: The particle size of acid modified starch is similar to that of native corn starch( 12.9 μm) ,and is reduced significantly after the micronization. The crystalline structure of the acid pretreated corn starch is destroyed by the ball milling,part of the polarization cross disappear,and the intensity of birefringence is weakened.

  6. [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.

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

    Science.gov (United States)

    Phong, P. T.; Manh, D. H.; Nguyen, L. H.; Tung, D. K.; Phuc, N. X.; Lee, I.-J.

    2014-11-01

    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.

  8. Glueballs amass at RHIC and LHC Colliders! - The early quarkless 1st order phase transition at $T=270$ MeV - from pure Yang-Mills glue plasma to GlueBall-Hagedorn states

    CERN Document Server

    Stoecker, Horst; Schramm, Stefan; Senzel, Florian; Greiner, Carsten; Beitel, Maxim; Gallmeister, Kai; Gorenstein, Mark; Mishustin, Igor; Vasak, David; Steinheimer, Jan; Struckmeier, Juergen; Vovchenko, Volodymyr; Satarov, Leonid; Xu, Zhe; Zhuang, Pengfei; Csernai, Laszlo P; Sinha, Bikash; Raha, Sibaji; Biró, Tamás Sándor; Panero, Marco

    2016-01-01

    The early stage of high multiplicity pp, pA and AA collider is represented by a nearly quarkless, hot, deconfined pure gluon plasma. According to pure Yang-Mills Lattice Gauge Theory, this hot pure glue matter undergoes, at a high temperature, $T_c = 270$ MeV, a first order phase transition into a confined Hagedorn-GlueBall fluid. These new scenario should be characterized by a suppression of high $p_T$ photons and dileptons, baryon suppression and enhanced strange meson production. We propose to observe this newly predicted class of events at LHC and RHIC.

  9. High productive technique for polishing free surface with elastic ball type wheel on grinding center%橡胶轮研磨中心高效抛光自由曲面的技术

    Institute of Scientific and Technical Information of China (English)

    吴晓君; 孙树栋

    2007-01-01

    Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding centers have been developed, which are used for free surface polishing in the present work. The new polishing technique applies the same cutting locus as used in the cutting process to remove only cusp height effectively, keeping the form accuracy generated in the cutting process.

  10. 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)

  11. Solution-state 2D NMR of ball-milled plant cell wall gels in DMSO-d6/pyridine-d5†

    Science.gov (United States)

    Ralph, John

    2014-01-01

    NMR fingerprinting of the components of finely divided plant cell walls swelled in DMSO has been recently described. Cell wall gels, produced directly in the NMR tube with perdeutero-dimethylsulfoxide, allowed the acquisition of well resolved/dispersed 2D 13C–1H correlated solution-state NMR spectra of the entire array of wall polymers, without the need for component fractionation. That is, without actual solubilization, and without apparent structural modification beyond that inflicted by the ball milling and ultrasonication steps, satisfactorily interpretable spectra can be acquired that reveal compositional and structural details regarding the polysaccharide and lignin components in the wall. Here, the profiling method has been improved by using a mixture of perdeuterated DMSO and pyridine (4:1, v/v). Adding pyridine provided not only easier sample handling because of the better mobility compared to the DMSO-d6-only system but also considerably elevated intensities and improved resolution of the NMR spectra due to the enhanced swelling of the cell walls. This modification therefore provides a more rapid method for comparative structural evaluation of plant cell walls than is currently available. We examined loblolly pine (Pinus taeda, a gymnosperm), aspen (Populus tremuloides, an angiosperm), kenaf (Hibiscus cannabinus, an herbaceous plant), and corn (Zea mays L., a grass, i.e., from the Poaceae family). In principle, lignin composition (notably, the syringyl : guaiacyl : p-hydroxyphenyl ratio) can be quantified without the need for lignin isolation. Correlations for p-coumarate units in the corn sample are readily seen, and a variety of the ferulate correlations are also well resolved; ferulates are important components responsible for cell wall cross-linking in grasses. Polysaccharide anomeric correlations were tentatively assigned for each plant sample based on standard samples and various literature data. With the new potential for chemometric analysis

  12. A novel application of α-glucosyl hesperidin for nanoparticle formation of active pharmaceutical ingredients by dry grinding.

    Science.gov (United States)

    Tozuka, Yuichi; Imono, Masaaki; Uchiyama, Hiromasa; Takeuchi, Hirofumi

    2011-11-01

    The effectiveness of α-glucosyl hesperidin (Hsp-G) as a novel grinding aid for the preparation of drug nanoparticles by dry grinding was investigated. Poorly water-soluble drugs and Hsp-G were mixed at a weight ratio of 1/5 and ground for 60 min by a vibrational ball mill. It was evident that all poorly water-soluble drugs used in this study formed nanoparticles after the ground mixtures were dispersed into distilled water. The dissolution profile of glibenclamide from the ground mixtures of glibenclamide/Hsp-G showed dramatic improvement from that of untreated drug crystals. Administration of the ground mixture of glibenclamide/Hsp-G to rats resulted in a significantly higher rate of decrease in blood glucose levels than that of untreated glibenclamide. The area above the time-curve of plasma-glucose concentrations using the ground mixture of glibenclamide/Hsp-G was 6-fold higher than that using untreated glibenclamide. The improved dissolution rate due to nanoparticle formation of glibenclamide, induced by co-grinding with Hsp-G, was responsible for this improvement.

  13. Experimental Research on Grinding Technology for an Oxide Lead-zinc Ore in Shanxi%陕西某氧化铅锌矿磨矿技术试验研究

    Institute of Scientific and Technical Information of China (English)

    缑明亮; 武俊杰; 杨柳

    2013-01-01

    The steel ball filling system of the ball mill has influence on the grinding fineness,argillization degree and grinding efficiency.Directed at the properties of this ore,through the two aspects of the filling amount and the ratio of different size of balls,the research on the grinding technology,grinding efficiency and argillization degree was carried on to find the optimal filling system.As a result,the optimal grinding condition was determined as the steel ball size of 30mm,29mm,27mm,18mm,15mm and the ratio of the ball weight as 5.89,5.51,46.56,19.4,12.64.Meanwhile,the filling amount is 10.56kg.This kind of filling system has the characteristics with high grinding efficiency and low degree of argillization,benefiting for the improvement of the mineral processing index.%球磨机钢球的充填制度对磨矿产品的细度、泥化程度,磨矿功效都会产生影响.本次试验研究针对陕西某氧化铅锌矿的性质特点,主要从钢球的充填量、不同钢球尺寸配比两方面进行磨矿技术研究,检测磨矿功效及泥化程度,找到较佳的钢球装填制度.最终确定的较佳的磨矿条件为:钢球尺寸30mm、29mm、27mm、18mm、15mm,钢球的重量百分配比依次为15.89、5.51、46.56、19.4、12.64,钢球的充填量为10.56kg.这样的钢球充填制度磨矿功效高,磨矿产品的泥化程度相对小,有利于提高选矿指标.

  14. Effect of glucosamine HCl on dissolution and solid state behaviours of piroxicam upon milling.

    Science.gov (United States)

    Al-Hamidi, Hiba; Edwards, Alison A; Douroumis, Dionysis; Asare-Addo, Kofi; Nayebi, Alireza Mohajjel; Reyhani-Rad, Siamak; Mahmoudi, Javad; Nokhodchi, Ali

    2013-03-01

    Piroxicam is a non-steroidal anti-inflammatory drug that is characterised by low solubility and high permeability. In order to improve the drug dissolution rate, the co-grinding method was used as an approach to prepare piroxicam co-ground in the carriers such as glucosamine hydrochloride. As, this amino sugar (glucosamine HCl) has been shown to decrease pain and improve mobility in osteoarthritis in joints, therefore, the incorporation of glucosamine in piroxicam formulations would be expected to offer additional benefits to patients. The effect of the order of grinding on the dissolution of piroxicam was also investigated. Co-ground drug and glucosamine were prepared in different ratios using a ball mill. The samples were then subjected to different grinding times. In order to investigate the effect of the grinding process on the dissolution behaviour of piroxicam, the drug was ground separately in the absence of glucosamine. Mixtures of ground piroxicam and unground D-glucosamine HCl were prepared. Physical mixtures of piroxicam and glucosamine were also prepared for comparison. The properties of prepared co-ground systems and physical mixtures were studied using a dissolution tester, FTIR, SEM, XRPD and DSC. These results showed that the presence of glucosamine HCl can increase dissolution rate of piroxicam compared to pure piroxicam. Generally, all dissolution profiles showed the fastest dissolution rate when ground piroxicam was mixed with unground glucosamine. This was closely followed by the co-grinding of piroxicam with glucosamine where lower grinding times showed the fastest dissolution. The solid state studies showed that the grinding of piroxicam for longer times had no effect on polymorphic form of piroxicam, whereas mixtures of piroxicam-glucosamine ground for longer times (60 min) converted piroxicam polymorph II to polymorph I.

  15. C, N co-doped TiO2/TiC0.7N0.3 composite coatings prepared from TiC0.7N0.3 powder using ball milling followed by oxidation

    Science.gov (United States)

    Hao, Liang; Wang, Zhenwei; Zheng, Yaoqing; Li, Qianqian; Guan, Sujun; Zhao, Qian; Cheng, Lijun; Lu, Yun; Liu, Jizi

    2017-01-01

    Ball milling followed by heat oxidation was used to prepared C, N co-doped TiO2 coatings on the surfaces of Al2O3 balls from TiC0.7N0.3 powder. The as-prepared coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrophotometer (UV-vis). The results show that continuous TiC0.7N0.3 coatings were formed after ball milling. C, N co-doped TiO2/TiC0.7N0.3 composite coatings were prepared after the direct oxidization of TiC0.7N0.3 coatings in the atmosphere. However, TiO2 was hardly formed in the surface layer of TiC0.7N0.3 coatings within a depth less than 10 nm during the heat oxidation of TiC0.7N0.3 coatings in carbon powder. Meanwhile, the photocatalytic activity evaluation of these coatings was conducted under the irradiation of UV and visible light. All the coatings showed photocatalytic activity in the degradation of MB no matter under the irradiation of UV or visible light. The C, N co-doped TiO2/TiC0.7N0.3 composite coatings showed the most excellent performance. The enhancement under visible light irradiation should attribute to the co-doping of carbon and nitrogen, which enhances the absorption of visible light. The improvement of photocatalytic activity under UV irradiation should attribute to the synergistic effect of C, N co-doping, the formation of rutile-anatase mixed phases and the TiO2/TiC0.7N0.3 composite microstructure.

  16. Measurement of moisture in mill feed ore

    Energy Technology Data Exchange (ETDEWEB)

    Timm, A.R.; Moench, P.; Moisel, E. (Council for Mineral Technology, Randburg (South Africa))

    1985-04-01

    The control of the moisture in the feed to a mill is very important for efficient mill operation. Water is added continuously to the ore fed to a mill to maintain a suitable mix of ore and moisture in the mill. However, problems arise because of the large variation in the moisture content of the ore, which affects the efficiency of the grind. If too little moisture is present, the mill is unable to grind the ore finely enough, creating instead a thick 'porridge' that causes the mill to choke up. On the other hand, too much moisture results in inefficient grinding because the ore is flushed through the mill too quickly. Several techniques are available for measuring moisture and Mintek undertook an investigation in an attempt to develop a reliable robust moisture meter suitable for monitoring the moisture content of ore, which include the following: neutron backscattering, infrared absorption, microwaves, capacitance and moisture as a function of conductivity.

  17. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    Science.gov (United States)

    Saramak, Daniel; Krawczykowska, Aldona; Młynarczykowska, Anna

    2014-10-01

    This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

  18. Production of scallop shell nanoparticles by mechanical grinding as a formaldehyde adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Shinya, E-mail: syama@mmm.muroran-it.ac.jp [Muroran Institute of Technology, College of Environmental Technology (Japan); Suzuma, Akifumi [Muroran Institute of Technology, Division of Applied Sciences (Japan); Fujimoto, Toshiyuki; Kuga, Yoshikazu [Muroran Institute of Technology, College of Environmental Technology (Japan)

    2013-04-15

    Scallop shells, which are a waste product in the seafood industry, are disposed more than 200,000 ton per year in Hokkaido, Japan. We report effective uses and simple application for discarded shells as a formaldehyde adsorbent. The adsorption performance of scallop shells to remove formaldehyde vapor is investigated. Planetary ball milling under dry conditions and subsequent water addition realize shells with a crystallite size (35-90 nm) and equivalent size of the specific surface area (41-191 nm) in the nanometer range. The comminution properties of the scallop shells, especially the grinding limit, are estimated via a semi-theoretical consideration for the grinding limit. Additionally, the adsorbed amount of gaseous formaldehyde using a self-designed adsorption line is estimated. The nanosized scallop shells exhibit an excellent adsorption performance rather than the feed shell, and the adsorbed amount is positively correlated with the specific surface area of the shell. Hence, scallop shells have potential to adsorb volatile organic compounds.

  19. Effect of ball milling and thermal treatment on exchange bias and magnetocaloric properties of Ni{sub 48}Mn{sub 39.5}Sn{sub 10.5}Al{sub 2} ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Czaja, P., E-mail: p.czaja@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Kraków (Poland); Przewoźnik, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Fitta, M.; Bałanda, M. [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 152 Radzikowskiego Str., 31-342 Krakow (Poland); Chrobak, A. [A. Chelkowski Institute of Physics, University of Silesia, 4 Uniwersytecka Str., Katowice 40-007 (Poland); Kania, B. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Kraków (Poland); Zackiewicz, P. [Institute of Non Ferrous Metals, 5 Sowinskiego Str., Gliwice 44-100 (Poland); Wójcik, A.; Szlezynger, M.; Maziarz, W. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Kraków (Poland)

    2016-03-01

    The combined effect of ball milling and subsequent heat treatment on microstructure, magnetic, magnetocaloric and exchange bias properties of Ni{sub 48}Mn{sub 39.5}Sn{sub 10.5}Al{sub 2} ribbons is reported. The annealing treatment results in the increase of the critical martensitic transformation temperature. The magnetic entropy change ΔS{sub M} of the order of 7.9 and −2.3 J kg K{sup −1} for the annealed 50–32 µm powder fraction is determined. This is less than in the as melt spun ribbon but appears at a considerably higher temperature. At the same time EB is decreased due to annealing treatment. This decrease is attributed to the strengthened ferromagnetic exchange coupling due heat induced stress and structural relaxation. - Highlights: • Milling and annealing of Ni–Mn–Sn–Al ribbons increases the MT temperature. • ΔS{sub M} equal to 7.9 and −2.3 J kg K{sup −1} for the annealed 50–32 µm powder fraction. • Exchange Bias decreases due to annealing treatment. • Milling and annealing are useful for tuning of properties of Ni–Mn–Sn–Al alloys.

  20. Integrated Modeling and Intelligent Control Methods of Grinding Process

    Directory of Open Access Journals (Sweden)

    Jie-sheng Wang

    2013-01-01

    Full Text Available The grinding process is a typical complex nonlinear multivariable process with strongly coupling and large time delays. Based on the data-driven modeling theory, the integrated modeling and intelligent control method of grinding process is carried out in the paper, which includes the soft-sensor model of economic and technique indexes, the optimized set-point model utilizing case-based reasoning, and the self-tuning PID decoupling controller. For forecasting the key technology indicators (grinding granularity and mill discharge rate of grinding process, an adaptive soft-sensor modeling method based on wavelet neural network optimized by the improved shuffled frog leaping algorithm (ISFLA is proposed. Then, a set point optimization control strategy of grinding process based on case-based reasoning (CBR method is adopted to obtain the optimized velocity set-point of ore feed and pump water feed in the grinding process controlled loops. Finally, a self-tuning PID decoupling controller optimized is used to control the grinding process. Simulation results and industrial application experiments clearly show the feasibility and effectiveness of control methods and satisfy the real-time control requirements of the grinding process.

  1. 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

  2. Optimization of Preventive Grinding of Backup Roll against Contact Fatigue Cracking

    Institute of Scientific and Technical Information of China (English)

    DOU Peng; LI You-guo; LIANG Kai-ming; BAI Bing-zhe

    2005-01-01

    In order to optimize the current grinding procedure of the backup roll of 2050 continuously variable crown (CVC) mills, the behavior of rolling contact fatigue (RCF) cracking was investigated. Two RCF short cracks, including vertical short crack and ratcheting short crack initiated from ratcheting, were observed. The behavior of both RCF cracks was analyzed in detail. Then a modified grinding procedure was proposed according to the behavior of RCF cracks and the preventive grinding strategy.

  3. Preparation of Bismuth Subcarbonate by Ball-milling Coversion Method Using Bismuth Oxide%球磨转化法由氧化铋制取次碳酸铋研究

    Institute of Scientific and Technical Information of China (English)

    蒋叶; 唐朝波; 唐谟堂; 杨声海; 何静; 陈永明; 杨建广

    2013-01-01

      针对次碳酸铋传统制备工艺存在试剂消耗大、产生大量氨氮废水等问题,提出了一种用氧化铋和碳酸氢铵机械球磨直接制备次碳酸铋新工艺,考察了碳酸氢铵浓度、液固体积质量比、球料质量比、反应时间对氧化铋转化率的影响。结果表明,在碳酸氢铵浓度为2.5 mol/L、液固体积质量比为7∶1、球料质量比为8∶1、反应时间为2 h、室温条件下,氧化铋转化率达93.23%。该工艺流程简短,成本低,转化母液可循环利用,解决了传统工艺试剂消耗大及产生大量氨氮废水等问题。%A new process for preparation of bismuth subcarbonate by ball-milling coversion method using bismuth oxide has been proposed .T he effects of ammonium bicarbonate concentrate ,liquid/solid ratio ,mass ratio of ball to bismuth oxide and milling time on conversion rate of bismuth oxide were ex-amined .The results showed that the direct conversion rate of bismuth oxide colud reach 93 .23% under the optimum conditions which the ammonium bicarbonate concentration was 2 .5 mol/L ,liquid/solid ratio was 7∶1 ,mass ratio of ball to bismuth oxide was 8∶1 ,and milling 2 hours at room temperature . The process has the advantage of short procedure ,cheap reactant ,low cost ,and mother liquid can be u-tilized circularly .

  4. Preparation of Mn3O4 from manganese sulfate by solid-state ball milling reaction at room temperature%硫酸锰室温固相球磨制备四氧化三锰

    Institute of Scientific and Technical Information of China (English)

    马玉文; 冯雅丽; 李浩然

    2013-01-01

    利用软锰矿吸收硫酸镁热解尾气二氧化硫制得硫酸锰,再与碳酸氢铵室温下固相球磨反应,制备出前躯体碳酸锰,经热分解获得四氧化三锰.分别考察了物料比、球磨时间、球料比等因素对硫酸锰转化率的影响,采用XRD对产物进行了分析.结果表明,在n(碳酸氢铵)∶n(硫酸锰)=3.5∶1、球磨时间为40 min、球料质量比为5∶1时,硫酸锰的转化率可达99.8%,将固相产物在1 000℃热解1h后所制备的四氧化三锰纯度为99.9%.该工艺操作简单,产品纯度高,成本低,为硫酸锰制备四氧化三锰提供了新的途径.%Manganese sulfate was prepared by reaction between pyrolusite and sulfur oxide from the pyrolysis of magnesium sulfate.Mn3O4 can be prepared by pyrolysing the precursor MnCO3.The precursor was synthesized by solid-state ball milling reaction between NH4HCO3 and MnSO4 · H2O at room temperature.Effects of materials mix ratio, milling time, and ball-feed mass ratio on the conversion of manganese sulfate were investigated respectively.The products were analyzed by XRD.Results showed that the conversion rate of MnSO4 · H2O could reach 99.8% under the conditions of mix ratio 3.5:1 (amount-of-substance ratio of NH4HCO3 to MnSO4 · H2O),milling time 40 min, and ball-feed mass ratio 5:1 .The Mn3O4, whose purity was 99.9%, can be prepared by pyrolysing manganese carbonate at 1 000℃ for 1 h.The process has the advantages of simple in operation, high product purity, and low cost, and it can provide a new route for the preparation Mn3O4 from MnSO4 · H2O.

  5. Study on Process of Preparing Fe-Al2O3 Magnetic Abrasive by High Energy Ball Milling%高能球磨法制备Al2O3/Fe磁性磨粒的工艺研究

    Institute of Scientific and Technical Information of China (English)

    王晓峰; 李文辉

    2013-01-01

    Magnetic abrasive finishing machining technology is a new technology to use the magnetic field force produced by permanent magnetic or electromagnetic device asthe driving force of magnetic abrasive finishing machining of parts surface,which can realize the surface polishing,deburring,eliminating the micro crack,and reducing the surface roughness of parts.4 new technology of preparing magnetic abrasives used high energy ball milling was put forward and the working principle was analyzed in the ball milling.Pure iron powder was used as the magnetic phase,corundum powder as the abrasive,and three different times Fe-Al2O3 magnetic abrasives were prepared by high energy ball milling method.X-ray diffraction and SEM were used to analyze the morphology and phase components of the magnetic abrasives.Magnetic flux density of the magnetic abrasives were tested by the instrument.It finds that the process is easy and low cost,so it would have great hope to accomplish large-scale industrialized production.%磁性磨粒光整加工技术是利用永磁或者电磁发生装置产生的磁场力作为磁性磨粒的源动力对零件表面进行光整加工的一种新技术,它可以实现对零件进行表面抛光、去除毛刺、消除微观裂纹、降低表面粗糙度等加工.提出应用高能球磨法制备磁性磨粒的新工艺,分析了球磨过程中的工作原理.用纯铁粉作为磁性体,三氧化二铝粉作为磨料相,采用高能球磨法制备了三种不同时间的Fe-Al2O3磁性磨粒.采用X射线衍射仪和扫描电子显微镜分析了该磁性磨粒的物相组成和外观形貌,用特斯拉仪测试了磁性磨粒的磁感应强度.发现了该工艺简单,成本低,且有望进行大规模工业化生产.

  6. Dechlorination of pentachlorophenol by grinding at low rotation speed in short time

    Institute of Scientific and Technical Information of China (English)

    Zhi Xu; Xiaoyu Zhang; Qingzhi Fei

    2015-01-01

    In order to apply grinding method for degradation of pentachlorophenol (PCP) to an industrial scale, the propor-tion of different materials [CaO, SiO2 and CO(NH2)2] and the size of grinding balls were examined. For saving en-ergy and increasing dechlorination efficiency, the rotation speed and grinding time were maintained at relatively low values. At a mass ratio of grinding bal s to materials (40:1), PCP was added into a big steel jar (300 ml) with other materials to grind at 300 r·min−1 for 5 h. The results indicated that when PCP was mixed with CaO and SiO2 in a molar ratio of 1:60:60, the best dechlorination of 58.4%was achieved. CO(NH2)2 could not be used as hydro-gen donor in the dehalogenation by mechanochemical reaction, since it restrained the dechlorination process. The size of grinding balls has significant effect on the reaction. The experiment with 5 mm steel balls indicates that the weight is too light to provide appropriate energy for the reaction, while steel balls of 10 and 15 mm could give better dechlorination reaction. It indicates that dechlorination depends on the mass of balls and fill rate.

  7. Ball clay

    Science.gov (United States)

    Virta, Robert L.

    2010-01-01

    The article reports on the global market performance of ball clay in 2009 and presents an outlook for its 2010 performance. Several companies mined ball call in the country including Old Hickey Clay Co., Kentucky-Tennessee Clay Co., and H.C. Spinks Clay Co. Information on the decline in ball clay imports and exports is also presented.

  8. 球磨法制备POE-g-MAH/OMMT增韧母粒及其对PA6增韧改性%TOUGHENING MODIFICATION OF PA6 BY POE-g-MAH/OMMT TOUGHENING PARTICLE PREPARED BY BALL GRINDING METHOD

    Institute of Scientific and Technical Information of China (English)

    王力; 熊玉竹; 罗金中

    2011-01-01

    通过球磨法制备马来酸酐接枝(乙烯-辛烯)共聚物(POE-g-MAH)/有机化蒙脱土(OMMT)增韧母粒,并将其用于尼龙(PA)6的增韧改性.结果表明,球磨法制备的POE-g-MAH/OMMT增韧母粒尺寸比较均匀,有少量POE-g-MAH进入OM MT片层之间,导致OMMT片层间距有所增加.POE-g-MAH/OMMT增韧母粒在PA6基体中分布较均匀,但有轻微的团聚现象.随着POE-g-MAH/OMMT增韧母粒含量的增加,PA6/(POE-g-MAH/OMMT)共混物缺口冲击强度呈上升趋势,且当增韧母粒质量分数超过15%时,PA6/(POE-g-M AH/OMMT)共混物的力学性能优于PA6/POE-g-MAH共混物.当增韧母粒质量分数为15%、POE-g-MAH/OMMT母粒质量比为80/20时,PA6/(POE-g-MAH/OMMT)共混物缺口冲击强度和拉伸强度达到最高.%POE-g-MAH/OMMT toughening particles were prepared by ball grinding method and were used to modify the toughness of PA6. The results showed that the size of POE-g-MAH/OMMT particles prepared by ball grinding method was uniform. A small amount of POE-g-MAH get into the layers of OMMT, which increased the pitch of OMMT layers. The dispersion of POE-g-MAH/ OMMT particles in PA6 matrix was better, but a slight agglomeration of particles occurred. With content of the POE-g-MAH/OMMT particles increasing, the notched impact strength of PA6/( POE-g-MAH/OMMT) blend increased. When the mass fraction of toughening particle exceed 15% ,the mechanical properties of PA6/( POE-g-MAH/OMMT) blend were higher than PA6/POE-g-MAH blend. When the mass fraction of toughening particle was 15% and mass ratio of POE-g-MAH/OMMT was 80/20, the notched impact strength and tensile strength of PA6/( POE-g-MAH/OMMT) blend were highest.

  9. Preparation of Mo-Re-C samples containing Mo7Re13C with the β-Mn-type structure by solid state reaction of planetary-ball-milled powder mixtures of Mo, Re and C, and their crystal structures and superconductivity

    Science.gov (United States)

    Oh-ishi, Katsuyoshi; Nagumo, Kenta; Tateishi, Kazuya; Takafumi, Ohnishi; Yoshikane, Kenta; Sugiyama, Machiko; Oka, Kengo; Kobayashi, Ryota

    2017-01-01

    Mo-Re-C compounds containing Mo7Re13C with the β-Mn structure were synthesized with high-melting-temperature metals Mo, Re, and C powders using a conventional solid state method with a planetary ball milling machine instead of the arc melting method. Use of the ball milling machine was necessary to obtain Mo7Re13C with the β-Mn structure using the solid state method. Almost single-phase Mo7Re13C with a trace of impurity were obtained using the synthesis method. By XRF and lattice parameter measurements on the samples, Fe element existed in the compound synthesized using the planetary ball milling machine with a pot and balls made of steel, though Fe element was not detected in the compound synthesized using a pot and balls made of tungsten carbide. The former compound containg the Fe atom did not show superconductivity but the latter compound without the Fe atom showed superconductivity at 6.1 K.

  10. STABLE DIAMOND GRINDING

    Directory of Open Access Journals (Sweden)

    Yury Gutsalenko

    2010-06-01

    Full Text Available The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute «diamond-spark grinding» as applied to processing by means of diamond wheel. Implementation of diamond-spark grinding technologies on the basis of developed generalized theoretical approach allows to use the tool with prescribed tool-life, moreover to make the most efficient use of it up to full exhausting of tool-life, determined by diamond-bearing thickness. Development is directed forward computer-aided manufacturing.

  11. Effect of microstructure on abrasion amount of steel balls for mill%显微组织对球磨机钢球磨损量的影响

    Institute of Scientific and Technical Information of China (English)

    张达富; 刘锦燕; 陈义

    2016-01-01

    Effect of microstructure on abrasion of steel balls by two different heat-treatment was studied by the abrasion-test machine,metalloscope and scanning electron microscopy (SEM) .The results show that the abrasion amount of high hardness steel balls with martensite microstructure is larger,and the relatively low hardness of tempered martensite and retained austenite erosion rate is lower.It is found that the abrasion mechanism of steel balls is given priority with peeling method,which indicates that the wear resistance of steel balls is directly related to the microstructure.%分别采用磨损试验机、金相显微镜和扫描电镜(SEM)等研究了两种热处理工艺下的钢球显微组织对磨损量的影响.结果表明,硬度较大的含马氏体组织的钢球磨损量较大,而硬度相对较低的回火马氏体+残留奥氏体磨损量较低.钢球的磨损机理以剥落方式为主,这说明钢球的耐磨性与显微组织有直接关系.

  12. 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)

  13. Grinding Properties of Abandoned Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHENG Fang-yu; WANG Li-jiu; LI Qiang

    2007-01-01

    The grinding properties of abandoned concrete, which consists primarily of hardened cement, limestone aggregate and river sand, are studied. Theoretical models of grinding are used to explain the experimental observation. The results show that 1) The principle disintegration mechanism of hardened cement and river sand is volumetric grinding, although at later stages grinding of cement becomes difficult because of its flaked structure; 2) The limestone grinding process can be divided into two steps. First, volumetric grinding, with an obvious component of surface grinding, followed by primarily surface grinding as the micro-particle content increases; 3) Initially, the principle mechanism of grinding limestone and river sand is volumetric grinding, albeit less efficient grinding than if these components were ground separately, and; 4) After 10 to 20 min of grinding the grinding bottleneck phenomenon appears and after 20 min of grinding the content of micro-particles is large and surface grinding is the main mechanism while the particle size of the mixture is smaller than that of separately ground river sand and cement but bigger than that of separately ground limestone.

  14. Synthesis and analysis of nanocrystalline β1-Cu3Al and β2-NiAl intermetallic-reinforced aluminum matrix composite by high energy ball milling

    Science.gov (United States)

    Nguyen, Hong-Hai; Nguyen, Minh-Thuyet; Kim, Won Joo; Kim, Jin-Chun

    2017-01-01

    Nanocrystalline β1-Cu3Al and β2-NiAl intermetallic compounds were in-situ reinforced in the aluminum matrix with the atomic composition of Al67Cu20Ni13 by the mechanical alloying of elemental powders. Both β1-Cu3Al, β2-NiAl phases that can be only co-synthesized in Cu base alloys have been obtained after 15h milling in this study. The phase evolution during milling process was investigated by X-ray diffraction. The β1-Cu3Al, β2-NiAl phases were metastable with further milling time up to 40 h. Specially, unreacted Al matrix has been totally transformed to amorphous state in the final powder. A remarkable crystalline size of 6.5 nm was reached after 15 h milling time. Thermal stability of the milled powder was also studied by differential thermal analysis. It is shown that β1-Cu3Al, β2-NiAl phases were stable up to higher than 550 °C. Moreover, the inter-diffusion between Al matrix and Cu3Al within the temperature range of 620-740 °C led to the formation of superstructure ζ1-Al3Cu4 phase.

  15. A 6-DOF parallel bone-grinding robot for cervical disc replacement surgery.

    Science.gov (United States)

    Tian, Heqiang; Wang, Chenchen; Dang, Xiaoqing; Sun, Lining

    2017-05-24

    Artificial cervical disc replacement surgery has become an effective and main treatment method for cervical disease, which has become a more common and serious problem for people with sedentary work. To improve cervical disc replacement surgery significantly, a 6-DOF parallel bone-grinding robot is developed for cervical bone-grinding by image navigation and surgical plan. The bone-grinding robot including mechanical design and low level control is designed. The bone-grinding robot navigation is realized by optical positioning with spatial registration coordinate system defined. And a parametric robot bone-grinding plan and high level control have been developed for plane grinding for cervical top endplate and tail endplate grinding by a cylindrical grinding drill and spherical grinding for two articular surfaces of bones by a ball grinding drill. Finally, the surgical flow for a robot-assisted cervical disc replacement surgery procedure is present. The final experiments results verified the key technologies and performance of the robot-assisted surgery system concept excellently, which points out a promising clinical application with higher operability. Finally, study innovations, study limitations, and future works of this present study are discussed, and conclusions of this paper are also summarized further. This bone-grinding robot is still in the initial stage, and there are many problems to be solved from a clinical point of view. Moreover, the technique is promising and can give a good support for surgeons in future clinical work.

  16. 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.

  17. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    Energy Technology Data Exchange (ETDEWEB)

    Poffo, C.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.b [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Souza, S.M.; Triches, D.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Biasi, R.S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

    2011-04-01

    Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 {sup o}C the heat transfer is controlled by crystalline component.

  18. Model Predictive Control for an Industrial SAG Mill

    DEFF Research Database (Denmark)

    2012-01-01

    identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are the primary units in a grinding chain and also the most power consuming units. Therefore, improved...... control of SAG mills has the potential to signicantly improve eciency and reduce the specic energy consumption for mineral processes. Grinding circuits involving SAG mills are multivariate processes. Commissioning of a control system based on a classical single-loop controllers with logic is time...

  19. 高能球磨法制备超细镍粉的研究%Preparation of Ultrafine Nickel Powder by High-energy Ball Milling

    Institute of Scientific and Technical Information of China (English)

    李黎瑛; 张振忠; 赵芳霞; 寿奉良

    2012-01-01

    The influences of milling time and process control agents on the preparation of ultrafine nickel powder were studied systematically by granularity test, SEM and XRD. The results show that: with increasing milling time, the nickel powder particle size decreases rapidly at first and then the particle size changes slightly, the nickel powder can milling effectively by adding process control agent KH-570, the dispersion properties, sheet extent and the surface cleanliness are also improved. Milling 36 h the nickel powder with the process control agent KH-570 can obtain 5. 76 μm high-purity nickel powder.%采用粒度测试、SEM和XRD等分析手段,系统研究了球磨时间和过程控制剂对制备超细镍粉的影响.结果表明:随着球磨时间的延长,镍粉的粒度在初期减小较快,后期的减小趋于平缓;过程控制剂KH-570的加入能有效加快超细镍粉的细化,提高分散性能、片状化程度和表面的洁净度.加入过程控制剂KH-570,球磨36 h,能获得粒度为5.76 μm的高纯镍粉.

  20. 磷石膏-碳铵-氨水球磨制备硫酸铵和碳酸钙%Ammonium Sulfate and Calcium Carbonate Prepared by Ball-milling from Phosphogypsum-Ammonium Bicarbonate-Ammonia Water

    Institute of Scientific and Technical Information of China (English)

    李娜; 邓跃全; 董发勤; 罗绍东; 李珊珊; 彭宝瑶

    2013-01-01

    Ammonium sulfate and calcium carbonate were prepared using phosphogypsum, ammonium bicarbonate and ammonia water as raw materials by ball-milling technique. The optimum conditions were explored through orthogonal test, the major elements and phase composition of two kinds of products were analyzed by XRF and XRD, and the grain size distribution and poisonous elements of calcium carbonate were determined using laser particle size analyzer and ICP. The analysis results showed that the optimum technological conditions were as follows: the liquid-solid ratio was 0.5, the response time was 45 min, the ball-material ratio was 3:1, rotational speed was 600 r/min, and the average conversion reaction was up to 97.95%; the product quality of ammonium sulfate reached the standard of byproduct ammonium sulfate, poisonous and harmful elements contents of calcium carbonate were far lower than quality criteria of soil environment allows. Preparation of ammonium sulfate and calcium carbonate from phosphogypsum by ball-milling achieved the purpose of effectively using phosphogypsum.%  以磷石膏、碳酸氢铵和氨水为原料,采用球磨工艺制备硫酸铵和碳酸钙.通过正交试验设计,探索磷石膏球磨制备硫酸铵和碳酸钙的最佳工艺条件,采用 XRF 和 XRD 分析了2种产物的化学组成及物相组成,采用激光粒度仪和 ICP 分别测定了碳酸钙的粒度分布及有毒有害元素含量.结果表明,球磨制备硫酸铵和碳酸钙适宜的工艺条件为:液固比0.5,反应时间45 min,球料比3∶1,转速600 r/min,反应的平均转化率达97.95%;硫酸铵产品质量达到了副产硫酸铵标准,碳酸钙中有毒有害元素的含量远低于土壤环境质量标准要求.磷石膏球磨制备硫酸铵和碳酸钙,实现了磷石膏的高效利用.

  1. Ball clay

    Science.gov (United States)

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the global ball clay mining industry, particularly in the U.S., as of June 2011. It cites several firms that are involved in ball clay mining in the U.S., including HC Spins Clay Co. Inc., the Imerys Group and Old Hickory Clay Co. Among the products made from ball clay are ceramic tiles, sanitaryware, as well as fillers, extenders and binders.

  2. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  3. Development of database and searching system for tool grinding

    Directory of Open Access Journals (Sweden)

    J.Y. Chen

    2008-02-01

    Full Text Available Purpose: For achieving the goal of saving time on the tool grinding and design, an efficient method of developing the data management and searching system for the standard cutting tools is proposed in this study.Design/methodology/approach: At first the tool grinding software with open architecture was employed to design and plan grinding processes for seven types of tools. According to the characteristics of tools (e.g. types, diameter, radius and so on, 4802 tool data were established in the relational database. Then, the SQL syntax was utilized to write the searching algorithms, and the human machine interfaces of the searching system for the tool database were developed by C++ Builder.Findings: For grinding a square end mill with two-flute, a half of time on the tool design and the change of production line for grinding other types of tools can be saved by means of our system. More specifically, the efficiency in terms of the approach and retract time was improved up to 40%, and an improvement of approximately 10.6% in the overall machining time can be achieved.Research limitations/implications: In fact, the used tool database in this study only includes some specific tools such as the square end mill. The step drill, taper tools, and special tools can also be taken into account in the database for future research.Practical implications: The most commercial tool grinding software is the modular-based design and use tool shapes to construct the CAM interface. Some limitations on the tool design are undesirable for customers. On the contrary, employing not only the grinding processes to construct the grinding path of tools but the searching system combined with the grinding software, it gives more flexible for one to design new tools.Originality/value: A novel tool database and searching system is presented for tool grinding. Using this system can save time and provide more convenience on designing tools and grinding. In other words, the

  4. Low-Rank Coal Grinding Performance Versus Power Plant Performance

    Energy Technology Data Exchange (ETDEWEB)

    Rajive Ganguli; Sukumar Bandopadhyay

    2008-12-31

    The intent of this project was to demonstrate that Alaskan low-rank coal, which is high in volatile content, need not be ground as fine as bituminous coal (typically low in volatile content) for optimum combustion in power plants. The grind or particle size distribution (PSD), which is quantified by percentage of pulverized coal passing 74 microns (200 mesh), affects the pulverizer throughput in power plants. The finer the grind, the lower the throughput. For a power plant to maintain combustion levels, throughput needs to be high. The problem of particle size is compounded for Alaskan coal since it has a low Hardgrove grindability index (HGI); that is, it is difficult to grind. If the thesis of this project is demonstrated, then Alaskan coal need not be ground to the industry standard, thereby alleviating somewhat the low HGI issue (and, hopefully, furthering the salability of Alaskan coal). This project studied the relationship between PSD and power plant efficiency, emissions, and mill power consumption for low-rank high-volatile-content Alaskan coal. The emissions studied were CO, CO{sub 2}, NO{sub x}, SO{sub 2}, and Hg (only two tests). The tested PSD range was 42 to 81 percent passing 76 microns. Within the tested range, there was very little correlation between PSD and power plant efficiency, CO, NO{sub x}, and SO{sub 2}. Hg emissions were very low and, therefore, did not allow comparison between grind sizes. Mill power consumption was lower for coarser grinds.

  5. Non-isothermal synergetic catalytic effect of TiF{sub 3} and Nb{sub 2}O{sub 5} on dehydrogenation high-energy ball milled MgH{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tiebang, E-mail: tiebangzhang@nwpu.edu.cn; Hou, Xiaojiang; Hu, Rui; Kou, Hongchao; Li, Jinshan

    2016-11-01

    MgH{sub 2}-M (M = TiF{sub 3} or Nb{sub 2}O{sub 5} or both of them) composites prepared by high-energy ball milling are used in this work to illustrate the dehydrogenation behavior of MgH{sub 2} with the addition of catalysts. The phase compositions, microstructures, particle morphologies and distributions of MgH{sub 2} with catalysts have been evaluated. The non-isothermal synergetic catalytic-dehydrogenation effect of TiF{sub 3} and Nb{sub 2}O{sub 5} evaluated by differential scanning calorimetry gives the evidences that the addition of catalysts is an effective strategy to destabilize MgH{sub 2} and reduce hydrogen desorption temperatures and activation energies. Depending on additives, the desorption peak temperatures of catalyzed MgH{sub 2} reduce from 417 °C to 341 °C for TiF{sub 3} and from 417 °C to 336 °C for Nb{sub 2}O{sub 5}, respectively. The desorption peak temperature reaches as low as 310 °C for MgH{sub 2} catalyzed by TiF{sub 3} coupling with Nb{sub 2}O{sub 5}. The non-isothermal synergetic catalytic effect of TiF{sub 3} and Nb{sub 2}O{sub 5} is mainly attributed to electronic exchange reactions with hydrogen molecules, which improve the recombination of hydrogen atoms during dehydrogenation process of MgH{sub 2}. - Highlights: • Catalytic surface for MgH{sub 2} is achieved by high-energy ball milling. • Non-isothermal dehydrogenation behavior of MgH{sub 2} with TiF{sub 3} and/or Nb{sub 2}O{sub 5} is illustrated. • Dehydrogenation activation energies of synergetic catalyzed MgH{sub 2} are obtained. • Synergetic catalytic-dehydrogenation mechanism of TiF{sub 3} and Nb{sub 2}O{sub 5} is proposed.

  6. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

    High Performance Grinding and Advanced Cutting Tools discusses the fundamentals and advances in high performance grinding processes, and provides a complete overview of newly-developing areas in the field. Topics covered are grinding tool formulation and structure, grinding wheel design and conditioning and applications using high performance grinding wheels. Also included are heat treatment strategies for grinding tools, using grinding tools for high speed applications, laser-based and diamond dressing techniques, high-efficiency deep grinding, VIPER grinding, and new grinding wheels.

  7. 球头铣刀曲面加工的刀具切触区域解析建模%Analytical Modeling of Cutter Engagement Regions in Ball-end Milling of Curved Surface

    Institute of Scientific and Technical Information of China (English)

    王亮; 王敏杰; 魏兆成; 王升福

    2012-01-01

    针对球头铣刀三维曲面加工,提出一种刀具切触区域仿真的通用解析模型.采用微分方法,将曲面加工过程离散为一系列连续的微小斜平面稳态加工.以每一小斜面切削过程为研究对象,建立描述刀具进给方向变化的数学模型,针对不同的进给方向并基于空间坐标系旋转变换,提出一组确定刀具切触边界曲线及各边界交点的解析公式,以精确界定刀具切触区域的封闭几何.通过与Z-Map模型的切触区域仿真对比,验证了本文模型的有效性及其精确高效的特点.%This paper presents a generalized analytical model of cutter engagement region simulations for ball - end milling of 3D curved surface. With differential method, the curved surface machining is treated as a series of sequential small inclined surfaces steady state milling. According to the cutting process of each small inclined surface, the mathematical models which are used to describe the variation of cutter feed direction are established. Through space coordinate system rotation transformation, a set of analytic formula of cutter contact boundaries and the intersection points are proposed, in order to exactly determine the closed geometry of engagement regions for different feed directions. The effectiveness and characteristics of accuracy and high - efficiency of the model presented in this paper are verified by the comparison of engagement region simulations with Z - Map model.

  8. Effect of Grinding Techniques on Absorbing Characteristics of Short Iron Fibers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Microwave-absorbing properties of iron fibers can be adjusted by their aspect ratio. This paper presents several modification techniques for grinding long iron fibers to a suitable aspect ratio. The grinding instruments include pulsator, jet mill and muller. The aspect ratio distribution, microstructure, electromagnetic parameter and refiectivity of the samples were analyzed and discussed in detail. The results show that the fractions of 5<aspect ratio<40 for the three methods are 69.03%, 81.11% and 80.2%, respectively, that is,suitable short iron fibers can be obtained by the jet mill and muller. Furthermore, the short iron fibers milled by jet mill and muller have better absorbing propterties than those obtained by the pulsator under the same condition. Therefore, their microwave absorption properties can be improved by regulating the electromagnetic parameters with grinding.

  9. M(o)ssbauer study on Fe-doped TiO2 by high-energy ball milling%高能球磨法制备的含铁TiO2的穆斯堡尔谱研究

    Institute of Scientific and Technical Information of China (English)

    蒋冬梅; 潘晓燕; 石旺舟; 马学鸣

    2006-01-01

    The structural evolution of Fe-doped TiO2 by high-energy ball milling was investigated by X-ray diffraction and M(o)ssbauer spectroscopy. The results show that the original anatase-TiO2 transforms to srilankite-type and rutile-type during ball milling. Iron atoms are preferable to dissolve in rutile-TiO2 and there are two relative doublets appearing in M(o)ssbauer spectra. A doublet is found in the condition of Fe atoms dissolved in srilankite TiO2 lattice. M(o)ssbauer spectra show that the composition distribution is nonuniform in TiO2 during the mechanical alloying with Fe atoms rich at the interface or surface of TiO2 crystalline.

  10. Design of the Soymilk Mill based on TRIZ Theory

    Directory of Open Access Journals (Sweden)

    Jiang Fan

    2013-05-01

    Full Text Available The soymilk mill is an important food machine, but its volume is too large to be suitable for house using. This study first analyzes some problems in the soymilk mill miniaturization. For these problems, the thinking tools, evolutionary tools and contradiction solving tool of TRIZ theory are used to resolve the conflict in the integration of grinding and boiling and in the keep grinding effect, to tackle the optimization problem in the grinding stria structure and mill plate speed, then the Dwarfs method and substance-field analysis model is used in solving the interference and the conditions water supply problems which are encountered in the design of the global structure and a micro soymilk mill is designed. Finally, the mechanical analysis model about soy granules, soymilk particles in the grinding zone and the computational model of motor starting torque are obtained; they provide the reference data for application of soymilk mill.

  11. Characterization of nanostructured alpha-Fe2O3-SnO2 solid solutions prepared by high energy ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lin, R.; Mørup, Steen

    1998-01-01

    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....

  12. Characterization of nanostructured alpha-Fe2O3-SnO2 solid solutions prepared by high energy ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lin, R.; Mørup, Steen

    1998-01-01

    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....

  13. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  14. Discussion on the structure optimization of parts in design liaison of the order(manufacture)of large-scale ball mills%大型球磨机订购(制造)设计联络中零部件结构优化的探讨

    Institute of Scientific and Technical Information of China (English)

    刘永松; 来绩伟

    2015-01-01

    In light of the problems in the use of large-scale ball mills,the flaws in the structure of main parts of ball mills are analyzed and countermeasures are proposed.Through design liaison,structure optimization of main parts is conducted in advance to eliminate the flaws.The structure optimization of main parts in design liaison works double efficiently in improving the operation rate of ball mills.%针对大型球磨机使用中存在的问题,对球磨机主要零部件结构缺陷进行分析并提出解决方案。通过设计联络,提前对球磨机主要零部件结构进行优化,消除设备缺陷。大型球磨机设计联络中对主要零部件结构进行优化,对提高球磨机的运转率有着事半功倍的作用。

  15. Structure, magnetic and magnetoresistance properties of Pr{sub 0.67}Sr{sub 0.33}MnO{sub 3} manganite oxide prepared by ball milling method

    Energy Technology Data Exchange (ETDEWEB)

    Cherif, W., E-mail: wajdi_cherif@yahoo.fr [Sfax University, Faculty of Sciences, B.P. 1171, 3000 Sfax (Tunisia); Ellouze, M., E-mail: mohamed.ellouze@fss.rnu.tn [Sfax University, Faculty of Sciences, B.P. 1171, 3000 Sfax (Tunisia); Lehlooh, A.-F., E-mail: foued.elhalouani@enis.rnu.tn [King Faisal University, Hofuf 31982 (Saudi Arabia); Elhalouani, F., E-mail: alehlooh@yahoo.com [Sfax University, National School of Engineers, B.P. W, 3038 (Tunisia); Mahmood, S.H., E-mail: s.mahmood@ju.edu.jo [University of Jordan, Amman (Jordan)

    2012-07-15

    A sample of Pr{sub 0.67}Sr{sub 0.33}MnO{sub 3} nanoparticles was synthesized by the ball milling method. X-ray diffraction pattern of the sample showed orthorhombic system with Pnma space group. The average crystallite size of 110 nm was obtained by both Scanning Electron Microscopy and X-ray diffraction. Magnetic measurements showed para-to-ferromagnetic transition with a Curie temperature of T{sub C}=269 K. Electrical investigations showed that all our samples exhibit a semi-conducting behavior above T{sub C} and a metallic-like one at lower temperatures. The sample exhibited a large magnetoresistance of 30% at room temperature in an applied magnetic field of 2 T. The transport and the magnetic properties were interpreted in terms of the existence of magnetic polarons in the sample. - Highlights: Black-Right-Pointing-Pointer Magnetic and structural properties of Pr{sub 0.67}Sr{sub 0.33}MnO{sub 3} nanoparticles. Black-Right-Pointing-Pointer Average particle size from 110 nm fabricated by mechanical system. Black-Right-Pointing-Pointer Large magnetoresistance of 30% at room temperature.

  16. Electrical and dielectric properties of Na1/2La1/2Cu3Ti4O12 ceramics prepared by high energy ball-milling and conventional sintering

    Science.gov (United States)

    Mahfoz Kotb, H.; Ahmad, Mohamad M.

    2016-12-01

    We report on the measurements of the electrical and dielectric properties of Na1/2La1/2Cu3Ti4O12 (NLCTO) ceramics prepared by high energy ball-milling and conventional sintering without any calcination steps. The x-ray powder diffraction analysis shows that pure perovskite-like CCTO phase is obtained after sintering at 1025 °C-1075 °C. Higher sintering temperatures result in multi-phase ceramics due to thermal decomposition. Scanning electron microscope observations reveal that the grain size is in a range of ˜3 μm-5μm for these ceramics. Impedance spectroscopy measurements performed in a wide frequency range (1 Hz-10 MHz) and at various temperatures (120 K-470 K) are used to study the dielectric and electrical properties of NLCTO ceramics. A good compromise between high ɛ‧ (5.7 × 103 and 4.1 × 103 at 1.1 kHz and 96 kHz, respectively) and low tan δ (0.161 and 0.126 at 1.1 kHz and 96 kHz, respectively) is obtained for the ceramic sintered at 1050 °C. The observed high dielectric constant behavior is explained in terms of the internal barrier layer capacitance effect.

  17. Magnetic properties and coercivity mechanism of Sm{sub 1-x}Pr{sub x}Co{sub 5} (x=0-0.6) nanoflakes prepared by surfactant-assisted ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Xu, M. L.; Yue, M., E-mail: yueming@bjut.edu.cn; Wu, Q.; Li, Y. Q.; Lu, Q. M. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

    2016-05-15

    Sm{sub 1-x}Pr{sub x}Co{sub 5} (x=0-0.6) nanoflakes with CaCu{sub 5} structure were successfully prepared by surfactant-assisted high-energy ball milling (SAHEBM). The crystal structure and magnetic properties of Sm{sub 1-x}Pr{sub x}Co{sub 5} (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 Sm{sub 1-x}Pr{sub x}Co{sub 5} nanoflakes were systematically investigated. XRD results show that all the nanoflakes have a hexagonal CaCu{sub 5}-type (Sm, Pr){sub 1}Co{sub 5} main phase and the (Sm, Pr){sub 2}Co{sub 7} 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 (H{sub A}) and H{sub ci} of decrease monotonically. Maximum energy product [(BH){sub 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 H{sub A} on the coercivity of flakes.

  18. Hydrogen storage properties of a Mg-Ni-Fe mixture prepared via planetary ball milling in a H{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Song, Myoung Youp; Baek, Sung Hwan [Division of Advanced Materials Engineering, Department of Hydrogen and Fuel Cells, Research Center of Advance Materials Development, Engineering Research Institute, Chonbuk National University, 664-14 1ga Deogjindong Deogjingu, Jeonju, Jeonbuk, 561-756 (Korea); Bobet, Jean-Louis [ICMCB, CNRS (UPR 9048), Universite de Bordeaux 1, 33608 Pessac cedex (France); Hong, Seong-Hyeon [Powder Materials Research Center, KIMS, Korea Institute of Machinery and Materials, 66 Sangnamdong, Changwon, Kyungnam, 641-010 (Korea)

    2010-10-15

    A sample composition has been designed based on previously reported data. An 80 wt%Mg-13.33 wt%Ni-6.67 wt%Fe (referred to as Mg-13.33Ni-6.67Fe) sample exhibited higher hydriding and dehydriding rates after activation and a larger hydrogen storage capacity compared to those of other mixtures prepared under similar conditions. After activation (at n = 3), the sample absorbed 4.60 wt%H for 5 min and 5.61 wt%H for 60 min at 593 K under 12 bar H{sub 2}. The sample desorbed 1.57 wt%H for 5 min and 3.92 wt%H for 30 min at 593 K under 1.0 bar H{sub 2}. Rietveld analysis of the XRD pattern using FullProf program showed that the as-milled Mg-13.33Ni-6.67Fe sample contained Mg(OH){sub 2} and MgH{sub 2} in addition to Mg, Ni, and Fe. The Mg(OH){sub 2} phase is believed to be formed through the reaction of Mg or MgH{sub 2} with water vapor in the air. The dehydrided Mg-13.33Ni-6.67Fe sample after hydriding-dehydriding cycling contained Mg, Mg{sub 2}Ni, MgO, and Fe. (author)

  19. 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

  20. TX1600G 数控镗铣加工中心滚珠丝杠热特性分析%Thermal Characteristics Analysis of Ball Screw of TX1600G CNC Boring and Milling Machining Center

    Institute of Scientific and Technical Information of China (English)

    孙军; 秦显军; 钱彬彬; 黄圆

    2015-01-01

    This paper takes TX1600G CNC bor-ing and milling machining center as example and mainly studies the impact of different feed speed and coolant flow on the system heat balance,under the conditions of the moving heat source.To un-derstand the ball screw in actual working condi-tions,ANSYS was first used to establish a simpli-fied three dimensional model of the ball screw, and then the heat source was moved to simulate heat transmission on nut and bearing,so the tem-perature model and thermal error compensation model of lead screw are established.Results show that the increase of feed speed can shorten the time for heat balance of the system,but the thermal e-quilibrium temperature was increased;coolant flu-id can effectively reduce the thermal equilibrium temperature and the thermal equilibrium time. Thermal error modeling and the analysis of tem-perature field also provide necessary theoretical ba-sis to the thermal compensation of the system.%以 TX1600G 数控镗铣加工中心为例,主要研究在移动热源施加条件下,不同的进给速度以及冷却液流量对系统热平衡的影响。为得到滚珠丝杠在实际工作中的状态,利用 ANSYS 建立丝杠的简化三维模型,施加移动热源来模拟螺母和轴承的传动热量,从而得到丝杠的温度模型,建立热误差补偿模型。结果表明,进给速度的增加可以缩短系统的热平衡时间,但热平衡温度有所升高;冷却液可以有效地降低热平衡温度和缩短热平衡时间。热误差模型建立和温度场分析,为系统的热补偿提供必要的理论依据。

  1. COAL MICRONIZATION STUDIES IN VIBRATING MILL IN TERMS OF COAL WATER SLURRY (CWS FUEL PREPARATION

    Directory of Open Access Journals (Sweden)

    Michał Rejdak

    2017-03-01

    Full Text Available The paper presents the results of coal milling tests in aspect of slurry fuel preparation. The tests were carried out with the use of vibrating mill with working chamber of 47.5 dm3. The influence of milling time, amount and composition of grinding aids on degree of fineness and particle size distribution has been investigated. It has been found that the efficiency of the grinding process (in this type of milling device depends primarily on the milling time and the share of grinding aids and - to a lesser extent - on their polydispersity. The study allows to conclude that the grinding time, composition and share of used grinding aids enable to control the final grain size of coal which has an impact on apparent viscosity of coal water slurry.

  2. Novel spin glasses by mechanical milling

    Institute of Scientific and Technical Information of China (English)

    周国富; H.Bakker

    1996-01-01

    Novel spin-glass alloys were synthesized by milling intermetallic compounds and also by milling mixtures of crystalline elemental powder in a high-energy ball mill.Spin glass behaviour was found in amorphous Co2Ge,which was amorphised by milling in mechanically disordered crystalline GdAl2 in ball-milled crystalline and amorphous CoZr,and in mechanically alloyed Co-Cu,which formed a supersaturated f.c.c.solid solution.All these materials are binary alloys and tlie concentration of the magnetic element is high,which makes them novel types of spin glasses.It is shown that ball milling may not only lead to structural metallic glasses,but can also generate the magnetic pendant of a structural glass,namely the spin glass.

  3. 基于S7-300PLC的球磨机配料过程自动控制系统%Automatic Control System of Ball Mill Blending Process Based on S7-300 PLC

    Institute of Scientific and Technical Information of China (English)

    王全铁; 包岩峰

    2011-01-01

    Ball mill blending process is one of the key producing processes in the sintering alumina production.In this blending process,raw materials are ground and blended in the mill to produce raw slurry.The automatic control system was designed and developed by using S7-300 PLC of Siemens Company in consideration of this industry features and technique requested.The structure,functions and control strategy of this system were all discussed,and the control software was developed.Control software includes the logic control program,continuous control program and picture monitoring.The proposed control system can not only improve the quality of raw slurry,but also can lower energy consumption and create more profit for its enterprise.%球磨机配料过程是氧化铝行业对原料进行加工处理的重要工序。在该过程中,碱赤泥浆等多种原料被输送到球磨机中进行混合、研磨后形成生料浆。针对该工业过程的特点及技术要求,利用Siemens公司的S7-300 PLC设计并开发了球磨机配料过程的自动控制系统,包括系统的结构和功能、硬件设计、各种软件程序的开发等。其中软件程序的开发包括逻辑控制程序、连续控制程序和监控画面的开发。所设计和开发的控制系统不仅可以大幅度提高生料浆质量,同时可以节能降耗,为企业创造更多的效益。

  4. Gray Prediction Model-free Adaptive Control Strategy of Ball Mill%球磨机灰色预测无模型自适应控制策略

    Institute of Scientific and Technical Information of China (English)

    马光; 李栋; 杨晓冬

    2016-01-01

    The ball mill load control system is a complex system featuring large time hysteresis,time-varying,strong nonlinearity,multivariable and strong coupling. In order to further overcome the large time lag and uncertainty and other problems of such load control system,the scheme of gray prediction model - free adaptive control ( MFAC ) is proposed. For this control system, PID, gray prediction PID, MFAC, and gray prediction MFAC are respectively applied in simulation analysis. The applications verify the feasibility and rationality of this strategy,and it is indicated that gray prediction model-free adaptive control has good control performance and practical value.%球磨机负荷控制系统是一个具有大时滞、强时变性、强非线性及多变量与强耦合等特性的复杂系统。为了更好地克服球磨机负荷控制系统中存在的大滞后和不确定性等问题,提出了灰色预测无模型自适应控制( MFAC )策略。在控制系统下,分别采用PID、灰色预测PID、MFAC及灰色预测MFAC进行控制仿真分析。实际应用验证了该策略的可行性与合理性,表明了灰色预测无模型控制策略具有良好的控制性能和实用价值。

  5. Hydrogen Storage Properties and Mechanism of Mg-In-Zn Ternary Solid Solution by Ball Milling%球磨制备Mg-In-Zn三元固溶体的储氢性能及机理

    Institute of Scientific and Technical Information of China (English)

    钟海长; 赖桂文; 朱子文; 郑青榕

    2014-01-01

    Mg0. 92 In0. 05 Zn0. 03 ternary solid solution with reduced lattice constants was prepared by the method of sintering-ball milling. The phases, phase transitions during hydrogenation and dehydrogenation process and microstructure of the alloy were analyzed by powder X-ray diffraction ( XRD) . The morphology and phase distributions were observed by SEM. PCT and kinetic curves were measured by Sievert’ method to determine the apparent activation energy of hydrogenation, enthalpy and entropy change of hydrogenation and dehydrogenation. The results show that Mg0. 92 In0. 05 Zn0. 03 ternary solid solution has good activation performances and kinetic properties, with the enthalpy of hydrogenation reduced to -68. 6 kJ/mol H2 .%采用“烧结-球磨”方法制备Mg0.92 In0.05 Zn0.03三元固溶体合金,减小了Mg的晶格常数.利用粉末X-射线衍射分析合金的相组成、微观结构和吸放氢过程的相转变,通过扫描电镜观察合金的微观形貌及相分布.采用体积法测定合金的等温吸放氢曲线( PCT)和动力学曲线,确定了合金的吸放氢反应焓变、熵变及氢化反应激活能.结果表明: Mg0.92 In0.05 Zn0.03三元固溶体具有良好的活化性能和动力学性能,脱氢反应焓降低至-68.6 kJ/mol H2.

  6. 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

  7. Influence of high-energy ball-milling on properties of CuCo/ZrO2 catalyst for higher alcohols synthesis%高能球磨对CuCo/ZrO2催化剂合成低碳醇性能的影响

    Institute of Scientific and Technical Information of China (English)

    士丽敏; 邓思玉

    2011-01-01

    研究高能球磨技术对浸渍法制备CuCo/ZrO2催化剂结构与合成低碳醇性能的影响,借助N2吸附-脱附等温线、扫描电镜、X射线衍射和程序升温还原等测试技术对催化剂进行表征,并以CO加氢合成低碳醇为模型反应对其催化性能进行评价.研究结果表明,催化剂制备过程中引入高能球磨技术可显著提高CuCo/ZrO2催化剂的CO转化率和C2+OH选择性.%The catalytic properties of high-energy ball-milled CuCa/ZrO2 catalysts for the synthesis of higher alcohols from syngas and the effects of high-energy ball-milling method on the structure and per formance of the catalysts were Investigated. The catalysts were characteriied by means of BET,SEM,XRD and H2-IPB techniques. The results indicated that CO conversion and selectivity to C2+OH were enhanced significantly when the high-energy ball-miffing method was used in the process of the catalyst preparation.

  8. Unsteady-State Grinding Technology (II) Experimental Studies of Grinding Forces and Force Ratio

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force F n, tangential grinding force F t and a component force acting along the direction of longitudinal feed which is usually neglected because of insignificance. The normal grinding force F n has influence upon surface deformation and roughness of workpiece, while the tangential grinding force ...

  9. Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

    Directory of Open Access Journals (Sweden)

    Fernández Luco, L.

    2003-12-01

    Full Text Available In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.

    En la fabricación de cemento portland es una práctica creciente la utilización de aditivos para optimizar el proceso de molienda; éstos quedan incorporados en el producto final y pueden influir sobre las características y propiedades del cemento, morteros y hormigones. En este trabajo se presenta la evaluación de dos aditivos comerciales en la molienda conjunta de clínker de cemento portland y yeso comercial, tratados en un molino a bolas a escala de laboratorio, en forma comparativa con un cemento sin aditivo producido en forma equivalente. Las conclusiones indican que los aditivos de molienda tienen influencia en las características del cemento resultante, incrementando su superficie y modificando su microestructura y estado de agregación; los morteros mejoran sus prestaciones mecánicas a todas las edades y se reduce la demanda de agua

  10. Preparation of bismuth subcarbonate by liquid ball-milling transformation method from bismuth oxide%液相球磨法由氧化铋制备次碳酸铋的动力学

    Institute of Scientific and Technical Information of China (English)

    叶龙刚; 蒋叶; 唐朝波; 陈永明; 唐谟堂

    2014-01-01

    In order to solve the problems of environment pollution and high cost in traditional process of bismuth subcarbonate preparation, a new process using ball-milling transformation method from NH4HCO3 and Bi2O3 was proposed. Additionally, the kinetics of bismuth subcarbonate preparation was studied. Effects of reaction temperature, particle size of bismuth oxide, solid-to-liquid ratio and concentrations of ammonium bicarbonate on the conversion rate of bismuth oxide were studied. The results indicate that the conversion rate of bismuth oxide significantly increased under the conditions of higher temperature, smaller particle size, higher concentration of ammonium bicarbonate and smaller solid-to-liquid ratio. The XRD and ICP-AES analyses show that the purity of product is high. The reaction kinetics with activation energy of 9.783 kJ/mol was analyzed by shrinking core model, and the whole transformation process is controlled by solid product layer diffusion. A semi-empirical kinetics equation was obtained to describe the conversion process.%为解决传统次碳酸铋生产过程中成本高和环境污染问题,提出采用液相球磨法由氧化铋制备次碳酸铋的新工艺,研究用碳酸氢氨和氧化铋制备次碳酸铋反应过程的动力学,考察反应温度、氧化铋粒度、液固比以及碳酸氢氨浓度对氧化铋转化率的影响。结果表明,在9~30°C的范围内,升高反应温度、减小氧化铋粉末的粒度、扩大液固比以及提高碳酸氢氨浓度均有利于氧化铋转化率的提高。对反应产物的表征分析表明,产品的纯度较高、杂质少;SEM结果显示产品次碳酸铋主要呈针棒状形态。反应过程受产物层的扩散控制,可用未反应收缩核模型描述,反应的表观活化能为9.783 kJ/mol,同时获得了描述反应过程的半经验动力学方程。

  11. 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...

  12. The effects of lifter configurations and mill speeds on the mill power draw and performance

    Science.gov (United States)

    Usman, Husni; Taylor, Patrick; Spiller, D. Erik

    2017-01-01

    Grinding mills used in the mining industries are the most energy-intensive operation and require a large number of wear resistant materials as well. The 1-m mill was used to investigate the effects of three lifter configurations, namely Hi (High), Rail and Hi-Lo (High-Low), and mill speeds on the mill performance. The MillTraj software was also utilized to simulate the outermost charge trajectories of the mill. At the given operating conditions, the power draw of Hi lifter was slightly lower than that of the Rail and the Hi-Lo and thus, the Hi lifter showed improvement in the mill efficiency. The product size distributions of the different lifters are very close and the size distribution of Hi-Lo lifter is slightly finer than those of the other lifters. At 74% critical speed, the size distributions of the Rail and Hi-Lo lifters were finer than at 70% critical speed, while that of Hi lifter otherwise occurs. At 80% critical speed, the size distributions of the lifters were coarser than at 74% critical speed. In this case, the outer charge trajectories of each lifter could go down on the mill shell rather than on the toe of the mill charge, resulting in ineffective grinding. Increasing face angles and/or mill charge would allow the mill to be operated at higher speeds.

  13. Effects of mechanical milling on the carbothermal reduction of oxide of WC/Co hardmetal scrap

    Science.gov (United States)

    Lee, Gil-Geun; Ha, Gook-Hyun

    2016-03-01

    The effects of mechanical milling on the carbothermal reduction of oxidized WC/Co hardmetal scrap with solid carbon were examined. Mixed powders were manufactured by milling the WC/Co hard metal scrap oxide and carbon powder in either a tumbler-ball mill or a planetary-ball mill. The milling type affected the carbothermal reduction of the oxide owing to the differing collision energies (mechanical milling energies) in the mills. The hardmetal scrap oxide powder (WO3, CoWO4) milled at high energy was more greatly reduced and at a lower temperature than that milled at lower mechanical energy. The formation of WC by the carburization reaction with solid carbon reached completion at a lower temperature after higher-energy milling than after lower-energy milling. The WC/Co composite particles synthesized by the combined oxidationmechanical milling-carbothermal reduction process were smaller when the initial powder was milled at higher mechanical energy.

  14. Dispersion Stability and Mechanism of Nano-WS2 Particulates in Base Lubrication Oil after High Power Ultrasund/Ball-milling/Surface Modification Treatment%超声球磨活化处理后纳米WS2颗粒在基础润滑油中的分散稳定性及机理

    Institute of Scientific and Technical Information of China (English)

    毛大恒; 刘阳; 石琛

    2013-01-01

    Nano-WS2 particulates were dispersed in PAO6 base lubrication oil by using the methods of ballmilling stir,ball-milling stir/surface modification and high power ultrasound/ball-milling stir/surface modification on homemade ultrasonic/ball milling experimental device,the dispersion stability of nano-WS2 particulates in base oil and the effect of surface modifier on diepersion stability of WS2 were studied,and the despersive mechanism was analysed,too.The results show that the dispersion state of the nano-WS2 particulates was best after compound action of high power ultrasonic/ball-milling stir/surface modification.The mechanism show that compound action of high power ultrasonic/ball-milling stir/surface modification could break up the nano-WS2 agglomerations and then strengthen the surfactivity of nano-WS2 particulates,and thus lead to the change of particulates' surface characteristics from hydrophilicity to lipophilicity,After surface modifying,the long carbon chains on WS2 surface could form stereo-hindrance layer,combined with solvation layer formed by lubricant molecule,to prevent nanometer particulates from aggregate,and ultimately made nanometer WS2 particulates dispered in baseoil stably for a long time.%用自制的超声球磨试验装置采用不同的分散方法(球磨搅拌分散,球磨搅拌、表面活性剂分散,强超声、球磨搅拌、表面活性剂分散)将纳米WS2颗粒分散于PAO6基础润滑油中,研究了纳米WS2颗粒在基础油中的分散稳定性以及表面活性剂对纳米WS2颗粒分散稳定性的影响,并对其分散机理进行了分析.结果表明:强超声、球磨搅拌、表面活性剂分散的复合处理对提高纳米WS2颗粒在基础油中分散稳定性的效果最好,其机理是将基础油中的纳米WS2团聚体解聚,并使解聚后的纳米WS2颗粒表面活性增强,表面特性由亲水疏油转变为亲油疏水,经表面修饰后的纳米WS2颗粒被长碳链极性分子和润滑油分子所包围,

  15. 基于残留高度球刀铣削粗糙度建模及参数优化∗%Modeling of Surface Roughness with Ball-end Cutters Milling Based on Scallop Height and Optimum of Cutting Parameters

    Institute of Scientific and Technical Information of China (English)

    肖军民

    2015-01-01

    基于P20模具钢数控球刀铣削试验,对表面粗糙度的影响因素进行了研究。在试验数据极差分析的基础上得出了如下结论:加工残留高度是球刀铣削粗糙度最重要的影响因素。基于试验数据,利用最小二乘多元线性回归方法,推导并求解出P20模具钢球刀铣削粗糙度的数学模型。利用最优化设计方法和MATLAB优化工具箱,以加工效率为目标函数和以粗糙度预测模型为约束条件,针对实际的问题优选了铣削工艺参数。优化的工艺参数在保证表面加工质量的基础上可大幅提高加工效率,这为数控加工企业降低生产成本提供了重要的理论依据和案例参考。%The affecting factors on surface roughness are studied based on NC milling tests with ball-end cut-ters for P20 mould steel. Based on the analysis of the test data conclusions are as follows:scallop height is the most important influencing factors of surface roughness for ball-end cutters milling. Based on the experi-mental data, the mathematical model of surface roughness with ball-end cutters milling for P20 mould steel is derived and solved by using of regression analysis method of least square. Aiming at the actual milling problem the cutting parameters are optimized by using of optimum tool-box of MATLAB software and opti-mal design method. The optimized cutting parameters can greatly improve the machining efficiency ensuring quality of the machined surface, it provides the important theory evidence and case reference for NC machi-ning enterprises to reduce production costs.

  16. Bouncing Balls that Spin

    Science.gov (United States)

    Knipp, Peter

    2008-01-01

    When a ball bounces elastically against a floor, the vertical component (v[subscript y]) of the velocity of the ball's mass-center changes sign. This is a special case of the elastic collision of two balls (i.e., two objects, neither of which is much more massive than the other), in which case the balls' post-collision relative velocity (=…

  17. 葛花粉体高效球磨制备技术及其醒酒活性测定%High efficient ball milling technology and determination alcohol metabolism of Flos puerariae

    Institute of Scientific and Technical Information of China (English)

    许阳; 杜先锋; 王一见

    2013-01-01

    The mechanism for Flos puerariae facilitating alcohol metabolism was studied.The relativity between particle size and the release rate of efficacy was demonstrated.The activity of alcohol dehydrogenase (ADH) in vitro and the dissolution of total material and flavonoids from four kinds of powder of Flos puerariae which used different methods to shatter were compared.The results showed that four kinds of powder could activate ADH,but grade Ⅱ powder had an obvious advantage over grade Ⅰ powder in the total dissolution test.Its instant dissolution can reached 8.6 times of that of plant body.There was the same trend in the amount of flavonoids dissolution and the activation rate of ADH.The amount of flavonoids dissolution in grade Ⅱ powder was 57.98% higher than that in plant body and activation rate was 2 times of that in it.The grade Ⅱ powder which was gained by high efficient ball milling technology had a more beneficial effect on these tests than other powder.It was also indicated that it was useful to select Flos puerariae to facilitate alcohol metabolism,this new efficient technology provided a theoretical basis for the development of new sober up functional foods.%为探究葛花粉体粒径与功效释放速度的相关性及其醒酒机理,通过比较4种不同粉碎方法处理得到的植物本体、常规粉体、Ⅰ级粉体、Ⅱ级粉体在总物质溶出度、黄酮溶出量及乙醇脱氢酶(ADH)体外活性实验方面的差异性,发现4种粉体均可在体外激活乙醇脱氢酶,但在总溶出度上Ⅱ级粉体优于Ⅰ级粉体,其次是常规粉体和植物本体,其瞬时溶出度可达到植物本体的8.6倍.在黄酮溶出量和ADH激活率上也呈现相同趋势,Ⅱ级粉体黄酮溶出含量较植物本体提高57.98%,激活率为本体的2倍.实验表明,采用高效球磨技术制备的葛花Ⅱ级粉体较其他粉体均呈现出最优实验结果,且其醒酒作用机制与其能激活乙醇脱氢酶有关,为开发新

  18. Bruxism (Teeth Grinding or Clenching) (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Bruxism (Teeth Grinding or Clenching) KidsHealth > For Parents > Bruxism ( ... called bruxism , which is common in kids. About Bruxism Bruxism is the medical term for the grinding ...

  19. Modulus Proposal for a Multi Axes Grinding of Sculptured Surfaces

    Science.gov (United States)

    Jandečka, Karel

    2009-11-01

    This paper presents the use of the CAD/CAM system Cimatron for free programming of NC grinding machines. NC technology use, first of all in milling, turning and drilling operations, is widely dispersed at present. Development of these technologies depends to some extent on the cutting tools which are to be produced and sharpened to a high quality. Usable properties of the cutting tools, e.g. the shape accuracy, the quality of function surfaces, etc., are inspired by the production technology used. This technology plays a main role in production and sharpening of powerful and complex shaped cutting tools.

  20. Effect of grinding time of synthesized gadolinium doped ceria (GDC10 powders on the performance of solid oxide fuel cell

    Directory of Open Access Journals (Sweden)

    Fatma Aydin

    2014-03-01

    Full Text Available Ceria-based materials are prospective electrolytes for low and intermediate temperature solid oxide fuel cells. In the present work, fully dense CeO2 ceramics doped with 10 mol% gadolinium (Gd0.1Ce0.9O1.95 were prepared with a sol–gel method and commercially purchased GDC10 electrolyte powders were processed. Particle sizes of synthesized electrolyte powders were minimized by ball-milling method. Grinding of the samples were performed in different times intervals (12 h, 15 h, 18 h, 20 h, 25 h, 30 h, 35 h, 40 h and 45 h. Then, these powders were prepared to obtain of solid oxide fuel cells (SOFCs. Performances of these cells having an active area of 1 cm2 were tested using a fuel cell test station that measured in different temperatures (650 and 700 °C. In the present study, gadolinium doped ceria (GDC10 synthesiszed powders were investigated by using XRD and SEM images. Performance values of synthesized GDC10's in different temperature were compared to by commercial GDC10. Commercial GDC10's performance at 650 °C were tested, and maximum current density of 0.413 W/cm2 and maximum current density of 0.949 A/cm2 were obtained. Commercial GDC10 at 650 °C has better result. However, synthesized GDC10's performance at 700 °C demonstrated better results than commercial GDC10's. The performance tests of samples which are 20 h mill showed that they have the maximum power density of was obtained as 0.480 W/cm2 and maximum current density of as 1.231 A/cm2.

  1. Unsteady-State Grinding Technology (I) Theoretical Generalization and Research on Grinding Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In conventional grinding theory, it is obvious that there must be a very high hardness difference between grains of the grinding wheel and workpieces. The best grinding wheels are those giving the lowest "natural limiting surface roughness" while cutting at appreciable plunge velocities. With the development of new materials and new machining processes, conventional theories of grinding techniques are no longer suitable to explain many phenomena in the course of grinding procedures. In dealing with precisio...

  2. AN INNOVATIVE METHOD FOR FORMING BALLS FROM SCRAP RAIL HEADS

    Directory of Open Access Journals (Sweden)

    Zbigniew Pater

    2016-09-01

    Full Text Available The paper describes a new method for forming grinding media balls from scrap rail heads. This forming method involves the following operations: cutting the rail head to the desired length combined with lateral pressing of the produced workpiece; flashless die forging and sizing of balls in a helical impression. The proposed method was verified by numerical simulation which involved the modeling of a forming process for producing 80 mm diameter balls. As a result of the modeling, it was possible to examine the changes in the workpiece shape during each forming operation, the variations in loads and torques, as well as the distribution of temperatures enabling performing another forming operation, i.e. quenching. The results confirm that the designed method can be used to produce balls.

  3. Ultrasonic precision optical grinding technology

    Science.gov (United States)

    Cahill, Michael J.; Bechtold, Michael J.; Fess, Edward; Wolfs, Frank L.; Bechtold, Rob

    2015-10-01

    As optical geometries become more precise and complex and a wider range of materials are used, the processes used for manufacturing become more critical. As the preparatory stage for polishing, this is especially true for grinding. Slow processing speeds, accelerated tool wear, and poor surface quality are often detriments in manufacturing glass and hard ceramics. The quality of the ground surface greatly influences the polishing process and the resulting finished product. Through extensive research and development, OptiPro Systems has introduced an ultrasonic assisted grinding technology, OptiSonic, which has numerous advantages over traditional grinding processes. OptiSonic utilizes a custom tool holder designed to produce oscillations in line with the rotating spindle. A newly developed software package called IntelliSonic is integral to this platform. IntelliSonic automatically characterizes the tool and continuously optimizes the output frequency for optimal cutting while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more accurate surface. Utilizing a wide variety of instruments, test have proven to show a reduction in tool wear and increase in surface quality while allowing processing speeds to be increased. OptiSonic has proven to be an enabling technology to overcome the difficulties seen in grinding of glass and hard optical ceramics. OptiSonic has demonstrated numerous advantages over the standard CNC grinding process. Advantages are evident in reduced tool wear, better surface quality, and reduced cycle times due to increased feed rates. These benefits can be seen over numerous applications within the precision optics industry.

  4. THERMAL STUDY ON THE GRINDING OF GRANITE WITH SUPERABRASIVE TOOLS

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In the present paer, a thermal study was conducted for the grinding of granite with diamond tools. Three types of grinding-straight surface grinding, deep grinding(circular sawing), and vertical spindle grinding-were studied. Some surface grinding tests were also conducted using a CBN(cubic boron nitride) wheel. Temperature distributions on the workpiece surface were measured using a foil thermocouple and the energy partition to the workpiece was estimated using a temperature matching method. The temperature for CBN surface grinding was found to be much higher than for diamond grinding. Energy partitions to the granite were 30%~36% for CBN surface grinding, 25%~32% for diamond surface grinding, about 53% for vertical spindle grinding, and 5.5%~9% for diamond deep grinding. The low energy partition value in deep grinding also suggested that more of the heat generated by grinding in this case can be conducted to the grinding tool and promote tool wear.

  5. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Gröning, Holger Andreas

    2014-01-01

    A deductive kinematic model of creep-feed and speed-stroke grinding processes is developed to identify possibilities to reduce the energy introduced into the workpiece. By computer tomography analysis and tactile measurements of the grinding wheel the pore volume and the static cutting edge number are determined and included in the model. Based on the kinematic model and the grinding wheel characteristics an analytical evaluation of the specific grinding energy for speed-stroke and creep-feed grinding is carried out. The deducted process design is evaluated in experimental investigations. The

  6. GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS

    DEFF Research Database (Denmark)

    Borsetto, Francesca; Bariani, Paolo

    for the manufacturing of miniature parts by micro milling puts further challenges on to the manufacturing process. The whole geometry of the tools cannot be directly downscaled with the tool diameter. Besides the physical limit in the reduction of the cutting edge radius constituted by the grain size of sintered...... carbides the error motion during the grinding wheels do not allow using identical paths for tools having differences in diameter of more than one order of magnitude. Thus grinding paths for micro and mills are simplified in comparison to those for larger tools of similar shape. [1] The aim of the present...... report is to develop procedures for the geometrical characterization of micro end milling tools in order to define a method suitable for the quality assurance in the micro cutting field....

  7. Force Characteristics in Continuous Path Controlled Crankpin Grinding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Manchao; YAO Zhenqiang

    2015-01-01

    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  8. The effects of pf grind quality on coal burnout in a 1 MW combustion test facility

    Energy Technology Data Exchange (ETDEWEB)

    Richelieu Barranco; Michael Colechin; Michael Cloke; Will Gibb; Edward Lester [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering, Nottingham Fuel and Energy Centre

    2006-05-15

    A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1 MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of extremes in fuel characteristics experienced by coal importing utilities in Europe. Each coal was fired in the unit at a range of grind sizes to determine the overall impact of a variable performance from a mill. The levels of unburnt carbon in the resultant flyashes for the two coals showed significantly different behaviour. For the higher volatile coal, the unburnt carbon was found to be insensitive to grind quality. However, the coarser grinds of the other coal produced significantly lower unburnt carbon than expected when compared with the finest grinds. Generally the results indicate that the installation of improved classification technology, leading to a finer product, will help to lower unburnt carbon levels. Nevertheless, further work will be necessary to establish the levels of diminishing returns for grind size, burnout performance and grind costs. 21 refs., 4 figs., 4 tabs.

  9. Affecting mechanism of grinding aid during ultrafine grinding%超细粉碎过程助磨剂的作用机理

    Institute of Scientific and Technical Information of China (English)

    杨华明; 邱冠周

    2000-01-01

    通过粉体ζ-电位、矿浆粘度测定及光电子能谱(XPS)和分散率分析,研究了搅拌磨超细粉碎滑石粉过程中助磨剂的助磨行为.分析了六偏磷酸钠与滑石粉的表面作用及吸附特性,提出了助磨剂在超细粉碎过程中的吸附模型.此外,探讨了助磨剂对超细粉碎行为的影响.研究结果表明,助磨剂通过与滑石粉的吸附作用,降低了矿浆粘度,从而提高了超细粉碎的效率.%The aiding behavior of hexametaphosphate(hexa) during uhrafine grinding of talc with stirred mill is studiedthrough analysis of ζ-potenfial,pulp viscosity,XPS and scattering rate in the paper. The surfacial effect and adsorptioncharacteristics of Hexa on talc particles are analysed. A typical model of grinding aid during ultrafine grinding is given.Effect of Hexa on ultrafine grinding behavior is also discussed. The results show that it is the adsorption of Hexa and re-ducing pulp viscosity that improve the grinding efficiency.

  10. 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…

  11. Preparation of Carbon Nanotubes(CNT)/TiO2 Composite Powder by High Energy Ball Milling and Sol-Gel and its Properties%高能球磨和溶胶凝胶制备碳纳米管掺杂TiO2复合粉及其性能

    Institute of Scientific and Technical Information of China (English)

    陈守刚; 赵文杨

    2011-01-01

    Carbon nanotubes(CNT)/TiO2 nanocomposite powder has been prepared by high energy ball milling and sol-gel methods. The morphology, microstructure and photocatalytic activity of the products were characterized by scanning electron microscopy , X-ray diffraction, and UV-vis spectroscopy. The results show that the photocatalytic activity of this composite synthesised by 5% carbon nanotubes and TiO2 powders powder is improved effectively. The composite powder prepared by high energy ball milling method is smaller in size and more uniform in distribution with better photocatalytic activity and is more practical than that prepared by sol-gel.%采用高能球磨法和溶胶-凝胶方法制备了碳纳米管掺杂的Ti02纳米复合粉体,通过扫描电子显微镜、X射线衍射、紫外分光光度计等方法对比分析了复合粉体的形貌、微观结构以及光催化活性.实验结果表明,5%碳纳米管掺杂的Ti02复合粉体的光催化活性得到了有效提高,其中高能球磨法制备的复合粉体颗粒细小、分布均匀,具有更好的光催化活性和实际应用意义.

  12. 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.