Ball Milling Parameters Research Articles

CNT Reinforced Aluminium Matrix Composite-A Review

This paper summarises the research work carried out in the field of carbon nanotube (CNT) aluminium matrix composites which are being investigated for their use in automobile and aerospace industries because of their low density and high specific strength .This paper addresses a brief description on fabrication techniques particularly ball milling which aims to achieve homogeneous distribution of CNT in the matrix. Also, the effect of ball milling parameters on CNT dispersion and the effect of CNT reinforcement on mechanical properties-toughness and hardness and friction and wear behaviour has been critically reviewed as well. The analysis presented here would be instrumental in the future design of high strength CNT/Al matrix composites.

Ball-Milling of Graphite and Multi-Wall Carbon Nanotubes

The structural modification of graphite and multi-wall carbon nanotubes (MWCNTs) during ball-milling was examined. A comparison of structures after ball-milling was made between graphite and MWCNTs. The ball milling parameters were also examined: milling atmospheres, milling methods, milling mode and the addition of additive materials. In some experiments, hard materials such as alumina or silica were added to graphite and MWCNTs as additives to see whether graphite and MWCTs were shortened by ball-milling. The ball-milling of graphite and MWCNTs with liquid additives reduced the agglomeration of MWCNT and transformed graphite to graphenes. The ball-milling of MWCNTs under impact mode usually resulted in the formation of an amorphous phase, whereas that under friction mode induced the fattening of nanotubes. The results showed that a variety of carbon nanomaterials could be obtained by the proper controlling of ball milling. The structurally modified graphite and MWSNTs are expected to be utilized for energy storage application.

Parametric optimization of NiFe2O4 nanoparticles synthesized by mechanical alloying

Abstract In this study, the Taguchi robust design method is used for optimizing ball milling parameters including milling time, rotation speed and ball to powder weight ratio in the planetary ball milling of nanostructured nickel ferrite powder. In fact, the current work deals with NiFe2O4 nanoparticles mechanochemically synthesized from NiO and Fe2O3 powders. The Taguchi robust design technique of system optimization with the L9 orthogonal array is performed to verify the best experimental levels and contribution percentages (% ρ) of each parameter. Particle size measurement using SEM gives the average particle size value in the range of 59–67 nm. X-ray diffraction using Cu Kα radiation is also carried out to identify the formation of NiFe2O4 single phase. The XRD results suggest that NiFe2O4 with a crystallite size of about 12 nm is present in 30 h activated specimens. Furthermore, based on the results of the Taguchi approach the greatest effect on particle size (42.10 %) is found to be due to rotation speed followed by milling time (37.08 %) while ball to powder weight ratio exhibits the least influence.

Effects of Processing Parameters on the Synthesis of (K0.5Na0.5)NbO3Nanopowders by Reactive High-Energy Ball Milling Method

The effects of ball milling parameters, namely, the ball-to-powder mass ratio and milling speed, on the synthesis of (K0.5Na0.5)NbO3 nanopowders by high-energy ball milling method from a stoichiometric mixture containing Na2CO3, K2CO3, and Nb2O5 were investigated in this paper. The results indicated that the single crystalline phase of (K0.5Na0.5)NbO3 was received in as-milled samples synthesized using optimized ball-to-powder mass ratio of 35 : 1 and at a milling speed of 600 rpm for 5 h. In the optimized as-milled samples, no remaining alkali carbonates that can provide the volatilizable potassium-containing species were found and (K0.5Na0.5)NbO3 nanopowders were readily obtained via the formation of an intermediate carbonato complex. This complex was mostly transformed into (K0.5Na0.5)NbO3 at temperature as low as 350°C and its existence was no longer detected at spectroscopic level when calcination temperature crossed over 700°C.

Tribosynthesis of Fe3–xMnxC Phases via Mechanical Alloying and Annealing

Powderous crystalline materials of the composition Fe3-xMnxC have been prepared by first synthesizing Fe3C via mechanical alloying in a planetary mill followed by the addition of elemental manganese and arc-plasma melting or via the classic ceramic route in an electric furnace. The milling time for the synthesis of Fe3C was significantly reduced through adjusting the parameters of the planetary ball mill. When the ball-to-powder ratio was lowered, significantly larger batches were possible. Sintering in a fired tubular furnace was found to be the method of choice for the aftertreatment of the nanocrystalline Fe3-xMnxC powders as exemplified by X-ray Rietveld refinements.

Preparation of La-Mg-Ni Hydrogen Storage Composite Alloys by Mechanical Alloying

LaNi5-xwt%Mg hydrogen storage alloys with different Mg content were made from pure La, Mg and Ni metal powder by mechanical alloying, selecting appropriate ball-milling parameters in 0.4MPa hydrogen atmosphere. The characterizations for hydrogen storage alloy show that a multi-phase alloy composed of MgH2, LaH3, Mg2NiH4 and Ni was obtained, the alloy have two hydrogen desorption temperature range, and the alloy with 25wt% Mg content can desorb hydrogen up to 4.02wt%.

탄소 나노튜브의 볼밀링 시 구조 변화

We examined various ball-milling parameters which affect the structural and morphological modification of multi-wall carbon nanotubes. In particular, the effect of milling mode and the use of different milling agents were examined. Friction milling mode induced more structural changes than impact milling mode except the use of dry ice as a milling agent. Wet milling was helpful for reducing more effectively the agglomeration of nanotubes than dry milling. The use of hard solid particles such as silica and alumina as milling agents resulted in an effective shortening of nanotubes, but often susceptible to the amorphization and the destruction of crystallinity.

Effects of mechanical alloying process and sintering methods on the microstructure and thermoelectric properties of bulk Bi0.5Sb1.5Te3 alloy

In this study, bulk ternary alloy Bi0.5Sb1.5Te3 was fabricated by mechanical alloying combined with hot pressing (HP) and spark plasma sintering process (SPS), respectively. Differences in microstructure and thermoelectric properties between HP samples and SPS specimens with different ball milling parameters were investigated visually. The results showed that certain improvement in rotate speed of ball milling process can reduce the formation time of Bi0.5Sb1.5Te3 powders from 60 h to 12 h. Mechanical alloying process had an important effect on the Seebeck coefficient of Bi0.5Sb1.5Te3 alloy, negative Seebeck coefficient may even appear due to the deformation induced donor-like effect. The study also discovered that laminated structure was much more familiar in hot pressed Bi0.5Sb1.5Te3 alloy compared with that in the spark plasma sintering samples. The figure of merit of Bi0.5Sb1.5Te3 alloy was enhanced with the increasing hot pressing temperature and reached 0.0027 K−1 around room temperature. Spark plasma sintered samples with 450 rpm + 60 h + 20:1 ball milling parameters have the maximum figure of merit 0.0048 K−1 which is about 1.5 times higher than the maximum TE value of HP samples.

Modeling Load Parameters of Ball Mill in Grinding Process Based on Selective Ensemble Multisensor Information

Due to complex dynamic characteristics of the ball mill system, it is difficult to measure load parameters inside the ball mill. It has been noticed that the traditional single-model and ensemble-model based soft sensor approaches demonstrate weak generalization power. Also, mill motor current, feature subsets of the shell vibration and acoustical frequency spectra contain different useful information. To achieve better solutions and overcome these problems mentioned above, a selective ensemble multisource information approach is proposed in this paper. Only the useful feature subsets of vibration and acoustical frequency spectra are portioned and selected. Some modeling techniques, such as fast Fourier transform (FFT), mutual information (MI), kernel partial least square (KPLS), brand and band (BB), and adaptive weighting fusion (AWF), are combined effectively to model the mill load parameters. The simulation is conducted using real data from a laboratory-scale ball mill. The results show that our proposed approach can effectively fusion the shell vibration, acoustical and mill motor current signals with improved model generalization.

Mechanical alloying of lanthana-bearing nanostructured ferritic steels

A novel nanostructured ferritic steel powder with the nominal composition Fe–14Cr–1Ti–0.3Mo–0.5La2O3 (wt.%) was developed via high energy ball milling. La2O3 was added to this alloy instead of the traditionally used Y2O3. The effects of varying the ball milling parameters, such as milling time, steel ball size and ball to powder ratio, on the mechanical properties and microstructural characteristics of the as-milled powder were investigated. Nanocrystallites of a body-centered cubic ferritic solid solution matrix with a mean size of approximately 20nm were observed by transmission electron microscopy. Nanoscale characterization of the as-milled powder by local electrode atom probe tomography revealed the formation of Cr–Ti–La–O-enriched nanoclusters during mechanical alloying. The Cr:Ti:La:O ratio is considered “non-stoichiometric”. The average size (radius) of the nanoclusters was about 1nm, with number density of 3.7×1024m−3. The mechanism for formation of nanoclusters in the as-milled powder is discussed. La2O3 appears to be a promising alternative rare earth oxide for future nanostructured ferritic steels.

Reversible hydrogen storage in the Li–Mg–N–H system – The effects of Ru doped single walled carbon nanotubes on NH3 emission and kinetics

In this study, the LiNH2–MgH2 (2:1.1) complex hydride system (Li–Mg–N–H is investigated in terms of hydrogen ab/desorption kinetics and the concomitant NH3 emission levels. By selecting more intense ball milling parameters, the hydrogen ab/desorption kinetics were improved and the NH3 emission reduced. However, it is shown that NH3 emission cannot be completely eliminated during ball milling. Single walled carbon nanotubes (SWCNTs) and 20 wt.% Ru doped SWCNTs are utilized as catalysts to study their effects on NH3 emission and kinetics characteristics of the Li–Mg–N–H system. The SWCNT doped sample did not show any kinetics improvement, whereas the SWCNT-20Ru doped sample showed similar kinetics performance as that of the base sample. More importantly, the presence of SWCNT increased the NH3 emission as compared to the base sample. On the other hand, SWCNT-20Ru doping reduced the NH3 emission compared to the SWCNT doping, but did not eliminate it completely. As revealed from the mass spectrometry signals, the SWCNT-20Ru catalyst starts to decompose NH3 at a temperature as low as 200 °C.

Oily nanosuspension for long-acting intramuscular delivery of curcumin didecanoate prodrug: Preparation, characterization and in vivo evaluation

The objective of this study was to prepare the nanocrystals of curcumin didecanoate (CurDD) by wet ball milling and to investigate the comparative pharmacokinetics of oily nano- and micro-suspensions after intramuscular (i.m.) administration to rats. Upon optimizing the wet ball milling parameters, CurDD nanocrystals were produced with median particle size of ∼500nm and the freeze-dried nanocrystals were readily dispersed in peanut oil to form stable nanosuspensions. Although the nanosuspension appeared to exhibit slower clearance from the injection site after i.m. injection, compared to microsuspension (∼5μm), a significantly higher maximum plasma curcumin concentration (69.0ng/ml) was observed for the former than that for the latter (18.5ng/ml). In addition, the nanosuspension provided significant higher plasma curcumin concentrations and brain CurDD contents for at least 15days than the microsuspension, except for the initial times. A single i.m. injection of nanosuspension appeared to achieve reversal effect on reserpine-induced hypothermia for at least 13days. This study demonstrates that CurDD nanosuspension may act as a long-acting i.m. injectable for sustained delivery of curcumin, potentially applicable to elicit a long-lasting antidepressant effect.

Optimisation of Ball Milling Parameters for Refinement of Waste Jute Fibres to Nano/Micro Scale in Dry Conditions

Abstract Inpresentstudy,optimizationoffouroperatingparametersofhighenergyplanetaryballmill(i.e.millingtime,millingspeed,balltomaterialratioandballsize)ondrygrindingofjutefibrewastewasperformed.Athree-levelBox-Behnkendesigncombiningaresponsesurfacemethodologywasemployedtostudytheresponseintermsofparticle size and % sticking of material to mill. Analysis of variance of milling parameters showed coefficient ofdetermination of 0.927 and 0.903 for particle size and material sticking respectively. The model equations weresubsequently optimized using the canonical analysis with the help of SYSTAT software to minimize the particlesizeandmaterialsticking.Theoptimumconditionswerefound12mmforballsize, 47minformillingtime, 9forballtomaterialratioand870rpmfor milling speed. KeyWords :Jutefibrewaste,Highenergy planetary ball milling, Particle size distribution, Material sticking,Box-Behnkendesign 1. Introduction Thenanofibrilsornanocrystalsofcellulosehavebeenextractedinpreviousresearchworkfromseveralnaturalsourceslikecotton[1],sisal[2],jute[3-5],soybean[6],wheatstrawandsoyhulls[7],hemp[8],etcbymechanical[9-10],chemical[2],enzyme[11]orcombination of techniques [12]. The chemical method employsstrongacidhydrolysistreatmenttoremovetheamorphousregionsof cellulose fibres and separate nanocrystalline cellulose (NCC)whereas mechanical method involves high-pressure shear refiningtreatment to produce nanofibrillar cellulose (NFC) together withcrystalline and amorphous regions [13]. However the use of acidtreatmentovermechanicaltreatmentwasfoundtohavenumberofdrawbacks, such as longer time of separation of nanocrystals,potential degradation of cellulose, corrosivity, and environmentalincompatibility[13-14].Thereforesomeresearchersemployedthealternative route of mechanical treatment through various wayslike grinding [13, 15,16], high pressure homogenizing [16],cryocrushing [6, 8], ultrasonic treatment [12, 14], etc to extractNFC rather than NCC. This paper deals with preparation ofnanocellulose from waste jute fibres in the textile industry bysimple, quick and environment friendly ball milling process. Themain objective of the present study was to utilise the short fibreswhich could not be spun into yarn, for reinforcement inbiodegradable composite applications.Ballmillingprocessisamechanicalprocesswhichreliesontheenergyreleasedatthepointofcollisionbetweenballsaswellasonthe high grinding energy created by friction of balls on the wall[17]. When the mill rotates, balls are picked up by the mill walland rotate around the wall due to centrifugal force leading togrinding of material due to frictional effect. On the other handthere is also reverse rotation of disc with respect to mill whichappliescentrifugalforceinoppositedirectionleadingtotransitionof balls on opposite walls of mill giving impact effect.Basedonourpreviousresearch[13,15,18],duringdrygrindingofjutefibres,significantincreaseintemperatureduetoimpactofballs resulted in sticking of material on the milling media.Consequentlythedepositedmassofmaterialsloweddowntherateof refinement of particles and provided wider size distribution. Inorder to avoid increase in temperature and to increase millingefficiency, ball milling parameters for dry pulverisation of jutefibres must be optimised. The objective of present study is tooptimize the four milling parameters i.e. milling time (MT),millingspeed(MS),balltomaterialratio(BMR)andballsize(BS)with use of Box-Behnken design and response surfacemethodology.

Effect of Ball-Milling Parameter on the Synthesis of MWCNT/Alumina Hybrid Compound

The effects of ball-milling parameter on the structures and properties of the synthesis of multi-walled carbon nanotubes (MWCNT)/alumina hybrid compound via methane decomposition process using Ni-Alumina catalyst were researched. The structural evaluation of particles compound was investigated by particle size analysis, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), FTIR spectrometer and scanning electron microscopy (SEM). The results indicated that with 300rpm 15h, the microstructure of the hybrid compound is greatly refined, and methane decomposition process distributed uniformly, thus increasing the efficiency of the carbon nanotubes growth process.

Effect of Ball Milling Parameters on the Synthesization of Carbon Nanotube Aluminium Nano Composite

Recently, carbon nanotubes (CNTs) are attracting much interest as fibrous materials for reinforcing aluminium matrix composites due to unique properties such as high strength, elastic modulus, flexibility and high aspect ratios. However, the quality of the dispersion is the major concern factor which determines the homogeneity of the enhanced mechanical and tribological properties of the composite. This work study and characterized the nanocomposite prepared with different weight percentage of CNT in aluminium matrix using powder metallurgy route under high energy planetary ball milling operations. The ball milling was performed for three hours at different milling speeds and under controlled atmosphere. The experimental results showed homogeneous dispersion of CNTs in aluminium matrix at 300 rpm. The preliminary mixing of CNTs and aluminium powder in a tube via manual shaking could be the main contributing factor in achieving uniform dispersion of CNT in aluminium matrix after ball milling. The addition of ethanol as a process control agent reduced the agglomeration of CNTs in the matrix. Control atmosphere during milling also prevented the formation of inter metallic compounds such as aluminium carbide in the composite.

Back-calculation of mechanical parameters of shell and balls materials from discrete element method simulations

Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main parameters of a transparent ball mill constructed in mineral processing laboratory of the University of Tehran. The mill shell and crushing balls are made of Plexiglas® and compressed glass respectively. The true values of mechanical parameters for these materials, required for DEM modeling, were unknown. The authors back-calculated the best values of mechanical properties of Plexiglas and compressed glass materials based on a large number of DEM simulations. Back-calculation procedure was mainly based on the comparison between electrical power draw measured in real mill and mechanical power draw calculated by DEM model while trying to simulate particle flow regime inside the real mill accurately. The results showed that the optimal number and design of lifters can be adequately determined by improving torque and kinetic energy in crushing elements through DEM simulation trials based on the back-calculated mechanical parameters.

Influence of ball milling parameters on the structure of the mechanically alloyed SiBCN powder

SiBCN powders were prepared by an improved mechanical alloying technique, using cubic silicon, graphite and hexagonal boron nitride powders as raw materials. The influences of ball milling parameters on the structures and the particle size distribution of the prepared powders were carefully studied by XRD, HRTEM, EFTEM and particle-size analysis. Results show that well amorphized SiBCN powder can be prepared when the rotation speed of the vials is between 600 and 800rpm, the ball-to-powder mass ratio is larger than 20:1, and the milling time is longer than 20h. A higher rotation speed and a larger ball-to-powder mass ratio may enhance the power input into the powder, and hence facilitate the formation of SiC crystallites. While a longer milling time has little influence on the powder microstructure, it promotes the reaction between silicon and carbon atoms. The optimized ball milling parameters are 600rpm, 20:1, 30 or 40h, respectively. The prepared SiBCN powders mainly consist of near-spherical agglomerates, 4.6–5.3μm in the average particle size. The particle size distribution of these powders is slightly affected by the variation of ball milling parameters.

Feature extraction and selection based on vibration spectrum with application to estimating the load parameters of ball mill in grinding process

Feature extraction and selection are important issues in soft sensing and complex nonlinear system modeling. In this paper, a new feature extraction and selection approach based on the vibration frequency spectrum is proposed to estimate the load parameters of wet ball mill in grinding process. This approach can simplify the modeling process. In this study, the vibration acceleration signals are first transformed into the frequency spectrum by fast Fourier transform (FFT). Then the candidate features are extracted and selected from the frequency spectrum, which include characteristic frequency sub-bands, spectral principal components, and features of local peaks. Mutual information, spectral segment clustering and kernel principal component analysis are used to obtain these candidate features. Finally, a combinatorial optimization method based on adaptive genetic algorithm selects the input sub-set and parameters of the soft sensor model simultaneously. This approach is successfully applied in a laboratory scale wet ball mill. The test results show that the proposed approach is effective for modeling the parameters of mill load.

A Mathematical Model for Predicting the Internal Parameters of Ball Mill

The internal parameters of ball mill are very important in the grinding process and have significant impact on the grinding results. Accurate measurement of the internal parameters of ball mill is crucial and indispensable for optimization and control of grinding process. In this paper, a novel tri-sensor measurement method was used to measure the external signals (i.e., bearing pressure, sound intensity and power consumption) of ball mill. Mathematical models, which link the external signals of ball mill with its internal parameters, were established to predict the internal parameters of ball mill. Experimental results showed that the mathematical models could directly predict the internal parameters of ball mill once the external signals were obtained. The tri-sensor measurement method and the mathematical models proposed in this paper provided a new way and solid basis for optimization and control of ball milling.

Preparation of Cu-Zn Alloy by Different High Energy Ball Milling

Cu-Zn alloy was prepared by high energy ball milling of elemental copper and zinc by the Simoloyer attrition mill, the different parameters such as milling time, ball-to-powder ratio and rotational speeds were analyzed. The results show that the different Cu-Zn alloy phase can be produced by different ball milling parameters, It has been found that milling time is highly significant to refining process, and the ratios of ball to powder are also benefited to the new phase form.