Effect of Milling Parameters on DEM Modeling of a Planetary Ball Mill

The effects of the milling parameters involving shape of powder particles, rotation speed, and ball-to-powder diameter (BPDR) on DEM modeling in the planetary ball mill were investigated. BPDR was varied from 1 to 10. The results revealed that the size and shape of the powder particles do not give a significant change in simulation results when BPDR attains maximum value of 10. The increasing of BPDR leads to the increase of simulation time and size. Hence, the effect of change of the powder particle shape on the calculated data size is not significant. The results also revealed that the increasing rotation speed increases impact energy between powder particles.

Noisy-power dissipation and efficiency in NiO/Fe_2O_3 wet grinding by planetary ball mill

The relationship between the efficiency of NiO/Fe2O3 wet grinding and noisy-power dissipation was studied. The optimal grinding parameters were found as: a slurry water content of 64.10%-85.47%, ball number ratio of 360/20, revolution speed of 300.9 r/min, powder-filling ratio of 10.88%, ball-filling ratio of 20.53%-23.88%, and grinding time of approximately 6 h. The discrete element method(DEM) was employed to analyze relationship between the noisy-power dissipation and the grinding efficiency, and equations describing the relationship were derived. The mean particle size of the ground powder decreased with a decrease in the degree of noisy-power dissipation, while the grinding efficiency and the amount of specific impact power used decreased with an increase in the degree of noisy-power dissipation.

Calibration of DEM Parameters to Simulate a Planetary Ball Mill

Planetary ball mill is a powerful tool, which has been used for milling various materials for size reduction. The discrete element method (DEM) was used to simulate the dynamics of particle processes in a planetary ball mill. This work includes the calibration of DEM parameters to simulate a planetary ball mill using EDEM Altair 2021.2 software, which provides both faster workflows and results. The iterative input parameters changed to a close correlation between the simulation and experimental results are attained. The results showed that the standard tests could be used to generate various experimental reference values for the calibration. The numerical modeling results agree with theexperimental, indicating that the calibrated parameters are accurate.

Synthesis of Fe_3O_4 nanoparticles by wet milling iron powder in a planetary ball mill

Fe3O4 nanoparticles with sizes ranging from 30 to 80 nm 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%） in a planetary ball mill equipped with stainless steel vials using iron balls under distilled water with a ball-to-powder mass ratio of 50：1 and at a 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.

Mechanical Properties of Al/BN Nanocomposites Fabricated by Planetary Ball Milling and Conventional Hot Extrusion

In this study,Al matrix nanocomposites containing 1,2 and 4 wt% nano-boron nitride were fabricated by mechanical milling and hot extrusion.The mechanical properties of all extruded samples were evaluated.Also,the morphology and microstructure of the milled composite powders were characterized using two types of electron micro-scope.The results showed that a high fraction of the boron nitride nanoparticles dissolved and formed a solid solution in Al matrix during the milling process.Through the process of solid solution formation,the work hardening rate of the composite powders increased.This led to a morphological change in the composite powders and resulted in equiaxed shape.The powder particle size also decreased after the milling process.By increasing boron nitride content within a range of 0--4 wt% in the hot extruded samples,tensile stress increased from 212 to 333 MPa.The hardness of the nanocomposite samples including 1,2 and 4 wt% boron nitride improved approximately 55,70 and 90% in comparison with pure Al,respectively.

Refinement of TiB_(2)Powders with High-speed Planetary Mill and Its Effect on TiB_(2)Sinterability

Titanium diboride ceramic was produced via spark plasma sintering(SPS)using finer TiB_(2)powder made by high-speed planetary ball milling.The effects of ball milling parameters on the composites and particle size of TiB_(2)powder were investigated.It was shown that the average particle size of TiB_(2)powder decreased from 5.8 to 1.59μm and the wear rate of WC balls was 1.58 wt%,when the ball-to-powder weight ratio(BPR),the rotary speed and milling time and were 10:1,600 rpm and 20 min,respectively.The content of WC in TiB_(2)powder can be limited below 4.58 vol%by optimizing the milling conditions.The sintering temperature of TiB_(2)powder milled can be decreased obviously,and the mechanical properties are evidently improved and the microstructure becomes more homogeneous when the powder of TiB_(2)becomes finer.The relative density,hardness,bending strength,and fracture toughness of the TiB_(2)ceramic fabricated at 1700℃reach the optimal values,which are 98.13%,19.14 GPa,756 MPa,and 5.71 MPa·m~(1/2),respectively.The decrease of TiB_(2)particle size and the introduction of WC are the potential reasons for the improvement of TiB_(2)ceramic performance.

Modelling of the High-Energy Ball Milling Process

In this paper, the milling parameters of high energy ball mill (Fritsch Pulverisette 7) like vial geometry, number and size of balls and speed of the mill were modelled and discussed. Simulations through discrete element method (DEM) provide correlation between the milling parameters. A mathematical model is used to improve and develop this process. The results show that the loss of powder mass can remarkably improve the performance of milling. The balls made of stainless-steel have a positive effect on the milling efficiency. The simulation shows that the high ball milling velocities can contribute to faster particle size reduction.

Simulation of a Laboratory Scale Ball Mill via Discrete Element Method Modelling

Discrete Element Method (DEM) is a powerful tool for simulating different types of mills. It also used for computing different types of particles such as rocks, grains, and molecules. DEM has been widely used in the field of rock mechanics. In the present work, DEM approach is applied to model the milling media (powder particles and balls) inside a planetary ball mill and to estimate the distribution of particles of a dry powder during milling. In fact, the efficiency of the DEM strongly depends on the input parameters. The DEM simulation results indicated that DEM is a promising tool for the simulation of the dynamic particles motion and interactions within planetary ball mill. These results could be utilized to further develop the synthesis performance, anticipate the reaction, and reduce the wear in the dry milling reactions.

Particle morphology control for spherical powder fabrication using the ball milling process with DEM simulation

Characteristics of spherical particles on copper powder and changing sizes were studied in a ball mill under various experimental conditions,such as different ball diameters,high rotation speeds,and milling times,using a discrete element method(DEM)simulation.This experiment has investigated the characteristics of spherical particle morphology evolution involved in the mechanical alloying of copper powder.The morphological evolution of the copper particle was analyzed using scanning electron microscopy(SEM).A spherical copper particle was shown with a roundness value using imageJ software.The DEM was used to simulate the ball motion in a planetary ball mill,and the impact energy and shear energy generated during the collision were analyzed to estimate the contact number between the ball and the ball wall.Therefore,as the size of the ball decreased,the number of ball-to-ball and ball-to-wall contacts increased accordingly,and the spherical shape of the copper powder changed.

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

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 diffraction （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/rain. 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.

Influences of substrate temperature on microstructure and corrosion behavior of APS Ni_(50)Ti_(25)Al_(25) inter-metallic coating

In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.

Advantageous mechanochemical synthesis of copper(Ⅰ)selenide semiconductor,characterization,and properties

Copper(I)selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball mill.The kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se mixtures.The X-ray diffraction confirmed the orthorhombic crystal structure of Cu_(2)Se with the crystallite size∼25 nm.The surface chemical structure was studied by X-ray photoelectron spectroscopy,whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu^(+)and Se^(2−)oxidation states.Transmission electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure,as well.The optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence spectroscopy.The direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size effect.This type of Cu_(2)Se synthesis can be easily adapted to production dimensions using an industrial vibratory mill.The advantages of mechanochemical synthesis represent the potential for inexpensive,environmentally-friendly,and waste-free manufacturing of Cu_(2)Se.