Effect Of Ball Milling Time Research Articles

Effect of processing parameters and carbon to metal ratio on microstructure and mechanical properties of (MoTaTiVW)Cx high entropy carbide produced by reactive spark plasma sintering

(MoTaTiVW)Cx high entropy ceramics with varying carbon to metal ratio in the range of 0.75-0.97 were synthesized by by reactive spark plasma sintering. The effect of ball milling time on particle size, phase evolution and carbon pick-up due to toluene decomposition were studied. Formation of single-phase high entropy carbide having face-centered cubic (FCC) crystal structure was confirmed by X-ray diffraction (XRD), electron backscattered diffraction (EBSD) and Selected area diffraction pattern (SAED) analysis of the sintered compacts. Transmission Kikuchi Diffraction images revealed presence of equiaxed nature of the grains. Transmission electron microscopy images revealed the presence of an intergranular phase at grain boundaries and triple junctions. 3D-Atom Probe Tomography studies showed uniform distribution of elements within the grains with some segregation of impurity elements Fe and Co to the grain boundaries indicating minor contribution of liquid phase sintering to densification. The grain size of single-phase sintered compacts ranged between 1.69 ± 0.60 μm to 4.6 ± 1.0 μm. A low sintering temperature and higher milling time resulted in finer grain size The microhardness was found to increase with milling time and C/M ratio. The microhardness, Young’s modulus and indentation fracture toughness lied between 2221 HV0.1 to 2732 HV0.1, 370 GPa to 473 GPa, 3.6 MPa.m1/2 to 4.4 MPa.m1/2, respectively. The highest microhardness and indentation fracture toughness was found to be 2732 ± 80 HV0.1 and 4.4 MPa.m1/2 on par with reported literature for other high entropy carbides.

Effect of ball milling activation on CO2 mineralization performance in fly ash and fire resistance capabilities of mineralized product

Coal-fired power generation has always been a major energy supply source globally. However, a large amount of CO2 is emitted with the combustion of coal resources, and fly ash, a by-product of coal combustion, is also accumulated in large quantities. The application of CO2 mineralization in fly ash can not only reduce CO2 emission but also effectively manage industrial waste, thereby promoting environmental sustainability. This paper used the mechanical ball milling method to activate fly ash and investigated the effects of ball milling time and speed on the CO2 sequestration in fly ash. At 30 min ball milling time and 400 r/min ball milling speed, the modified fly ash achieves a good CO2 sequestration capacity of 81.70 gCO2/kgFA. Compared with raw fly ash, the CO2 consumption of treated fly ash is higher at 75.41 mmol/mL. The specific surface area and pore volume of treated fly ash are larger at 1.57 m2/g and 4.33 cm3/kg respectively, which is beneficial for enhancing mass transfer capacity and the carbonation effect. As the ratio of mineralized product/coal increases from 0.5 to 4, the crossing-point temperature increases from 157.20 °C to 165.15 °C. Based on the experimental results, the paper discussed the mechanism of ball milling activation to enhance the carbonation effect of fly ash. This study provides theoretical references for the environmentally friendly utilization of fly ash.

Microstructure and hydrogenation/dehydrogenation properties of ball-milled PrMg12/Ni alloy powders

Amorphous and nanocrystalline PrMg12 is ball-milled with 30 wt% Ni powder. The impact of ball milling time on the thermodynamics and kinetics of hydrogen storage in this alloy is systematically studied. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) were employed to characterize the phase composition and microstructure. The result shows that the microstructure of PrMg12+30 wt%Ni alloy is predominantly amorphous and nanocrystalline. Prior to hydrogen absorption, the primary phases were identified as PrMg12, Ni and Mg2Ni. Following hydrogenation, these phases transform into MgH2 and Mg2NiH4. Pressure-composition-temperature (PCT) curves and kinetic data were acquired using a Sieverts apparatus. The thermodynamic and kinetic parameters are calculated by combining Van't Hoff equation, JMAK model and Arrhenius equation. The effect of ball milling time on the enthalpy and entropy changes of hydrogen desorption was found to be negligible. Notably, the activation energy for dehydrogenation reached a minimum value of 79.86 kJ/mol after 10 h of ball milling.

Effect of ball milling time on Sr0.7Sm0.3Fe0.4Co0.6O2.65 perovskites and their application as semiconductor layers in dye-sensitized solar cells

The practical utilization of TiO2 as a semiconductor in dye-sensitized solar cells (DSSCs) has been set back by poor visible light absorption, high charge carrier recombination, and low electrical conductivity, which reduce the power conversion efficiency (PCE) and sustainability of the device. In this respect, perovskites with excellent properties, such as large surface area, good optical properties, high electrical conductivity, and superior electrochemical stability, have recently emerged as promising alternatives capable of overcoming the drawbacks of TiO2. Herein, Sr0.7Sm0.3Fe0.4Co0.6O2.65 (SSFC) perovskites were prepared via the ball milling method at various milling times of 0, 5, and 10 h, and the obtained samples were denoted by SSFC-0, SSCF-5, and SSCF-10, respectively. Increasing the ball milling time led to a significant reduction in nanoparticle size and agglomeration, which, in turn, increased the surface area and electrical conductivity of the samples. As a consequence, the SSFC-10 perovskite exhibited the smallest average particle sizes (18.9 nm) with the largest surface area (61.8 m2 g−1) and minimum defects, which allowed for efficient electron transport, resulting in the best electrical conductivity of 49.8 S cm−1. Ultimately, DSSCs fabricated using SSFC-10 semiconductor layers achieved an optimum PCE of 6.01 %, which is an improvement of 8.67 %, 1.1 %, and 6.56 % for SSFC-0 (3.69 %), SSFC-5 (4.96 %), and TiO2 (5.64 %), respectively. Thus, varying the ball milling time can be used as an effective technique to tailor the physicochemical properties of SSFC to suit desired applications, particularly the fabrication of highly efficient and sustainable DSSC semiconductor layers.

Synthesis of lead-free piezoelectric potassium sodium niobates for the preparation of anti-fouling KNN porous membrane

Potassium sodium niobates (KNNs) have garnered significant attention owing to their lead-free nature and potential for use in self-cleaning membranes. This paper presents the synthesis of (K0.5Na0.5)NbO3 materials for the fabrication of porous membranes, which enable in situ ultrasonic resonance to effectively eliminate contaminants from the membrane surface. KNN powder was synthesized via solid-state reactions, and the membranes were prepared using conventional sintering techniques. The effects of ball-milling time and calcination temperature on the phase structure, pore size, permeance, flexural strength, chemical stability, and piezoelectric properties were comprehensively investigated. The optimal membranes exhibited an average pore size of approximately 300 nm, a porosity of 23 %, and permeance of 220 L m−2 h−1 bar−1 at a sintering temperature of 1050 °C. A polarized electrical field with a strength of 1 kV/mm was applied to the membranes, resulting in an ultrasonic response of 20 mV at an excitation voltage of 20 V with a frequency of 200 kHz. Furthermore, the in situ anti-fouling performance was evaluated by conducting filtration tests on a 500 ppm oil-in-water (O/W) emulsion, demonstrating that the stationary flux increased by 46.7 % when subjected to an excitation voltage of 60 V.

Effect of Ball Milling Time on Microstructure and Hydrogen Storage Properties of Nd5Mg41Ni Alloy

Effect of Ball Milling Time on Microstructure and Hydrogen Storage Properties of Nd5Mg41Ni Alloy

Perfectly dense ceramics of highly pure calcium manganese oxide

Immensely thermally stable and perfectly dense ceramics of highly pure calcium manganese oxide (CaMnO3) powders is realized at optimized minimal processing temperature and time using cost-effective ball-milling and hot-press techniques. The effect of ball milling time on the calcination time to prepare highly pure CaMnO3 powder and sintering time on the temperature adequate enough to achieve perfectly dense CaMnO3 ceramics is studied thoroughly and systematically. The as-synthesized single phase CaMnO3 is attained by mixing precursors of calcium carbonate and manganese oxide, using high energy ball milling for longer time followed by calcination for shorter time duration and vice-versa. A decrease in particle size in as-synthesized CaMnO3 is noticed for powders prepared with longer ball milling and shorter calcination times. The minimal time required for achieving highly pure and fine-grained powders containing sub-micrometer particles of CaMnO3 is accomplished by ball milling the precursor mixture for 12 h and calcining at 1273 K for 2 h. Relative density of 99.03% is achieved for the as-synthesized CaMnO3 powders hot pressed at 1073 K for 30 min.

Influence of particle size gradation on the preparation of highly concentrated coal-water slurry and the development of a gradation model

ABSTRACT Aiming at the problem that low-rank coal is unsuitable for making CWS (coal-water slurry) and lacks an accurate particle size gradation prediction model. This paper expounds on the effects of ball milling time and speed on the concentration and rheology of CWS under different grinding conditions. After size grading, the slurry’s bimodal parameters and particle size distribution are studied. Based on the BP neural network, a particle size distribution model more suitable for low-rank coal is established in this paper. The results show that the slurry concentration in the graded coal sample increases by 4% higher than that of the ungraded coal sample. The BP neural network model accurately predicts the relationship between bimodal parameters and slurry concentration based on bimodal parameters. In the context of grain size gradation, the optimized particle size cumulative distribution model, denoted as y = x n − x K n x 100 n − x K n + K { ( K + 10 % > x > K% } , demonstrates enhanced alignment with the attributes of low-rank coal. This underscores the paper’s contribution in providing a more fitting particle size distribution model for low-rank coal in the context of CWS production.

Outstanding strength-ductility balance in a Ti–N alloy by tuning ball milling time

The trade-off between strength and ductility is a prevalent issue in strengthening commercially pure titanium (CP–Ti). This study presents a method to prepare ultra-high strength Ti–N alloys with adequate ductility using ball-milling (BM) and spark plasma sintering (SPS) techniques, based on nitrogen solid solution and grain refinement strengthening. The effect of ball milling time of mixed powders on mechanical properties of Ti–N alloys was studied systematically. Quantitative analysis reveals that solid solution strengthening and grain refinement strengthening worked synergistically to enhance yield strength of alloys. The Ti–N alloys with the most favorable mechanical properties demonstrated a yield strength of 1606 MPa and a compressive plastic strain of 14.44 %. The development of novel Ti–N alloys provides a viable strategy for the advancement of high-performance titanium alloys using ubiquitous elements.

Effect of ball milling time and reaction solution concentration for preparation of irregular shape zirconia toughened alumina ceramic particles by alginate sol-gel method

In this study, we come up with a new sol-gel approach to prepare ZTA ceramic particles. Alginate was used as gelatinizer and special-shaped ZTA ceramic particles green bodies were made. After forming process, ZTA ceramic particles green bodies were prepared in different ball milling times and different reaction solution concentration and then sintered at different temperatures. The results shows that when the green body were prepared for 10 h ball milling and 0.5 mol/L reaction solution concentration, when sintered at 1400 °C, the ZTA ceramic particles has the best performance. Phase composition analyses revealed that ZTA ceramic particles by Alginate sol-gel method were mainly α-Al2O3 and ZrO2. SEM results and the face elements analyzation showed that the above sintered ZTA ceramic particles have the fine grain size and confirm the excellent performance.

Effect of Ball Milling Time on the Microstructure and Properties of High-Silicon-Aluminum Composite.

The duration of ball milling greatly influences the characteristics of high-silicon-aluminum composite during the ball milling process. This study examines how the microstructure, thermal conductivity, and hardness of a high-silicon-aluminum composite are affected by different ball milling times. We exposed the powder to various durations of ball milling and employed different pellet ratios. Following this treatment, the powder underwent consolidation via discharge plasma sintering. Our findings show that with a pellet ratio of 10:1 and a milling duration of 8 h, the powder particles were refined, resulting in a more uniform and dense material composition. This refined material boasted a thermal conductivity of 111.6 W/m·K, a Brinell hardness of 136.8 HBW, and a density of 2.304 g/cm3. This method facilitates the creation of a uniform composite powder composition. It encourages the development of a fine-grain structure, which enables the production of particle-reinforced composites with superior properties.

La0.6X0.1Te0.3MnO3 system with significant refrigerant capacity at low magnetic field and double magnetic entropy change peaks: effect of ball-milling time on physical and critical behaviors

We have investigated the ball-milling time effect on different physical properties of La0.6X0.1Te0.3MnO3 (X is a lacuna) system (LT) milled for 1 h (LT-1h), 3 h (LT-3h), and 6 h (LT-6h). According to Williamson-Hall method, as the ball-milling duration is increased, the material’s crystallite size decreases from approximately 145 to 99 nm for LT-1h and LT-6h, respectively. Electronic study was also investigated. The Zero-Field-Cooling and Field-Cooling (ZFC/FC) magnetization measurements illustrated that all the systems are presenting a ferromagnetic to paramagnetic phase transition around Curie temperature (TC). This transition is around 176, 182, and 183 K accompanied by a decrease in the magnitude in both ZFC and FC data. Thus, increasing the ball-milling time of the sample leads to the elevation of TC and does not enhance the magnitude of the magnetization the fact that it affects the magnetic interactions between atoms. By increasing the ball-milling duration, the proportion of homogeneity is increased, and the material becomes slightly more resilient, according to the Curie-Weiss law. Additionally, it is accompanied with an increase in coercivity and a decrease in the saturation magnetization and remanence. Based on the AC-susceptibility, raising the ball-milling time facilitates the appearance of a spin-glass (SG) state. The relative cooling power (RCP) value in the LT-1h sample at 2 T is 108% (211.758 J kg−1) compared to that of the Gd at 2 T. Consequently, the LT sample could be a permanent magnet in a magnetic refrigerator. Noting that raising the ball-milling time weakens the RCP. Both LT-1h and LT-3h systems are belonging to the tricritical mean field model. However, for LT-6h, the model changed and the best one became the 3D-Ising model. Hence, the ball-milling time influences also the universality class.

Effect of milling time and sintering temperature on the microstructure and binder distribution of spark plasma sintered NbC-Ni cermets

Niobium carbide (NbC) based cermets are emerging as strong contenders to replace conventional tungsten carbide (WC) based cermets for applications involving abrasion and wear resistance due to their superior mechanical, physical, and chemical properties. NbC cermets with various binders have been explored in literature and nickel has emerged as a promising candidate binder material. Mechanical mixing (MM) followed by spark plasma sintering (SPS) has been shown to be one of the effective methods to synthesize NbC-Ni cermets. However, the effect of certain crucial process parameters during the MM + SPS process on the end product have not been established. To address this, the present study reports the effect of ball milling time and the effect of sintering temperature on the microstructure, binder distribution, hardness, and indentation fracture toughness of NbC – 16 vol% Ni cermets synthesized using MM + SPS. Insufficient milling time resulted in inhomogeneous binder distribution in the consolidated cermets and sintering above a certain temperature resulted in complete loss of binder. Therefore, the combination of sufficient milling time and an appropriate sintering temperature was essential to obtain a consolidated cermet with homogeneous microstructure and uniform mechanical properties.

Effect of Ball-Milling Process on Microwave Absorption Behaviors of Flaky Carbonyl Iron Powders.

Electromagnetic (EM) wave absorption performance is greatly affected by the microscopic morphology of the absorbing material particles. In this study, a facile and efficient ball-milling method was applied to increase the aspect ratio of particles and prepare flaky carbonyl iron powders (F-CIPs), one of the most readily commercially available absorbing materials. The effect of ball-milling time and rotation speed on the absorption behaviors of the F-CIPs was investigated. The microstructures and compositions of the F-CIPs were determined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The EM parameters were measured using a vector network analyzer (VNA) in the frequency range of 2-18 GHz. The results indicated that the ball-milled flaky CIPs exhibited a better absorption ability than the raw spherical CIPs. Among all the samples, the sample milled at 200 r/min for 12 h and the sample milled at 300 r/min for 8 h showed remarkable EM parameters. The ball-milling sample with 50 wt.% F-CIPs had a minimum reflection loss peak of -14.04 dB at a thickness of 2 mm and a maximum bandwidth (RL < -7 dB) of 8.43 GHz at a thickness of 2.5 mm, a result that conformed with the transmission line theory. Hence, the ball-milled flaky CIPs were considered to be beneficial for microwave absorption.

Improved hydrogen storage thermodynamics and kinetics of La–Ce–Mg–Ni alloy by ball milling

Reducing particle size and modifying surface state by ball milling are recognized as a useful method to improve the hydrogen absorption kinetics of Mg-based alloys. In order to obtain amorphous and nanocrystalline structures, ball milling was used to process the as-cast La7Ce3Mg80Ni10 alloy ingot. The effects of ball milling time (5–30 h) on the structures and the thermodynamics and kinetics of hydrogen absorption/desorption of the as-milled alloys were studied. The XRD, SEM and TEM were applied to investigate the structure of the alloys. The Sievert apparatus, DSC and TGA were applied to study the isothermal and non-isothermal properties of hydrogen absorption/desorption. The Arrhenius and Kissinger methods were used to calculate the activation energy of hydrogen desorption. The results indicate that the 10 h-milled alloy has the optimal activation performance and hydrogen absorption/desorption kinetics. Prolonging or shortening the ball milling time results in the impaired hydrogen storage properties. The 10 h-milled alloy in fully activation state can absorb 4 wt% H2 in 80 s at 473 K and 3 MPa, and it can desorb 3 wt% H2 in 191 s at 573 K and 1 × 10−4 MPa. The hydrogen desorption enthalpy (ΔH) of the 10 h-milled alloy is 74.21 kJ/mol. Moreover, the 10 h-milled alloy has the smallest apparent activation energy for hydrogen desorption (62.9 kJ/mol), which is the reason why it has the optimal hydrogen storage properties.

Effect of Ball Milling Treatment on Compositional Gradients in Functionally Graded Materials Fabricated by Centrifugal Slurry Methods

Ceramic-metal functionally graded materials (FGMs) are advantageous to two dissimilar materials joined directly together, which includes smoothing of thermal stress distributions, minimization or elimination of stress concentrations and singularities at the interface corners and increase in bonding strength. In this study, ZrO2/ 304 stainless steel (SUS304) FGMs with continuous gradient manners, not stepwise manners, were fabricated by a combination of centrifugal slurry methods and spark plasma sintering (SPS). The size and surface smoothness of the powders of SUS304 highly affected formation of compositional gradient patterns in the FGMs. Effects of ball milling time and ball sizes on such conditions of the powders as well as compositional gradients in the FGMs were investigated by microstructure observations with element analysis and hardness probing on the cross sections of the FGMs.

Effect of ball milling time on the magnetoelectric coupling effect of the multiferroic liquid CoFe2O4–Ba0.8Sr0.2TiO3

Effect of ball milling time on the magnetoelectric coupling effect of the multiferroic liquid CoFe2O4–Ba0.8Sr0.2TiO3

Effects of ball milling time on the microstructure and hydrogen storage performances of Ti21.7Y0.3Fe16Mn3Cr alloy

TiFe alloy can store hydrogen at room temperature and low hydrogen pressure, and its theoretical hydrogen storage capacity is up to 1.8 wt%. However, TiFe alloy needs to be activated at high pressure (5 MPa hydrogen) and high temperature (673–723 K), which limits the practical application of TiFe alloy. The as-cast Ti 21.7 Y 0.3 Fe 16 Mn 3 Cr alloy was milled for 0, 0.5, 0.75, 1, and 3 h to study the effects of ball milling on phase structures and hydrogen storage performances. Emphasis was focused on the activation process of as-milled alloys at different temperatures, including the activation process at 483, 443, and 403 K. The results show that the alloys were consisted of TiFe phase, and [Fe, Cr] solid solution. The nanocrystalline boundary produced by milling and the phase boundary provided by the second phase provide a large number of channels for hydrogen diffusion and promote the improvement of hydrogen storage performances. The time required for activation process of as-milled alloys was significantly reduced, and the activation time of as-milled (0.75 h) was only 4 min, and its enthalpy variation for hydrogen absorption and desorption was 22.943 and 26.215 kJ mol −1 H 2 , respectively. • The phase composition and micro-structure of the milled Ti 21.7 Y 0.3 Fe 16 Mn 3 Cr alloy were studied. • Nanocrystalline boundary produced by milling provides many channels for hydrogen diffusion. • Ball milling improves the activation process of the alloy and shortens the activation time. • The optimum milling time of the alloy is 45 min, and its activation time is shortened to 4 min.

The relationship between structural evolution and high energy ball milling duration in tin reinforced Mg alloys

In this study, 9 wt% Sn reinforced Mg alloys are produced by high energy ball milling and conventional sintering method. Effect of ball milling time (30 min, 2 h, 4 h, 8 h, and 12 h) on particle and grain morphology is detected by SEM examination. Phase evolution and solid solution mechanism is monitored by XRD analysis. Sintering process is carried out at 400 °C with 2 h sintering duration under Ar atmosphere. Platelet structure in powder morphology is observed up to 4 h ball milling, which is linked with the texture formation on < 002 > direction in hexagonal structure of Mg. This platelet formation is broken into smaller and monodispersed particle morphology with further milling process due to excessive plastic deformation which eventually provide homogenous dispersion of reinforcement element. Furthermore, ball milling process after 4 h triggers solid solution along with formation of intermetallic phase (Mg2Sn) according to crystallographic approach. The highest relative density values is measured in 8 h milling duration. Besides, the highest hardness value is achieved along with proper distribution of reinforcement element in 8 h condition. The hardness values is increased almost 85% comparing with pure ball milled Mg and 74% increment comparing with as cast Mg. The highest elastic modulus values is measured at 8 h milling condition by ultrasound method and this value is found in reasonable range. By introducing 12 h ball milling process, density, hardness and elastic modulus properties of 9 wt% Sn-Mg alloy is diminished because excessive amount of intermetallic phase formation on grain and grain boundaries. Therefore, 8 h high energy ball milling process is chosen the most suitable condition for this materials system to obtain proper powder packing and sinterability along with superior physical and mechanical properties.

Effect of ball milling time on the microstructure and compressive properties of the Fe-Mn-Al porous steel

Effect of ball milling time on the microstructure and compressive properties of the Fe-Mn-Al porous steel