Milling Duration Research Articles

Synthesis of nanocrystalline zinc powder: Investigating the influence of crystallite size and lattice strain on Debye-Waller factors

In this investigation, nano-sized zinc particles were synthesized through a ball milling process. The Zn metal powder, milled for durations ranging from 0 to 150 h, underwent analysis using X-ray diffraction (XRD). The study focused on determining PS (particle size) and assessing the influence of LS (lattice strain) on the DWFs (Debye–Waller factors), employing XRD principles. LSs were induced in zinc through varying milling durations, and X-ray diffractograms were captured at different stages of the milling process. The results revealed a reduction in PS and an increase in LS with prolonged milling, reaching a predominantly amorphous state at 150 h. By establishing the correlation between strain and effective DWF, the study estimated DWFs for zero strain in zinc.

Characterization of mechanochemical modification in SiC powder

In this study, SiC powder was prepared via a mechanochemical method utilizing high-energy ball milling. The SiC powder, subjected to varying milling durations, was analyzed using X-ray diffraction, Masterizer2000, and scanning electron microscopy. The results indicate that SiC powder achieves a uniform distribution of particle size after 5 min of ball milling, resulting in smaller particle diameters and a larger specific surface area. Concurrently, it exhibits high solid activity and enhanced purity. This suggests that a brief period of ball milling is sufficient to significantly improve the physical properties of SiC powder, which is crucial for applications requiring high material purity and reactive surface area.

Milling Time Effects on the Thermal Degradation, Density, and Porosity of Coconut Shell-Reinforced Epoxy Biocomposites

Polymer biocomposites are sustainable and environmentally friendly materials that can be applied to the building, furniture, aerospace, and automotive industries. In this study, biocomposites made of coconut shell-reinforced epoxy resin were prepared and characterised. Initially, the coconut shells were 200 mesh. Then, they were milled by using a ball mill for 10, 20, 30, and 40 h. The biocomposites were manufactured by using a compression method while keeping a constant ratio of filler and matrix at 85 vol.%: 15 vol.%. The effects of ball milling duration on the thermal degradation and physical properties of biocomposites were examined. The thermal degradation of coconut shell biocomposite occurred at 250 – 400 °C. Its thermal degradation temperature increased with the increasing milling times. The density of the coconut shell biocomposite was 1.087 g/cm3 for 0 h (without milling the fillers). Its density increased to 1.248 g/cm3 for 40 h of milling duration. Meanwhile, the porosity of coconut shell biocomposite decreased from 17.5% (0 h milling duration) to 12.1% (40 h milling duration). It was found that there was a correlation between thermal degradation and physical properties (density and porosity). This study revealed that the thermal degradation and physical properties of the biocomposites can be enhanced by decreasing the size of the fillers.

Microstructure and magnetic properties of MnBi powders prepared by various ball milling processes

The MnBi intermetallic compound with high purity of low-temperature phase MnBi (LTP-MnBi) and high maximum energy product (BH)max were successfully prepared using various ball milling processes. The effects of ball milling speed and duration on the microstructures, phase compositions, and magnetic properties of MnBi alloys were systematically investigated. The particle size of MnBi and the purity of LTP-MnBi gradually decreased with increasing ball milling speed. An optimized ball milling speed of 175 rpm resulted in MnBi powder with the (BH)max of 9.22 MGOe and a squareness (M r/M s) of 93.7%. Furthermore, the ball milling duration was optimized to observe its impact on the MnBi alloy. As the duration increased, the average particle size of MnBi decreased from 27 μm at 0 h to 1.84 μm at 10 h. Simultaneously, the coercivity (H c) increased from 0.7 T at 0 h to 1.7 T at 10 h. Ultimately, the powder ball milled at 175 rpm for 5 h exhibited the highest (BH)max of 11.3 MGOe.

Calcite-aragonite transformation in an eggshell: a crucial role of organics and assessment of the impact of milling conditions on its extent using Taguchi design.

Phase transformations during high-energy ball milling, a tool of mechanochemistry, are interesting due to the possible production of metastable phases without the need for artificially introducing high temperatures and pressures. In our work, the transformation of calcite to aragonite in an eggshell is studied in detail. The presence of organic material, in either the naturally present eggshell membrane, or artificially supplied L-cysteine, was found to be crucial for the phase transformation to occur, its decomposition leading to a pressure increase necessary for aragonite formation. The presence of sulfur in the organics seems to be crucial, as corroborated by much lower phase transformation extent when utilizing sulfur-free organics for comparison. The degree of the transformation in an eggshell was strongly dependent on the used milling conditions. The optimization was assessed using the Taguchi method, namely using a 44 orthogonal array. The optimized parameters encompassed milling time, sample mass, milling speed and duration of breaks and it was shown that sample mass has a decisive effect on the amount of obtained aragonite. Under the most efficient conditions, 73.7% of aragonite was obtained. Prolonging milling until 4 hours further boosts the transformation, reaching 89.9% of aragonite, but further milling leads to the collapse of the aragonite structure and pure calcite was observed after 5 hours.

Milling parameter optimization for the refinement of NiO/Al mixtures and the synthesis of Ni/Al2O3 nanocomposites

This study examined the effects of milling parameters on the development of Ni/Al2O3 nanocomposites and the refinement of NiO and Al powders. Ball milling of certain mixtures was followed by sintering at 800 and 1100 ?C for 2 h. The X-ray diffraction results of the dry-milled powders indicated that increasing the ball-to-powder weight ratio from 20:1 to 42:1 resulted in finer particles, which enabled the synthesis of Ni/Al2O3 nanocomposites by milling at 200 rpm for 1.5 h. Extending the milling duration at lower rotational speeds yielded powders with nanoscale particle sizes. However, as shown by scanning electron microscopy and energy dispersion spectroscopy, a nanocomposite with metallic matrix was formed by the mechanochemical reaction, and the crystallite size was estimated using the Williamson?Hall plot. Furthermore, we used differential scanning calorimetry diagrams to analyze the effects of milling on the temperatures of phase transformation and/or reduction reactions. The tribological performance of the developed nickel metal matrix composite was investigated using a ball-on-disc tribometer under various loading conditions. Indeed, the friction coefficient increases with the applied forces and decreases with milling. Comprehensive examinations of the worn surfaces were carried out using a scanning electron microscope and a 3D optical profiler.

Enhancing Sodium-Ion Energy Storage of Commercial Activated Carbon by Constructing Closed Pores via Ball Milling.

Mechanical ball milling is a prevalent technology for material preparation and also serves as a post-treatment method to modify electrode materials, thus enhancing electrochemical performances. This study explores the microstructure modification of commercial activated carbon through mechanical ball milling, proving its efficacy in increasing sodium-ion energy storage. The evolution of activated carbon's physical and chemical properties during ball milling was systematically examined. It was observed that the quantity of closed pores and the graphitization degree in activated carbon increased with extended ball milling duration. The sodium storage mechanism in activated carbon transitions to an insertion-pore filling process, significantly elevating platform capacity. Additionally, ball-milled activated carbon demonstrates remarkable long-term cycling stability (92% capacity retention over 200 cycles at 200 mA g-1) and rate performance. This research offers a novel approach to developing advanced anode materials for sodium-ion batteries.

Is roller milling – the low energy wet bead media milling – a reproducible and robust milling method for formulation investigation of aqueous suspensions?

Long-acting injectables have shown to offer a prolonged release of a drug compound up to several months, providing the opportunity to increase patient compliance for treatment of long-term and chronic conditions. Different formulation technologies have already been utilized for long-acting injectables, and especially aqueous suspensions with crystalline drug particles in the sub-micron range have sparked an interest for future development of long-acting injectables. Wet bead milling is a common top-down process used to prepare nano- and microsuspensions of crystalline drug particles with the addition of surfactants in the dispersion medium, which are working as stabilizers to prevent agglomeration or crystal growth that ultimately may influence the physical stability of nano- and microsuspensions. To examine the reproducibility of the suspensions manufactured and the behavior of their physical stability, i.e., changes in particle sizes over time, low-energy roller mill was utilized for the manufacturing of nano- and microsuspensions in the present study. Investigated formulation parameters was stabilizer type and concentration and milling parameters varied in bead size and duration of milling. The obtained results demonstrated that the physical stability of suspensions containing the two model compounds, cinnarizine and indomethacin, was highly affected by the constitution of surfactant and processing. Various size classes were obtained and accompanied by high variations between the individual samples that indicated uneven and unpredictable milling by the low-energy roller mill, limiting the possibility to prepare reproducible and physical stable suspensions. Short-term stability studies revealed clear tendencies towards reversed Ostwald ripening of suspensions stabilized with poloxamer 188 that contained cinnarizine as the drug compound, and to a smaller extent suspensions containing indomethacin. Furthermore, X-ray Powder Diffraction confirmed no alteration of the drug compounds crystal structure after roller milling for multiple days.

Effect of Spindle Speed and Feed Rate on Surface Roughness and Milling Duration in the Fabrication of Milled Complete Dentures: An In Vitro Study

Milling machines have made denture fabrication possible with high accuracy in a short time. However, the relationship between the milling conditions, accuracy, and milling duration has not been clarified. This study aimed to clarify the effects of milling conditions on surface roughness and milling duration. The specimen was designed using CAD software and milled using PMMA disks. In milling, the parameters of finishing the specimen surface were adjusted. Three different spindle speeds and four different feed rates were set. Twelve combinations of each parameter were used for milling, and the surface roughness and milling duration were measured. Results showed that the surface roughness significantly increased with the feed rate on the slopes of the specimen. The surface roughness differed with the spindle speed on the left and right slopes. The spindle speed and feed rate did not affect the surface roughness on the flat surface. The milling duration was not affected by the spindle speed but decreased as the feed rate increased. In conclusion, by increasing both the spindle speed and feed rate, the milling duration could be shortened while maintaining a constant surface quality. The optimum milling conditions were a spindle speed of 40,000 rpm and feed rate of 3500 mm/min.

Comprehensive investigation of the impact of milling time on microstructural evolution and tribological properties in Mg-Ti-SiC hybrid composites

This research delves into the effects of milling time on the properties of Mg-Ti dual matrix composites reinforced with nano SiC powders, processed via spark plasma sintering. The study, driven by the need for advanced materials with enhanced wear resistance for the aerospace and automotive sectors, focuses on microstructural evolution and wear characteristics. It aims to understand how varying milling durations influence particle morphology, crystallite structure, and consequently, tribological behavior. Initial observations indicate a decrease in average particle size to 5.72 µm, followed by an increase to 14.83 µm due to cold welding and particle trapping, demonstrating the dynamic nature of particle morphology under different milling conditions. X-ray diffraction analysis reveals a notable reduction in magnesium's crystallite size with increased milling, suggesting plastic deformation. This study underscores that smaller crystallite sizes do not always correlate with strain, especially in smaller dimensions. Additionally, the research records variations in density and hardness, influenced by milling time and particle dispersion, with hardness showing a complex variation, peaking at 108 HV. Overall, the findings highlight the critical role of milling duration in shaping the microstructure and determining the mechanical and wear properties of Mg-Ti-SiC composites. This investigation contributes to the optimization of wear resistance in these composites, enhancing their applicability in high-performance industrial applications.

CO2 reduction employing MgH2 for CH4–H2 mixtures production through mechano-chemical processes

The CO2 methanation employing MgH2 as a source of hydrogen is investigated via mechano-chemical processes through ball milling at room temperature under different experimental conditions such as the presence/absence of catalyst, the milling duration, the molar ratio between the hydride and CO2 and the pre-milling of Ni–MgH2 mixture. The positive effect of Ni addition is demonstrated. After 5h of milling under CO2, the absence of catalyst causes the CH4 yield to drop from 70.0 to 59.0%, from 73.0 to 33.5% and from 54.0 to 40.1%, considering molar ratios of 4:1, 3:1 and 2:1, respectively. The pre-milling of nickel-catalyzed system or the addition of CNTs do not provide significant improvements. This investigation shows that similar methane yields to those obtained by thermo-chemical methods can be achieved, but involving shorter times (5 h versus 24 h) and lower temperatures (room temperature versus 400 °C). The ball collisions during milling allow overcoming passivation phenomena of MgH2 and Mg, promoting the methanation process but with lower selectivity as contamination with Fe from the milling jar provides a catalytic alternative route for the generation of C2–C3 hydrocarbons.

Impact of ball milling on the cubic Sb2O3 into orthorhombic Sb2O3 and SbO2 materials – Structural and other characterization studies

The present investigation adds new information about the cubic Sb2O3 and orthorhombic Sb2O3 and SbO2 phases to the scientific society. In this work, the Sb2O3 (commercial) powder was ball-milled in a tungsten carbide (WC) jar using WC balls with different diameters at 300 ​rpm for several time intervals (1, 3, 5, 10, 20, and 30 ​min and 1, 2, 5, 10, 20, and 30 ​h) and reported their findings of structural, thermal, optical, and morphology. Interestingly, the ball-milled powder undergoes phase transformation from cubic Sb2O3 into orthorhombic Sb2O3 and SbO2 in a short duration (3–30 ​min) of ball milling. While the 0, 1, and 3 ​min ball milled samples preserve the cubic Sb2O3 structure, the 5 ​min ball milled sample exhibits a nearly single-phase orthorhombic Sb2O3 structure. Mixed phases of orthorhombic Sb2O3 and SbO2 phases are seen for the 10–20 ​min ball milled samples. For a 30 ​min ball milled sample, an orthorhombic SbO2 phase is observed. Furthermore, the 1, 3, 5, 10, 20, and 30 ​h ball milled samples retain the orthorhombic SbO2 phase. Maximum weight loss of 34.4 ​% is noted for the commercial Sb2O3 powder, whereas the 1 and 3 ​min of ball-milled samples reveal the weight loss of 9.3 and 4.7 ​%, respectively. The other ball-milled samples exhibit both weight loss and weight gain in the thermogravimetric analysis (TGA) curves. The Raman features of ball-milled orthorhombic SbO2 are quite different from those of other types of antimony-based oxides. Bar/bundle-shaped and spherical-shaped with agglomerated particles are seen for the commercial Sb2O3 phase and ball-milled (1 and 30 ​h) SbO2 phase samples.

Investigate the effect of milling time on puncture resistance of STF impregnated Kevlar composites

Ball milling time is an important factor that affects the rheological properties of shear thickening fluid (STF), which is rarely studied. In this study, SiO2 particles with a diameter of 500 nm and PEG 200 were mixed and milled for 4, 6, 8, 16, and 24 h in an omnidirectional planetary ball mill to obtain the corresponding shear thickening fluids (STFs). Through TGA, SEM, DLS, and other characterization methods, it was found that a long ball milling duration would lead to the surface breakage and wear of SiO2 in STF. The effects of STFs with different milling durations on the inter-yarn friction and puncture resistance of STF-Kevlar composites were also studied. The results show that the STFs produced with a ball milling time of 4 h or 6 h are not uniform, with some semi-solid lump remained. Compared with other milling time durations, the peak viscosity of STF with a milling time of 8 h can better improve the friction between yarns in the fabric and the fabric puncture resistance.

Structural and mechanical evaluation of a new Ti-Nb-Mo alloy produced by high-energy ball milling with variable milling time for biomedical applications

The main focus of this work is to investigate the impact of varying milling times (2 to 18 h) on the structural and mechanical properties of the developed Ti-Nb-Mo alloy. The morphology, phase composition, microstructure, and mechanical behavior of milled and sintered Ti-25Nb-25Mo alloy samples were characterized systematically using x-ray diffraction, scanning electron microscope, optical microscope, and Vicker microhardness. It was noted that the quantity of the β-Ti phase increased as the milling time increased. After 12 h of milling, the synthesized alloys exhibited a spherical morphology and texture with homogeneous distribution. The milled alloys' structural evolution and morphological changes were found to be dependent on their milling duration. Morphological analysis revealed that the crystallite size and mean pore size decreased when the milling duration increased, reaching minimum values of 51 nm and < 1 μm, after 12 and 18 h respectively. As the milling time increased, the grain size decreased, resulting in an increase in density, microhardness, and elastic modulus. Ti-25Nb-25Mo will presents good anti-wear ability and higher resistance to plastic deformation due to enhanced mechanical characteristics (H/E, and H3/E2). Hence, the developed Ti-25Nb-25Mo alloys with reduced elastic modulus and desirable mechanical properties were found to be a promising option for biomedical applications.

Thermal stability of Ni3Al microstructure and microhardness after spark plasma sintering

The effect of high-temperature annealing on the structural-phase state and microhardness of Ni3Al samples obtained by spark plasma sintering after high-energy ball milling has been studied. Using X-ray diffraction analysis, scanning and transmission electron microscopy, a comparative study of the features of the structural-phase state of Ni3Al samples depending on the duration of preliminary high-energy ball milling and annealing temperature was carried out. Temperatures have been identified that ensure simultaneous grain growth at a high density of nuclei, which contributes to the formation of a fine-grained structural state. Depending on the state of the material, the corresponding microhardness values have been determined. The influence of the annealing temperature on the strengthening mechanisms has been analyzed.

Understanding the synergetic effects of mechanical milling and hot pressing on bimodal microstructure and tribo-mechanical behavior in porous Ti structures

The utilization of porous biomedical implants featuring a bimodal microstructure has garnered substantial interest within the scientific community. This study delves into the intricate interplay between processing parameters, microstructural attributes, and the tribo-mechanical performance of titanium grade 4, showcasing its potential to serve as implants to address compromised cortical bone tissue. The investigation meticulously examines the impact of milling duration (10 and 20 h), proportion of milled powder (50 and 75 wt%), and the volume fraction of space-holding agents (40–60 vol% NaCl) on the resulting characteristics of the bimodal microstructure, which plays a crucial role in achieving optimal biomechanical equilibrium. The Vickers microhardness, conventional and instrumented (P-h curves), and the wear behavior (ball-on disk) are discussed in terms of bimodal microstructure distribution, particle size and porosity level inherent to the fabrication conditions (mechanical milling + space-holder + hot-pressing). In general terms, milling time and milled powder fraction were the most influent parameters on the final properties of the materials. With the processing route used, the achieved microhardness values and wear behavior are comparable with those obtained by means of surface modifications or alloys. The Young's moduli obtained were in the range of 30–50 GPa, which could help to reduce the shielding phenomenon, while presenting a good mechanical resistance and wear behavior. In light of these findings, the fabricated specimen, composed of 75 wt% milled powder subjected to a 10-h milling duration, supplemented by a 60 vol% fraction of NaCl, emerges as a prime candidate manifesting superior biomechanical equilibrium. This judicious configuration exhibits a promising trajectory for its application in bone replacement endeavors.

Synthesis and characterization of Ball Milled Thallium Nanopowder by Hall-Williamson and X-ray diffraction method

This research paper investigates the production of thallium (Tl) nanopowder using the ball milling (BM) technique. Pure Tl metal ingots were carefully filed to create a powder sample, which was subsequently subjected to ball milling for varying durations of 2, 4, 6, 8, 10, and 12 h. The aim of the study was to examine the influence of ball milling on the particle size (PS) and atomic disorder of the Tl nanopowder. The results revealed that longer ball milling times led to a significant reduction in particle size. The initial particle size of 198 nm for 0 h of ball milling decreased to 68 nm after 12 h of milling. This indicates that extended milling duration effectively reduced the size of Tl particles. Furthermore, the Debye-Waller factor (DWF), which characterizes atomic vibrations and disorder within the nanopowder, was investigated. The study found that as the ball milling time increased from 0 to 12 h, the DWF exhibited a corresponding increase from 1.80 to 1.90. This suggests that extended ball milling induced greater atomic disorder in the Tl nanopowder. The findings of this study contribute to a better understanding of the effects of ball milling on the properties of nanomaterials. The significant reduction in particle size and the increase in atomic disorder observed with longer milling durations have implications for various applications requiring fine-tuned particle characteristics and enhanced atomic-level behavior.

High wurtzite content ZnS:Mn with better luminescent performances prepared at lower temperature by a ball milling method

Mechanoluminescent ZnS:Mn phosphor should have a main crystalline structure of wurtzite to get stronger mechanoluminescence. However, preparations of ZnS:Mn with high wurtzite content usually require a high calcination temperature of 1050–1150 °C. Here, we propose an effective strategy of using ball milling premix to greatly reduce the preparation temperature of wurtzite-ZnS:Mn phosphors. X-ray diffraction shows that ZnS:Mn with more than 90 wt% of wurtzite content could be obtained at a calcination temperature of 800 °C, which is 250 °C lower than that without milling. Moreover, the photoluminescence (PL) and mechanoluminescence (ML) of ZnS:Mn phosphors synthesized with a proper milling duration can be considerably enhanced (an enhancement of ∼188% for PL, ∼422% for ML) than those without milling, which maybe correlative with the higher wurtzite content. These findings offer a practical strategy for the large-scale preparation of highly-mechanoluminescent ZnS:Mn and hold the potential to facilitate the development and production of other high-performance phosphors.

Effect of blending duration on physical, mechanical and tribological behavior of aluminum matrix composites: An experimental analysis

Aluminum matrix composites exhibit a vibrant role in the present research and scientific world due to their astonishing features compared to other conventional materials. Among the various techniques available for processing these composites, powder metallurgy (P/M) is considered one of the prominent techniques. This is because of its identical dispersal of the fillers, near net shape samples, etc. wherein blending is the most imperative step of the process. To accomplish efficient blending of the phases for composite preparation, ball milling is found to be suitable. In this paper, aluminum matrix composites filled with 20 wt% novel reinforcement (extracted from Aegle marmelos) is synthesized via the P/M technique by varying the blending duration from 60 to 240 min to study its effect on the behavior of composites. The mixing of the constituents is carried out at 300 rpm with a ball-to-powder ratio of 10:1 in ball milling. The blended powders were then compacted and sintered in an inert gas atmosphere for consolidation. The hardness, density, and wear tests were conducted to characterize the developed composite specimens. The microstructural characterization was carried out using an optical microscope and SEM, and the elemental composition of the synthesized composite was studied using EDS techniques. The hardness and density were found to have a growing influence up to a ball milling duration of 180 min and beyond this time there is found to be a decrement in the characteristics of the composites. This is due to the damage of the reinforcements observed during lengthier ball milling duration. The wear behavior of the fabricated specimens followed the same trend. Further, grey relational analysis was adopted in this study to determine the degree of relationship between the blending duration and the composites’ behavioral performance.

Effects of Alloying Elements and Mechanical Alloying on Characteristics of WVTaTiCr Refractory High-Entropy Alloys.

Refractory high-entropy alloys (RHEAs) are among the promising candidates for the design of structural materials in advanced nuclear energy systems. The effects of Cr, V, Ta, and Ti elements and ball milling on the microstructural evolution and mechanical properties of model RHEAs were investigated. The results show that W-rich BCC1 and Ta-rich BCC2 solid solution phases were generated after a long milling duration. After high-temperature sintering, the (Cr, Ta)-rich phase associated with the Laves phase was observed in the Cr-containing model RHEAs. In addition, a high level of Ti, Ta, and V contents promoted the in situ formation of oxide particles in the alloys. Complex TiTa2O7 and Ta2VO6 oxide phases were identified by TEM, which suggests a solid-state reaction of Ti-O, Ta-O, and V-O subjected to high-energy ball milling. The oxide particles are uniformly dispersed in the BCC matrix, which can result in dispersion strengthening and the enhancement of mechanical properties.