High Energy Planetary Ball Mill Research Articles

The Influence of Mechanical Activation on Hydrogen Absorption by Intermetallic Compound LaNi2.5Co2.4Mn0.1

The influence of mechanical activation in a high energy planetary ball mill on hydrogen sorption and structural properties of intermetallic compound LaNi2.5Co2.4Mn0.1 in relation to its application as a filler in composite metal-polymer membranes for hydrogen separation from gas mixtures was studied. It has been determined that the basic results of performed processing are the decrease in the coherent scattering domain size and the increase in lattice microstrain while the unit cell parameters remain unchanged. In the temperature range of 298–333 K, the hydrogen absorption and desorption isotherms were measured, and the values of the related enthalpy and entropy, which do not depend on mechanical activation time, were determined. The results of this work allow us to consider the obtained data as reference values to describe the hydrogen sorption behavior of a metal-hydride component in composite membranes with satisfactory accuracy.

Enhanced sinterability and in vitro bioactivity of barium-doped akermanite ceramic

This paper reports on the influence of substituting barium (Ba2+) ions on the structural, mechanical and in vitro biological properties of akermanite prepared via high-energy wet planetary ball milling and sintering. The results obtained showed that the properties of the prepared bioceramics are highly dependent on Ba2+ content. It was found that Ba2+ resulted in improved densification (≥90%), and better apatite-forming ability of akermanite ceramic, without altering phase composition. Herein, the enhancement in diametral tensile strength (DTS), Vickers microhardness (HV) and fracture toughness (KIC) for Ba2+-doped akermanite bioceramics are reported for the first time. It was also found that after 21 days of immersion in simulated body fluid (SBF) solution, the doped ceramic surface was completely covered with apatite crystals, indicating Ba2+ encouraged apatite crystals deposition. Therefore, Ba2+-doped akermanite bioceramic could be an attractive alternative bioresorbable material for bone tissue engineering applications.

Experimental study on the effect of sintering cycle and reinforcement of 1% niobium carbide (NbC) in aluminium metal matrix composite (Al-MMC)

In Today’s production scenario, Aluminium Metal Matrix Composites (AMMC) play a key role in Automotive and aircraft sectors for their improved mechanical properties. In the current situation, a great deal of work has been done on Aluminium (Al) base material, which is reinforced with various carbides such as Silicon Carbide, Tungsten Carbide and Boron Carbide in different proportions through powder metallurgy route for numerous applications. In spite of this, no work has been done on the combination of pure Aluminium (Al) and Niobium carbide (NbC) in powder metallurgy route through different sintering cycles. The main objective of the present work was to study and compare the physical and mechanical properties of the processed specimen through two different sintering cycles and to compare the results obtained. In this experimental study, 1% NbC powder was mixed with pure Al powder in the High Energy Planetary Ball Mill (HEPBM) and processed through the sintering cycles namely Conventional Sintering and Chu’s Two-Step Sintering process (TSS-C) followed by compaction. Four samples were obtained, such as two pure Al and two Al-1% NbC. In addition, studies have been conducted to examine density and micro-hardness. Finally, the results show that the mechanical properties of the TSS-C specimen with the addition of 1% NbC have a higher density and micro-hardness than the rest of the samples.

Surface magnetic interactions between Bi0.85La0.15FeO3 and BaFe12O19 nanomaterials in (1-x)Bi0.85La0.15FeO3-(x)BaFe12O19 nanocomposites

Two different sets of multiferroic nanocomposites i.e., (1-x)Bi0.85La0.15FeO3-(x)BaFe12O19 with x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.40, 0.50 and 1.00 have been synthesized by the solid-state reaction method and high energy planetary ball mill techniques. The peaks in the XRD patterns can be indexed to R3c crystal symmetry of Bi0.85La0.15FeO3 and P63/mmc crystal symmetry of BaFe12O19. It suggests the absence of any major chemical reaction between the two phases. Moreover, it is assumed thatBi0.85La0.15FeO3 and BaFe12O19 crystal symmetries are present in the composite independently. Magnetic properties have been improved significantly due to the incorporation of BaFe12O19 in the composites. Vegard's law suggests that the experimentally observed magnetizations are higher than that of theoretically calculated value. The difference between the theoretical and experimental magnetization as well as the anomaly in the magnetic hysteresis have been explained by considering the magnetic interaction correlation length between Bi0.85La0.15FeO3 and BaFe12O19 magnetic phases. The hysteresis loop width (ΔH) versus M plots has been introduced to understand the magnetic interaction (exchange bias) between Bi0.85La0.15FeO3 and BaFe12O19. Magnetocrystalline anisotropy increases with the increase in the percentage of BaFe12O19 in the composite.

Structural, Microstructural, and Magnetic Property Dependence of Nanostructured Ti50Ni43Cu7 Powder Prepared by High-Energy Mechanical Alloying

In the current study, Ti-Ni-Cu alloy powders were prepared by mechanical alloying using high-energy planetary ball mill under argon atmosphere. The effects of milling time on the evolution of structure, microstructure, and magnetic properties were analysed. Morphological observations indicated a narrow particle size distribution and homogeneous shape. According to the Rietveld analysis, during early milling stage (1–6 h), the milled powder consists of Ti-based solid solution [HCP-Ti(Ni,Cu)], Ni-based solid solution [FCC-Ni(Ti,Cu)], Cu-based solid solution [FCC-Cu(Ti,Ni)], and amorphous phase (28.52 wt%). For prolonged milling time, the NiTiCu (β19) was achieved from the pre-formed phases. Moreover, microstructural parameters varied considerably with milling time; the crystallite size was found to decrease to the nanoscale range, Ti (41), Ni (21 nm), Cu (16 nm), and β19 (29 nm), while the microstrain 1/2 increased due to the deformations and defects induced during the milling process. Magnetic measurements indicated that all powders exhibited a ferromagnetic behaviour irrespective of milling time whereas the corresponding magnetic parameters were found very sensitive to the milling time. This was associated with particle size refinement in addition to the phase composition and the amount of the amorphous phase; the higher the percentage of the amorphous phase was, the lower the values of Ms and Mr.

Tribological study of mechanically milled graphite nanoparticles codeposited in electroless Ni-P coatings

The present study focusses to enhance the wear resistance of electroless Ni-P coatings with the co-deposition of selflubricating nano graphite particles synthesized by mechanical milling using a high energy planetary ball mill. The coatings were developed on an aluminum substrate and nano graphite particles were co-deposited (4 g/l) into the Ni-P matrix using alkaline hypophosphite reduced electroless bath. Changes in properties after heat treatment at 220 °C for 4 h in vacuum have been correlated with morphological and microstructural changes shown by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) respectively. Energy dispersive analysis of X-ray (EDAX) determined the quality and elemental composition of coatings. Wear resistance, coefficient of friction (pin on disc) and microhardness of electroless Ni-P-graphite nanocomposite coatings were calculated and contrasted with Ni-P coatings. The outcomes reveal that the size of synthesized graphite nanoparticles is 20 nm. Microhardness and wear resistance of electroless coatings have improved after heat treatment. Excellent wear resistance has been observed at the cost of some hardness in Ni-P-graphite nanocomposite coatings over Ni-P coatings.

Magnetocaloric Properties of Nanostructured La0.7-xBixSr0.3MnO3 (x = 0.0, 0.1) Manganites Using Phenomenological Model

Magnetocaloric properties of nanostructured pristine and Bi-doped La0.7Sr0.3MnO3 samples, synthesised by high-energy planetary ball milling, are presented here. The aim of the study is to understand the effect of milling time on magnetic entropy change, relative cooling power and change in specific heat. The magnetocaloric property, defined as the change in the magnetic entropy, has been determined by using a phenomenological model applied to the magnetic susceptibility plots. Replacing 10% La by Bi in La0.7Sr0.3MnO3 significantly alters the change in magnetic entropy. Correlation between the particle size and magnetic entropy is observed in the present study. As the milling time increases from 0 h (bulk) to 48 h, the particle size reduces causing significant modifications in the magnetocaloric properties.

Design and characterisation of ex situ bulk MgB2 superconductors containing a nanoscale dispersion of artificial pinning centres

MgB2 pellets containing a nanoscale dispersion of artificial pinning centres have been successfully manufactured through a powder metallurgy route based on the oxide dispersion strengthened (ODS) concept more usually used for steels and superalloys. Commercial MgB2 powder and Y2O3 nano-powder were mechanically alloyed in a high energy planetary ball mill and consolidated using the field assisted sintering technique. The composite powders were ball milled for different times up to 12 h and characterised by means of particle size analysis, x-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The microstructure and superconducting properties were characterised by density, XRD, STEM and magnetic property measurements. The powder microstructure comprised Y2O3 particles dissolved into the MgB2 matrix. After consolidation there was a near-uniform dispersion of precipitated YB4 and MgO particles. A bulk 0.5 wt% Y2O3-MgB2 composite showed the best superconducting performance with a significant improvement in J c at high field compared with unmodified MgB2, and only a small reduction in T c . The results suggest that the ODS concept is promising to improve the superconducting properties of MgB2.

Novel synthesis and processing effects on the figure of merit for NbCoSn, NbFeSb, and ZrNiSn based half-Heusler thermoelectrics

The n-type NbCoSn, ZrNiSn and p-type NbFeSb half-Heuslers are promising thermoelectric materials with high figures of merit (ZT) for applications between 575 and 1000 ​K. By eliminating hafnium and utilizing low cost scalable production methods, the widespread commercialization of high temperature thermoelectrics could be achieved. In this work, half-Heuslers containing refractory metals (Nb and Zr) were produced by high energy planetary ball milling and their thermoelectric performance compared to half-Heuslers prepared by the conventional arc-melting synthesis route. Starting materials, as-milled powders, and consolidated samples were characterized by XRD, SEM, and EDS. The thermoelectric performance parameters were characterized using simultaneous Seebeck and electrical resistivity measurements and laser flash analysis. The mechanically alloyed NbCoSn and NbFeSb achieved ZT of approximately 0.53 (873 ​K) and 0.72 (873 ​K), respectively, comparing well to literature and prepared arc-melted monoliths. The results demonstrate mechanical alloying as a viable synthesis technique for refractory metal containing half-Heusler thermoelectrics.

Influence of Thermal-Treatment Effects on the Structural and Magnetic Properties of Sn1−xFexO2 Nanopowders Produced by Mechanical Milling

In this research work, iron-doped tin dioxide nanoparticles were successfully produced by high-energy ball-milling and their structural and magnetic properties were evaluated by means of room temperature X-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometry. In order to evaluate the thermal stability of the compounds, samples were subjected to a thermal treatment and their structural and magnetic properties were studied. The nanoparticles were produced by processing SnO2 commercial powders together with doping amounts of Fe2O3 commercial powder in a high-energy planetary ball-mill. X-ray diffraction showed the presence of a single crystalline structure (that of the host compound) in all samples. Mossbauer spectroscopy confirmed that Fe3+ ions substitute for Sn4+. It was also used to show the disorder induced by the incorporation of iron ions in the structure of the host matrix. Magnetic measurements showed the coexistence of paramagnetism and a weak ferromagnetism. The interaction between singly ionized oxygen vacancies and doping Fe ions is the suggested reason behind the ferromagnetic ordering observed in this research work. The observed ferromagnetism is interpreted in terms of the bound magnetic polaron model and the charge transfer model. The insertion of the transition metal Fe into SnO2 matrix resulted in ferromagnetism at room temperature even at high dopant concentrations.

A Novel Alumina-Magnesium oxide- Reduced Graphene Composite: Synthesis and Characterizations

A novel new alumina-magnesium oxide with reinforced of reduced graphene oxide (RGO) composite materials have been synthesized by using a horizontal high energy planetary ball milling process. The composite has very high density, improved mechanical properties, retaining strength under higher temperatures, and high thermal conductivity. Al2O3-MgO-RGO composites can be used as a novel material for many industrial applications. The effect of RGO in the combination of Al2O3 and MgO have a potential scope in several demanding fields, including automobile, aerospace, defenses, sports, electronics, bio-medical, and other industrial purposes. The prepared composites have been studied by Xray diffraction (XRD), Field emission scanning electron microscopy (FESEM), micro Raman spectroscopy, Transmission electron microscope, Automatic density meter, Particle size analyzer.

Development of a novel light weight Al35Cr14Mg6Ti35V10 high entropy alloy using mechanical alloying and spark plasma sintering

A new light-weight high entropy alloy (LWHEA) composition Al35Cr14Mg6Ti35V10 is designed using the thermodynamic parameters of stability with a density of 4.05 g cm−3. The alloy was prepared by mechanical alloying (MA) using a high-energy planetary ball milling and compacted by using spark plasma sintering (SPS). X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and hardness testing were used for analysis of the ball-milled powders and bulk sample. After 30h of milling a single-phase BCC was obtained with some minor impurities of WC. After SPS, the final microstructure was having one HCP and two BCC phases with minor contamination of WC embedded into it. The hardness of a light-weight Al35Cr14Mg6Ti35V10 alloy was found to be 460 HV which is superior to other Al, Mg, and Ti-based conventional alloys.

Effects of Different Stimuli on the Structure of Nano-Anatase and Poly(N-vinylcaprolactam) in the Nano-Anatase/Poly(N-vinylcaprolactam) Composites.

Nanocomposites based on poly(N-vinylcaprolactam) containing functional nano-anatase particles were produced by mixing and mechanical grinding of mixtures of poly(N-vinylcaprolactam) and Hombifine N (nano-anatase) powders in a porcelain mortar (method 1) and by mechanical milling of the same powders using a high-energy planetary ball mill (method 2). Differences in the diffraction patterns of nanocomposites prepared by method 1 (partial crystallization and an amorphization of nano-anatase particles in the nano-anatase/poly(N-vinylcaprolactam) composite) and method 2 (amorphization of nano-anatase particles) were found. An increase in the X-ray intensity was found to cause physical degradation of the polymer in nano-anatase/poly(N-vinylcaprolactam) composites depending on its prehistory. The preparation of nanocomposites by method 2 was shown to increase photocatalytic activity in the degradation of the dye methyl orange under ultraviolet light irradiation.

Effect of particulate fillers on creep behaviour of epoxy composites

In presented research work, high energy planetary ball milling process was employed to prepare different types of organic and inorganic particles by dry pulverization. The agricultural fibrous waste (i.e. Agave Americana, cornhusk, jute) was utilized to prepare organic particulate fillers whereas the wastes of basalt, carbon, glass and fly ash were utilized to prepare inorganic particles. The particles were then incorporated at 3 wt% loading into epoxy resin, and their properties were investigated for improvement in dynamic mechanical and creep behavior of epoxy composites.

Grain size effect on magnetic and dielectric properties of barium hexaferrite (BHF)

The barium hexaferrite (BaFe12O19) is synthesized by the modified sol-gel method. The nanoparticle BHF with different average particle sizes have been prepared by using the high energy planetary ball mill. The X-ray diffraction (XRD) patterns reveal that all the materials crystallize to hexagonal crystal symmetry with P63/mmc space group. It is observed that the maximum magnetization decreases with the decrease in the average particle size of BHF. However, the maximum dielectric constant is found to be for the BHF with average particle size ~24 nm.

Reactive Milling Induced Structure Changes in Phenylphosphonic Acid Functionalized LiMn2O4 Nanocrystals – Synthesis, Rietveld Refinement, and Thermal Stability

Spinel LiMn2O4 formed in a solid‐state reaction was treated with a high energy planetary ball mill. A mechanochemical in situ surface functionalization of the nanocrystallites with a size smaller than 10 nm was achieved by addition of phenylphosphonic acid. The functionalization was proven by infrared spectroscopy and it can be shown that it prevents the formation of Mn2O3 during the milling process. Structural changes of the samples were investigated via XRD and Rietveld refinement. Mild milling conditions induce an anisotropic broadening of the reflections caused by a distribution of lattice parameters. In this first stage, we propose a structure model based on orthorhombic LiMn2O4. DSC and in situ XRD measurements also verify the presence of the orthorhombic low temperature phase. Medium milling conditions induce a change of intensities, correlated to a cation disorder. Harsher milling conditions induce the transformation to a tetragonal phase. The thermal stability of the formed phases was investigated via in situ high temperature XRD. The reformation of cubic spinel is observed in all samples; however, the transition point depends on the previous milling parameters.

Corrosion behaviour of thermally sprayed Mo added AlCoCrNi high entropy alloy coating

AlCoCrNi alloy was modified by adding Mo to increase its corrosion resistance. Mo was successfully added to the alloy using mechanical milling. All the five constituents of the alloy were milled in a high-energy planetary ball-mill for 20 h. The effective concentration of Mo in the alloy was 10%. At equal intervals, samples were taken for phase formation studies using X-ray diffractional analysis (XRD). The micro-structural characterization was carried out to confirm the homogeneity of the alloy using Field emission scanning electron microscopy (FESEM). The resultant high entropy alloy (HEA) powder was thermally sprayed over a 316l substrate using High-velocity Oxy-fuel (HVOF) technique. Corrosion characteristics of the coating were studied using potentio-dynamic polarization (PDP) test under standard condition. The corrosion properties of the coating were compared with conventional NiCrSiB corrosion resistant coating. The AlCoCrMoNi HEA system offers better resistance to corrosion than NiCrSiB coating.

The effect of mechanical treatment of TiNi powder on structure and phase composition

In this work, the study of the effect of mechanical treatment of TiNi powder on structure and phase composition is presented. The powder was processed in high-energy planetary ball mill for different time. It has been shown that the average particle size measured by scanning electron microscopy changes not monotonous after mechanical treatment, but form of particles changes. The coherently diffracting domain size decreases from 43 nm to 5 nm with increasing of mechanical treatment time that significantly less than the average particle size measured by laser diffraction method and the average particle size calculated from the obtained values of the specific surface. That is to say, the powder particles consist of several crystallites. The width of all peaks changes after 10 s of mechanical treatment that can correspond to an increasing of the defect density. The lattices parameters of all phases change not more than 0.8 % after mechanical treatment. Two processes compete during mechanical treatment, characterizing either brittleness or plasticity. Many defects appear during mechanical treatment stipulate a quasi-amorphous state with increasing of mechanical treatment time.

Optimising the influence of novel citric acid-assisted mechanochemical modification of corncob on Cu2+, Pb2+ and Zn2+ removal

ABSTRACT In this study, the mechanochemical treatment with and without reagent (citric acid) was presented as a new modification method to improve the adsorptive capacity of corncob in the removal of Cu2+, Pb2+ and Zn2+ heavy metal ions from aqueous solutions. A high-energy planetary ball mill was used for modification. The parameters affecting both reagent-assisted (CA-MCM)/non-reagent (MCM) modifications and adsorption effectiveness were investigated via the response surface methodology approach. As a result of optimisation, over 95% heavy metal removals were achieved for both modified materials. To explain the adsorption mechanism; isothermal, kinetic, thermodynamic and activation parameters were examined. The pseudo-second-order and Langmuir isotherm models were found to be appropriate for all adsorbents and heavy metals. According to the thermodynamic parameters, the adsorption processes were spontaneous and endothermic. Desorption studies were conducted to determine the reusability of the adsorbents. Ternary adsorption system of metals was also investigated. Characterisation studies were carried out using Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), and surface analysis (point of zero charge (pHpzc), Boehm titration) to investigate the effects of modifications on the adsorbents’ surface and chemical structure. In addition, the financial advantages of the modification methods were demonstrated by alternative selection and cash flow analyses. All the results revealed that this method as a low-cost and eco-friendly alternative modification treatment to increase the adsorption efficiency of agricultural waste of similar nature.

X-ray peak broadening on microstructure, and structural properties of titanium and Ti-6Al-4V alloys

In this present work, the effect of milling duration on the microstructure and structural properties of titanium and Ti-6Al-4V alloy powders were investigated. Ti and Ti-6Al-4V alloy powders were mechanically alloyed using high energy planetary ball mill for different milling durations (AR, 10 and 20 h) at room temperature. The milled powders were characterized by XRD and HR-SEM analysis. Structural properties such as Crystal size, lattice strain, dislocation density and lattice parameter were examined by using X-ray peak broadening analysis in Williamson hall method i.e., Uniform Deformation Model (UDM). XRD peaks for different milled powders showed significant peak broadening and grain refinement. The Microstructure and size distribution of powder particles, grain size and morphology of Ti and Ti-6Al-4V alloy milled powders were characterized using High Resolution Scanning Electron Microscope (HR-SEM).