Planetary Ball Milling Machine Research Articles

The Effect of AZ61 Content on Mechanical Strength and Surface Hardness of PA6-AZ61 Magnesium Alloy

In this study, a Polyamide 6 (PA6)-AZ61 magnesium alloy composite and pure PA6 were fabricated using a compression molding instrument. Both the matrix and reinforcement were prepared in powder form. A planetary ball milling machine was employed to mix the PA6 and AZ61 micro powders. The effects of AZ61 content at different percentage on the final properties of the composite were investigated. X-ray diffraction (XRD) analysis and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) were employed to verify the uniformity of the mixing process and to confirm the composition of both the raw materials and the composite. The result, relative to pristine PA6, the ultimate tensile strength (UTS) demonstrated a substantial increment of 48.3%, reaching 58 MPa. Whereas the yield strength (YS) exhibited a notable surge to 49.38 MPa, constituting a 52.9% enhancement. Additionally, the PA6-5AZ61 composition achieved the highest microhardness value at 21.162 HV, signifying a remarkable 66.3% augmentation compared to the unalloyed PA6 material. This result suggests that AZ61 has the potential to improve the properties of the matrix material.

MECHANOSYNTHESIS OF MMC Cu-C DOPED WITH Ti FOR APPLICATION OF PANTOGRAPH CONTACT STRIP (PCS)

This research was conducted to determine the effect of the addition of Titanium (Ti) and the sintering temperature variation on MMC CuC alloys as reinforcing elements. The process of this research uses powder metallurgical method with an alloying technique in Mechanical Alloying using a Planetary Ball Mill (PBM) machine with a speed of 600 rpm for 2 hours, the ratio of powder to the ball mill is 10:1. The compacting process is carried out using dies 11 mm in diameter and compacting pressure of 90 Kg/cm2. The sintering process is carried out three times, with variations in sintering of 800oC, 900oC, and 1000oC with sintering time for 1 hour in the tube furnace in the argon gas vacuum environment. The number of samples used in this study amounted to 9 samples with variations in alloy and temperature sintering, consist of MMC CuC alloy with addition of Ti 0%, 0.5%, 1.5% (T=800 oC), MMC CuC with addition of Ti 0%, 0.5%, 1.5% (T=900 oC), and MMC CuC with addition of Ti 0%, 0.5%, 1.5% (T=1000 oC). The tests included Vickers hardness testing, metallography testing, XRD testing, and SEM-EDS testing. The addition of Ti elements and varying sintering temperature had an effect on the hardness value of MMC CuC material with the highest hardness value in samples with 1.5% Ti alloy (800oC) which is 87.25 HV, and the lowest porosity value is 2.491% in the sample of 1.5% Ti (1000oC).

Size effect on magnetism and large magnetocaloric effect of Haldane chain antiferromagnet Er2BaNiO5

We investigated the size effect on magnetocaloric effect (MCE) of Haldane spin-chain antiferromagnet Er2BaNiO5. The bulk sample was prepared by solid state route and the nano-size samples (N-4 h, N-8 h) were produced by using the high-energy planetary ball mill machine. The crystal structure was obtained by the refinement of XRD results and the SEM images. The present magnetization results indicated that the decreasing of average crystallite size induced enhancement of magnetization and paramagnetic-like behavior. The zero-approaching of θp values for N-8 h revealed the suppression of the dominant antiferromagnetic (AFM) interactions in bulk sample. The fitting results of Haldane gap stated clearly its dramatical reduction which is consistent with the weaken of magnetic interactions. The size effect also presented great influence on MCE. The negative MCE in bulk sample disappeared and instead of monotonically increasing of MCE in N-4 h and N-8 h samples. The maximum entropy change (-ΔSmax) of N-8 h increased nearly 3.2 times compared to bulk sample. The increasing of PM ions in nano-samples were verified by the ESR results, in which the bulk sample showed unavailable ESR signals due to the complex competing 3D AFM interactions. While for the nano-samples, the ESR signals of Er3+ and Ni2+ ions were observed with the g value of gEr = 6.1 and gNi = 2.28. The size-effect on MCE in Er2BaNiO5 opened new approach of the research on magnetic refrigeration.

Effect of PbO Incorporation with Different Particle Sizes on Structural and Mechanical Properties of Polystyrene

Abstract Two different sizes of lead oxide (PbO) nanoparticles, notably PbO(A) and PbO(B) with sizes of 78 and 54 nm, respectively, were produced using a high-speed planetary ball milling machine under specific operating parameters. Following this, the novel polystyrene (PS) nanocomposite PS/PbO was prepared using compression molding by embedding 10, 15, 25, and 35 wt. % of PbO(Bulk), PbO(A), and PbO(B) into PS separately. The composite was further characterized by Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and laser-induced breakdown spectroscopy (LIBS). FTIR results confirmed the presence of PbO and indicated physical adsorption of the nanoparticle onto the PS matrix surface. SEM, EDS, and LIBS analyses revealed a more efficient diffusion of PbO in the PS matrix with the decrease of the nanoparticle size. On the other hand, tensile and Vickers microhardness tests were performed to investigate the composite’s mechanical properties. The stiffness was, indeed, enhanced with increasing weight fraction as well as with decreasing particle size of PbO. The strength of the composite was optimized with 15 wt. % of PbO. The microhardness test revealed an indentation size effect behavior of the composite and an increase in Hv values with PbO loads up to 15 wt. %. Accordingly, by adjusting the filler particle size and concentration, the mechanical properties of the composite were enhanced, increasing their use in a variety of applications such as coating, insulation, and radiation shield.

Mechanical ball milling: A sustainable route to induce structural transformations in tungsten disulfide for its photocatalytic applications

An improved method for mass production of good-quality tungsten disulfide (WS2) nanosheets via ball milling of commercial powder of WS2 with different ball sizes is reported in this paper. Bulk/Commercial WS2 (Wc) powder was milled in a high energy planetary ball milling machine using two different ball sizes with diameter 0.5 mm and 7 mm in two separate milling jars. The as-prepared WS2 nanosheets (W0.5 and W7) corresponding to 0.5 mm and 7 mm ball size respectively, were investigated in detail using several characterization techniques, such as Scanning electron microscopy (SEM) for morphological analysis, X-ray diffractometry (XRD) for crystal structure analysis, Fourier transform infrared spectroscopy (FTIR) for functional group analysis and Brunauer-Emmett-Teller (BET) characterization for surface area and pore size/distribution analysis. Ultraviolet–Visible diffuse reflectance spectroscopy (UV–Vis DRS) was performed for bandgap analysis, Time resolved photoluminescence (TRPL) was done for exciton decay studies and Mott-Schottky (MSK) characterization for flat band positions. W7, as a photocatalyst showed enhanced performance of ∼95% in degrading both Methylene blue (MB) and Methyl orange (MO) dyes while as W0.5 showed enhanced surface area. Highly efficient adsorbents were obtained in this whole process of wet ball milling optimized for the degradation of MB and MO dyes. So, the prepared material is potential candidate for wastewater treatment.

Effect of 45S5 bioactive glass on the sintering temperature of titanium-hydroxyapatite composite

Titanium (Ti) is widely known for its good mechanical properties and corrosion resistance. However, it has poor biocompatibility. Hydroxyapatite (HA) is a biocompatible material but has poor mechanical properties. Making Ti-HA composite creates a promising choice of biomaterial in dental and medical applications. However, creating a Ti-HA composite requires sintering at high temperatures which leads to oxidation of Ti. The aim of this study was to reduce the sintering temperature of Ti-HA composite by incorporating 45S5 Bioactive Glass (BG) without compromising the chemical, physical and mechanical properties of the composite. In this study, a Ti-HA-BG composite with wt% of 45-45-10 respectively was produced via powder metallurgy. This was compared with the control composite consisting of 50 wt% Ti- 50 wt% HA. Powders according to the above-mentioned ratio were milled at 200 rpm for 5 hours by using a planetary ball milling machine. Samples were then compacted into cylindrical pellets via uniaxial pressing at 1500 psi and sintered in an atmospheric furnace at 1000 °C, 1100 °C and 1200 °C for 4 hours. Ti-HA and Ti-HA-BG sample characteristics were examined and compared by using Fourier Transformed Infrared Spectroscopy (FTIR), Energy Dispersive X-Ray (EDX) and X-Ray Diffraction (XRD). The density and volumetric expansion of the composites were also measured and compared. Results from XRD data indicate the reduction of oxidation of Ti and decomposition of HA in Ti-HA-BG composite at lower temperature in comparison to Ti-HA composite. The density of Ti-HA-BG composites are higher compared to Ti-HA composite while the volumetric expansion of Ti-HA-BG composites is lesser than Ti-HA composite. Therefore, BG is a low melting point additive that acts as a good sintering aid to effectively lower the sintering temperature while maintaining the desired properties of initial components.

Microstructural evaluation of ball-milled nano Al2O3 particulate-reinforced aluminum matrix composite powders

Abstract A mechanically alloyed mixture of Al-1 wt.% nano-alumina (n-Al2O3) composite powders was produced using a planetary ball milling machine. Different milling times were applied to investigate the effect of milling time on the dispersion and microstructure of n-Al2O3 particulate reinforcement within the aluminum matrix. A good homogeneous dispersion of n-Al2O3 particulates was observed after 8 h of milling. Longer milling times had no significant effect on the dispersion and morphology of n-Al2O3 particulates within the aluminum matrix because a steady state had been reached.

Influence of Ni Precursors on the Structure, Performance, and Carbon Deposition of Ni-Al2O3 Catalysts for CO Methanation.

Three Ni-Al2O3 catalysts were prepared, in planetary ball-milling machine, by the mechanochemical method with Al(NO3)3·9H2O as the aluminum precursor, (NH4)2CO3 as the precipitant, and Ni(NO3)2·6H2O, NiCl2·6H2O, and Ni(CH3COO)2·4H2O as nickel precursors (the corresponding catalysts were labeled as Ni-NO, Ni-Cl, and Ni-Ac). The prepared catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), and N2 adsorption–desorption technologies, and CO methanation performance evaluation was carried out for the catalysts. Results showed that the catalyst with Ni(NO3)2·6H2O as the precursor presented good Ni dispersibility and a small Ni grain size of 6.80 nm. CO conversion, CH4 selectivity, and yield of the catalyst were as high as 78.8, 87.9, and 69.8%, respectively. Carbon deposition analysis from temperature-programmed hydrogenation (TPH) characterization showed that the H2 consumption peak area of the three samples followed the order: Ni-NO (2886.66 au) < Ni-Cl (4389.97 au) < Ni-Ac (5721.65 au), indicating that the Ni-NO catalyst showed higher resistance to carbon deposition, which might be due to its small Ni grain size.

Holey Reduced Graphene Oxide/Carbon Nanotube/LiMn0.7Fe0.3PO4 Composite Cathode for High-Performance Lithium Batteries

Introduction Graphene is a single atomic monolayer of graphite and has been found a variety of applications in energy conversion and storage devices, due to the excellent properties such as high carrier mobility (~10,000 cm2 V−1 s−1 at room temperature), structural flexibility, chemical and thermal stability, mechanical strength and ultrahigh theoretical specific surface area (2630 m2g−1) [1]. However, when the graphene sheet has large area, the wrapping of active materials may hinder the transportation of Li+ between active particles and electrolyte, especially at high charge/discharge rates.Herein, holey graphene oxide (h-GO) [2], which is made by a green wet ball-milling of GO in one step without using any catalysts or chemicals, is combined with carbon nanotubes (CNTs) and LiMn0.7Fe0.3PO4 (LMFP) to make a composite cathode for lithium batteries [3]. Results show that the LMFP cathode with h-GO/CNT shows a remarkedly improved electrochemical performances due to the facilitated Li+ transport pathway, compared to that with conventional GO/CNT. This study provides a new approach for fabricating holey graphene and can open up new possibilities for applications on power sources. Results and discussion The synthesis of h-GO and LMFP composite material is shown in Fig. 1. Graphite oxide suspension (~0.6 mg/mL) was obtained by mixing with purified water and after the ultrasonic treatment for 3 hours. Subsequently, the ball-milling of 50 mL GO suspension was performed in a planetary ball-mill machine with 30–120 g of 100 mm size zirconia balls for 20 min at 400 rpm (the corresponding weight ratio of balls to GO aqueous suspension is 0.6−2.4). The balls were fully removed by sieve afterward. Finally, the mixture was freeze-dried for 12 hours. LMFP, h-GO, CNTs and binder were mixed at a mass ratio of 95.6%: 2%: 0.4%: 2% and coated onto Al foil to obtain a cathode electrode. Electrochemical characteristics were evaluated by preparing a 2032 type coin cell using Li foil as the counter electrode. The electrolyte was 1 mol dm-3 LiPF6/EC-DEC (1: 2).SEM image of the synthesized h-GO is shown in Fig. 2. It is found that irregular micropores can be generated on the surface of GO after the ball-milling of GO aqueous suspension. At the conference, we will show that the more balls used, the more and bigger holes could be observed. That is, the hole size and surface density could be controlled by the adjustment of the weight ratio of balls to GO aqueous suspension. We will also show that LMFP electrode with h-GO/CNT can deliver more than half of discharge capacities than that with conventional GO/CNT at a higher discharge rate (>=20 C), also superior to that with h-GO or CNT only. The use of h-GO made by the other method, such as the chemical etching method, the performances will also be discussed. The scalable and robust synthesis method of h-GO and the novel properties of h-GO/CNT reported here greatly advance the practicality of using it as electrodes in lithium batteries as well as other energy storage technologies. Acknowledgment We thank Taiheiyo Cement Co., Ltd for the providing of LiMn0.7Fe0.3PO4 powders and NIMS for the TEM measurement. Reference 1. Han, et.al., Small. 9 (2013). 2. Y. Xu, et al., Nat. Commun. 5 (2014). 3. D. Ding, et.al., J. Power Sources. 449 (2020). Figure 1

Improvement Parameters of Hydrogen Generation from Water under Stainless-Steel-Mediated Ball Milling Conditions

Abstract Mechanochemical energy derived from the collision and friction among stainless-steel (SUS304) balls and a vessel by a planetary ball mill machine effectively facilitated H2 generation from H2O. The number and size of the balls significantly affected the H2 generation efficiency. Additionally, the change in the crystal structure of the stainless-steel between the austenite and martensite states was also an important factor in improving the H2 generation efficiency.

Production of silica-based ceramics sintered under nitrogen atmosphere from rice husk and sugarcane bagasse ash

Nitride silica-based ceramics were prepared by sintering under nitrogen atmosphere using rice husk ash and bagasse ash as raw materials. X-ray Fluorescence Spectrometry (XRF) and X-ray Diffractometor (XRD) studies revealed that the main phase of rice husk ash (after calcined at 600°C for 6 h.) was amorphous silica, whereas the sugarcane bagasse ash contained quartz and CaCO3. Thus, both ashes would be a good source for silica. Two batches of the 100 wt% rice husk ash (RHA100) and the mixture of 50 wt% rice husk ash and 50 wt% bagasse ash (RHA50BA50) were wet milled using planetary ball milling machine, and were then dried at 90°C. The powders were uniaxially pressed at the pressure of 150 MPa. The disk shape samples were sintered at 1300-1500°C in the nitrogen atmosphere with gas flow rate of 600 ml/min. The physical and mechanical properties of the sintered disk shape samples were determined. The phase structure and microstructure of the samples were investigated using XRD and SEM techniques, respectively. The main phases obtained after sintering were cristobalite, tridymite, α and β-silicon nitride and SiC. The RHA50BA50 sample sintered at 1450°C showed the optimum properties with low firing shrinkage, low water absorption and high strength.

Development and characterization of a novel hybrid magnetorheological elastomer incorporating micro and nano size iron fillers

Owing to its benefit of changing stiffness, Magnetorheological Elastomers (MRE) can be effectively used as base isolator in buildings and bridges to resist unpredictable loading conditions e.g. seismic activities. This research aims to study the effects of using Iron nanoparticles in silicon rubber matrix on dynamic properties of MRE's and to make MRE more adaptable to seismic forces, specifically at high strains. Micro-sized iron particles were reduced to nanoparticles using a planetary ball milling machine. Samples, using a mixture of nano & microparticles were prepared for different percentage concentrations. The experimental test rig was set up for dynamic shear testing under known amplitude, frequency, and magnetic flux density summing up to total 180 tests. The experimental results revealed that the use of nanoparticles had a significant increase in the effective stiffness by 13% at higher strains and low flux values. Further attaining MR effect at a higher frequency is difficult using only larger sized fillers however for hybrid MREs, the magnetrheological effect was higher for higher frequency. The maximum MR effect was observed for samples with 40% iron content.

High Throughput Experimental Technologies for Li-Ion Batteries

Next generation Lithium ion batteries materials with higher energy, lower cost, long lifetime, and better safety, require the investigation of unknown lithium-ion systems and a vast amount of experiments. Advanced cathode, anode and electrolyte materials discovery is one possible solution to the rapid optimization. In this work, MTI Corporation and MTI SZKJ’s effort on modify the existing technologies to develop a high throughput materials experimental line for Lithium-ion batteries materials research are reviewed and discussed.The first step is high throughput, automatic dispensing of solid powders or liquid. Five powder or six liquid dispensing heads and balances, with one dispensing head for each material component, are integrated with a carousel type sample changer for automatic powder or liquid dispensing with varying ratios between different material components. The second step is high throughput ball milling of the as-dispensed powder samples. With 4 sets of 4 cavity milling jars, totally 16 parallel ball milling experiments of 10 g samples can be carried out in a planetary ball mill machine. The mixed powder samples are then high throughput pellet pressed by a 10 ton electric hydraulic press with a carrousel type sample changer. Next, a compact 16-channel tube furnace up to 1100 °C is employed for sintering, annealing, or quenching operations. Finally, the elemental compositions of bulk samples are high throughput analyzed by an X-ray fluorescence (XRF) scanning system for providing instant feedbacks to the synthesis / processing steps. Keywords: Li-ion Batteries Materials Discovery, High Throughput Figure 1

The influence of nickel loading on the structure and performance of a Ni–Al2O3 catalyst for the hydrogenation of 1,4-butynediol to produce 1,4-butenediol

In combination with a planetary ball-milling machine, a Ni–Al2O3 catalyst was prepared by a mechanochemical method.

Compositional Dependence of Mössbauer Spectra for Mechanically Milled (Fe1-xAlx)2O3

Introduction Although α-Fe2O3 is promising anode material of LIB for excellent theoretical capacity as 1007 mAhg-1, it shows the severe cycle deterioration due to conversion reaction during the charge-discharge process. We have considered that the formation of Fe2O3-Al2O3 solid solution allows the Fe ions to react reversibly around the original site in the corundum-type structure. Although both α-Fe2O3 and α-Al2O3 have the corundum-type structure, solid solution ranges are restricted within 10% from the both end components [1]. In recent years, we have successfully obtained the Fe2O3-Al2O3 solid solution for all the compositional range through the mechanochemical synthesis method. It was also found that the obtained solid solution shows good cycle characteristics as an anode material of LIB [2]. Nevertheless, this solid solution has just been newly found and any magnetic property has not been clarified yet. In this study, we have carried out the Mössbauer measurement to discuss the magnetic properties of Fe2O3-Al2O3 solid solution. Experimental The solid solutions of (Fe2O3)1-x(Al2O3)x (x = 0, 0.1, 0.25, 0.33, 0.50 and 0.67) were prepared by mechanical alloying method. About 0.5 g of the stoichiometric mixtures of γ-Fe2O3 and γ-Al2O3 were put into a silicon nitride milling vessel with 20 ml in volume accompanied by 10 silicon nitride balls with 10 mm in diameter without any solvent. A planetary ball milling machine has been operated with the rotation speed of 800 rpm for 240 min. Mössbauer measurement was performed on the obtained samples of (Fe1-xAlx)2O3 (x = 0, 0.1, 0.25, 0.33 ,0.50 and 0.67) at room temperature. 57Co was used as a gamma ray source for Mössbauer measurement. Results and Discussions Fig. 1 shows the Mössbauer spectra of (Fe1-xAlx)2O3 measured at room temperature for x = 0, 0.1, 0.25, 0.33, 0.5 and 0.67. For the Fe2O3 (x = 0) obtained by milling, the sextet spectrum was observed. This would correspond to weak ferromagnetism appearing from a cant structure, in which the spin of Fe is slightly inclined from 90° to the c-axis direction. This spectrum is essentially similar to the α-Fe2O3 reagent without milling. The Mössbauer spectra gradually changed into doublet with increasing the concentration of aluminum x and the change is almost completed to the x = 0.5. Fourier transform of the EXAFS signal shows that |χ| peak value around 1.5 Å corresponding to Fe-O distance did not vary significantly, while that around 2.5 Å for Fe-Fe distance decrease with x. Dilution of Fe3+ with Al3+ would result in the change in spin interaction, or (Fe1-xAlx)2O3 changes from weak ferromagnetism to the paramagnetic state by reducing spin interaction.

Compressive quasistatic and dynamic behavior of SiC/ZrO2 aluminum-based nanocomposite

This research investigated the mechanical properties of aluminum-based nanocomposite. The spark plasma sintering method was adopted to fabricate the samples. The nanoparticles and the base metal powder were mechanically mixed in four volumetric ratios under an argon-gas-neutral atmosphere using a planetary ball milling machine. The dynamic and static compressive behaviors of the samples were studied under three different loading rates, and the microhardness of the specimens was measured. Results revealed significant improvements in microhardness, quasistatic, and the dynamic compressive strength, which can be attributed to several mechanisms, including the load transfer effect, Hall-Patch strengthening, Orowan strengthening, coefficient of thermal expansion, and elastic modulus mismatch effects. The most effective mixture was found to be 92 vol% of Al, 4 vol% of SiC, and 4 vol% of ZrO2. This combination of raw materials led to ultimate strengths of 204.517, 396.825, and 572.624 MPa at strain rates of 0.33, 13.33, and 2000 s−1, respectively.

Optical and Dielectric Properties of PMMA/α-Fe2O3–ZnO Nanocomposite Films

In this study, α-Fe2O3–ZnO mixed particles were incorporated into the poly methyl methacrylate (PMMA) matrix by using solvent casting process. In order to prepare a powder mixture, mechanical milling process was used. α-Fe2O3 synthesized by precipitation method and ZnO nanoparticles were mixed with same amount and milled with planetary type ball milling machine for 1 h. Morphological and structural examinations of the produced powders were conducted with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optical and dielectrical properties of composite materials produced with different amount of reinforcement (0.1 wt%, 0.5 wt% and 1.0 wt%) were examined by using UV–Vis spectrophotometry and vector network analyzer (VNA). It was observed that optical transmittance reduced with increasing reinforcement amount. Dielectric properties of produced pellet composites with 4 mm thickness were conducted between 70 and 110 GHz and the results showed that the real and complex permittivity and dielectric loss values of PMMA/α-Fe2O3 is higher than those of neat PMMA, PMMA/ZnO and PMMA/α-Fe2O3–ZnO.

Structure and Electrochemical Properties of a Mechanochemically Processed Silicon and Oxide-Based Nanoscale Composite as an Active Material for Lithium-Ion Batteries

Si is essential as an active material in Li-ion batteries because it provides both high charge and optimal cycling characteristics. A composite of Si particles, Cu particles, and pure H2O was realized to serve as an anode active material and optimize the charge–discharge characteristics of Li-ion batteries. The composite was produced by grinding using a planetary ball mill machine, which allowed for homogenous dispersion of nanoscale Cu3Si as Si–Cu alloy grains and nanoscale Si grains in each poly-Si particle produced. Furthermore, some Si particles were oxidized by H2O, and oxidized Si was distributed throughout the composite, mainly as silicon monoxide. As a result, each Si particle included silicon monoxide and conductive Cu3Si materials, allowing for effective optimization of the recharging and charge-discharge characteristics. Thus, a new and simple process was realized for synthesizing a Si active material composited with silicon oxides, including silicon monoxide. This Si-rich conductive material is suitable as an anode for Li-ion batteries with high charge and optimized cycling properties.

Preparation of Mo-Re-C samples containing Mo7Re13C with the β-Mn-type structure by solid state reaction of planetary-ball-milled powder mixtures of Mo, Re and C, and their crystal structures and superconductivity

Mo-Re-C compounds containing Mo7Re13C with the β-Mn structure were synthesized with high-melting-temperature metals Mo, Re, and C powders using a conventional solid state method with a planetary ball milling machine instead of the arc melting method. Use of the ball milling machine was necessary to obtain Mo7Re13C with the β-Mn structure using the solid state method. Almost single-phase Mo7Re13C with a trace of impurity were obtained using the synthesis method. By XRF and lattice parameter measurements on the samples, Fe element existed in the compound synthesized using the planetary ball milling machine with a pot and balls made of steel, though Fe element was not detected in the compound synthesized using a pot and balls made of tungsten carbide. The former compound containg the Fe atom did not show superconductivity but the latter compound without the Fe atom showed superconductivity at 6.1K.

An experimental investigation of the physical properties of the graphene/multi-walled carbon nanotubes composite

In this present work, the physical characteristics of the graphene/MWCNTs composite have been studied. Surface modification has been done by grinding process and acid treatment where planetary ball milling (PBM) machine for grinding in aqueous circumstance and a mixture of HNO3 and H2SO4 for acid treatment have been executed. Though, there are many researches of GN and MWCNTs nanoparticles based on individually as well as combined with other nanoparticles have been accomplished, reports on the combination of these two nanoparticles are negligible. In this paper, IR thermography, morphological and structural characteristics of modified GN–MWCNTs by field emission scanning electron microscopy, Raman spectroscopy and dispersibility analysis by sedimentation, UV–Vis spectroscopy, electric conductivity and thermal conductivity measurements have been presented in order to report the characteristics of GN/MWCNTs composite. Acid treatment as well as wet grinding of GN/MWCNTs composite at 500rpm for 2h gives the highest thermal conductivity enhancement which is 4.29% at 40°C.