Homogeneous Particle Distribution Research Articles

Investigating the mechanical properties of titanium dioxide reinforced magnesium composites

Titanium dioxide reinforced magnesium alloy was synthesized in the current work by employing the stir casting process to alter its weight proposal. Its mechanical proportions were investigated for structural and functional applications. The microstructure of synthesized nano composites was examined with an optical microscope, and the findings revealed that the presence of nano reinforcement particulates leads to a decrease in the density of the dendritic pattern as well as a homogeneous distribution of nano reinforcement particles throughout the magnesium phase. Hardness (18.24%), tensile strength (22.12%), compressive strength (24.32%), and wear resistance (26.52%) were examined in accordance with ASTM standards. Titanium dioxide reinforced magnesium nanocomposites showed considerable improvements in their mechanical characteristics when compared to as cast alloy. This was the case when compared to the mechanical properties of as cast alloy.

Structural and magnetic conduct in Sm and Al substituted Ba0.9Sm0.1Fe10Al2O19 M-type hexaferrites at different sintering temperatures

The hexagonal ferrites with composition Ba0.9Sm0.1Fe10Al2O19 has been prepared by using conventional solid state reaction method. As prepared samples were then sintered at different sintering temperatures to analyze the effects on magnetic and structural properties of Barium hexa ferrites. These samples were then characterized by using various techniques. For structural characterization x-ray diffraction technique was used. XRD results confirmed phase pure hexagonal structure. No impurity peaks were observed. For Morphological analysis of all the samples Scanning Electron Microscopy (SEM) was utilized. SEM micrographs suggested the formation of hexaferrites material with homogenous distribution of particles. Magnetic properties were measured by permanent magnetic measuring system. Magnetic conduction of material was tested under varying magnetic field of ± 30 KOe at room temperature. The saturation magnetization value was observed 48.55 emu g−1 and coercivity 5.01KOe for the sample sintered at 1220 °C. As the sintering temperature rises, the values for magnetic saturation decreases to 46.24 emu g−1 and coercivity increases up to 5.26 KOe at 1270 °C.

Ultrasound Induced a More Homogeneous Distribution of TiB2 Particles in Al Matrix During Solidification

Ultrasound Induced a More Homogeneous Distribution of TiB2 Particles in Al Matrix During Solidification

Graphene/macrocylic Yb nanocomposite as counter electrode in dye sensitized solar cell

In recent article, ligand octaaza-bis-α-diimine and its Yb complex grafted upon GO have been synthesized and characterized using scanning electron microscopy, fourier transform infrared spectroscopy, energy dispersive spectroscopy, raman spectroscopy, x-ray diffraction, and cyclic voltammetry techniques. The composites with varying ratio's GO/Yb (1:1), (1:3) and (1:10) have been investigated as counter electrode in dye sensitized solar cell. The fabricated device was analysed using current density–voltage, incident photon-to-current conversion efficiency, and electrochemical impedance spectroscopy techniques. The device fabricated with highest ratio (1:10), exhibit the highest Voc, Jsc values and it showed the maximum PCE value of 7.98%. Due to the homogeneous distribution of catalytic Yb particles on the surface of RGO, the RGO/Yb CE demonstrated effective electrocatalytic activity. According to the findings, a DSSC with RGO/Yb CE can demonstrate the efficiency highest than platinum (Pt) CE and thus can replace traditional Pt CE DSSCs to reduce the cost of solar cells.

Ultra-low-temperature lead-free multicomponent alloy solder for application in heat-sensitive electronic components

This manuscript describes the development of a lead-free multicomponent solder alloy composed of Sn, Bi, In, Cu, and Zn for heat-sensitive electronic devices. The microstructure comprises a homogeneous distribution of CuZn particles embedded in a eutectic mixture of Sn (solid solution) and InBi with a melting temperature of 83.7 °C. The average thickness of the generated intermetallic compounds between solder/substrate (Cu) was < 4 µm with a wetting contact angle below 55°, which is acceptable in the electronic industries. Additionally, the solder's shear stress (12.94 ± 1.50 MPa) is lower than commercial counterparts; but it shows a much higher shear strain (0.53 ± 0.06 mm/mm). Thus, the developed system could have great potential for applications in ultra-low-temperature lead-free solders.

In English

Oil and oil products enters surface waters as a result of man-made disasters, caused, in particular, by military operations. In order to prevent ecological catastrophe, it is necessary to remove hydrocarbons from water surface. The paper is devoted to the development of materials for the extraction of non-polar liquids from aqueous media. Magnetic sorbents based on non-carbonized biopolymers (both plant cellulose and keratin) are proposed. Biopolymer matrices of different morphology on the level of fiber bundles were used for the composite preparation. Dependent on origin, the matrices are characterized by different morphologies at the level of fiber bundles: they are straight (cellulose obtained from wood and corn cobs), helical (cellulose of tea leaves or scaly (keratin from animal wool). Magnetite particles were inserted into biopolymer matrices after the removal of non-cellulose and non-keratin inclusions from them. The samples were investigated with SEM and FTIR techniques, magnetite was identified with XRD analysis. The most homogeneous distribution of magnetic particles, a size of which is less than 1 mm, was found for the matrix obtained from corn cobs. This composite contained the least amount of iron (0.24 mass. %), namely this sample demonstrates the best flotation. The sorbent based on cellulose from tea leaves contained 71% of iron: the particles sink almost completely. The capacity towards non-polar liquids was estimated as follows (g g–1): 1.6–8.6 (vegetable oil), 10.5–16.4 (crude oil), 9.8–14.5 (kerosene). After the removal of crude oil from water surface, no film of this liquid was visually observed. The value of chemical oxygen demand was » 0.2 mgO2 dm–3, this is less than the demand for drinking water. Moreover, the sorbent can be easy removed from water surface with magnet. As found, the sorbents can be used for removal of toxic metal ions from water. As found, magnetic particles improves sorption of Pb2+ ions but decrease Cd2+ sorption. Thus, the sorbents with small content of inorganic modifier can be used for the removal of oil and oil products from water surface. The sorbents, which demonstrate bad flotation, can be used for the recovery of inorganic ions. The advantages of biopolymer-based sorbents over known material is a simple preparation procedure that involves cheap and available feedstock. Moreover, the sorbents can be easy separated from aqueous phase with magnet.

Incorporation of strontium-containing bioactive particles into PEOT/PBT electrospun scaffolds for bone tissue regeneration

The combination of biomaterials and bioactive particles has shown to be a successful strategy to fabricate electrospun scaffolds for bone tissue engineering. Among the range of bioactive particles, hydroxyapatite and mesoporous bioactive glasses (MBGs) have been widely used for their osteoconductive and osteoinductive properties. Yet, the comparison between the chemical and mechanical characteristics as well as the biological performances of these particle-containing scaffolds have been characterized to a limited extent. In this work, we fabricated PEOT/PBT-based composite scaffolds incorporating either nanohydroxyapatite (nHA), strontium-containing nanohydroxyapatite (nHA_Sr) or MBGs doped with strontium ions up to 15 wt./vol% and 12,5 wt./vol% for nHA and MBG, respectively. The composite scaffolds presented a homogeneous particle distribution. Morphological, chemical and mechanical analysis revealed that the introduction of particles into the electrospun meshes caused a decrease in the fiber diameter and mechanical properties, yet maintaining the hydrophilic nature of the scaffolds. The Sr2+ release profile differed according to the considered system, observing a 35-day slowly decreasing release from strontium-containing nHA scaffolds, whereas MBG-based scaffolds showed a strong burst release in the first week. In vitro, culture of human bone marrow-derived mesenchymal stromal cells (hMSCs) on composite scaffolds demonstrated excellent cell adhesion and proliferation. In maintenance and osteogenic media, all composite scaffolds showed high mineralization as well as expression of Col I and OCN compared to PEOT/PBT scaffolds, suggesting their ability to boost bone formation even without osteogenic factors. The presence of strontium led to an increase in collagen secretion and matrix mineralization in osteogenic medium, while gene expression analysis showed that hMSCs cultured on nHA-based scaffolds had a higher expression of OCN, ALP and RUNX2 compared to cells cultured on nHA_Sr scaffolds in osteogenic medium. Yet, cells cultured on MBGs-based scaffolds showed a higher gene expression of COL1, ALP, RUNX2 and BMP2 in osteogenic medium compared to nHA-based scaffolds, which is hypothesized to lead to high osteoinductivity in long term cultures.

ZnFe2O4 Magnetic Material: A Comparative DFT and DFT + U Study

Solid-state synthesis has been used to create ZnFe2O4 materials. The physical phases of ZnFe2O4 were characterized using X-ray diffraction (XRD). Above 800 °C. The particle size of pure ZnFe2O4 is between 20 and 50 nm, and a homogeneous particle distribution were achieved. Materials Studio Software was used to simulate the band structure, density of states (DOS), and optical characteristics of ZnFe2O4 using density functional theory (DFT). The results suggest that using the GGA + U functional to compute the energy band of normal spinel ZnFe2O4 is a good method. The direct band gap of ZnFe2O4 crystal is 1.502 eV. Near the Fermi level, the conduction band of ZnFe2O4 contributes to the 3d orbital of Fe and the 2p orbital of O, whereas the valence band contributes primarily to the 2p orbital of O. In the visible light area, ZnFe2O4 possesses outstanding optical characteristics and significant absorption. It may be utilized as a visible light photocatalytic material, and it also contains magnets, which makes recycling easier.

Synthesis of Ni doped-TiO2 Thin Film Photocatalysts on Glass Surfaces

Thin film of TiO2 modified Ni2+ cationic (Ni doped-TiO2) thin films were synthesized from titanium tetraisopropoxide (TTIP) and Ni(NO3)2.6H2O using the combined sol-gel and dip coating method followed by calcination at 500oC for an hour. This study aims to determine the concentration of Ni2+ and the optimum number of layers for application as self-cleaning. Frontier transform infrared (FTIR) spectrophotometric analysis observed a shift in the vibration absorption peak of Ti-O towards a smaller wave number as an indication that the Ni2+ cationic have incorporated in the TiO2matrix in forming Ni-TiO2. Based on the of x-ray diffraction (XRD) it is known that Ni-TiO2 has anatase crystalline phase with a crystallite size of 149.20 nm. Diffuse reflectance ultraviolet-visible (DRSUV-Vis) spectrophotometry showed a decrease in the bandgap energy (3.2 eV to 2.22 eV). Surface morphological by scanning electron microscopy (SEM) method showed that the addition of polyethylene glycol (PEG) resulted in a more homogeneous distribution of particles than thin films without PEG. The self-cleaning activity of Ni-TiO2 was tested for surface hydrophilic properties by measuring the contact angle of water and oil droplets under visible light illumination.

Mechanical and thermal expansion behavior of hybrid aluminum matrix composites reinforced with SiC particles and short carbon fibers

In recent years, the research of hybrid composites reinforced by multiple reinforcements has received increasing attention because these composites have great potential to be tailored for various applications. In the present work, hybrid aluminum (Al) matrix composites reinforced with SiC particles and carbon fibers (SiCp-Cfs/Al composites) were fabricated by the colloidal dispersion and suction filtration method. It was found that SiCp-Cfs/Al composites had a dense structure and the carbon fibers and SiC particles were uniformly distributed in the Al matrix. The mechanical properties of SiCp-Cfs/Al composites with different reinforcement volume fractions were investigated. The results showed that the SiCp-Cfs/Al composites exhibited high tensile strength and elastic modulus (tensile strength 207 MPa and elastic modulus 92 GPa) when the volume fraction of SiC particles was 5% and the volume fraction of carbon fiber was 7%, which were significantly higher than that of SiCp/Al composites with 5% volume fraction of SiC particles (tensile strength 112 MPa and elastic modulus 80 GPa). The homogeneous distribution of carbon fibers and SiC particles in the Al matrix, which serves as co-reinforcing, is responsible for the high tensile strength and elastic modulus of SiCp-Cfs/Al composites. The coefficient of thermal expansion (CTE) of SiCp/Al composites and SiCp-Cfs/Al composites were measured at temperatures ranging from 25 °C and 400 °C. The results showed that the addition of carbon fibers caused the CTE of SiCp-Cfs/Al composites to be much lower than that of SiCp/Al composites.

Influence of Microstructure on Fracture Mechanisms of the Heat-Treated AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion

Few systematic studies on the correlation between alloy microstructure and mechanical failure of the AlSi10Mg alloy produced by laser-based powder bed fusion (L-PBF) are available in the literature. This work investigates the fracture mechanisms of the L-PBF AlSi10Mg alloy in as-built (AB) condition and after three different heat treatments (T5 (4 h at 160 °C), standard T6 (T6B) (1 h at 540 °C followed by 4 h at 160 °C), and rapid T6 (T6R) (10 min at 510 °C followed by 6 h at 160 °C)). In-situ tensile tests were conducted with scanning electron microscopy combined with electron backscattering diffraction. In all samples the crack nucleation was at defects. In AB and T5, the interconnected Si network fostered damage at low strain due to the formation of voids and the fragmentation of the Si phase. T6 heat treatment (T6B and T6R) formed a discrete globular Si morphology with less stress concentration, which delayed the void nucleation and growth in the Al matrix. The analysis empirically confirmed the higher ductility of the T6 microstructure than that of the AB and T5, highlighting the positive effects on the mechanical performance of the more homogeneous distribution of finer Si particles in T6R.

Technological Evaluation of Algae-Based Fillers for Polymer 3D Printing

One approach to reducing the environmental footprint of conventional polymers is to compound them with bio-based fillers. Plant-based materials have already been successfully used as polymer fillers. In this context, algae-based fillers received minor attention. Due to their unique growth efficiency and ability to capture large amounts of CO2, the use of algae-based fillers could have economic and ecologic advantages. In this work, a possible use of algae as a sustainable filler for filament materials was technologically evaluated. In practical investigations, conventional polyethylene-terephthalate-glycol (PETG) was mixed with the microalgae spirulina platensis and chlorella vulgaris and extruded to 3D printing filaments. Based on printed test specimens and material samples, the printability, mechanical, and thermal properties of the composite were determined. Filaments with a homogeneous distribution of algae particles and stable diameters up to a filler content of 30 wt.% could be produced. All filaments had good printability and adequate moisture sensitivity for higher algae contents. For 30 wt.% the tensile strength of the produced filaments decreases from 54 MPa to 24 MPa, the flexural strength decreases from 87 MPa to 69 MPa, and the material operating temperature decreases slightly from 70 °C to 66 °C. The addition of smaller amounts of algae results in minor changes regarding the overall performance. The properties of the material were comparable to those of other natural fillers such as wood, bamboo or cork. The main objective of adding bio-based materials to polymeric matrices can be achieved. Our results suggest that algae-based filaments can be produced as a more sustainable and low-cost material.

Clean Universal Solid-State Recovery Method of Waste Lithium-Ion Battery Ternary Positive Materials and Their Electrochemical Properties

The regeneration and utilization of metallic elements in waste lithium-ion batteries (LIBs) have caused growing notice from researchers and battery manufacturers because of the increasing amount of waste LIBs and limited lithium resources. In this work, we propose a novel valuable metal leaching system in waste positive materials of LIBs via a recyclable clean solid-state conversion method, which was simple and easy to realize a high utilization rate of waste resources. In this leaching system, approximately neutral ammonium sulfate solid was used as the bifunctional leaching agent based on reduction and acidification in the leaching procedure of ternary positive materials (NCMs). The roasting process of (NH4)2SO4 and NCMs was followed by the main metallic elements in NCMs being transformed into soluble sulfates, which could be completely leached in the water leaching procedure. The roasting–leaching process parameters were systematically investigated on the molar ratio, roasting temperature, and time. Under optimal conditions, all the leaching rates of Ni, Co, Mn, and Li achieved 99%. After generating sulfate solution by water leaching, the spherical ternary material precursor was co-precipitated with a (NH4)2CO3 precipitant, and the formed (NH4)2SO4 was recycled for the next batch, thus achieving a green and low cost recyclable route. The re-synthesized LiNi1/3Co1/3Mn1/3O2 (NCM111) with homogeneous size particle distribution and good layered hexagonal structure of α-NaFeO2 was obtained as a cathode material after high-temperature calcination with uniform particle size distribution and intact layered structure with a hexagonal crystal system of α-NaFeO2, which well meets the commercial requirements for LIBs in terms of electrochemical properties.

A comparative study on mechanical and ballistic performance of functionally graded Al6061 composites reinforced with B4C, SiC, and Al2O3

In the present study, functionally graded Al6061 composites reinforced with boron carbide (B4C), silicon carbide (SiC), and alumina (Al2O3) were prepared using the stir and centrifugal casting techniques. Arc-shaped functionally graded metal (FGM) specimens were treated with a hot-rolling process to enhance their mechanical properties and obtain laminated plates. Then, the impacts of ceramic reinforcements on the density, microhardness, tensile strength, and ballistic resistance of FGMs were studied. Moreover, the microstructural properties of the specimens were analyzed to elucidate the particle gradient from the inner to the outer surface. As a result, the microstructure observations revealed that the ceramic particles are dispersed from the inner to the outer periphery of the FGMs with centrifugal acceleration. A more homogeneous particle distribution was obtained in B4C-reinforced FGM compared to those of SiC and Al2O3. The hot-rolled FGM specimen reinforced with B4C offered the lowest density. The microhardness was improved by 32% and 30.4% in the inner to outer regions of the SiC- and Al2O3-reinforced FGMs, respectively, while it was improved by 22.6% in B4C-reinforced FGM. On the other hand, the tensile strength and elongation of the B4C-reinforced FGM specimen were better than those of the SiC- and Al2O3-reinforced FGMs. In addition, the highest ballistic protection was achieved with B4C-reinforced laminated FGM at an impact speed of 664.25 m/s with a penetration depth of 14 mm, while the impact speeds of SiC- and Al2O3-reinforced FGMs were 500.88 and 435.23 m/s, respectively.

Genetic effects of Mg-Zr master alloy in extruded thick sheets of ZK60 magnesium alloy

The genetic impact of Mg-Zr intermediate alloys is demonstrated in this article using ZK60 extrusion plates. The results demonstrate that the fine homogeneous distribution of submicron and nanoscale Zr particles is a critical contributor to the quality of the ZK60 alloy. It demonstrates that intermediate alloys have a genetic impact in the preparation of magnesium alloys.

Electrospun Polyvinyl Butyral Nanofibers Loaded with Bismuth Oxide Nanoparticles for X-ray Shielding

The combination of electrospun nanofibers and nanoparticles is opening up potential in the field of nanocomposite materials. This paper presents a composite electrospun nanofibrous material for X-ray shielding purposes consisting of a polyvinyl butyral polymer matrix and bismuth oxide nanoparticles. The organic–inorganic composite nanofibers considered in this paper, produced via the ex situ approach, attained a high content of nanoparticles of up to 95 wt %. The high content of nanoparticles inside the composite nanofibers was acquired via the application of the highly productive needleless electrospinning method. The resulting material is flexible and has a high drape and good air and steam permeability. The content of particles in the nanofibers was proved by the thermogravimetric analysis, and the homogeneous distribution of particles inside the nanofibers and within a whole nanofibrous layer was demonstrated via energy dispersive spectroscopy-scanning electron microscopy. In addition, samples of the composite electrospun nanofibers were tested for cytotoxicity, which revealed that the nanofibers were cytocompatible in all concentrations. The radiation attenuation properties of the samples were investigated via X-ray and γ-ray spectral measurements at a narrow beam geometry. The principal experimentally determined quantity for the tested samples was X- and γ-ray attenuation for the considerable energies of the spectra. The mass attenuation coefficients were calculated for the final composite electrospun material, which was supplemented by a composite nanofibrous material covering layer. With respect to photon energies higher than 40 keV, the attenuation coefficients were observed to be comparable with a commercially produced anti-radiation vest, which had a similar mass density as both the final composite electrospun material and the covering layer. Monte Carlo (MC) simulations in the FLUKA code were conducted to determine the photon attenuation for the respective energies in the tested samples. The results were compared to those determined experimentally, and the MC model was verified.

Elaboration of X-ray shielding of highly barite-loaded polyester concrete: structure, mechanical properties, and MCNP simulation

Various research has been done in manufacturing and designing different types of radiation shielding. In this study, lead-free polymer composite panels with new special formulations have been prepared and characterized to prevent radiation leakage in medical facilities at the diagnostic energy range (60 – 120 keV). Polyester resin is used as a binder along with large amounts of mineral barium sulfate (barite) aggregate (more than 70 % by weight). SEM micrographs showed a homogeneous distribution of barite particles. Then the effects of adding barite on the physical, mechanical, and thermal properties of composite panels were investigated. The results showed that increasing the percentage of barite powder in the formulation, with the high wetting capability of polyester resin, improved physical and mechanical properties. The composite panel containing 80 wt% of barite had the highest tensile and flexure strength. Also the thermal stability of the composite panel containing 90 wt% of barite was 40 °C to 50 °C more than other samples. The samples' mass attenuation coefficient (μm) was calculated experimentally and theoretically using MCNP-5 simulation software and the XCOM program. Experimental and calculated results have been compared and were found to be in reasonable agreement. In general, with increasing barite content, the composite shielding panel became denser and μ increased while HVL and TVL values decreased. In addition, the studied shields were superior to lead by virtue of their non-toxic nature and will be a radiation shielding solution in making wall panels.

Effect of hybrid reinforcement and number of passes on microstructure, mechanical and corrosion behavior of WE43 Mg alloy based metal matrix composite

In this work, a hybrid metal matrix composite with WE43 magnesium alloy as matrix and a hybrid mixture of NiTi, iron, and tin as reinforcement was fabricated using friction stir processing (FSP). The effect of the number of FSP passes on the grain morphology, distribution of reinforced particles, and mechanical properties were evaluated. Scanning electron microscope with energy dispersive spectroscopy was used to study the distribution of reinforced particles, a more uniform distribution was found in the double pass friction stir processed (DP-FSPed) specimen. The grain size was marginally smaller in the DP-FSPed sample compared to the single pass friction stir processed (SP-FSPed) sample. The processed samples showed an increment in hardness values, however, the distribution of hardness values was found uniform in the case of the DP-FSPed specimen, due to better mixing and homogenous distribution of reinforcement particles. The ductility of the DP-FSPed specimen increased by 126 % as compared to the SP-FSPed specimen. The corrosion rate was evaluated using the potentiodynamic polarization test and was found to be higher in the case of the DP-FSPed specimen.

Force and stiffness behavior of natural rubber based magnetorheological elastomer bushing

This research introduces a magnetorheological elastomer (MRE) bushing that has the potential to be applied to vibration control for automotive applications. An annular shape of MRE bushing is designed and fabricated by natural rubber (NR) based MRE with homogenous distribution of carbonyl iron particles (CIPs). The component consists of five parts, which are the inner and outer pipes, MRE, coil bobbin that wound by an electromagnetic coil, top and bottom ring plates, and housing. Based on a conceptual design, the electromagnetic circuit is simulated using Finite Element Method Magnetics (FEMM) software for analyzing the distribution of magnetic flux. The fabricated MRE bushing is undergone a compression test and load adhesion test for the performance evaluation. The compression test is conducted by using the Universal Testing Machine (UTM) under various applied currents to obtain the force-displacement and stiffness behavior of the device. This study demonstrated that higher forces and stiffness are achieved compared to other MRE bushings. From here, at 5.5 mm of displacement, the ranges of forces are from 7.1 kN (off-state) to 8.5 kN (on-state at 2.5 A). Furthermore, the stiffness is increased by 19% from off-state to 2.5 A. Overall, the fabricated MRE bushing shows a significant response with the presence of the magnetic field from the simulation studies and experimental results. Thus, it has the potential for vibration control due to the ability to control rigidity.

Analyzing the influence of the investment casting process parameters on microstructure and mechanical properties of open-pore Al–7Si foams

Aluminum alloy foams with high specific compressive strength and good energy absorption capacity are widely used as structural materials and shock absorbers. The investment casting process offers an interesting opportunity for the production of open-pore aluminum foams. However, foam casting differs from casting of solid parts, and there is a lack of practical knowledge about the microstructure tuning of the ultra-thin cast struts. Our study focuses on the influences of the casting conditions such as mold temperature on the microstructure and consequently on the mechanical properties of aluminum-silicon alloy foams. We investigated microstructural features using various metallography techniques and defined mechanical properties under uniaxial compression test. Here, we observed improvements in the strut microstructure together with decrease of the mold filling by reduction of the mold temperature. Microstructure improvements involve transformation of a single dendritic aluminum grain in each strut to globular grains along with a more homogeneous distribution of the silicon particles across the strut cross-section. These changes bring higher ductility and energy absorption efficiency to the foams, which are evident from the smoother plateau of the stress-strain curves. Decline of the mold filling, on the other hand, has negative effect on the overall mechanical properties.