Mixture Of Nanopowders Research Articles

Influence of the Mechanosynthesis Duration on the Structural, Electronic, and Electrochemical Characteristics of SiO2/TiO2 Nanocomposite

Abstract The study investigated of the duration effect of the high-energy machining in a vibrating mill on the performance of lithium power source cathode material based on SiO2/TiO2 nanopowder. The relationship between the electronic structure, crystalline parameters, morphological features of the nanopowder mixture, and the electrochemical characteristics of the prototype battery with a cathode based on it was established. Combination of scanning electron microscopy, X-ray diffraction, ultra-soft X-ray emission spectroscopy, galvanostatic, and potentiodynamic analysis was used for materials characterization. It was concluded that SiO2/TiO2 nanopowder mixture after mechanosynthesis treatment during 5 minutes reveals most promising electrochemical characteristics in terms of possible application as primary and secondary power sources. This result is caused by the desorption of absorbed moisture, the grinding of the initial agglomerates, and the formation of a high charge state of oxygen due to the creation of a weak π-bond between the nanoparticles surface of both oxides during such a brief treatment. Further increase of processing duration promotes the agglomeration of the nanocomposite and a significant reduction in the electrochemical characteristics of the lithium power source.

Optimizing solar panel performance: a novel algorithm incorporating a duct with helical tape filled with a mixture of water and hybrid nano-powders

Optimizing solar panel performance: a novel algorithm incorporating a duct with helical tape filled with a mixture of water and hybrid nano-powders

From mixed brookite/anatase TiO2 nanopowder to sodium titanates: Insight into morphology, structure, and photocatalytic performance

A method to obtain sodium titanate nanoribbons starting from a mixture of brookite and anatase TiO₂ nanopowder is described. As-prepared TiO2 nanopowder with a major brookite phase was used as a precursor in an alkaline hydrothermal approach, where the temperature was kept at 200 °C. The influence of hydrothermal treatment and consequent annealing temperature (T = 500 °C) on the crystal structure, phase composition, and morphology of samples were investigated by X-ray powder diffraction (XRPD), Raman and FTIR spectroscopy, and electron microscopy techniques (FESEM, HRTEM). All these methods point out that the hydrothermally treated sample, containing the NaTi3O6(OH)(H2O)2, Na2Ti3O7, and Na2Ti9O19, is dominated by layer-structured sodium hydroxititanate dihydrate. The annealing leads to the formation of rare sodium titanates, Na3Ti6O13 and Na2Ti9O19, with tunnel structures where the hexatitanate with increased sodium content prevails. The photocatalytic activity of synthesized nanostructures was tested in the degradation process of Reactive Orange (RO16) azo-dye upon UV excitation. It appears that photocatalytic activity is lower after hydrothermal treatment, but subsequent annealing makes sodium titanate nanoribbons faster in the degradation of RO16. The research implies that these sodium titanate nanostructures are promising photocatalytic materials and should be considered in the future for removing different pollutants from water.

Mathematical modeling of unsteady process of cold storage within a container filled with nanomaterial incorporating Galerkin method

This research focuses on simulating the freezing involving a mixture of H2O and alumina nano-powders. It sheds light on the complex relationship between the characteristics of nano-powders and freezing dynamics, offering valuable insights applicable to various fields, including cryopreservation and thermal energy storage. By utilizing the Galerkin approach and incorporating an adaptive grid, the research introduces an elliptic container with a cold surface and strategically placed rectangular fins. The investigation examines how the characteristics of nano-powders, particularly their size (dp) and concentration (ϕ), influence different scenarios. Notably, changes in powder size have a significant effect on freezing time, initially decreasing by approximately 20.22 % before increasing by 19.1 %. Moreover, the sensitivity of powder size decreases with lower powder concentrations. For example, at ϕ = 0.02, an augment in dp primarily reduces the time by about 11.72 %, followed by an increase of 10.98 %. The most substantial improvement occurs when ϕ is optimized, resulting in a remarkable 41.27 % reduction in freezing time.

Polycarbosilane-grafted silicon carbide nanoparticles as a high-yielding non-oxide ceramic precursor

Silicon carbide (SiC) is a multifunctional material with a myriad of potential applications, from high-power electronics to friction applications to power generation. Grafting preceramic polymers (PCPs) from SiC nanoparticles would create a platform for forming SiC via a polymer derived route that would have advantages over simple particle-PCP slurries and may enable new additive manufacturing inks or spreadable coatings with controlled rheology. Grafting PCPs directly on SiC powders would greatly improve dispersion of these particles and yield a single component system. Moreover, PCP-grafted-SiC would be a new addition to the burgeoning field of polymer grafted nanoparticles (PGNPs). Herein, SiC nanoparticles were surface-modified in a grafting-from polymerization reaction to create polycarbosilane (PCS) grafted SiC. Surface grafting was verified through a number of analytical techniques and the synthesized materials were pyrolyzed at 1600 °C. The PCS-grafted SiC retained 66 % of its pre-pyrolysis mass, representing a significant improvement over PCS-grafted silica nanoparticles from our previous work (20 wt% yield). In addition to an increased ceramic yield, the grafting of PCS to SiC also resulted in the formation of a SiC phase not present in the simple physical mixture of SiC nanopowder in PCS. This study demonstrated that PCP-grafted nanoparticles (GNPs) can be synthesized utilizing non-oxide nanoparticle cores with desirable rheology, opening possibilities for future ceramic inks and coatings.

Epoxy Resin-Assisted Cu Catalytic Printing for Flexible Cu Conductors on Smooth and Rough Substrates.

Flexible copper conductors have been extensively utilized in flexible and wearable electronics. They can be fabricated by using a variety of patterning techniques such as vacuum deposition, photolithography, and various printing techniques. However, vacuum deposition and photolithography are costly and result in material wastage. Moreover, traditional printing inks require posttreatment, which can damage flexible substrates, or grafting polymers, which involve complex processes to adhere to flexible substrates. Therefore, this study proposes a facile method of fabricating flexible metal patterns with high electrical conductivities and remarkable bonding forces on a diverse range of flexible substrates. Catalytic ink was prepared by using a mixture of epoxy resin, copper nanopowder, and nanosilica. The ink was applied to a variety of flexible substrates, including a poly(ethylene terephthalate) (PET) film, polyimide film, and filter paper, using screen printing to establish a bridge layer for subsequent electroless deposition (ELD). The catalytic efficiency was significantly improved by treating the cured ink patterns with air plasma. The fabricated flexible metals exhibited excellent adhesion and desirable electrical conductivity. The sheet resistance of the copper layer on the PET substrate decreased to 9.2 mΩ/□ after 150 min of ELD. The resistance of the flexible metal on the PET substrate increased by only 3.125% after 5000 bending cycles. The flexible metals prepared in this study demonstrated good foldability, and the samples with filter paper and PET substrates failed after 40 and 70 folds, respectively. A pressure sensor with a bottom electrode consisting of a copper interdigital electrode on a PET substrate displayed favorable sensing performance.

Synthesis and Characterization of PMMA/HAP/MgO Nanocomposite as an Antibacterial Activity for Dental Applications

The current work focuses on the preparation of magnesium oxide nanoparticles using aqueous magnesium chloride salts and sodium hydroxide powder by a simple chemical precipitation method and at an annealing temperature of 700 °C for 6 hours. The structural and morphological properties of the magnesium oxide nanoparticles were investigated using X-ray diffraction (XRD). Polycrystalline cube and using the Scherer equation showed a crystalline size of 17.23 nm. EDS analyzes showed high purity. Scanning electron microscopy (FESEM) showed the spherical shape of the magnesium oxide particles. With particle size within the range (65-185) nm. While a (PMMA)-HAP nanocomposite was synthesized. -MgO) for use in dental applications such as fillings and dentures. A nanocomposite (PMMA-HAP-MgO) was manufactured by manual molding method by strengthening the poly methyl methacrylate polymer with certain weight ratios(1%,5%,and 10%) from a mixture of nano powder where the added ratios were (99%PMMA-1%HAP,95%PMMA-7.4%HAP-0.3%MgO,and 90%PMMA-9.4%HAP-0.3%MgO). The topographical properties (surface roughness) of the nanocomposite samples were studied by testing them with an atomic force microscope. The results showed an increase in the value of pure PMMA, where the use of nanoparticle filler by 5% (4.7% HAP -0.3% MgO) affected both the roughness and the root mean square ratio of the distribution of nanoparticles on the surface of the composite and the shape of the particles led to a roughness more than the polymer pure. The antibacterial activity of the polymeric overlay was examined on the bacteria that cause dental caries for (Streptococcus mutans), where the zone of inhibition were (1 mm, 2 mm, 5 mm) for the nanocomposite and no activity for pure PMMA.

Energy storage unit with complex geometry including mixture of water and nanomaterial analyzing solidification

The unsteady conduction mechanism during converting liquid water to ice has been analyzed in this research. The container with the shape of a rectangular closed cavity has been equipped with fins. Also, a mixture of CuO nano-powders and water has been applied to enhance the conduction mechanism that is the main force of the freezing. Effects of size and fraction of additives were investigated in the result section. Style of the mesh has altered with the increase of time. With increase of ϕ, the conduction mode has been improved about 39.04 % and freezing time reduces from 11.58 s to 7.06 s. The best size of CuO nano-powders is 40 nm and changing size from 30 to this optimized size makes freezing time decrease about 18.02 %.

Numerical development for freezing of phase change material loading nanoparticles for improving water treatment

The container with a wavy insulated wall and one branch shaped fin has been applied in this study. The process of freezing was simulated based on implicit way via Galerkin approach. The testing material is a mixture of H2O and nano-powders of alumina. The fraction of additives is less than the critical value for assumption of single phase mixture. Verification test has demonstrated the correctness of the modeling procedure. The utilizing denser mesh close the region of ice front makes the accuracy of modeling to increase. Owing to the negligible speed of liquid water, the associated terms in governing equations have been discarded. Regarding the utilized diameter of alumina, dp = 40 nm is the best option which leads to a lower period of freezing. With dispersing alumina with optimum size, the solidification time declines about 41.22 %.

Thermodynamic analysis for peristaltic flow of Carreau-Yasuda magneto nanofluid through a porous medium

Thermodynamic analysis for mixed convective peristaltic transportation of Carreau–Yasuda (CY) magneto nanofluid is presented. The assumed nanofluid is a mixture of graphene nano-powder and ethylene glycol. The Carreau–Yasuda model is considered to represent the non-Newtonian features of nanofluids. A mathematical model is developed under the effects of a porous medium, variable thermal conductivity, Brownian motion, viscous dissipation, magnetic field, thermophoresis, and Ohmic heating assumptions. Mass and heat transfer aspects are also considered. The flow and heat/mass transfer equations were made using Buongiorno’s model of nanofluids. No-slip and zero mass flux boundary conditions are entertained for velocity, thermal, and concentration profiles. A numerical solution via built-in technique is obtained for a coupled system of equations. Graphical outcomes predict that due to Ohmic heating characteristics temperature profile increases. The heat transfer rate at the wall decreases for higher thermal conductivity parameter. The irreversible rate can be controlled by maintaining Darcy’s number. The concentration of nanomaterials increases when the thermophoresis parameter is improved. Fluid velocity is slowed down by enhancing the Hartman number and it improves by enhancing the thermal Grashof number.

Многофункциональная система визуализации на основе лазера и усилителя яркости на парах бромида меди

A multifunctional system meant to image the surface of energetic materials during combustion based on copper bromide vapor gain media is proposed. The system allows quickly implement various methods of active visualization and is based on a high-speed video camera, an illuminating laser, and a copper bromide vapor brightness amplifier. Depending on imaging needs, the main components of the system can be configured as a laser-illuminating system, a single-channel laser monitor, or a laser monitor with synchronous laser illumination. A high-voltage pulsed power supply allows connecting both one laser tube and two at the same time, while switching operating modes can be carried out on- the-fly. The source generates one or two synchronized sequences of high-voltage pulses for pumping gasdischarge tubes with a voltage of up to 6 kV and a frequency of 20 kHz. Due to the use of gas discharge tubes with independent control of temperature parameters, the operating modes with a pump power of 500–700 W for each channel can be realized. To generate pump pulses for laser media, a two-channel thyratron circuit for the direct discharge of storage capacitors were used, charged by a common stabilized voltage source provided by a step-down pulse stabilizer and a pulse shaper for charging storage capacitors based on a bridge inverter. A transistor modulator with adjustable delay lines carries out synchronization of the laser illumination and the brightness amplifier in the mode with synchronous laser illumination with an accuracy of ±1 ns.The experimental data of the system operation in various modes are presented. The imaging results for the surface of mixtures of metal nanopowders during combustion, obtained with various configurations of the laser system, are presented.

Synthesis of cBN-hBN-SiCw Nanocomposite with Superior Hardness, Strength, and Toughness.

Nanocomposites with one-dimensional (1D) and two-dimensional (2D) phases can demonstrate superior hardness, fracture toughness, and flexural strength. Cubic boron nitride-hexagonal boron nitride-silicon carbide whiskers (cBN-hBN-SiCw) nanocomposites with the simultaneous containing 1D SiCw and 2D hBN phases were successfully fabricated via the high-pressure sintering of a mixture of SiCw and cBN nanopowders. The hBN was generated in situ via the limited phase transition from cBN to hBN. Nanocomposites with 25 wt.% SiCw exhibited optimal comprehensive mechanical properties with Vickers hardness of 36.5 GPa, fracture toughness of 6.2 MPa·m1/2, and flexural strength of 687.4 MPa. Higher SiCw contents did not significantly affect the flexural strength but clearly decreased the hardness and toughness. The main toughening mechanism is believed to be a combination of hBN inter-layer sliding, SiCw pull-out, crack deflection, and crack bridging.

STUDY OF THE MICROSTRUCTURE AND PHASE FORMATION IN CERAMICS BASED ON Zn, Sn AND Ti OXIDES

Ceramics was obtained from the mixture of ZnO, SnO2 and TiO2 nanopowders by the method of solid-state sintering at 1123 K and 1443 K. The indicated nanopowders are used as components in arc dampers and for dispersion-strengthening in silver-based electrical contact materials. The phase formation and microstructure of the obtained material were studied by the methods of scanning electron microscopy, energy dispersive microanalysis and X-ray phase analysis. It is shown that at a sintering temperature of 1123 K a dispersed structure was formed, with the size of the Zn2TiO4 and ZnO phases being 0.5 – 1.0 µm. The solid phase reactions in the system ZnO/TiO2 at Тsint = 1123 K resulted in the formation of two-phase ceramics ZnO/Zn2TiO4 with the residual amounts of the phases of zinc and tin oxides. At Тsint = 1443 K there occurred the grain growth, Zn2SnO4 became the predominant phase and there remained a certain amount of the zinc and tin oxide phases.

Properties of Compacts from Mixtures of Calcium Fluoride Micro- and Nanopowders

In this work, compacts from mechanical mixtures of CaF2 micron powder (MCP) with CaF2 nanopowder (NP) additives were produced, with mass ratios of the mixture components ranging from 10:0.125 to 10:1, respectively, using magnetic pulse (MP) and static pressing (SP) methods. The effects of pressure (Pp) and pressing temperature (Tp), concentration and phase composition of the additive on the density and color of compacts were studied, taking into account the properties of the initial components of the mixtures. The evolution of pulsed cathodoluminescence (PCL) spectra and photoluminescence (PL) of compacts from pure powders and their mixtures depending on Pp, Tp and characteristics of initial CaF2 NP was also studied. A new near-infrared (NIR) band associated with fluoride vacancies was discovered with a maximum at ~765 nm in PCL spectra of compacts produced by MP at a temperature of 425 °C. A blue band at 435 nm associated with impurity oxygen vacancies in the CaF2 lattice was found in PL spectra compacts of pure NP and powder mixtures. The density of compacts of pure NP and MCP reached 89% of the theoretical density, and the density of compacts of mixtures did not exceed 78%. The defective structure and phase composition of the CaF2 NP had a decisive effect on the luminescent properties of compacts from mixtures of micro- and nanopowders.

Modeling investigation for energy storage system including mixture of paraffin and ZnO nano-powders considering porous media

In this work, air conditioning unit with involve of porous media has been presented. The duct has several five-lobed cylinders containing the paraffin (RT27) and for augmenting the conductivity of such material, it was mixed with nano-sized particles of ZnO. To include the related terms of porous media, wiremesh approach was applied and turbulent regime for air zone was considered. Owing to solar irradiation, air becomes warmer up to T = 311.15K outside the duct and with entering within the duct makes paraffin to convert to liquid. So, not only the solar energy can be stored, but also the needed cool air inside the building can be provided. Mixing nanoparticles with paraffin leads to higher level of conduction which decline the required time for full melting about 5.22% when Re = 7000, γ = 0.95. With utilizing porous media, the needed time will be decreased about 37.15% when Re = 7000, φ = 0.035. As power of blower augments, the period of melting decreases around 41.77% when γ = 0.95, φ = 0.035. Among the scrutinized cases, the minimum required time for achieving full melting is 7985s which can be attained if γ = 0.95, φ = 0.035, Re = 7000.

Novel processing route for design and manufacturing of metal toughened nanoceramics: Al–Al2O3 nanocermets

Monolithic alumina is a highly brittle ceramic with a very low fracture toughness, making it an unreliable material for mechanical and structural applications. Ceramic-metal composites (cermets) are the subject of intensive interest to obtain materials which can address the intrinsic brittleness of ceramics without compromising their high strength and light weight. In the present investigation, aluminium-alumina (Al–Al 2 O 3 ) nanocermets were developed. The nanocermets possessed the toughness of Al phase and the strength of reinforced nano Al 2 O 3 particles. The nanocermets green bodies were prepared such that upon sintering each adjacent Al 2 O 3 grain was conformally coated with a continuous Al film. Mechanical milling via a combination of cryo-milling and ball-milling was used to prepare Al–Al 2 O 3 nano-powder mixture. Spark plasma sintering was used to consolidate the green nanocermets. Results show that specimens prepared from 35 h milled powders exhibited superior mechanical properties as compared to other nanocermets, with an improvement in microhardness, elastic modulus, compressive strength, and flexural strength by 88%, 78%, 69% and 40% with respect to sintered pure Al. The indentation toughness of 35 h milled nanocermet showed an increment of 12.5% with respect to sintered pure Al 2 O 3 . Characterization techniques such as XRD, SEM, HR-TEM, X-ray tomography were employed to investigate the phase evolution and structural morphology, while FEM simulations were performed for understanding the crack propagation mechanisms in nanocermets. Figure Description: A novel processing route devised from the combination of cryo-milling and ball-milling of elemental Al and Al 2 O 3 powders, followed by spark plasma sintering (SPS) for the development of toughened and strengthened Al–Al 2 O 3 nanocermets (metal-ceramic nano-systems). An attempt has been made to utilize the favourable physical and mechanical attributes of ductile metal phase and brittle ceramic phase to fabricate nanocermets with enhanced mechanical properties. These nanocermets will find use in structural applications requiring components with high strength to weight ratio, such as automotive parts, ballistic armours and jet propulsion systems. • Al 0.2 -(Al 2 O 3 ) 0.8 nanocermets possessing the toughness from ductile Al and strength from brittle Al 2 O 3 are developed. • A combination of cryo-milling and ball-milling is used for the preparation of nanosized Al-Al 2 O 3 powder mixtures. • An optimized cryo-milling of 10 h transforms micron-sized Al particles into nanometric thin sheets. • Enhanced wettability of Al and Al 2 O 3 at the grain boundary interface is achieved for metal-ceramic nano-systems. • Toughening of brittle Al 2 O 3 by metallic Al phase transforms the inter-granular fracture into trans-granular mode.

An experimental study on the performance of water-based CuO nanofluids in a plate heat exchanger

The fluids added nanoparticle known as nanofluids, are used in various heat transfer systems due to some advantages they provide. The most prominent features are improvement in heat conduction and classical fluid is being replaced with working fluid in micro-channels, heating installations and various other areas where heat transfer is important. In the present study, the hydrodynamic and thermal performance of a plate heat exchanger in a modeled heating system with CuO nanofluid have been analyzed experimentally. The system consists of two basic parts as cooling water circuit and heating main circuit in which CuO nanofluid circulates. The experiments have been conducted at three different flow rate for the nanofluids with volume fractions of 0.27, 0.56, 0.81 and 1.1. The hydrodynamic parameters considered in the study are pumping power and pressure drop, while the thermal parameters are effectiveness of the heat exchanger, heat conduction coefficient and Nu number. The results of the study show that the plate heat exchanger takes the highest value of effectiveness 96% at ϕ = 0.81 in the plate heat exchanger. It has also been determined that the heat convection coefficient increased with the increase in nanopowder mixture ratio in accordance with the data in the literature. In addition, a new correlation for Nusselt number of Nu = 11.3453 ∗ Re0.199194 ∗ Pr0.305504 ∗ ϕ0.00965827 has been proposed for CuO nanofluid including volume fraction (ϕ) as well as Reynolds and Prandtl numbers.

Ultrafast sodium-ion storage in an interconnected Ni/Ni3S2 nanocomposite with long-term cycling performance

Nickel sulfide (Ni3S2) is a potential anode candidate for sodium-ion batteries due to its abundance, stable structure, and low price. However, its rate and cycling performance require improvement for practical applications. This paper reports the facile synthesis of a unique composite consisting of an interconnected nickel/nickel sulfide nanocomposite (Ni/Ni3S2) by heating a mixture of nickel nanopowder and sulfur. The interconnected nanostructured backbone of the nickel nanoparticles facilitates continuous electron pathways in the composite, while the embedded nanosized nickel sulfide domain reduces the diffusion length and improves reaction kinetics. The Ni/Ni3S2 electrode exhibits excellent rate performance in dimethyl ether (DME) electrolyte, with a current density of 80 A g−1 and capacity of 151 mA h g−1; it also exhibits stable, ultralong cycling performance. Synergism between the unique nanostructure of the composite and the low-viscosity DME electrolyte may be responsible for the extraordinary cycling and rate performance. A full cell with a Na3V2(PO4)3 (NVP) electrode delivers a capacity of 111 mA h g−1 at 100 A g−1; moreover, the Ni/Ni3S2–NVP full cell retains 55% of its capacity after 5000 cycles at 20 A g−1. The developed strategy, which uses a conductive metal-nanoparticle/metal-sulfide nanocomposite, is applicable to other systems and is scalable for practical applications.

The effect of a mixture of iron and nickel nanopowders of various concentrations on the growth and yield of corn

This paper shows the effect of various doses of a mixture of nanopowders of metals-microelements of iron and nickel (Fe + Ni) on the growth of corn, yield and its structure. Various doses of a mixture of Fe+Ni nanopowders were studied in the range of 0.5-2.0 g/t for corn ROSS 145 MB (grain hybrid). A mixture of iron and nickel nanopowders is effective in dressing corn before sowing. When using a dose of NP Fe + Ni 1.0 g/t, the height of plants in the phase of 5-6 leaves increased by 7.1%, in the flowering phase the leaf area increased by 18.4% higher than the control. It is shown that a mixture of Fe+Ni nanopowders 1.0 g/t increased the yield of green mass with cobs by 12.6%, cobs without a wrapper - by 14.3%, the weight of 10 cobs - by 185 g or 10.9% higher than the control. Under the influence of the optimal dose of nanopowders NP Fe + Ni 1.0 g/t in corn grain, the ash level increased by 0.18%, crude protein - by 1.4%, the amount of fat practically did not change. The content of vitamins has changed significantly, for example, vitamin C in the experiment is almost 2 times higher than the control, vitamin A - by 48%, vitamin E - lower than the control by 20%.

Submicron imprint patterning of compound sheet with ceramic nanopowder

Nanoimprint lithography is a highly productive process and has an advantage in its resolution of printed patterns. In this paper, inorganic materials are imprinted using mixtures of nanopowders and polymer binder as starting materials. In our previous work, line-and-space patterns with the smallest pitch of about 8 μm were shown on sintered ceramic sheets using ceramic powders with the smallest particle size of about 100 nm. In this study, we prepare alumina powders with an average particle size of about 100 nm and five kinds of molds with line-and-space patterns with line widths from 10 μm to 250 nm. The line-and-space patterns were observed on all sintered samples. Although the patterns were not clear on the finer patterns, this result is remarkable. Also, we discuss how the pattern was affected by mold size and particle size.