Powder Technology Research Articles

A facile polymeric gel route synthesis of high-voltage LiNi0.5Mn1.5O4 cathode material for Lithium-ion batteries

High-voltage LiNi0.5Mn1.5O4 cathode material has gradually been one of the research hotspots. In this study, LiNi0.5Mn1.5O4 was prepared via a facile polymeric gel route. Compared with conventional sol-gel method, polymer network gel route can greatly improve the synthesis efficiency. The microstructure of as-synthesized LiNi0.5Mn1.5O4 was octahedron with uniform distribution. It proved an excellent electrochemical performance. The discharge capacities of as-synthesized LiNi0.5Mn1.5O4 were 132.2, 116.2, 102.5 and 82.3 mAh·g−1 at rates of 0.2, 2.0, 5.0 and 10 C, respectively. Over 60 cycles, the rate was restored to 0.2 C again, the discharge capacity (129.2 mAh·g−1) retention rate was 97.7% of initial capacity. The study we have performed showed that polymeric gel route was a facile powder technology to prepare high-performance LiNi0.5Mn1.5O4 cathode material.

Special Invited Reviews “Art and Powder Technology”

Special Invited Reviews “Art and Powder Technology”

Studying Wear Behavior of Ni-Ti- Ag Shape Memory Alloy Synthesized by P/T

Because of the unique properties, Ni-Ti based shape memory alloys (SMAs) are increasingly attractive for a wide variety of engineering applications such as actuators, biomedical, or robot coupling. In this work, a third alloying element, namely nanoparticles of Ag (which is insoluble in Ni-Ti matrix), is added by powder technology to the Ni-Ti alloy to produce a Ni-Ti-Ag alloy. The Nanoparticles of the Ag element are added at 3, 5, 7, and 10 wt. % to produce four alloy specimens with different mixtures. The mixing process was done by a horizontal mixer for 120 min with a speed of 350 rpm, and then the mixture was compacted by using a compacting pressure of 600 MPa. Afterward, the compacted specimens were sintered at 600/min for 6 hrs. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to evaluate the microstructure and phases of the products. DSC examination was used to characterize the phase transformation temperatures in heating and cooling. Wear behavior was defined by using the pin-on-disc technique, and the hardness of the samples was calculated using Vickers's hardness apparatus. The results of this work showed that the nano-Ag added at 7 and 10 wt. % were distributed homogeneously in the Ni-Ti matrix, and that Ag slightly decreased hardness and increased the wear rate. The value of shape memory effect (SME) for the produced alloy was about 89.9% and the phase transformation in heating was at a temperature of about 186.48 and in cooling of about 140.3 for the specimen that contains 10 wt.% Ag nanoparticles.

Experimental investigation on deposition reduction of different types of dust on solar PV cells by self-cleaning coatings

This paper aims to examine deposition reduction performance of different types of dust on solar PV cells by the self-cleaning coatings. Four types of dust were obtained from the Powder Technology Inc. USA (Dust A), the Henan province in the central China (Dust B), the Guangzhou city in the Southern China (Dust C) and the sand in the construction site (Dust D), respectively. The micro and macro patterns of particles, the particle deposition density, the transmittance and the output power reduction of PV system after dust deposition were investigated carefully. It was found that the particle deposition density on the solar cell covering glass is obviously decreased by the coating. The deposition density of the sand particles is 36.77% of that on the uncoated glass case, which is the minimum among the four types of dust because of the high Young’s modulus and low surface energy of the sand. The self-cleaning coating has the best power efficiency improvement performance for the dust C (about 24.35%), followed by the dust B (about 19.83%) and dust D (about 18.21%). The dust A has the minimum efficiency improvement (about 12.47%) by the super-hydrophobic coating.

Biogenic nano silver: Synthesis, characterization, antibacterial, antibiofilms, and enzymatic activity

Powder technology covers many fields from medicine to material science. Especially easy synthesis of nano- and micro-sized particles and low-cost synthesis with non-toxic chemicals are essential. The ability to design nanoparticles according to the application area and desired features is an advantage for many applications. Nanoparticles biosynthesis is under research due to broad biomedical practise. To synthesize of silver nanoparticle from the plant extract, Corylus avellana (Hazelnut) leaves were utilized for bioreduction of silver nitrate. The plant extract is thoroughly mixed with silver nitrate solution, studied the synthesis of nanoparticles using UV–Vis spectroscopy. The nanoparticles were characterized by SEM and XRD-Pattern. XRD analysis proved that the size range of the nanoparticles was 32 nm. Scanning microscope images also demonstrate nanoparticles having spherical shape and a mean size between 9 nm and 50 nm. The antibacterial effect of AgNPs obtained from hazelnut leaves demonstrated antibacterial effect against all tested bacteria strains. The results demonstrated that the plant extract acts as a good bioreductant for the production of silver nanoparticles. This compound was good inhibitor of the α-glycosidase, human carbonic anhydrase I and II isoforms, and cholinesterase enzymes. The results were obtained with Ki values of 12.84 ± 0.41 µM for α-glycosidase, 27.94 ± 3.77 µM for hCA I, 36.12 ± 6.03 µM for hCA II, 47.05 ± 6.83 µM for BChE, and 53.94 ± 7.55 µM for AChE, respectively.

Study on Present Situation of Active Stimulation of Recycled Fine Powder

The text describes the current research status of activation technology of recycled fine powder. The influences of all excitation methods on recycled fine powder are introduced, Based on the analysis of the advantages and disadvantages of the existing excitation methods, the paper puts forward suggestions for energy-saving improvement of mechanical grinding, searching for new chemical activators, controlling temperature and humidity and so on, so as to further promote the recycling of recycled fine powder in China.

The Laser Surface Treatment Effective on Structural Properties for Invar Alloy (Fe-Ni) Type Prepared by Powder Technology

This research aimed to prepare (Fe-Ni) alloy by powder technology method for its technological and commercial importance. Iron and Nickel powders were tacking then their powders mixed and blended together with percent (63% Fe-37% Ni), then the powders compacted isostatic cold pressure at (6 ton). Laser surface treatment was done for the samples with different energies (0, 200, 260, 300) mJ and pulse time (10 sec) At a distance (100 cm). The X-ray diffractions test indicated that all samples have Face Center Cubic (F.C.C), and the samples at 300 mJ has best properties which include increase of phases intensity and decrease of grain size according to Debye-Scherrer equation. The Atomic Force Microscope (AFM) also shows better properties with increase laser energy. Where increased soft-ness of surface, homogeneity surface and decrease in grain size with increase laser energy. The laser analysis resulted that melting all surface molecules which led to improvement in the structural properties.

Effect of sintering temperature on magnetic hysteresis characteristics of powder alloy Fe-30Cr-8Co (wt.%)

In this work, we studied the effect of sintering temperature (1100 - 1400 °C) and thermomagnetic treatment (TMT) on the magnetic hysteresis characteristics of the Fe-30Cr-8 Co alloy, obtained by powder technology. It has been shown that at sintering temperatures of 1200 °C and below, it is possible to obtain materials with high magnetic characteristics that ensure their technical application. Properties exceed the characteristics of analogues obtained by casting technology. In the range 1200 - 1250 °C, the largest increase in the density of samples is observed with an increase in sintering temperature with a simultaneous increase in the values of magnetic characteristics. It was revealed that the total duration of heat treatment for 40-80 hours is sufficient for the formation of the necessary structure that determines the magnetic properties of the material. Long-term heat treatment (up to 160 hours) contributes to a higher level of magnetic properties.

PARTEC 2019 – Overcome the Challenges in Particle and Powder Technology

AbstractNo abstract.

Overview Contents: Chem. Eng. Technol. 5/2020

Chemical Engineering & TechnologyVolume 43, Issue 5 p. 785-785 OverviewFree Access Overview Contents: Chem. Eng. Technol. 5/2020 First published: 23 April 2020 https://doi.org/10.1002/ceat.202070503AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume43, Issue5Special Issue: Particle and Powder Technology: PARTEC 2019May 2020Pages 785-785 RelatedInformation

Highlights: Chem. Eng. Technol. 5/2020

Chemical Engineering & TechnologyVolume 43, Issue 5 p. 786-787 Highlights Highlights: Chem. Eng. Technol. 5/2020 First published: 23 April 2020 https://doi.org/10.1002/ceat.202070504AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume43, Issue5Special Issue: Particle and Powder Technology: PARTEC 2019May 2020Pages 786-787 RelatedInformation

Packings of micron-sized spherical particles – Insights from bulk density determination, X-ray microtomography and discrete element simulations

The quantitative description of packing behaviour of particulate systems under consideration of realistic particle size distributions and material properties poses one challenging problem in powder technology, with impacts on a broad range of technological areas. Here we investigate the packing characteristics of micrometer to millimeter-sized, polydisperse spherical particle systems of glass, zirconia and copper by means of experimental measurements of the bulk density, X-ray microtomography (CT) and numerical simulations of the granular packings using a 3d discrete element method (DEM). The applied DEM method takes realistic material properties into account and considers the experimentally obtained particle size distributions as well as attractive inter-particle forces including adhesion (Johnson, Kendall, Roberts (JKR)) and non-bonded van der Waals (vdW) interactions. Good agreement of the packing densities predicted by DEM and observed in the experiments (bulk density determination & CT) is found. Moreover, we show that a simple mathematical expression for the packing fraction as a function of average particle size of the polydisperse powder system describes well our experimental and simulation results for all investigated materials, with only two fitting parameters. From the DEM simulations, the mean (first) coordination number in the respective polydisperse packing is extracted and discussed with respect to the experimentally obtained direct neighborhood detection from X-ray tomography and in context of previous works. The mean coordination number shows a rather broad variance due to the polydispersity of the samples considered. It also shows a remarkable dependency on the definition of particle contact. Therefore, caution is advised when evaluating coordination numbers with this quantity being highly dependent on the instrumental resolution.

Preparation and Deposition of Pr–Fe–B Permanent-Magnet Powder Using Pulsed Laser

We have already prepared a thin permanent magnet with the thickness of sub-millimeter by obtaining magnet powders using a pulsed laser deposition (PLD) method. In the article, the PLD followed by a flash annealing enabled us to deposit isotropic Pr–Fe–B magnet powders with coercivity $(H_{\mathrm {cj}})> 1000$ kA/m on a stainless thin shaft applicable to a miniaturized motor. Observation on the surface of Pr–Fe–B magnets and evaluation on the mechanical behavior were carried out. Since the surface of a Pr–Fe–B magnet was coated by a Pr oxide through an annealing process, their magnetic properties did not degrade after one year. We also confirmed that the Pr–Fe–B magnet has the possibility to be applied to a micro-magnetization process. It was clarified that the powder technology using the PLD is useful to propose a thin magnet applicable to a next-generation small motor.

Additive rheology of complex granular flows

Granular flows are omnipresent in nature and industrial processes, but their rheological properties such as apparent friction and packing fraction are still elusive when inertial, cohesive and viscous interactions occur between particles in addition to frictional and elastic forces. Here we report on extensive particle dynamics simulations of such complex flows for a model granular system composed of perfectly rigid particles. We show that, when the apparent friction and packing fraction are normalized by their cohesion-dependent quasistatic values, they are governed by a single dimensionless number that, by virtue of stress additivity, accounts for all interactions. We also find that this dimensionless parameter, as a generalized inertial number, describes the texture variables such as the bond network connectivity and anisotropy. Encompassing various stress sources, this unified framework considerably simplifies and extends the modeling scope for granular dynamics, with potential applications to powder technology and natural flows.

The effect of pulse frequency on the microstructure and surface mechanical properties of composite coatings on the surface of AISI304

Abstract This study investigated the in-situ formation of TiC–Al2O3 and TiB2–TiC–Al2O3 composite coatings on the surface of austenitic 304 stainless steel by the use of 3TiO2-4Al-3C and 3TiO2-4Al-B4C powder and argon arc cladding technology. The effects of pulse frequency 0–200 Hz on microstructure and mechanical properties of coating are studied. Microstructural study of coatings showed that the high cladding temperature triggered the self-propagating high-temperature synthesis of reinforcement phases TiC, Al2O3, and TiB2 at the surface of 304 stainless steel. The use of pulsed current instead of direct current reduced the hardness of the coating by increasing the dilution. Also, in both groups of coatings, no significant difference was found between the hardness distribution over the coating layer in the specimens coated with pulsed currents at frequencies of 10 and 200 Hz.

Characterization of Ni-Ti-Ag Shape Memory Alloy

In this paper, specimens of Ni-Ti shape memory alloy incorporating different percentages of Ag nanoparticles are constructed and three of its properties are studied which are density, porosity, and electrical conductivity. The specimens are constructed using powder technology. The construction process involved three main steps; mixing, compacting, and sintering. Before conducting the tests necessary to reveal the alloy properties mentioned above which represent the focus of this work, the constructed ternary Ni-Ti-Ag alloy specimens were first tested to check some of its characteristics and prove that the constructed alloy is a shape memory alloy. These tests included the Differential Scanning Calorimeter (DSC) test, the X-Ray Diffraction (XRD) test, the Scanning Electro-Microscopy (SEM) test, and the Shape Memory Effect (SME) test. The results of these tests reflected the homogeneous distribution of the Ag nanoparticles in the Ni-Ti matrix and indicated the formation of the austenite (Ti2Ni) and martensitie (Ti 002) phases, and that the alloy has a very good SME (89.9% for the 10 wt.% percentage of Ag nanoparticles). Next to this step, porosity test and electrical resistance test were carried out. The results and related calculations for these tests showed that increasing the weight percentage of Ag nanoparticles decreases the porosity and increases the density as well as the electrical conductivity.

Numerical Simulation of a Flow Field in a Turbo Air Classifier and Optimization of the Process Parameters

Due to the rapid development of powder technology around the world, powder materials are being widely used in various fields, including metallurgy, the chemical industry, and petroleum. The turbo air classifier, as a powder production equipment, is one of the most important mechanical facilities in the industry today. In order to investigate the production efficiency of ultrafine powder and improve the classification performance in a turbo air classifier, two process parameters were optimized by analyzing the influence of the rotor cage speed and air velocity on the flow field. Numerical simulations using the ANSYS-Fluent Software, as well as material classification experiments, were implemented to verify the optimal process parameters. The simulation results provide many optimal process parameters. Several sets of the optimal process parameters were selected, and the product particle size distribution was used as the inspection index to conduct a material grading experiment. The experimental results demonstrate that the process parameters of the turbo air classifier with better classification efficiency for the products of barite and iron-ore powder were an 1800 rpm rotor cage speed and 8 m/s air inlet velocity. This research study provides theoretical guidance and engineering application value for air classifiers.

Material Development Using the Inherent Features of Nano-cellulose and Nano-chitin: Necessity of Simple Processes and Cross-disciplinary Collaboration

Abstract For nano-cellulose materials, which have attracted attention in both academia and industry in recent years, to be used as a truly valuable material class, the author believes that their processing procedures must be both rational and simple. In addition, it is important to focus on areas where the outcomes cannot be achieved without these particular nanomaterials. These points also apply to nanomaterials obtained from the animal structural polysaccharide chitin. On this basis, the author’s group has recently achieved “creation of micro-patterning cell culture substrate by inkjet printing of chitinous nanocrystals” and “utilization of cellulose nanofibers as a module for microfluidic paper-based analytical device (μPAD)”. The direction of these projects also reflects some of the activities of the applied life science department that the author worked for until recently. Cellulosic materials, including traditional forms for industrial use, often exist as a powder state at some point in the production process. The author hopes that research on nano-cellulose and nano-chitin will be enhanced through collaboration with powder technology researchers.

Application of spray freeze drying to theophylline-oxalic acid cocrystal engineering for inhaled dry powder technology

Spray freeze drying (SFD) produces suitable particles for the pharmaceutical formulation of dry powders used in dry powder inhalers (DPIs). However, SFD particles have large specific surface area and are partially made up of amorphous solids; this state is hygroscopic and would lead to changes in physicochemical properties by humidity when the particles are stored over the long-term or under high humidity conditions such as in the lungs. This study focused on the application of SFD with a cocrystal technique which can add humidity resistance to the active pharmaceutical ingredients (APIs), and the investigation of the physicochemical properties under high humidity conditions. Cocrystal samples containing theophylline anhydrate (THA) and oxalic acid (OXA) in a molar ratio of 2:1 were prepared by SFD. The crystalline structure, thermal behavior, solid-state, hygroscopicity, stability, and aerodynamic properties were evaluated. Simultaneous in situ measurement by near-infrared and Raman (NIR-Raman) spectroscopy was performed to analyze the humidification process. The SFD sample had a porous particle and an optimal aerodynamic particle size (3.03 µm) although the geometric particle diameter was 7.20 µm. In addition, the sample formed the THAOXA cocrystal with partial coamorphous. The hydration capacity and pseudopolymorphic transformation rate of the SFD sample were much lower than those of THA under conditions of 96.4% relative humidity and 40.0°C temperature because of the cocrystal formation. The reasons were discussed based on the crystalline structure and energy. The SFD technology for cocrystallization would enable the pharmaceutical preparation of DPI products under environmentally friendly conditions.

Production of Foam Glass Materials from Silicate Raw Materials by Hydrate Mechanism

The ways of external protection of oil pipelines, their advantages and disadvantages were described. A method for protecting pipes using foam glass products, based on local raw materials, was proposed. The powder technology of the batch preparation and the hydration mechanism of foaming through the interaction of alkali and silica were chosen for this study, based on the existing methods of foaming of silicate raw materials. Compositions of the batch were developed, their foaming was carried out in the temperature range, corresponding to the pyro-plastic state, the effectiveness of the additional introduction of foaming substances was analyzed. The macro-and microstructure of the specimen, as well as their phase composition, were studied. The optimal composition and optimum foaming temperature for the production of foam glass materials were selected.