Study of mechanical spheroidization of powders obtained from waste metal shavings

2021 ◽  
pp. 41-46
Author(s):  
A. D. Samukov ◽  
M. V. Cherkasova ◽  
M. P. Kuksov ◽  
S. V. Dmitriev
Keyword(s):  
Energy Consumption ◽  
3D Printing ◽  
Spherical Shape ◽  
Spherical Particles ◽  
High Tech ◽  
Metal Powders ◽  
Powder Preparation ◽  
Russian Science ◽  
Additional Energy ◽  
Powder Particles

This paper covers the search for a new method for generating metal powders for additive manufacturing. Raw materials for 3D printing are subject to certain requirements regarding the spherical shape of the powder particles, which are not easily met. The powder preparation methods used in the powder metallurgy may not be directly used for 3D printing without additional energy consumption for the spheroidization operation. More high-tech principles of melt dispersion shall be used for the spheroidization (atomization) of powder particles. Metal waste grinding in ball or vibrating mills generally yields plate-like particles, also requiring the use of energy-intensive atomization technologies. However, an analysis of related foreign research provided an alternative that is to use two-stage grinding to obtain spherical metal powder particles. Continued research in mechanical spheroidization enables the simultaneous manufacture and grinding of the required spherical particles while maintaining practically the same energy consumption that had been previously required for the grinding process. In order to form a research program and establish the optimal grinding size in terms of energy consumption and the dependence between the ball diameter and the grinding and spheroidization results for metal particles, respective preliminary experiments were carried out. The results of these experiments were then used to formulate the conclusions required to develop a method for establishing the optimal grinding ball charge level and composition. The study was carried out under the grant issued by the Russian Science Foundation (project No. 20-79-10125).

Fabrication of Metal Powders Having Spherical Shape Particles (an Overview)

2007 ◽  
Vol 23 ◽  
pp. 95-98
Author(s):  
Zeno Spârchez
Keyword(s):  
Material Processing ◽  
Thermal Field ◽  
Influence Factors ◽  
Spherical Shape ◽  
Processing Method ◽  
Spherical Particles ◽  
Metal Powders

On the basis of a graphical classification devised by the author, the paper presents a brief analysis of the principal methods and procedures used for elaborating powders having spherical particles. The than discussion is focused on emphasizing and classifying the influence factors related to the material, processing method and equipment, which enables the obtaining of spherical particles. In the case of those methods which lead to both spherical and non-spherical particles, additional operations are needed the separation of the non-spherical particles, possibly followed by their conversion to spherical particles in a thermal field.

scholarly journals Regulation of powder particles shape and size at plasma spraying

2021 ◽  
pp. 7-15
Author(s):  
S. B. Ermakov ◽  
Keyword(s):  
Spherical Shape ◽  
Plasma Generator ◽  
Current Strength ◽  
Additive Technologies ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Gas Velocity ◽  
Technological Parameters ◽  
Powder Particles ◽  
Protective Gas

Additive technologies are among the most rapidly developing areas of modern production. To ensure the progressive movement of additive technologies development in the Russian Federation, it is necessary to provide maximum availability of additive raw materials – spherical metal powders for the domestic enterprises; however, the absence of domestic assemblies to produce such powders hampers the solution of this issue. Peter the Great St. Petersburg Polytechnic University has developed and successfully carried out industrial tests of a plasma atomization system for solid metal feedstocks of various chemical compositions. The paper presents the results of the study of the influence of some technological parameters on the granulometric size, shape, and defect structure of 12H18N9 steel and VG98 alloy powders. The paper includes the results of the research of the influence of such spraying parameters as the current strength and the plasma-forming gas velocity supplied to the plasma generator and the volume of protective gas supplied to the spray torch through the fluidized bed system nozzles located in the midsection of the atomizer spraying chamber. The study showed that by increasing the current strength and the plasma-forming gas velocity, it is possible to reduce the average size of the powder particles; and by changing the volume of the protective gas supply, it is possible to control the particle shape. The analysis of the chemical composition of the obtained powders shows that during the spraying process, there is no loss of alloying elements and the powder composition is the same as the original feedstock compositions. The paper gives the developed modes for the alloy feedstocks spraying, shows the possibility to produce metal powders with the level of the spherical shape factor of 92–96 % and minimal – not exceeding 0.5 % of powder aggregate weight – number of particles with nonmetallic inclusions, external and internal defects.

Interaction of Russian business with science: Points of contact and stumbling blocks

2021 ◽  
pp. 103-138
Author(s):  
Yu. V. Simachev ◽  
M. G. Kuzyk
Keyword(s):  
New Products ◽  
The State ◽  
High Tech ◽  
Institutional Interaction ◽  
Russian Science ◽  
Academic Organizations ◽  
The Past ◽  
Domestic Science ◽  
Research Organizations ◽  
The Impact

The paper assesses the influence of science–business cooperation on the activity of firms, analyzes the factors of interaction of Russian companies with academic organizations and universities in the research sphere, identifies barriers to the development of cooperation between business and science. It has been established that companies whose source of innovation was external R&D were more likely to grow over the past 5 years and to create new products. However, a significant effect of the impact of cooperation with domestic research organizations was found only for the dynamics of exports. It is shown that cooperation with domestic science is more typical for high-tech industries and large Russian businesses. The factor inducing firms to outsource research is a significant level of competition. The high cost of external research services and their insufficient quality hinder the development of scientific and production cooperation. One can point to such a barrier as low interest of research organizations in the volume of orders that firms can offer. This is caused by weak institutional change in the Russian science, preservation of its orientation at the state and major players, which significantly limits the opportunities for institutional interaction of small innovative firms with science. It has been shown that the state quite effectively “pushes” companies to interact with research organizations and universities, but the results of such interaction are often unsatisfactory for firms.

scholarly journals Ultraviolet and violet-blue emission of Zn doped MgO/mg(OH)2 particles prepared by one step spray pyrolysis method

2018 ◽  
Vol 1 (1) ◽  
pp. 57-66
Author(s):  
Fenfen Fenda Florena ◽  
◽  
Dwindra Wilham Maulana ◽  
Ferry Faizal ◽  
Bambang Mukti Wibawa ◽  
...  
Keyword(s):  
Spray Pyrolysis ◽  
Doping Concentration ◽  
Blue Emission ◽  
Spherical Shape ◽  
Spherical Particles ◽  
Spray Pyrolysis Method ◽  
Excitation Spectra ◽  
X Ray ◽  
Pyrolysis Method ◽  
One Step

Spherical particles of Zn doped MgO were prepared by one-step spray pyrolysis method. The crystalline nature and particle size of the samples were characterized by X-ray diffraction analysis (XRD). The morphology of samples was studied by scanning electron microscope (SEM) and the presence of Zn in the sample was confirmed by energy dispersive X-ray analysis (EDX). The optical properties of the samples were investigated using photoluminescence spectroscopy (PL) analysis to obtain excitation and emission spectra of the samples. Results indicated that the doped MgO particles exhibited a cubic structure without hexagonal wurtzite structure as the Zn concentrations were increased. Spherical shape and porous particles are found with increasing of doping concentration. The optical band gap of MgO altered with the addition of doping concentration. A considerable redshift of about ~0.08 – 0.13 eV in the excitation spectra of 2.22 eV emission band was revealed in Zn doped MgO samples. It was highlighted that Zn doped MgO prepared by the spray pyrolysis generated emission at UV-Vis wavelength required for many applications.

scholarly journals Designing and Developing Rechargeable Aluminium-Ion Battery using Graphite Coated Activated Charcoal Corncob as Cathode Material

2018 ◽  
Vol 14 (2) ◽  
pp. 99-104
Author(s):  
F. Fitriah ◽  
A. Doyan ◽  
S. Susilawati ◽  
S. Wahyuni
Keyword(s):  
Activated Charcoal ◽  
Spherical Shape ◽  
Aluminum Foil ◽  
High Energy ◽  
Spherical Particles ◽  
Carbon Particles ◽  
Main Requirement ◽  
Optimal Capacity ◽  
Coating Method ◽  
Varied Composition

One of the renewable energy storage systems that can be used today is the aluminum ion battery. In this study, aluminum foil was used as anode, polyetylene polyprophylene (PE/PP) as separator, electrolyte from AlCl3/[EMIm]Cl and graphite coated corncob, an activated charcoal, as cathode. Coating method of cathode materials was done by mixing both graphite and activated charcoal with varied composition 1:0.5, 1:1, 1:1.5, and 1:3. The coating process began by mixing the graphite and corncob with ethanol as a solvent for six hours, then heating in an oven at 80 °C for three days, gradual drying in a furnace at 350 °C for five hours and sintering at 600 °C for six hours. From this research, SEM results showed that carbon particles were evenly distributed, with spherical particles. The spherical shape was the main requirement of carbon formation in order to produce high energy. Based on the results, battery potential was 2.54 V with average of optimal capacity at a ratio of graphite and corncob activated charcoal 1:1.5 was 83.067 mAh/g. The highest efficiency was also at a ratio of 1:1.5 of 97.20%, because at this ratio, there was an increasing in percentage of element C 91.74%, greater than the percentage of element C on the other three cathode samples.Salah satu sistem penyimpan energi terbarukan yang bisa digunakan saat ini adalah baterai ion aluminium. Pada penelitian ini digunakan aluminium foil sebagai anoda, polyetylene polyprophylene (PE/PP) sebagai separator, elektrolit menggunakan AlCl3/[EMIm]Cl dan grafit terlapisi arang aktif tongkol jagung sebagai bahan katoda. Metode pelapisan bahan katoda dilakukan dengan mencampurkan grafit dan arang aktif dengan variasi komposisi 1:0,5, 1:1,1:1,5 dan 1:3. Proses pelapisan diawali dengan pencampuran grafit dan arang aktif tongkol jagung dengan ethanol sebagai pelarut selama enam jam kemudian pemanasan di oven pada suhu 80oC selama tiga hari, pengeringan bertahap di furnace pada suhu 350oC selama lima jam dan sintering pada suhu 600oC selama enam jam. Dari penelitian ini didapatkan hasil SEM menunjukkan bahwa partikel karbon terdistribusi merata, dengan bentuk partikel bulat (sphare).Sampelberbentuk bulat atau sphere merupakan syarat utama pembentukan karbon supaya dapat menghasilkan energi tinggi. Berdasarkan hasil uji baterai diperoleh potensial sebesar 2,54 Volt dengan rata-rata kapasitas optimal terjadi pada rasio grafit dan arang aktif tongkol jagung 1:1,5 sebesar 83,067 mAh/g. Efisiensi tertinggi juga terjadi pada rasio 1:1,5 sebesar 97,20%. Hal ini karena pada rasio 1:1,5 terjadi peningkatan persentase unsur C yakni 91.74% lebih besar dari persentase unsur C pada tiga sampel katoda yang lainnya.

scholarly journals Preparation Method of Spherical and Monocrystalline Aluminum Powder

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 375 ◽  
Author(s):  
Mateusz Skalon ◽  
Marek Hebda ◽  
Ricardo Buzolin ◽  
Gernot Pottlacher ◽  
Stefan Mitsche ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Aluminum Powder ◽  
Electron Backscatter Diffraction ◽  
High Surface ◽  
Spherical Shape ◽  
Production Method ◽  
Processing Temperature ◽  
Powder Preparation ◽  
New Production ◽  
Aluminum Particles

This paper presents a new production method for a spherical and monocrystalline aluminum powder. Aluminum powder of irregular particle shapes was mixed with silica nanoparticles and heated to a temperature above the melting point of aluminum. Due to its molten state, high surface tension, and poor wettability, the aluminum particles were transformed into liquid and spherical droplets separated by silica nanoparticles. The spherical shape was then retained when the aluminum particles solidified. The influence of the processing temperature on the particle shape, phase composition, and microstructure was investigated. Moreover, calorimetric, X-ray diffraction, grain size, and scanning electron microscopy with electron backscatter diffraction (SEM-EBSD) measurements of the particles’ microstructure are presented. It is proven that, by this means, a spherical and monocrystalline aluminum powder can be efficiently created directly from an air-atomized irregular powder. The observed phenomenon of particles becoming round is of great importance, especially when considering powder preparation for powder-based additive manufacturing processes.

scholarly journals Experimental study of microwave properties of composites filled with Permalloy powder

2018 ◽  
Vol 185 ◽  
pp. 02002
Author(s):  
Stanislav Y. Bobrovskii ◽  
Victor A. Garanov ◽  
Andrei S. Naboko ◽  
Alexei V. Osipov ◽  
Konstantin N. Rozanov
Keyword(s):  
Ferromagnetic Resonance ◽  
Skin Effect ◽  
Magnetic Loss ◽  
Spherical Particles ◽  
Loss Peak ◽  
Low Frequencies ◽  
High Frequencies ◽  
Permittivity And Permeability ◽  
Powder Particles ◽  
Shape Data

Frequency dependencies of permittivity and permeability of composites filled with Permalloy powder with various concentrations and shapes of particles have been measured and discussed. The powder particles of various shapes were obtained by mechanical milling of industrial Permalloy powder in organic media. Paraffin wax was used as a matrix for producing the composites. A shape data of the particles was obtained with an electron microscope. The permittivity and permeability were measured in the frequency range of 0.13 to 10 GHz. The shape of the particles changes from sphere to platelet with increase of milling time. The change leads to a shift of the ferromagnetic resonance (FMR) frequency and magnetic loss peak. It is shown that for larger particles, a decrease of the Q-factor of the ferromagnetic resonance is observed, which is explained by the strong influence of the skin effect. With increase of the concentration of the Permalloy particles in composite, the magnetic loss peak shifts to low frequencies. When the spherical particles are flattened, the resonance frequency shifts to high frequencies, which indicates that the shift to high frequencies due to the decrease of the skin effect and the change in the magnetic structure is stronger than the shift to the low frequencies by changing the shape and reducing the demagnetization.

scholarly journals Fracture Behavior of Bio-Inspired Functionally Graded Soft–Hard Composites Made by Multi-Material 3D Printing: The Case of Colinear Cracks

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2735 ◽  
Author(s):  
Mirzaali ◽  
Nava ◽  
Gunashekar ◽  
Nouri-Goushki ◽  
Doubrovski ◽  
...  
Keyword(s):  
3D Printing ◽  
Transition Zone ◽  
Digital Image ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Functionally Graded ◽  
Image Correlation ◽  
High Tech ◽  
Fracture Properties ◽  
Gradient Function

The functional gradient is a concept often occurring in nature. This concept can be implemented in the design and fabrication of advanced materials with specific functionalities and properties. Functionally graded materials (FGMs) can effectively eliminate the interface problems in extremely hard–soft connections, and, thus, have numerous and diverse applications in high-tech industries, such as those in biomedical and aerospace fields. Here, using voxel-based multi-material additive manufacturing (AM, = 3D printing) techniques, which works on the basis of material jetting, we studied the fracture behavior of functionally graded soft–hard composites with a pre-existing crack colinear with the gradient direction. We designed, additively manufactured, and mechanically tested the two main types of functionally graded composites, namely, composites with step-wise and continuous gradients. In addition, we changed the length of the transition zone between the hard and soft materials such that it covered 5%, 25%, 50%, or 100% of the width (W) of the specimens. The results showed that except for the fracture strain, the fracture properties of the graded specimens decreased as the length of the transition zone increased. Additionally, it was found that specimens with abrupt hard–soft transitions have significantly better fracture properties than those with continuous gradients. Among the composites with gradients, those with step-wise gradients showed a slightly better fracture resistance compared to those with continuous gradients. In contrast, FGMs with continuous gradients showed higher values of elastic stiffness and fracture energy, which makes each gradient function suitable for different loading scenarios. Moreover, regardless of the gradient function used in the design of the specimens, decreasing the length of the transition zone from 100%W to 5%W increased the fracture resistance of FGMs. We discuss the important underlying fracture mechanisms using data collected from digital image correlation (DIC), digital image microscopy, and scanning electron microscopy (SEM), which were used to analyze the fracture surface.

Additional Energy Dissipation of Vehicles on a Gradient Road

2013 ◽  
Vol 361-363 ◽  
pp. 2304-2307
Author(s):  
Rui Ling Yu
Keyword(s):  
Numerical Simulation ◽  
Energy Consumption ◽  
Energy Dissipation ◽  
Energy Loss ◽  
Additional Energy ◽  
Energy Consumption Model ◽  
Consumption Model

The additional energy consumption model of vehicles on a gradient road is introduced in this paper. The numerical simulation of the model shows that the additional energy consumption varies with the different slope. Larger solpe means less additional energy loss on a uphhill road while it is the contrary tendency on the downhill road. The analysis of the simulation result is consistent with the actual.

Modeling of Interaction Layers from Conductive Microparticles with TE Electromagnetic Wave

2013 ◽  
Vol 646 ◽  
pp. 245-248
Author(s):  
Anton Anzulevich ◽  
Leonid But’ko ◽  
Sergey Moiseev ◽  
Il’ya Zotov
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Radiation ◽  
Incident Radiation ◽  
Spherical Particles ◽  
Metal Powders ◽  
Micro Particles ◽  
Wave Heating ◽  
Powder Metals ◽  
Size Of Particles

Dependences of distribution, penetration, reflection and absorption of microwaves in the layers of conductive micro-particles on the frequency of the incident radiation and size of particles are obtained and investigated. Layers of conductive spherical particles as the shell, and without it are accepted in our work as the most common model of powder metals. So, this study allows to describe and classify features of electromagnetic wave heating of various metal powders and to predict the performance, in which it will be effective heating of metal powders by electromagnetic radiation.

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