Method Of Electroerosion Dispersion Research Articles

Structure and properties of powders obtained by electrodispersion of pure Nickel metal waste in distilled water

Purpose. Investigation of the composition, structure and properties of powder materials obtained by electrodispersion of nickel waste of the PNK-0T1 brand in an oxygen-containing medium – distilled water.Methods. To determine the composition, structure and properties of powder materials, samples of powders obtained from waste nickel grade PNK-0T1 were studied. The powder material was obtained by electroerosive dispersion in distilled water. Microanalysis of powder particles was carried out using a scanning electron microscope, an analysis of the size distribution of powder particles was obtained using a particle size analyzer, an X-ray spectral microanalysis of powder particles was carried out using an energy-dispersive X-ray analyzer embedded in a scanning electron microscope, an analysis of the phase composition of powder particles was carried out using X-ray diffraction on the diffractometer.Results. During the study, it was revealed that the shape of the particles obtained from nickel powders is spherical and elliptical, and agglomerates of smaller particles are also noted on the increase. Oxygen and nickel are present in the composition of powder materials. The phases of pure nickel and nickel oxide NiO are marked in the phase composition. From the analysis of the granulometric histogram, it follows that the particle size spread varies in the range of 0.26...18.62 microns, the average volume diameter of the particles was 5.2 microns.Conclusion. The obtained research results can be used to develop a new heavy pseudo-alloy using metal waste from expensive raw materials by the method of electroerosive dispersion, followed by improvement and optimization of the composition and structure of the alloy.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ХИМИЧЕСКОГО СОСТАВА МЕДЬСОДЕРЖАЩИХ МЕТАЛЛООТХОДОВ И ЭЛЕКТРОЭРОЗИОННОГО ПОРОШКА

The results of a study of the chemical composition of copper-containing metal waste and electroerosion powder are presented. Using a portable Niton Goldd spectrometer, it was found that copper-containing metal waste corresponds to the brand of the BrKN1-3 alloy. The data obtained made it possible to identify samples of the studied metal waste to be processed by the method of electroerosive dispersion into spherical powders suitable for additive manufacturing. As a result of comparing the percentage of chemical elements of the investigated metal waste of the BrKN1-3 alloy and the powder obtained by the method of electroerosive dispersion, minor discrepancies were found associated with an increase in the percentage of elements such as Pb, Zn, Fe, Sn in the powder, as well as with a decrease in elements such as Cu and Zr. Renovation of metal waste, including copper-containing metal waste, will contribute to resource conservation, import substitution and ensuring the technological sovereignty of the Russian Federation.

Structure and properties of powders obtained by electrodispersion of pure tungsten metal waste in distilled water

Purpose. Investigation of the composition, structure and properties of powder materials obtained by electrodispersion of tungsten waste of the VA brand in an oxygen–containing medium - distilled water. Methods. To determine the composition, structure and properties of powder materials, samples of powders obtained from waste tungsten of the VA brand were studied. The powder material was obtained by electroerosive dispersion in distilled water. Microanalysis of powder particles was carried out using a scanning electron microscope, analysis of the size distribution of powder particles was obtained using a particle size analyzer, X-ray spectral microanalysis of powder particles was carried out using an energy dispersive X-ray analyzer integrated into a scanning electron microscope, analysis of the phase composition of powder particles was carried out using X-ray diffraction on a diffractometer. Results. During the study, it was revealed that the shape of the particles obtained from powdered tungsten materials is spherical and elliptical, and agglomerates of smaller particles are also marked on magnification. Oxygen and tungsten are present in the composition of powder materials, while there are no joint structural components. The phases of pure tungsten in α and β modifications are noted in the phase composition. It follows from the analysis of the granulometric histogram that the particle size spread varies in the range of 0.092–62.59 microns, while the average particle diameterwas 5.73 microns. Conclusion. The obtained research results can be used to develop a new heavy pseudo-alloy using metal waste of expensive raw materials by the method of electroerosive dispersion with subsequent improvement and optimization of the composition and structure of the alloy.

Investigation of the Elemental Composition of Titanium Metal Waste by X-Ray Fluorescence Analysis

The purpose of this work was to study the elemental composition of titanium metal waste to be processed by the method of electroerosive dispersion into spherical powders suitable for additive manufacturing.Methods. When conducting experiments on X-ray fluorescence analysis of chemical composition, pieces of metal waste rods of a titanium alloy of an unknown brand were used. An X-ray fluorescence spectrometer Niton Goldd (USA) was used to determine the elemental composition and percentage of elements in the alloy under study. With this method, X-ray radiation is directed at the sample under study, the reflected wave spectrum is obtained and the characteristics of the spectrum of secondary fluorescent radiation of the sample are analyzed. In this case, electromagnetic waves form secondary X-ray radiation, i.e., characteristic lines that are characteristic of atoms of various elements and have their own individual characteristics. Thus, the elemental composition of the sample under study is determined, and the intensity of these lines shows the quantitative concentration of elements.Results. Using a portable Niton Goldd spectrometer, it was found that titanium metal waste corresponds to the grade of the OT4-0 alloy. The data obtained made it possible to identify samples of the studied metal waste to be processed by the method of electroerosive dispersion into spherical powders suitable for additive manufacturing. As a result of comparing the percentage of chemical elements of the studied metal waste and alloy OT4-0 according to GOST 19807-91, minor discrepancies were found due to the absence of elements such as O, Si, C, N and H. in metal waste. Apparently, this difference is related to their possible presence in small amounts up to 0.1% or complete absence.Conclusion. Renovation of metal waste, including titanium metal waste, will contribute to resource conservation, import substitution and ensuring the technological sovereignty of the Russian Federation.

Determination of Mass and Quantitative Productivity of the Process of Electrodispersion of Nickel Waste in Isopropyl Alcohol

The purpose of this study was to obtain electroerosive dispersed nickel by processing nickel waste by electrodispersing in isopropyl alcohol, as well as to study the performance of this process and the particle size of the obtained dispersed nickel.Methods. Nickel waste in the form of plates was processed into powder by electrodispersion at an experimental electroerosive dispersion plant (RF Patent No. 2449859) in an isopropyl alcohol medium. The study of the average particle size of the obtained electroerosive dispersed nickel was carried out using a laser particle size analyzer "Analysette 22 NanoTec".Results. For the first time, spherical nickel powders in the medium of isopropyl alcohol were obtained from industrial waste by the method of electroerosive dispersion. The parameters of the electroerosive dispersion unit necessary for the dispersion of nickel waste have been determined. A directly proportional dependence of the mass productivity of the process of electroerosion research of nickel waste dispersion on the voltage at the electrodes in isopropyl alcohol in the range of 120-220 V. has been experimentally established. The optimum for dispersing nickel waste in isopropyl alcohol is the voltage at the electrodes in the range of 200-220 V. It is established that the smallest particle size is nickel powder obtained at a voltage of 220 V at the electrodes, while the mass productivity at this value of the voltage at the electrodes is the maximum.Conclusion. Based on the presented experimental studies of the mass and quantitative productivity of the process of electroerosive dispersion of nickel waste in isopropyl alcohol, a high efficiency of the use of electrodispersion technology for obtaining dispersed nickel powder, which is not inferior to industrially used powders in terms of average particle size, has been established. It has been experimentally established that the smallest particle size has a nickel powder obtained at a voltage of 220 V on the electrodes, while the mass productivity at this value of the voltage on the electrodes is maximum.

X-ray Fluorescence Analysis of the Elemental Composition of Tungsten, Nickel and Copper

The purpose of this work was to conduct an X-ray fluorescence analysis of the elemental composition of tungsten, nickel and copper metal waste using an Olympus Delta portable spectrometer.Methods. To determine the chemical composition of raw materials, samples of metal waste in the form of copper rods, tungsten rods of various diameters and scraps of nickel plates intended for recycling were examined. To determine the elemental composition of metal waste, the method of X-ray fluorescence analysis (XFA) was chosen. The X-ray fluorescence method is based on the ratio of the intensity of X-ray fluorescence to the concentration of elements in the sample. Samples irradiated with powerful X-ray tube radiation, in response, emit characteristic fluorescent radiation of atoms proportional to their concentration in the sample. This method allows us to qualitatively assess the elemental composition of complex samples without violating their physico-chemical properties with minimal time costs. The Olympus Delta spectrometer was used as an express analyzer of metals and alloys, with the help of which experimental data on the composition of metal waste of tungsten, nickel and copper were obtained.Results. Based on the conducted studies aimed at X-ray fluorescence analysis of the elemental composition of tungsten, nickel and copper metal waste using the Olympus Delta portable spectrometer, it was found that the samples of the studied metal waste correspond to the following grades of alloys: tungsten rod made of tungsten grade VA; nickel plate made of nickel grade PNK-0T1; copper rod made of copper grade M3r.Conclusion. The results obtained will allow further research on their processing by the method of electroerosive dispersion and reuse in the production of heavy tungsten alloys. Renovation of metal waste, including tungsten, nickel and copper metal waste, will contribute to resource conservation, import substitution and ensuring the technological sovereignty of the Russian Federation.

ПРИМЕНЕНИЕ ВТОРИЧНЫХ ПОРОШКОВЫХ МАТЕРИАЛОВ ДЛЯ ВОССТАНОВЛЕНИЯ БРОНЗОВЫХ ДЕТАЛЕЙ ГИДРОМАШИН

During the operation of agricultural machinery, machine parts and their connections lose their operability, which requires their replacement. The cost of restoration is 50-60 percent of the cost of a new part. The presence of non-ferrous metal and alloy parts in the equipment, and in particular bronze, makes the issue of restoration even more urgent due to the high cost of such parts. Methods using powder materials are particularly successful in restoring worn parts. It is characteristic that in order to reduce the cost of such technologies, it is possible to resort to recycling of metal waste and obtain powder by electroerosive dispersion without special economic costs. (Research purpose) The research purpose is studying the restoration of bronze parts of hydraulic machines with secondary powder materials and analyzing the tribotechnical indicators of the coatings obtained. (Materials and methods) The following equipment was used in the work: an Elitron-52B pulse generator, a scanning electron microscope, a spark plasma sintering unit, an electric spark alloying unit, an X-ray fluorescence spectrometer, a metallographic microscope, a tribometer, analytical scales, a drying cabinet, a set of sieves. (Results and discussion) Electrodes were made from bronze powder obtained by the method of electroerosive dispersion. Using electric spark alloying, samples with coatings from a standard and a new obtained electrode were created. The tribotechnical properties of these coatings were compared. Metallographic and chemical analyses were performed. (Conclusions) The coatings obtained with the new electrode showed the best tribotechnical characteristics in dry friction. At boundary friction, their performance was worse, which may be due to an incorrect choice of lubrication, modes of electric spark alloying and a violation of the technology for obtaining the electrode itself. In general, the use of secondary powder materials for the restoration of bronze parts is relevant.

MODERNIZATION OF THE INSTALLATION FOR ELECTRIC EROSION DISPERSION

Very often, powders of metals and alloys are used in the technologies of repair and restoration of parts, as well as when creating new parts. With the development of mechanical engineering, high requirements are imposed on such materials, which are associated with certain physico-chemical and granulometric indicators. Currently, a large number of different methods for producing metal powders are known. Many of them have a number of disadvantages: high energy consumption, irregular particle shape, the presence of impurities. The method of electroerosive dispersion is one of the most energy-efficient and allows to obtain metal powders with particles of the correct shape and small sizes. However, existing installations do not make it possible to bring the process to the industrial level due to outdated and low-power components of electrical circuits. (Research purpose) The research purpose is increasing the productivity and efficiency of the installation for electroerosive dispersion, as well as improving the quality characteristics of metal powders obtained with its use. (Materials and methods) Studied literary sources, scientific papers and patents, used the laboratory installation of the CCP "Nano-Center" FNAC VIM. (Results and discussion) Described the process of electroerosive dispersion, examined the principle of operation of the existing laboratory installation. It was revealed that this installation has a number of disadvantages that significantly affect performance indicators and efficiency. They proposed modernization options and developed a new electrical circuit of the most important unit of the installation, which was supplemented with auxiliary electronic components. The structure was equipped with fundamentally new nodes. (Conclusions) The proposed scheme of an upgraded installation for electroerosive dispersion provides an increase in productivity and efficiency and meets modern industrial requirements.

POROSITY OF A HEAT-RESISTANT ALLOY MADE BY SPARK PLASMA SINTERING OF NICKEL POWDER OBTAINED BY ELECTRODISPERSING THE ZHS6U ALLOY IN WATER

Metallographic studies are required to expand the scope of practical application of powder materials obtained from waste of the ZhS6U alloy. The purpose of this work was to study the porosity of a heat-resistant alloy produced by spark plasma sintering of nickel powder obtained by electrodispersing the LC6U alloy in water. The work is based on the task of obtaining a heat-resistant nickel alloy with improved physical and mechanical properties and low cost. The alloy under study is obtained by spark plasma sputtering of nickel powders obtained by electroerosive dispersion of waste of the alloy ZhS6U in distilled water. The waste of heat-resistant alloy of the brand ZhS6U was used in the work, which was crushed by the method of electroerosive dispersion in distilled water at the original installation. Parameters of the installation during the disposal of waste ZhS6U: voltage at the electrodes 190–210 V; capacitance of the condenses 55–60 UF; pulse repetition frequency 180–200 Hz. As a result of local exposure to short-term electrical discharges between the electrodes, the alloy waste was destroyed with the formation of heat-resistant nickel powder particles. Sintering of heat-resistant nickel powder was carried out in the SPS 25-10 "Thermal Technology" system (USA) at a temperature of 1300 °C, a pressure of 40 MPa and a holding time of 10 min. It has been experimentally established that new heat-resistant alloys produced by spark plasma sintering of an electroerosive charge have a porosity of about 0.52 %. The practically nonporous structure of heat-resistant alloys is explained by the presence of particles of different fractions in the electroerosion charge, which ensures tight packing and the so-called "spark discharge plasma effect" during spark plasma fusion.

Application of secondary carbide powders for restoration and hardening of parts

Attention in this work is paid to the technology of obtaining powder materials from waste metals and alloys by the method of electroerosive dispersion and subsequent deposition of wear-resistant coatings. At present, it is important to look for new materials for the repair and restoration of parts of various equipment. Recycling of metal waste using electroerosive dispersion will reduce the cost of such materials. The most common way to restore parts is plasma-powder surfacing. In this case, the physical and technological parameters of the metal powders used are of particular importance. In the presented work, the expediency and relevance of the use of recycled powder materials in the technologies for the restoration and hardening of parts by the method of plasma-powder surfacing is proved. (Research purpose) Increasing the resource of parts of various equipment, restored and hardened with hard-alloy powder materials obtained by recycling waste from machinebuilding industries by the method of electroerosive dispersion. (Materials and methods) The work was carried out at the laboratory-experimental base of the Central Collective Use Center "Nano-Center" FGBNU FNATS VIM. To conduct research, a powder of the T15K6 brand was obtained from the waste of hard-alloy plates by the method of electroerosive dispersion. The following equipment was used: a pulse generator for electrospark processing of modes. Elitron-52B, Niton XL3t GOLDD + X-ray fluorescence spectrometer, set of sieves, ShS-80-01 SPU drying cabinet, Acculab ALC-210d4 analytical balance. (Results and discussions) Investigations were carried out on the elemental composition of the powders used, as well as the physical and mechanical properties of the coatings obtained on their basis by plasma-powder surfacing. (Conclusions) Studies have shown the rationality of using secondary hard-alloy powder materials in the technologies of plasma-powder surfacing in the restoration and hardening of parts. The hardness of the resulting coatings is much higher than the initial hardness of worn parts.

Corrosion-resistant polymer-based nanocomposite materials with a high level of microwave absorption and soft magnetic materials based on iron oxide nanopowder obtained by electroerosion dispersion

Nanopowder of iron oxide (mainly Fe3O4) has been obtained by electroerosion dispersion method and was used for manufacturing of gradient polymer-based microwave absorbing materials which absorb (1) on 36.6 GHz with a level of absorption of 99% (with a maximum penetration −40 dB and reflection −23 dB) and (2) on 10 GHz and 36.6 GHz with an absorption of 90% and 98.4%, correspondently (with a maximum reflection −18 dB and −10 dB and penetration −40 dB and −60 dB, respectively). It was demonstrated, that change of magnetic properties of the absorbing material under mechanical load can be used for non-destructive control. Sintered under high pressure-high temperature conditions (2 GPa, at 900, 1000, 1100, 1200 and 1300 °C for 4 min) iron oxide nanopowder in presence of hexagonal boron nitride (hBN) demonstrated soft magnetic behavior. Electron Backscatter Diffraction (EBSD) study has showed that during sintering the grains have grown beyond the superparamagnetic size limit inspire short annealing time. The structure of sintered materials was investigated using X-ray diffraction with a full-profile fitting procedure. The materials sintered at 2 GPa at 900 and 1000 °C contained 75–80 wt% of FeO and 25–20 wt% Fe. Materials sintered at 1100 oC, along with 32 wt% FeO and 2 wt% Fe, contained a significant amount of Fe3N: 66 wt%. However, materials sintered at 1200–1300 °C contain almost pure Fe3N phase. Thus, under conditions of high pressures and temperatures with increasing sintering temperature, reduction of iron oxide was observed, followed by its nitriding with nitrogen released from the boron nitride, which led to a reduction of coercive force and thus improving soft magnetic characteristics of the sintered materials. The scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) study of the sample, sintered at 1300 oC showed approximate composition of Fe3N0.8C0.3-0.6O0.06-0.3.

The Tribotechnical Properties of Electrosparks with a Secondary Bronze Coating

The high cost of metal powder materials and the energy consumption of the methods involved in their production have led to an increase in the cost of technologies for the restoration and hardening of parts. One method of solving this problem is the recycling of powders. A promising method for processing the waste from machine-building industries, including those utilizing non-ferrous metals and alloys, is electroerosive dispersion. Metallic powders from secondary raw materials obtained in this manner have good physical and mechanical properties, and their cost is two to three times less than the cost of industrial ones. However, the tribotechnical properties of the secondary powders of non-ferrous metals and their use in technologies for the restoration and hardening of parts are still poorly understood. This paper presents a comparative analysis of the tribotechnical properties of coatings obtained via an electric spark treatment with electrodes composed of bronze CuAl9Fe3 (CuAl8Fe3) (in the state of delivery), and coatings of sintered secondary bronze obtained via the method of electroerosive dispersion followed by spark plasma sintering. The results of the comparative tribotechnical tests under the conditions of dry friction showed that the complex indicator of wear resistance—the wear factor (F)—under dry friction conditions, for mates after an electrospark coating method with sintered secondary bronze, was 1.94 less than for mates with a CuAl9Fe3 (CuAl8Fe3) coating. This confirmed the high tribotechnical properties and the effectiveness of using cheap secondary bronze in repair production in technologies for restoring and strengthening worn parts of machines operating under dry friction conditions.

PRODUCING METAL POWDERS FOR ADDITIVE TECHNOLOGIES

Additive technologies become to be widely used in modern mechanical engineering. There are different methods and equipment for carrying out this task, but they all require a starting material - a metal powder with certain physical and chemical characteristics. In modern realities, it is important for Russia to provide itself with high-quality and inexpensive raw materials, which justifies the search for new methods. (Research purpose) The research purpose is considering the most popular and energy-efficient methods of manufacturing metal powder materials for additive manufacturing, justifying the use of a promising method of electroerosive dispersion, which allows obtaining powders with the required characteristics from mechanical engineering waste. (Materials and methods) Literature sources, scientific papers, as well as laboratory equipment were used to study the properties of powder materials, in detail: Olympus GX-51 inverted metallographic microscope, Microtrac Bluewave particle size analyzer, Autosorb-1 specific surface area analyzer, QUANTA 600 FEG electron-ion scanning microscope, drying cabinet SHS-80-01 SPU, a set of sieves according to GOST 2715-75, analytical scales Acculab ALC-210d4. (Results and discussion) Various atomization methods and the properties of metal powders that can be used in additive technologies were analyzed and described. The method of electroerosive dispersion was noted as promising and the powder material obtained with its help was studied. (Conclusions) Additive technologies are becoming more widespread. An urgent task is the search for new ways to obtain metal powders for their producing. The most promising is the method of electroerosive dispersion, which allows obtaining powders with specified properties from mechanical engineering waste. The particles of this powder have a regular rounded shape, high specific surface area and low porosity.

THE USE OF POWDER MATERIALS IN THE TECHNOLOGIES OF RESTORATION AND HARDENING OF AGRICULTURAL MACHINERY PARTS

Currently, a large number of different methods for producing metal powders are known. Most of them use ready-made raw materials and semi- finished products made from the source ore, which leads to an increase in the cost of the resulting product, so the issues of recycling of machine-produced waste become relevant. One of the most promising and energy-efficient methods of obtaining powders from any conductive materials is electroerosive dispersion. This method makes it possible to process metal waste and obtain raw materials for technologies for the restoration and hardening of agricultural machinery parts, gives a tangible economic effect. (Research purpose) The research purpose is to consider various methods of obtaining metal powders and to determine the most promising and technologically advanced of them for the restoration and hardening of parts; to justify the feasibility of processing machine-produced waste into powder material as an important resource-saving factor. (Materials and methods) The study uses literature sources, fundamental laws of physics and chemistry, basic laws of metallurgy, used a laboratory installation for electroerosive dispersion. (Results and discussion). The article describes the main methods of obtaining metal powders: mechanical, chemical, as well as a promising method of electroerosive dispersion. The method of electroerosive dispersion is considered the most promising method for obtaining metal powders. This method makes it possible to obtain powders from metal waste from machine- producing industries, suitable for reuse in technologies for the restoration and hardening of machine parts of agricultural machinery by iron, various types of surfacing and electric spark alloying. (Conclusions) Powder metallurgy provides valuable raw materials for the technologies of restoration and hardening of parts. In order to save money, it is advisable to obtaining metal powders from machine- produced waste. The method of electroerosive dispersion is characterized by relatively low energy costs and environmental cleanliness of the process.

STUDYING THE INFLUENCE OF THE TEMPERATURE ON MORPHOLOGY OF CONGLOMERATES FROM COPPER NANOPARTICLES OBTAINED BY ELECTROEROSION DISPERSION

Aim. To obtain conglomerates from copper nanoparticles by the method of electroerosive dispersion in various liquid media (in 1% starch solution, ethanol, acetone, kerosene, petroleum ether) at two different temperatures (negative and room). Assessment of the influence of this factor on the size and shape of the resulting conglomerates.
 Methods. Methods based on visual observation of the obtained particles using a digital microscope at a magnification of 600x.
 Results. The results are presented in the form of micrographs of the obtained particles.
 Conclusions. Conclusions are drawn on the study of the influence of the temperature factor on the morphology (size, shape and ordering) of the resulting conglomerates.

Выбор режимов электроискровой обработки для электродов из спеченной бронзы

The method of electrospark machining has proven itself well in the technology of repair and restoration of parts. The operational properties of coatings obtained by this method depend on the microstructure, chemical and phase composition of the electrode materials. A significant improvement in operational properties, for example, wear resistance, is achieved by the formation of nanostructured coatings using electrodes with a certain content of alloying nanomaterials. It is possible to obtain such materials at the lowest cost by electro-erosion dispersion of machine-building waste. This article discusses the electrodes obtained by sintering bronze powder obtained by the method of electroerosive dispersion. Such materials are new for the process of electrospark machining; therefore, it is important to study and select the optimal application modes, since a qualitative characteristic of the process is the indicator of the transfer of the electrode material to the part, which depends on the processing modes and installation parameters. The aim of the study is to select the modes of the installation for electrospark treatment for optimal deposition of the material, as well as to study the degree of coating increment during electrospark treatment. Coating was carried out using an installation for electrospark treatment mod. «Westron» type AI-007, electrode material was obtained by the technology of spark plasma sintering of bronze powder, surfacing was carried out on steel samples 14 × 14 × 40 mm in size, the work also used an Acculab ALC-210d4 analytical balance and an MG micrometer Н25 GOST 6507-90. All coatings were applied to samples with an equal area in three layers under different processing conditions. After that, the increment in the thickness and mass of the electrode material on the sample surface was measured. Based on the results of the work, formulas were obtained and graphs were built. The most optimal mode of coating with an electrode made of sintered bronze obtained from machine-building waste by the method of electroerosive dispersion was determined, which proves the consistency of this method of obtaining electrode materials.

Исследование процесса прессования и спекания шихты свинцово-сурьмянистого сплава ССу-3, полученной электроэрозионным диспергированием

The purpose of this study is to manufacture blanks from the charge obtained by the method of electroerosion dispersion, lead-antimony alloy - SSu3, under certain pressing and sintering parameters, to determine the effect of pressure on the density of the final blanks, as well as to find shrinkage dependencies during the sintering operation. Methods. To perform this study, a charge of lead-antimony alloy - SSu3, obtained by the method of electroerosive dispersion, was required. The pressing process was carried out in a mold specially designed for this study on a NORDBERG N3612 hydraulic floor press in two modes under load - 2.5 and 5 t. respectively, the holding time under pressure in both cases was 10 minutes. Sintering was carried out in a graphite crucible, which was placed in an oven for heating the molds EKPS - 10, where a constant temperature of 296 degrees is maintained for 120 minutes. Results. Experimentally, it was found that when the force is doubled, the density of the workpiece increases by 2%, which is due to a closer interaction between metal particles. It is noted that in order to create products with greater porosity, it is necessary to reduce the pressure during pressing, and to create products with greater hardness, more pressure is needed. The difference in the color of the workpieces is due to the degree of oxidation of the charge with oxygen during the cooling of the briquettes after pressing, the compounds of the alloy elements change during its oxidation with oxygen, oxides and lead peroxides are formed, which in turn affect the chemical properties of the alloy. Gray color has a low content of oxygen oxides, and brown, up to orange, is characterized by a high content of lead peroxides. Conclusion. The obtained results can be used for further study and improvement of the composition and structure of the alloy, as well as for the selection of optimal modes of pressing and sintering in further studies.

Comparative Characteristics of Wear Resistance of Gas-Dynamic Coatings Obtained Using Electroerosive Carbides

This work presents the results of studying of characteristics of wear resistance of gas-dynamic coatings obtained using electroerosive carbides, prepared by the method of electroerosive dispersing from wastes of VK8 hard alloys in distilled water and illuminating kerosene. Worn plates of the cutting tool from sintered hard alloys of the brand VK8 were used as dispersed material as well as electrodes. Samples with coatings from VK8 powders were prepared on the surface of metal products on a specialized plant for superfast gas-dynamic formation. The results obtained showed that the coatings obtained using electroerosive carbides, prepared by the method of electroerosive dispersion from wastes of hard alloys VK8 in water and illuminating kerosene, possess the best wear resistance due to the significantly higher content of free carbon.

Isolation of fine powder faction obtained by electroerosion dispersion method

The fundamental properties of metal powders with small particles change, which opens up a wide range of applications of such materials. Currently, nanopowders are used in many industries to improve the quality of the resulting products. (Research purpose) The research purpose is in isolating a fine fraction of metal powders obtained by electroerosive dispersion for further experiments with this material, and also proving the possibility of obtaining such fractions by this method. (Materials and methods) A fine fraction of metal powders obtained by the method of electroerosive dispersion was isolated, which proved its effectiveness in obtaining conductive powder materials with the desired final physical and mechanical properties. This method results in a fairly large spread across fractions. Authors received material for research on experimental installations of the "Nano-Center" Center for Collective Use. The article presents the methods of experimental research of fractional composition on the example of metal powders of hard alloy grades T15K6 and VK8, copper powder M1, brass powder LTs38MTsS2 and bronze powder BrAZh9-12 obtained by electroerosive dispersion. (Results and discussion) The metal powder was divided into three fractions, depending on the particle size: more than 0.071 mm, from 0.02 to 0.071 mm and less than 0.02 mm. The presence of fine particles of less than 1.5 microns in the total mass of the studied powders was proved using a membrane method with a ceramic filter. Sedimentation showed specific sizes of minimal particles (from 86.4 to 116 nm). (Conclusions) Based on the results of experiments, it is possible to obtain metal powders of a fine fraction using the method of electroerosive dispersion.

MORPHOLOGY AND ELEMENT COMPOSITION POWDER ALLOY POWDER VNZH-95, OBTAINED BY ELECTROEROSION DISPERSION IN KEROSIN

Residence permits pseudo-alloys are used for the manufacture of cylinder parts, bushings, complex-shaped blanks with curved surfaces: gyroscope rotors, inertial masses, erosion-resistant electrodes, funnel for cumulative charges, biological protection from gamma radiation. Recycling of tungsten pseudo-alloys residence permit is relevant and necessary due to the shortage of tungsten. A promising method of processing waste into fine powders is the method of electroerosive dispersion (EED) that we have chosen. The purpose of the work is to study the morphology and elemental composition of the powder of the VNZh-95 pseudo-alloy obtained by electroerosive dispersion in kerosene. In order to process the waste of the W-Ni-Fe alloy into powder, we used waste in the form of chips from the core of the VNZh-95 pseudo-alloy (Ni ̶ 3.2-3.7, Fe ̶ 1.5-2.0, W ̶ the rest). Kerosene is used as a working fluid. The EED process was carried out on the installation for obtaining powders from conductive materials (patent for the invention of the Russian Federation No. 2449859). The process was carried out at a voltage on the electrodes of 100 ... 110 V, the capacitance of the discharge capacitors 50 μF and a pulse repetition rate of 120 ... 130 Hz. The microstructure of the samples (along the transverse section) was studied using a Quanta 200 3D electron-ion scanning microscope. The powder obtained by the EED method for waste of VNZh-95 alloy in kerosene consists of particles of regular spherical shape (or elliptical) and irregular shape (conglomerates). Microanalysis of particles of electroerosive powder of pseudo-alloy VNZh-95 was carried out using an EDAX energy-dispersive x-ray analyzer built into the Quanta 200 3D scanning electron microscope. As a result of studying the elemental composition of the VNZh-95 pseudo-alloy powder obtained by EED in kerosene, it was found that the main elements are tungsten, nickel, iron, carbon and oxygen.