Electroerosion Dispersion Research Articles

Microstructure, Alloying Elements, and Phase Distribution in ZhS6U Alloy Samples Sintered from the Powders Fabricated by Electroerosion Dispersion of Waste

Microstructure, Alloying Elements, and Phase Distribution in ZhS6U Alloy Samples Sintered from the Powders Fabricated by Electroerosion Dispersion of Waste

Certification of the Hard-Alloy Powders Fabricated by Electroerosion Dispersion of a T5K10 Alloy in Kerosene

Certification of the Hard-Alloy Powders Fabricated by Electroerosion Dispersion of a T5K10 Alloy in Kerosene

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.

ANALYSIS OF THE PERFORMANCE OF THE ELECTROEROSIVE DISPERSION PROCESS IN THE ELECTROEROSIVE DISPERSION REACTOR

Mathematical model of the electroerosive dispersion reactor allows evaluating its performance. The number of spark discharges in the layer of granules is determined by the voltage per contact in the discharge chain. A bitrow chain of granules is compiled using a random number generator. A table of calculated and experimental data is given.

Prospects for improving the method of electroerosive disintegration of heavy pseudo-alloys (overview)

Modern methods of recycling scrap tungsten pseudo-alloys are considered. The improvement of the method of electroerosive dispersion of conductive granules by strengthening its electrohydraulic action for effective disintegration of tungsten pseudo-alloys into micro-components is discussed.

PROPERTIES AND COMPOSITION OF ELECTRIC EROSION POWDER FROM WASTE OF R18 TOOL STEEL

Currently, one of the promising methods of processing metal waste is electroerosive dispersion, which allows to obtain metal powder, including from the waste of tool steel P18. (Research Purpose) The research purpose is studying the properties and composition of the electroerosive powder obtained from the waste of P18 tool steel. (Materials and methods) Carried out grinding of waste steel P18 on an experimental installation by the method of electroerosive dispersion to obtain new powder materials. The process of electroerosive dispersion was carried out under certain installation modes. The granulometric composition of the particles of this powder was studied using the Analysette 22 NanoTec laser particle size analyzer. An experimental study was performed by dispersing ultrasound in a liquid. Metallography was studied using a Quanta 200 3D scanning electron microscope. X-ray spectral analysis was carried out using the scanning electron microscopy method with an energy-dispersion X-ray analyzer from EDAX, built into the Quanta 200 3D scanning electron microscope. The method of X-ray diffraction was used in X-ray diffraction analysis on a Rigaku Ultima IV diffractometer. (Results and discussion) It was shown that 50% of the powder particles correspond to the size of 44.13 micrometers. The elemental composition of the particles of the obtained metal powder from waste P18 was determined, the sample under study consists of the following chemical elements: carbon, oxygen, molybdenum, vanadium, chromium, iron and tungsten. The main phases of the powder material under study were established: Fe2W2C, FeV, Fe3O4. (Conclusions) Obtaining, studying the properties and composition of an experimental metal powder makes it possible to assess its potential for use in the production of products with specified characteristics, as well as hardening, restoration of car parts and agricultural machinery.

Production of electrodes by spark plasma sintering method of secondary powder materials

The article considers the practical possibility of manufacturing electrodes from secondary powder materials. Obtaining electrodes with desired properties suitable for electrospark alloying processes. Bronze powder obtained from waste metal scrap by electroerosive dispersion was used. The following equipment was also used: spark plasma sintering system SPS 10-3 from Thermal Technology, drying cabinet ShS-80-01 SPU, set of sieves according to GOST 2715—75, analytical balance Acculab ALC-210d4, XRD-6000 Shimadzu diffractometer, X-ray fluorescence spectrometer Niton XL3t 900 GOLDD+. Secondary bronze fine powder was subjected to pressure sintering in an SPS 10-3 spark plasma sintering system from Thermal Technology. The maximum temperature was 910 °C, pressure — 40 MPa. Materials before and after were examined for elemental composition. The resulting briquette was cut into electrodes, and test surfacing was carried out by the method of electrospark alloying. Using spark plasma sintering, it is possible to obtain electrodes from secondary bronze powder materials suitable for electrospark alloying processes.

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.

Optimization of manufacturing process of heat-resistant nickel alloy by spark plasma sintering of powders obtained by electroerosive dispersion of ZhS6U waste in water

The results of experimental studies aimed at optimizing the process of spark plasma sintering of powders obtained by electroerosive dispersion of waste heat-resistant nickel alloy ZhS6U in distilled water are presented. Optimal values of pressure, temperature and holding time of spark plasma sintering of electroerosive nickel powders providing a nonporous structure of a heat-resistant alloy with maximum hardness have been established.

Results of X-ray studies of tungsten-titanium-cobalt alloy made by spark plasma sintering of carbide electroerosive powders obtained in kerosene

The results of the conducted experimental studies aimed at conducting X-ray studies of tungsten-titanium-cobalt hard alloy made by spark plasma sintering of carbide powders obtained by electroerosive dispersion of T5K10 hard alloy waste in kerosene are presented. It is shown that the obtained new hard alloys have a fine-grained structure, elemental and phase compositions identical to the original dispersible hard alloy of the T5K10 grade.

ANALYSIS OF THE CHARACTERISTICS OF SINTERED PRODUCTS MADE OF CHROMIUM-CONTAINING ELECTROEROSIVE POWDERS

The article presents the results of the analysis of the characteristics of sintered productsmade of chromium-containing electroerosive powders. One of the main directions of the development of mechanical engineering technology at present is the improvement of existing and the development of new waste-free, environmentally friendly, material-saving production processes. Powder metallurgy plays a certain role in solving this problem. In recent years, much attention has been paid to the development of methods for the manufacture of high-density powder materials For the implementation of the planned studies, waste chromium-containing steels SHX15 andH13 have been selected. Powder materials were obtained by electrical erosion at the electro-erosive dispersion unit developed by the authors. Butyl alcohol was chosen as the working medium of dispersion. The powder was consolidated by the spark plasma sintering method using the spark plasma sintering system SPS 25-10 (Thermal Technology, USA). It is established that the microhardness of the sintered steel sample SHH15 is equal to 154 HV. The microhardness of the sintered steel sample H13 is equal to 461 HV. Itwas found that the porosity of the sintered steel sampleH13 is equal to 3.34%, and also that 95 % of the pores have a size of up to 2 microns. The porosity of the sintered steel sample SHH15 is 1.72 %, and also that 90 % of the pores have a size of up to 1 microns. According to the results of the research, it was found that the microhardness of the sintered sample made of steel SHH15 is lower than that of the sample made of steel H13. The porosity of a sample made of steel SHH15 is lower than that of a sample made of steel H13. Therefore, it can be concluded that sintered products made of powder material sta-li H13 have a harder surface and can be used in the production of small loaded parts.

INFLUENCE OF THE DISPERSION ENVIRONMENT ON THE PROPERTIES OF THE CHARGE OF LEAD-TIN BRONZE

This article presents the results of a study of the properties of the electroerosive charge obtained from the waste of lead-tin bronze BrO5C25, in particular, the influence of the chemical composition of the dispersion medium on the elemental and phase composition of the resulting electroerosive particles is evaluated. It has been established that when carrying out experiments on obtaining a charge in an oxygen-containing liquid (distilled water), a part of oxygen is present on the surface of the obtained particles. According to the results of the experiment, it was found that the main elements in the charge obtained by the method of electroerosive dispersion of BrO5C25 lead bronze waste in distilled water are oxygen, copper, tin, zinc and lead. The remaining elements are distributed relatively evenly in the mixture. Based on the performed X-ray diffraction microanalysis, it was found that the main phases in the charge obtained in distilled water are Cu, Pb(Cu2O2), Pb5O8, Pb, Sn. When carrying out experiments to obtain a charge in a carbon-containing liquid (illuminating kerosene), a part of carbon is present on the surface of the obtained particles. According to the results of the experiment, it was found that the main elements in the charge obtained by the method of electroerosive dispersion of lead bronze waste BrO5C25 in lighting kerosene are carbon, copper, tin, zinc and lead. The remaining elements are distributed relatively evenly in the charge. Based on the performed X-ray diffraction microanalysis, it was found that there are no carbide-forming elements in the alloy. The main phases in the charge obtained in lighting kerosene are also Cu, Pb(Cu2O2), Pb5O8, Pb, Sn. Thus, the influence of the dispersion medium on the elemental and phase composition of the electroerosive charge of lead-tin bronze BrO5C25 has been established.

Composition, structure and properties of hard alloy products from electroerosive powders obtained from T5K10 hard alloy waste in kerosene

The paper implements scientific and applied principles of coupling the technology of obtaining new powder materials from waste of hard alloys of the T5K10 brand by electroerosive dispersion and the technology of compacting them by SPS synthesis. The aim of the work was to study the composition, structure and properties of carbide products made from powders obtained by electrodispersing T5K10 alloy waste in kerosene. Electrodispersion of T5K10 alloy waste was carried out in lighting kerosene on a patented installation. The consolidation of the obtained powder was carried out by the spark plasma sintering (SPS) method using the spark plasma sintering system SPS 25-10. The choice of powders obtained by electroerosive dispersion of the T5K10 hard alloy waste was justified by its cost and properties. The resource of tungsten-titanium-cobalt hard alloys from T5K10 electroerosion powders is determined not only by the properties of the feedstock, but also by the technology of their production (SPS synthesis). Based on the conducted experimental studies, it can be concluded that the use of the spark plasma sintering method to produce products from powder obtained by electroerosive dispersion of the T5K10 alloy will ensure high performance of products (cutting tools) due to the uniformity of the surface, favorable structure and low porosity of the product. It is noted that hard alloys made of electroerosion dispersed T5K10 alloy particles obtained by spark plasma sintering under conditions of rapid heating and short working cycle duration have higher physico-mechanical properties compared to industrial alloys from which the initial powder particles were obtained by suppressing grain growth and obtaining an equilibrium state with submicron and nanoscale grain. This study was funded by the Russian Science Foundation, grant No. 22-29-00123, https://rscf.ru/project/22-29-00123/.

Disposal of used nanosorbents obtained during wastewater purification from Ni2+ ions in powder paint materials

The prospects of increasing the level of environmental safety of industrial enterprises as a result of the implementation of the latest sorption technologies for wastewater treatment are considered. An analysis of the effectiveness of the existing methods of sorption water purification, which contain compounds of heavy metals, was carried out. Highly effective magnetic sorbents were obtained by electroerosion dispersion, which contains polyvalent iron oxides.
 The effect of the method of introducing the sorbent into wastewater on the degree of its purification was investigated. The most effective results in water purification were achieved with the use of freshly obtained powder of electroerosion dispersion of iron in water in the form of a suspension, which allows to achieve a high degree of water purification from zinc ions - more than 99%. Such water meets the standards for washing parts in galvanic production with regard to the content of nickel ions. The expediency of recycling spent nano-sorbents in the composition of powder paint and varnish materials is shown. When a coating chemically stable in water treatment waste, which has ferromagnetic properties, is included in the composition, in quantity15% by weight high corrosion resistance of the coating is ensured and shielding of electromagnetic radiation increases approximately 3 times compared to the standard sample. The use of research results at enterprises will prevent environmental pollution with toxic substances, change outdated production technologies, ensure efficient and rational use of water, raw materials and energy in the industrial production system.

Structure and Properties of the Powders Fabricated by Electroerosion Dispersion of Lead–Antimony Alloys in Distilled Water

Structure and Properties of the Powders Fabricated by Electroerosion Dispersion of Lead–Antimony Alloys in Distilled Water

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.

Properties and Applications of Iron Oxide Nanopowders Produced by Electroerosion Dispersion

Properties and Applications of Iron Oxide Nanopowders Produced by Electroerosion Dispersion

Structure and properties of additive products manufactured from electroerosion powders

The paper considers the possibility of using electroerosion metal powders based on the Co-Cr alloy with different properties in additive technologies. Use of these powders opens up great opportunities for improving the technical and economic characteristics of products, and will contribute to a significant increase in their reliability, durability, weight reduction, reduction of manufacture and operation costs. The economic efficiency of the use of electroerosion cobaltchromium powders is due to the use of waste and low energy-intensive technology for their production. The aim of this work is studying the technology of powder fusion obtained by electroerosion dispersion of cobaltchromium alloy waste in alcohol, on porosity, microhardness and roughness of additive products. The process of electrodispersion, i.e. grinding of the KKhMS "Cellite" alloy (63 % Co, 27 % Cr, 5 % Mo, 2 % Ni, 2 % Fe) was carried out on an original patented installation. After dispersion of cobalt-chromium alloy waste, its destruction occurred as a result of local exposure to short-term electrical discharges between the electrodes located in the working fluid, with formation of powder particles. Butyl alcohol was used as the working fluid. The fusion of electroerosion cobalt-chromium powders was carried out by plasma on the original installation for layer-by-layer deposition, which allows varying the technological parameters of the process: the nozzle transition speed (mm/min), the distance between the nozzle and the construction zone (mm), and the fusion temperature (°C). Based on a set of experimental studies, it was found that the melting temperature of particles of electroerosion cobaltchromium powder practically does not effect on varying in the elemental and phase composition of samples; at the same time, with an increase of the melting temperature, the pores size and their number decrease, as well as an increase of microhardness with decrease of the height of irregularities and roughness in general are observed. The research was conducted under financial support of the Russian scientific fund. The project number 17-79-20336P.

Additive manufacturing parts made of cobalt-chromium powders synthesized by electroerosion dispersion

Considering the standard procedure for producing globular powder particles, the authors of this paper propose to use the process of electroerosion dispersion for the production of globular particles of certain size for 3D technology. The proposed process is characterized with energy efficiency and sustainability. The waste cobalt-chromium alloy of the TsELLIT grade was used for the purposes of the study. Cobalt-chromium powders were produced by electroerosion dispersion on a special unit designed for conductive materials. Through experiments, it was established that as the particle dispersion rises, the baking process goes faster resulting in enhanced mechanical properties of the final products. Oxides present in fine-grained powders contribute to the intensity of the baking process as they are subject to reduction under heat impact. The spongy texture that forms when the oxides are gone from the metal surface appears to be more active compared with the oxide-film-free surface. The conducted study showed no changes to the structural and phase state of the specimens. Hence, all four specimens retained the following phases: Co, Cr, Ni и Cr3Ni2. The increasing dispersion and specific surface area of the powder leads to decreased porosity and increased microhardness in the final product. Due to the presence of particles of various sizes, the powder layer appears to be denser as cavities and micropores occurring between coarser particles get filled up. This results in lower roughness and higher compression and bend strength in baked parts. This study proves the possibility to control the structure and physico-mechanical properties of additive manufacturing parts made of powders that are obtained from waste cobalt-chromium alloys by electroerosion dispersion. This helps reduce the reliance on imported powders suitable for additive manufacturing while also cutting the cost of the final products.

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.