Influence of ultrasound and surface-active substances on the dispersion of metal powders

2020 ◽  
pp. 91-97
Author(s):  
Il’ya V. Romanov ◽  
Roman N. Zadorozhniy
Keyword(s):  
Ultrasonic Field ◽  
Research Purpose ◽  
Powder Materials ◽  
State University ◽  
Metal Powders ◽  
Adhesion Properties ◽  
Noticeable Improvement ◽  
Negative Feature ◽  
Powder Particles ◽  
Material Studies

It is scientifically proven that reducing the particle size in metal powders leads to a noticeable improvement in the materials properties. The shape of powder particles and their nanoscale are of great importance in sintering technologies for the formation of dense homogeneous alloys, as well as in additive manufacturing. A negative feature of nanoparticles is that they can stick together and form agglomerates and aggregates. (Research purpose) The research purpose is in proving the influence of ultrasound on the dispersion of metal powders, as well as studying the issue of preventing sticking of particles of powder materials with the help of surfactants. (Materials and methods) The article presents conducted tests at the Lomonosov Moscow state University. Authors used three brands of powder obtained by electroerosive dispersion (T15K6, Lc38mts2 and Brazh9-12), a high-class portable digital ultrasound device of the Logiq-E series, a scanning electron microscope of the DESK-TOP AURA series, and a Spectro-photocolorimeter “Spekol-210”. (Results and discussion) A suspension of metal powders in distilled water was subjected to ultrasound for 1, 5 and 10 minutes. The percentage of particles of three fractions was studied on a scanning microscope: 40-150; 150-300 and more than 300 nanometers. Polyethylene glycol PEG-35 was introduced into the suspension in different proportions to study the effect of surfactants. Solutions were studied using a spectrophotometric method to determine the adsorption of surfactants on the filler. (Conclusions) The effect of ultrasound on the dispersion of metal powders has been proved. It was hypothesized that conducting the process of electroerosive dispersion in an ultrasonic field can provide a better quality powder material. Studies with the use of surfactants have shown the prospects of their use for adsorption modification of metal fillers in order to improve the adhesion properties.

Investigation of pre-sprayed powders for electric contact welding

2020 ◽  
pp. 143-149
Author(s):  
Dinar R. Masalimov ◽  
Roman R. Galiullin ◽  
Rinat N. Sayfullin ◽  
Azamat F. Fayurshin ◽  
Linar F. Islamov
Keyword(s):  
Adhesion Strength ◽  
Electrical Contact ◽  
Research Purpose ◽  
Flame Spraying ◽  
Powder Materials ◽  
Electric Contact ◽  
Metal Powders ◽  
Unstable Flow ◽  
Gas Flame ◽  
Contact Welding

There are a number of difficulties in the electrical contact welding of powder materials: shedding of powder from the surface of a cylindrical part, impossibility of hardening the layer during welding due to flushing of the powders with coolant and unstable flow of powder into the welding zone. One solution is pre-spraying the powder in some way. (Research purpose). The research purpose is investigating the possibility of electric contact welding of metal powders preliminarily sprayed by a gas-flame method, namely, adhesion strength and losses during preliminary gas-flame spraying of powders. (Materials and methods) Powders of grades PG-NA-01, PrKhIIG4SR, PRZh3.200.28 were sprayed onto flat samples of St3 steel, polished to a roughness of Ra 1.25. The strength of powder adhesion to the base was studied by the cut method. (Results and discussion) The percentage loss of the powder as a whole is 3-23 percent for all the distances studied. The greatest powder losses appear at a distance of more than 180 millimeter from the tip of the burner for powders of grades PG-NA-01 and PrKhIIG4SR. The smallest powder losses were observed for PrZh3.200.28 powder, which totaled 3-7 percent. The maximum adhesion strength of the sprayed powders to the surface was 22.1 megapascals' when spraying the PG-NA-01 powder. The adhesion strength of powders of the grades PrKhIIG4SR and PrZh3.200.28 is small and amounts to 0.2-3 megapascals'. (Conclusions) The use of preliminary flame spraying of powders for their further electric contact welding is possible using PG-NA-01 grade powder, while the best adhesion to the base (that is more than 20 megapascals') is achieved with a spraying distance of 120-140 millimeter. The smallest powder losses during flame spraying are achieved at a spraying distance of 100-160 centimeters', at which the powder loss for the studied grades was 4-12 percent.

Powder materials and methods for their preparation

2020 ◽  
pp. 108-118
Author(s):  
Anna P. Karpunicheva ◽  
Dar’ya A. Lebedeva
Keyword(s):  
Powder Metallurgy ◽  
Fire Hazard ◽  
Point Of View ◽  
Research Purpose ◽  
Powder Materials ◽  
Metal Powders ◽  
Resource Saving ◽  
Technical Literature ◽  
Mechanical Methods ◽  
Information Materials

Powder metallurgy, along with other knowledge-intensive industries, is one of the priority areas of high-quality, modern, technologically advanced production, one of the main tasks of which is resource-saving technologies. (Research purpose) The research purpose is in analyzing the existing methods for obtaining metal powders and metal-like compounds in order to review and systematize information. (Materials and methods) The methodological basis is the scientific and technical literature on the topic of manufacturing materials for powder metallurgy. The solution of the problem was carried out by means of comparative and logical analysis based on theoretical and empirical methods of scientific research. (Results and discussion) There are two groups of methods for producing metal powders: mechanical and physical-chemical, as well as methods for manufacturing metal-like compounds. Each of the production methods is analyzed from the point of view of technology, equipment, feasibility of application and the resulting materials. (Conclusions) When manufacturing powders by mechanical methods, there is a high probability of particles of grinding bodies or linings entering the final product. Dispersion allows to automate the process, adjust the properties of powders at a fairly low energy consumption. Physical and chemical methods of production require complex equipment, as well as compliance with safety regulations due to high fire hazard.

Methods for obtaining metal powder materials

2019 ◽  
pp. 137-145
Author(s):  
Ivan A. Shemberev ◽  
Vitaliy A. Zuyevskiy
Keyword(s):  
Metal Powder ◽  
Raw Materials ◽  
Research Purpose ◽  
Powder Materials ◽  
Metal Powders ◽  
Resource Saving ◽  
Important Place ◽  
Manufacturing Method ◽  
New Energy ◽  
Almost All

In practice, a large number of methods for obtaining metal powders are known, their diversity is due to the technological capabilities of manufacturing powders in several ways from different types of raw materials, as well as different requirements for the characteristics of powders for various fields and conditions of application. Metal powders in most cases are a secondary product, the properties of which are affected by the manufacturing method, so the theoretical foundations of their production occupy an important place in the processes of powder metallurgy. (Research purpose) The research purpose is in analyzing existing methods for obtaining metal powder materials and develop a new energy-and resource-saving method for obtaining powders, such as electroerosive dispersion. (Materials and methods) Authors have studied literary sources, works of prominent scientists and specialists on the subject of research. (Results and discussion) The article presents the main methods of powder production: mechanical and physical-chemical, as well as a relatively new method of electroerosive dispersion. More productive methods of obtaining powders are being introduced into production, in which considerable attention is paid to methods of cleaning powders from oxygen and carbon, controlling the shape of particles and their sizes. (Conclusions) Analysis of existing methods for obtaining powder materials has shown that they do not fully meet the requirements for quality composition of new technological solutions, in particular, additive technologies. The development of fundamentally new methods for obtaining powders, such as electroerosive dispersion, is a promising direction that makes it possible to obtain powders from almost all conductive materials, adjusting the size and shape of granules.

Isolation of fine powder faction obtained by electroerosion dispersion method

2020 ◽  
pp. 119-127
Author(s):  
Il’ya V. Romanov ◽  
Roman N. Zadorozhniy
Keyword(s):  
Fine Particles ◽  
Fine Fraction ◽  
Fine Powder ◽  
Physical And Mechanical Properties ◽  
Ceramic Filter ◽  
Research Purpose ◽  
Powder Materials ◽  
Metal Powders ◽  
Large Spread ◽  
Wide Range

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.

INCREASING THE WEAR RESISTANCE OF THE WORKING BODIES OF AGRICULTURAL MACHINES BY THE HDTV METHOD WITH ADDING POWDER OF THE EED METHOD

2020 ◽  
Vol 4 (141) ◽  
pp. 123-131
Author(s):  
IL’YA ROMANOV ◽  
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
High Frequency ◽  
Machine Building ◽  
Abrasive Wear Resistance ◽  
Research Purpose ◽  
Powder Materials ◽  
Agricultural Machinery ◽  
Resource Saving ◽  
Working Bodies

The development of energy and resource-saving methods and technologies for strengthening and restoring the working bodies of agricultural machinery will increase their abrasive wear resistance and durability by using materials from machine-building waste and reduce the cost by 10-30 percent without reducing operational characteristics. (Research purpose) The research purpose is in increasing the abrasive wear resistance and durability of cultivator legs by surfacing powder materials obtained by electroerosive dispersion from solid alloy waste by high-frequency currents. (Materials and methods) Authors obtained a powder for research on their own experimental installations of the CCP "Nano-Center" of electroerosive dispersion from waste of sintered hard alloys of the T15K6 brand. The microhardness of powders and coatings on microshifts was measured using the PMT-3 device, and the hardness of coatings with the KMT-1 microhardometer was measured using the Rockwell method according to GOST 9013-59. The microwave-40AV installation was used to assess the wear resistance of materials of working bodies of tillage machines. (Results and discussion) In the course of laboratory wear tests the relative wear resistance of samples hardened by high-frequency surfacing currents significantly exceeds the wear resistance of non-hardened samples made OF 65g steel, accepted as the reference standard. (Conclusions) Based on the results of experimental studies, the article proposes a new resource-saving technological process for strengthening the working bodies of agricultural machinery through the use of materials from machine-building waste, which allows increasing the abrasive wear resistance of working bodies by 1.5-2 times due to the use of tungsten-containing materials.

scholarly journals Influence of parameters of impulse laser impact on the formation of the gradient of the structure of porous titanium powder

2018 ◽  
pp. 88-94
Author(s):  
D. V. Minko
Keyword(s):  
Laser Radiation ◽  
Titanium Powder ◽  
Structural Characteristics ◽  
Selective Laser Sintering ◽  
Light Flux ◽  
Laser Action ◽  
Pulsed Laser ◽  
Powder Materials ◽  
Solid Core ◽  
Powder Particles

The possibility of selective laser sintering of graded porous and compactly porous structures by surface fusion of powder particles is demonstrated while maintaining a solid core, which leads to the formation of interparticle contacts in the presence of a liquid phase. The interaction of the light flux of the laser pulse with the surface of the powder particles under multiple reflection is considered. It is shown that the effect of single pulses of laser radiation leads to the formation of sintered structural elements of a powder material having a diameter approximately equal to the diameter of the focal spot. Technological regimes of pulsed laser action are established at which steady contact formation of titanium powder particles of the fractional compositions under study occurs. The possibility of obtaining powder materials with a gradient structure by controlling the parameters of pulsed laser action is experimentally demonstrated. It was found that accurate dosing of thermal energy and the number of pulses of laser radiation makes it possible to minimize shrinkage of powder layers in the absence of particle conglomeration, to control the structural characteristics and properties of products, to preserve the microstructure and phase composition of the initial materials.

scholarly journals Statistical Analysis of Results Obtained in the Hardening Surface of the Metal Powder Materials with Optical Radiation Impulses

2015 ◽  
Vol 20 (2) ◽  
pp. 79-85
Author(s):  
Ioan Virca
Keyword(s):  
Statistical Analysis ◽  
Metal Powder ◽  
Voltage Pulse ◽  
Optical Radiation ◽  
Experimental Program ◽  
Energy Sources ◽  
Powder Materials ◽  
Metal Powders ◽  
Analysis Of Results

Abstract The paper presents how is processed the data resulted from application of pulsed optical superficial treatments on surfaces of materials made of metal powders. The parameters of the electrotechnological regime work are variable in the experimental program, namely the distance between the axis focal energy sources and surfaces play, the number of energy pulses applied to the voltage pulse of optical radiation, which causes a statistical analysis more complex, after which it will precise drawing lessons that will lead to a calculation microhardness model in the superificial layer of material.

scholarly journals STUDY PARTICLE SIZE DISTRIBUTION OF ERODING POWDER LEAD BRONZES OBTAINED IN DISTILLED WATER

2018 ◽  
Vol 22 (4) ◽  
pp. 42-49
Author(s):  
E. V. Ageev ◽  
A. S. Pereverzev ◽  
A. S. Osminina ◽  
I. Yu. Grigorov
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Discharge Zone ◽  
Powder Materials ◽  
Average Particle ◽  
Distilled Water ◽  
Powder Particles ◽  
Local Exposure ◽  
Finely Dispersed Powder ◽  
Powder Lead

The article is devoted to the current problem of processing waste of conductive materials, in particular lead bronze, which accumulates in large quantities at enterprises. A promising method for processing any conductive material, characterized by wastelessness, ecological purity of the process, and low energy costs, is the method of electroerosive dispersion. The essence of the method of electroerosive dispersion is the destruction of current-conducting material as a result of local exposure to short-term electrical discharges between the electrodes. In the discharge zone, under high temperatures, heating, melting and partial evaporation of the material occurs, resulting in the formation of finely dispersed powder particles. At the same time, the electrical parameters of the installation will affect the productivity of the process for obtaining powder materials: the voltage at the electrodes, the capacitance of the discharge capacitors, and the repetition rate. The article presents the results of the analysis of particles of powdered lead bronze obtained by the method of electroerosive dispersion in distilled water from wastes, using the laser analyzer of particle sizes "Analysette 22 NanoTec". It has been experimentally established that the average particle size of powdered lead bronze is 9.73 μm, the arithmetic value is 9.731 μm. It was also found that the elongation coefficient (elongation) of particles with a size of 7.188 μm is 1.50.

Study of a hardened multilayer coating obtained by the cold gas-dynamic spraying with laser intensification

2020 ◽  
Vol 86 (7) ◽  
pp. 33-38
Author(s):  
A. I. Gorunov
Keyword(s):  
Multilayer Coating ◽  
Hardened Layer ◽  
Cold Gas Dynamic Spraying ◽  
Carbide Powder ◽  
Multilayer Coatings ◽  
Powder Materials ◽  
Layer By Layer ◽  
Gas Dynamic ◽  
Powder Particles ◽  
Cold Gas

When reconstructing products obtained using additive technologies based on layer-by-layer melting of metal powder by concentrated energy flows, it is advisable to use methods that minimize melting of the initial powder and reduce structural heterogeneity of the material. Cold gas-dynamic spraying with laser-induced intensification of the process (CGDSL) is one of them. The multilayer coatings obtained by the CGDSL method have a homogeneous metal structure though a significant surface roughness attributed to the particle size of the original powder is observed. The goal of the study is to develop a new method of post-processing of multilayer coatings obtained by CGDSL which can provide a hardened layer on their surface. A hardened layer is formed through introduction of boron carbide powder particles into the laser-molten region formed on the surface of the coating based on 316L stainless steel. An acoustic wave triggered by a «microexplosion» induced by a laser pulse above the surface pushes carbide particles in different directions. Some of them are embedded into the melt pool on the surface of the coating. Thus, the laser microdetonation cartooning of the surface of the CGDSL coating is implemeted. Study of the hardened layer revealed a high content of B, C, Cr, Fe, and Ni. Moreover, it is shown that solid carbides of rhombic form are formed in the hardened layer. Chemical and elemental analyzes showed that diamond-shaped carbides — carbides of the type (Fe, Cr)xBy — contain a high concentration of Cr, Fe and a relatively small percentage of C. Most likely formation of diamond-shaped carbides occurs due to interaction of chromium which is a part of the initial hardened coating with boron that released from the surface of BC particles under laser impact. The developed method provides hardening of the surface layer of the coating previously obtained by CGDSL by embedding the BC powder particles into the surface. The technology of hardening CGDSL coatings can be implemented using other powder materials.

10.22314/2618-8287-2020-58-4-148-156

2020 ◽  
Vol 4 (141) ◽  
pp. 148-156
Author(s):  
ILYA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Chemical Composition ◽  
Spherical Shape ◽  
Machine Building ◽  
Research Purpose ◽  
Working Fluid ◽  
Specific Method ◽  
Recrystallization Process ◽  
Central Research ◽  
Metal Powders ◽  
X Ray

Among the well-known repair technologies for restoring bronze parts, there are practically no technologies using metal powders from non-ferrous metals. Electroerosive dispersion is an energy-efficient process that makes it possible to obtain powdered copper and bronze from machine-building waste with lower costs and environmental impact. (Research purpose) The research purpose is in evaluating the physical and mechanical properties of bronze powders obtained by electroerosive dispersion from machine-building waste, and justifying the possibility of their application in the technologies of repair and restoration of parts. (Materials and methods) Authors received material for research on their own experimental facilities of the Nano-Center Central Research Center. Authors used an inverted metallographic microscope Olympus GX-51, a TESCAN VEGA II scanning electron microscope with an INCA Energy 350 X-ray spectral analysis system, a Microtrac Bluewave laser particle size analyzer, a Niton XL3t GOLDD+ X-ray fluorescence spectrometer, and a KMT-1 microhardness meter. (Results and discussion) The article presents qualitative and quantitative indicators of the bronze powder obtained by electroerosive dispersion, and the properties of this powder were evaluated for a specific method of production. The article presents granulometric composition of the powder, the shape and morphology of the particles, the fractional composition, microhardness and chemical composition. (Conclusions) In the studied powder, particles with a regular spherical shape prevail. The decrease in microhardness is explained by the recrystallization process. Differences in the chemical composition are explained by the interaction with the working fluid and various elements of the installation structure. Powder material obtained from bronze waste by electroerosive dispersion mostly corresponds to the parameters of the source metals and is suitable for the restoration and repair of parts.

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