The purpose of this study was to obtain molybdenum powder by processing molybdenum waste by electroerosive dispersion in distilled water, as well as to study the morphology and granulometric particle size of the resulting  powder.

Methods. Molybdenum waste was processed into powder at an experimental electroerosive dispersion plant (RF Patent № 2449859) in distilled water. The morphology and granulometric particle size of the obtained electroerosive molybdenum powder were studied using modern equipment and complementary methods of physical materials science: grain composition and results of dispersion analysis of average particle size (laser particle size analyzer Analysette 22 NanoTec); the shape and condition of the particle surface (scanning electron microscope (SEM) Quanta 200 FEG).

The results of the study of the physical properties of the powder material obtained at the experimental facility by electrodispersion of molybdenum waste in an aqueous medium indicate the high efficiency and cost-effectiveness of the electrodispersion technology, which ensures the production of molybdenum powder with a spherical particle shape, which is not inferior in its characteristics to industrially used powders. The following characteristics of molybdenum powder obtained by electrodispersing molybdenum waste have been experimentally established: the shape of molybdenum electroerosion powder particles is spherical, small particles of molybdenum powder form agglomerates; the particle sizes of molybdenum powder are from 0,25 to 100 microns; the average volumetric diameter is 38 microns; the specific surface area is 0,09 m2/g.

Conclusion. The conducted studies on the production of molybdenum powder from molybdenum waste by electroerosive dispersion will allow for the reuse in various industries of such an expensive and difficult-to-extract metal as molybdenum.

The purpose of the study is to identify the regularities of the formation of structural-phase transformations of the surface layers of technically pure titanium VT1-0 after various types of combined treatment.  

Methods. The article discusses two types of combined processing of technically pure titanium VT1-0: electro-explosive carburization + heat treatment and electro-explosive doping with yttrium + electron beam treatment. In the first case, electro–explosive carburization was carried out by introducing carbon graphite fibers into the explosion area, and in the second, a titanium foil weighing 100 mg was used as the explosive material, on which yttrium powder weighing 400 mg was placed. The structure of the alloyed layers was studied by light microscopy of straight and oblique cuts after chemical etching. The phase composition of the surface was determined using a DRON-2.0 diffractometer in the radiation of an iron anode. 

Results. As a result of the electroexplosive carburization of technically pure titanium VT1-0, a doping zone with a thickness of 20 microns was formed, a zone of thermal influence passing into the base is visible below. In both cases, a melting and alloying zone with a thickness of about 40 microns and a zone of thermal influence passing into the base were identified. The phase composition of the alloying zone includes titanium carbide, which significantly increases the functional properties of the modified layers. The three-phase composition of the zone of electroexplosive carburization of titanium, represented by a solid solution of carbon, titanium carbide and graphite, was confirmed by X-ray phase analysis.

Conclusion. Combined processing leads to the formation of a multilayer structure; a change in the phase composition of the material; improvement of surface quality without mechanical impact; increase in depth and increase in the functional properties of the hardening zone.

Purpose. Optimization of the process of electrodeposition of composite coatings from electrolytes-suspensions by the microhardness of coatings.

Methods. The wear-resistant powder for the electrolyte-suspension was obtained by electrodispersing waste of highspeed steel grade P6M5 in a liquid working medium. Electrodeposition of composite coatings from electrolytes-suspensions with the addition of electroerosive powders obtained from waste of high-speed steel grade P6M5 was carried out at the galvanic installation L1 DIGIT (Italy). Optimization of the process of electrodeposition of the electroerosion charge by microhardness was carried out by setting up a complete factor experiment and the method of steep ascent of Box and Wilson. The adequacy of the equations was checked using the Fisher criterion. Regression equations were checked for adequacy. The resulting equations were used to calculate the steep ascent along the response surface. Results. Based on the conducted experimental studies aimed at optimizing the process of electrodeposition of composite coatings from electrolytes-suspensions, the high efficiency of the use of electroerosive powders obtained from waste high-speed steel grade P6M5 as a hardening phase, which provides at low energy costs the production of wearresistant coatings suitable for practical use.

The limiting values of the optimization parameter y (microhardness) of 0.726 GPa at a current density of 20 A/dm², a deposition time of 60 minutes and a concentration of 5 g/l were experimentally determined for the ironification process. Conclusion. The conducted research will solve the problem of restoration and hardening of parts operating under conditions of intense wear by electrodeposition of composite coatings from electrolytes-suspensions. Practical examples of the implementation of the developed technology of electrodeposition of composite coatings from electrolytessuspensions with powders obtained by electroerosive dispersion of metal waste have shown that coatings with a dispersed phase have unique properties and can be used to solve a variety of tasks.

Purpose. Conducting an experiment aimed at the study of new tungsten-free hard alloys obtained on the basis of electroerosive tungsten-free carbide powder materials dispersed in a carbon-containing working fluid (kerosene lighting).

Methods. Spark plasma sintering systems SPS 25-10 Thermal Technology were used to obtain new tungsten-free hard alloys. Electroerosive tungsten–free carbide powder materials obtained by dispersing carbonitride alloy waste in a carbon-containing working fluid - lighting kerosene were selected as the material. After obtaining a sintered sample of a new tungsten-free hard alloy, studies of its elemental and phase compositions were carried out using an energydispersion X-ray analyzer from EDAX, built into a scanning electron microscope QUANTA 600 FEG and an X-ray diffractometer Rigaku Ultima IV.

Results. During the study, it was experimentally established that the main elements of the new alloy are Ti, Ni, Mo and C, which directly depends on the composition of the electroerosion powder. Analysis of the diffractogram of the phase composition of a new tungsten-free hard alloy obtained on the basis of an electroerosion powder showed the presence of titanium carbide phases TiC, as well as molybdenum nickelide MoNi₃ and pure nickel Ni and molybdenum Mo, which is also directly related to the phase composition of the electroerosion charge.

Conclusion. The obtained experimental data results allow us to conclude that the elemental and phase compositions of new tungsten-free hard alloys obtained by sintering an electroerosive powder material dispersed in a carbon- containing medium from carbonitride tungsten-free alloy waste depend on the composition of the starting material (charge).

Purpose. To study the effect of cyanidation on the structure of electrodeposited iron-tungsten and iron-molybdenum coatings.

Methods. To obtain electrodeposited iron-molybdenum and iron-tungsten coatings, chloride electrolytes of medium concentration were used. Ammonium molybdate (NH₄)₆Mo₇O₂₄∙4H₂O acted as a dopant in the electrolyte in the first case, and sodium tungstate NaWO₄∙4H₂O in the second case. Citric acid C₆H₈O₇ was used as a complexing agent. To carry out the experiments, the electrolyte was prepared from reagents of the chemical grades "HCh" and "ChDA", which were dissolved in distilled water. The acidity of the electrolyte was controlled using a Laboratory PhMeter 766 device. Cyanidation of the coatings was carried out in a pasty medium at temperatures of 873–923 K. The basis of the paste was carbon black and a nitrogen-containing component, in the ratio of 50% soot, 50% yellow blood salt. An organic adhesive was used as a binder.

Results. The maximum microhardness of iron-molybdenum coatings was 8300 MPa. These values were obtained for coatings containing 1.2...1.5% of the alloying element. The microhardness of coatings containing tungsten (1.75... 1.8% W) is at the level of 8250...8300 MPa. According to our data, alloys of electrodeposited iron with molybdenum (1.5% Mo) and tungsten (1. 8%W). The wear resistance of these coatings is much higher than the wear resistance of both pure electrodeposited iron coating and the base metal. The thickness of the studied coatings was 0.3...0.4 mm, the specific load at boundary friction was 7.5 MPa.

Conclusion. Cyaniding of electrodeposited alloyed iron makes it possible to obtain carbonitride layers of considerable thickness, having a hardness of up to 13000 MPa, as well as high wear resistance (5-6 times higher than the wear resistance of coatings without cyanidation).

The results of the study of cyanidation of electrolytic alloys used in the restoration of worn machine parts served as the basis for the development of a technology for hardening parts, convenient for repair production, which can significantly increase their durability, and, consequently, the reliability of repaired machines.

The purpose of the work was to study the influence of laser processing modes (cutting, cleaning, grinding) on the change in the structure and mechanical properties of the surface layer of parts made of 30XGSA steel obtained by various methods. 

Methods of research. As an object of study, we chose medium-alloyed structural steel grade 30KhGSA in cast (rod Ø8 mm) and hot-rolled (sheet 6 mm thick) states. To study the effect of laser cleaning on the change in the structure and mechanical properties of machine parts using laser cutting, special samples were made.

Results. It has been established that laser cleaning of hot-rolled steel grade 30KhGSA without preliminary surface treatment (in particular, mechanical grinding) leads to the formation of microcracks. Regularities of changes in the structure of the gas-laser thermal impact zone after laser cleaning are revealed. It is shown that laser surface cleaning leads to the formation of a denser structure and an increase in microhardness, which occurs due to the diffusion of carbon to the surface layers of the part. It has been established that the nature of the change in microhardness for all studied samples of 30KhGSA steel in the cast and hot-rolled states is the same: the highest values are achieved near the surface of gas-laser treatment and are, for example, for cast steel 250-320 HV, which is 1,3-1,6 times greater than the initial microhardness (194 HV), and for hot-rolled steel 247-273 HV, which is 1,5-1,6 times greater than the initial microhardness (168 HV). Thus, a hardened layer with increased wear resistance is formed on the surface of the part after gas-laser processing (laser cleaning and laser polishing).

Conclusion.The results obtained can be used in the creation of resource-saving material processing processes.

The purpose of this work is to compare the composition, structure and properties of lead-antimony alloys made by spark plasma sintering of powders obtained by electrodispersing waste of the CCu3 alloy in distilled water and lighting kerosene. 

Methods. Recycling of the initial SSu-3 alloy was carried out at an experimental facility for electrodispersion. The dispersion process was carried out in two working media - in kerosene and in water. As a result, a charge of a leadantimony alloy was obtained. Then the resulting charge was fused in the SPS 25-10 Thermal Technology system. The composition, structure and properties of the obtained alloys were studied using modern metallographic equipment.

Results. It has been established that the spark plasma fusion method makes it possible to obtain alloys from the resulting charge that have properties different from those used industrially. It is noted that the surface of these alloys is heterogeneous, has pores and cracks. X-ray spectral analysis of the alloy obtained in kerosene and distilled water showed that Pb, O and Sb are contained on the surface of both alloys. The analysis of the phase composition showed that the composition of the alloy obtained in kerosene lighting contains such phases as Pb₂OCO₃, Pb₂O₃, Sb₆O₁₃ and the phase of pure Pb, the composition of the alloy obtained in distilled water includes such phases as Sb₂O₄, Pb₃O₄ and the phase of pure Pb. Porosity analysis of the obtained alloys showed that the number of large pores is higher in the alloy obtained in water, but the pore area is lower than in the alloy obtained in kerosene. As a result of testing both alloys for microhardness, it can be concluded that the alloy obtained in distilled water has a higher microhardness.

Conclusion. The paper solves an important scientific and practical problem aimed at creating a progressive, environmentally friendly, low-tonnage and waste-free technology for producing new lead-antimony powders suitable for industrial use and alloys based on them.

Purpose. To develop a method for generating active bubbles and droplets containing a non-magnetic core and a shell of magnetic fluid, as well as to study the influence of the magnetic field on their dynamics.

Methods. The experiments were carried out on an experimental setup for studying the dynamics of droplet and bubble flow in magnetic liquids, developed based on known methods. An annular permanent magnet placed on top of an electromagnet was used as a source of an inhomogeneous magnetic field. A permanent magnet was used to study the effect of an external magnetic field on the dynamics of bubbles or droplets. The supply of the non-magnetic phase into the channel was carried out using a syringe pump. The dynamics of droplet and bubble flows were recorded by the passing light of the illuminator using a high-speed camera (Nikon 1).

Results. Studies of the dynamics of active bubbles and droplets formed in an inhomogeneous field of an annular magnet were carried out by injection a non-magnetic phase into a magnetic liquid. The influence of the magnetic field configuration on the velocity, acceleration, and size of active droplets has been studied. The phenomenon of selforganization of bubbles on the surface of the oil layer and the influence of an external magnetic field on the resulting inclusions are shown.

Conclusion. During the experiment, it was found that the separation of non-magnetic droplets and bubbles occurs from a levitating non-magnetic volume. The size and dynamics of bubbles and droplets can be controlled using an external magnetic field. As the current increases, the droplet velocity increases, the acceleration decreases, and the size decrease. This is due to a change in the configuration of the field created by the combined magnetic field source. With the phenomenon of self-organization of non-magnetic bubbles covered with a magnetic shell, it can be noticed that their diameter decreases with increasing concentration of magnetic fluid and the thickness of the shell increases. The application of a magnet in the direction of the bubbles makes the magnetic shell of the bubbles thinner, which leads to further destruction of the bubbles in cases when they are covered with a shell of low-concentrated MF. In the case of bubbles covered with a shell of concentrated magnetic liquids, they do not collapse.

Purpose of the study. To develop and manufacture a device based on a piezoactuator for mechanical deformation of samples during examination with an atomic force microscope. Study of the evolution of nanostructured surfaces using atomic force microscopy under mechanical stress.

Methods. Measurements of the movement of the piezoactuator by the capacitive method; examination of the surface on a confocal microscope; the formation of the studied films by magnetron sputtering; study of the topography of the surface of samples on an atomic force microscope.

Results. A test model of a device built into an atomic force microscope was made to study the deformation (compression) of samples using a piezoactuator. The capabilities of the device were tested using a confocal microscope. The spatial resolution of the device was achieved, which amounted to D±∆D = 1.071±0.160 µm (accuracy  15%), which made it possible to detect deformation of the surface of the fixed sample. Taking into account the highest temperature of transition to the superconducting state among metals, the choice of niobium as a material for studying structural changes during compression of a magnetron nanofilm on a substrate in the form of a metal plate with high elastic properties, which is characteristic of the HDD sensor head holder, is justified. Studies in the in situ compression mode of a niobium magnetron nanofilm using an atomic force microscope established and described nanoscale changes in the surface structure of a niobium nanofilm under the influence of a piezoactuator.

Conclusion. The tests carried out under the conditions of linear and controlled deformation, combined with nano- and microstructural studies in the in situ mode by atomic force microscopy, showed structural changes of the surface of the magnetron nanofilm from niobium, which indicates the activation of the mechanism of surface aggregation of nanoclusters forming the film.

Purpose. To investigate the surface shape of a flat layer of a magnetic fluid with a ferromagnetic cylindrical body in a uniform magnetic field

Methods. Magnetic fluids based on transformer oil MMT-44 and MMT-10 with saturation magnetization of 43.8 and  9.6 kA/m, respectively, were used in the experiments. A flat layer of magnetic fluid was formed by filling a non-magnetic rectangular cell 57x102 mm in size. The source of a uniform magnetic field is Helmholtz coils with a cylindrical working area 0.2 m in diameter and 0.2 m high. Deviations of the magnetic field strength do not exceed 0.2% in the area where the cell with the magnetic fluid is located. Distortions of a uniform magnetic field were created by a steel rod 10 mm in diameter placed in a magnetic fluid. A study was made of the deformation of the surface of a magnetic fluid in fields of different directions in the range of intensity up to 30 kA/m.

Results. Above a cylindrical ferromagnetic body immersed in a magnetic fluid, the fluid surface was studied under the action of a uniform external magnetic field. Also identified experimental dependences of the deformation amplitude of the free surface of liquids with different saturation magnetization on the magnitude of the acting external field in different directions. The phenomenon of hysteresis of the shape of the free surface of a ferromagnetic fluid is established when the direction of the change in the magnetic field changes. The range of critical fields in which the hysteresis of the free surface shape was observed was established.

Conclusion. The results of the study show that the shape of the free surface of a magnetic fluid with a cylindrical ferromagnetic rod is determined by the nature of the distortion of the uniform magnetic field introduced by the rod. The nature of the field distortion depends on the orientation of the rod relative to the field. The saturation magnetization, as well as the thickness of the liquid layer above the body, affects the shape of the liquid surface in addition to the orientation of the body. The results are of interest in the development of magnetically controlled heat exchange technologies, in vibration protection systems, as well as for control and measuring systems.

Purpose of research. Study of the conditions for the express determination of Mn, Si, Ca, Al, S forming nonmetallic inclusions in manganese steels using the ARL iSpark 8860 atomic emission spectrometer with spark excitation of spectra, evaluation and improvement of the calibration characteristics of the determination of elements, statistical confirmation of the correctness of measurement results.

Methods. Determination of elements forming nonmetallic inclusions  was carried out on an atomic emission spectrometer with spark excitation of spectra ARL iSpark 8860 manufactured by Thermo Fisher Scientific (USA). The preparation of samples for atomic emission spectral analysis was carried out using semi-automatic milling and flat-grinding machines. 

Results. The relevance of the development of an express methodology for the quantitative assessment of the level of non-metallic inclusions is substantiated and the prospectivity of using the spark atomic emission spectral method to determine the concentration of non-metallic inclusions in metal products is confirmed. Metrological characteristics of determination of mass fractions of Mn, Si, Ca, Al, S forming nonmetallic inclusions in manganese steels, equations of calibration functions and correlation coefficients, limits of detection and quantitative determination are established. The necessity of adjustment of calibration charts with the use of standard samples of the composition of manganese steels is shown. The improvement of the metrological characteristics of spectral analysis using standard samples of the composition of manganese steels UG-90 and UG-102 produced by ISO CJSC in the operating range of concentrations of the defined elements, reduction of the detection limits of Mn, Al and the error of determination for Mn, Si, Ca, Al was confirmed.

Conclusion. The metrological characteristics of determining the mass fractions of Mn, Si, Ca, Al, which make up the main nomenclature of nonmetallic inclusions (NMI) of manganese steels, have been improved. The high precision of measuring the concentration of elements included in the inclusions of the following types has been statistically confirmed: Al₂O₃, Al₂O₃-CaO-MgO, Al₂O₃-MgO, Al₂O₃-MnS, Al₂O₃-MnS-CaS, Al₂O₃-MnS-MgO, CaS, MnS. Using a simple Student's test, the absence of a systematic error in the results and the correctness of the determination of Mn, Si, Ca, total and soluble Al, which make up non-metallic inclusions, are shown. The successfully completed first stage of the study, in turn, will allow a high degree of reliability to assess the level of inclusions by spark atomic emission spectrometry in manganese steels.

The purpose of the work was to study the effect of the composition of the dye solution on the choosability of the dye and the quality indicators of the resulting coloring when dyeing textile materials of various nature with a direct dye.

Methods. The dyeing process was carried out using a direct scarlet light-strong dye. Textile materials of various natures were dyed: natural (cotton), artificial (viscose) and mixed (caproacetate). Dyeing was carried out using dye solutions according to the classical recipe of dyeing with direct dyes and using electroplating as additives.

The experiment was carried out in a kinetic version, where samples were taken at certain intervals during the process to analyze the dye content. The quantitative content of the dye in the working solution was monitored using a spectrophotometer of the PE-5400V type using the spectrophotometry method.

The work was carried out using aqueous dye solutions, in which distilled water obtained using an electric DEM 10 distiller acted as a medium. The process temperature was maintained using the UT-4300E ultrathermostat.

Results. Graphic and kinetic dependences of the content and selectivity of the direct scarlet light-resistant dye by various textile materials are obtained.

The conducted studies allow us to assert that the process of dyeing with a direct dye of cotton, viscose and caproacetate can be carried out in the presence of galvanic production waste. The dependence of the saturation and stability of the coloring obtained by dyeing textile materials of various nature in the presence of electroplating as an additive to physical and chemical influences has been established. Everywhere there is an increase in the color resistance to washing, dry and wet ironing and friction.

Conclusion. It has been revealed that the introduction of galvanic production waste into the dye solution has a positive effect not only on the choosability of direct dye by textile materials of various nature, but also on the resistance of coloring to various physical and chemical influences, namely: soap and soda treatments, dry and wet ironing and friction.