This study examines the effectiveness of processing dispersed strontium hexaferrite material in a beater mill within a magneto­liquefied layer formed by magnetic fields – an inhomogeneous alternating field with a frequency of 50 Hz and an induction gradient of 90 mT/m, and a constant field with an induction of 15.3 mT – under conditions where milling is accompanied by particle aggregation. The magnetic field lines are mutually perpendicular and parallel to the plane of the milling bodies. A comprehensive investigation of the changes in the dispersed composition and structural characteristics of the strontium hexaferrite powder with increased milling duration was conducted using scanning electron microscopy and X-ray diffraction analysis. The results show that processing the strontium hexaferrite dispersed system with an initial average particle size of 1558.5 µm in a magnetoliquefied layer for 120 min does not alter the phase composition of the powder. However, milling reduces the average particle size to 0.57 µm, decreases the size of the coherent scattering regions, increases the lattice microstrain of the SrFe₁₂O₁₉ phase, and raises the dislocation density. Magnetic properties of the powder samples before and after annealing were studied using a vibrating sample magnetometer at room temperature and normal atmospheric pressure. The conducted research allows for the assessment of the technological outcomes of processing the dispersed system in a magnetoliquefied layer, considering the collective effects that accompany milling.

A chemical-metallurgical method was used to synthesize fine tungsten powders with low oxygen content. The tungsten powders were obtained by hydrogen reduction of tungsten trioxide (WO₃) powders. Hydrogen was passed through a column with potassium hydroxide for drying. In the first series of experiments, three fractions of WO₃ powder of grade “P” 64–100 µm, 40–50 µm, and less than 25 µm were reduced at temperatures of 650, 800, and 950 °C. In the second series of experiments, tungsten powders were obtained by hydrogen reduction of three different WO₃ powders of grades “P”, “CP”, and “Tumelom”. The resulting tungsten powders had varying oxygen contents (0.043–2.18 wt. %) and average particle sizes ranging from 35 to 345 nm. X-ray diffraction analysis confirmed the presence of pure tungsten. The minimum oxygen content (0.043 wt. %) in the tungsten powder was achieved by reducing tungsten oxide of grade “CP” at 950 °C for 3 h.

To tackle the pressing challenge of protecting steel products in marine and coastal infrastructure from corrosion and tribo­corrosion, high-entropy coatings in the FeCrNiCo–Mo_x system were developed using automated vacuum electrospark deposition with specialized equipment. Discs with a diameter of 30 mm made from 30Kh13 steel were used as substrates. The coatings were applied using FeCrNiCo–Mo_x electrodes, where x = 0, 5, 10, and 15 at. %, produced by powder metallurgy. The structure, elemental, and phase compositions of the coatings were evaluated using XRD, SEM, and EDS methods. FeCrNiCo–Mo_x coatings were obtained through the remelting of the substrate and electrode material. Coatings with a moderate molybdenum content (2–5 at. %) formed a single-phase solid solution with an FCC lattice. At a Mo content of around 7 at. %, the formation of a second phase based on molybdenum with a BCC lattice was observed. The thickness of the FeCrNiCo coatings was 45 µm, while the addition of molybdenum to the coatings reduced this thickness to 32–34 µm. The corrosion and tribocorrosion resistance of the coatings was assessed in artificial seawater using electrochemical and tribological methods. Under stationary corrosion conditions, the coating with 2 at. % Mo exhibited the highest corrosion resistance, with a corrosion potential of 50 mV and a corrosion current density of 2 µA/cm². Under tribocorrosion conditions, the coating with 5 at. % molybdenum demonstrated the highest wear resistance, with a value of 2·10^–5 mm³/(N·m).

A study was conducted to investigate the influence of oiling agents with various formulations on the properties of coreless silicon carbide fiber from the perspective of its technological qualities. The oiling agents investigated included formulations of PMS-5, PMS-10, PMS-20 in isopropyl alcohol and acetone, aqueous emulsions of PMS-200 with the addition of dispersant IVP-317 and polyvinyl alcohol, an aqueous solution of PEG-400 (30 %), and an aqueous solution of starch (10 %). The evaluation of the oiling agent’s impact on the technological properties of the fiber was carried out through tensile strength testing, determination of the minimum bending radius, examination of the surface morphology of the oiled fibers, and the ability of the tested composition to bundle filaments together and reduce fuzzing. It was found that oiling agents using acetone and isopropyl alcohol as solvents led to the deterioration of the technological qualities of the treated fibers, significantly increasing their brittleness. The aqueous solution of polyethylene glycol (PEG-400) (30 %) poorly distributed on the fiber surface and reduced the strength characteristics of the samples after treatment. The strength of the samples treated with an aqueous starch solution (10 %) was found to be close to that of untreated fibers in tensile testing. This composition improved the homogeneity of the bundle and exhibited the best bonding pro­perties on the filaments within it, but the increased brittleness of the fibers after drying significantly reduced their technological efficiency. The use of PMS-200 aqueous emulsion with IVP-317 contributed to increased homogeneity and flexibility of the bundle but led to a deterioration in the strength characteristics of the samples compared to pure fiber. The best result was shown by the PMS-200 emulsion with the addition of polyvinyl alcohol and dispersant IVP-317. This composition increased flexibility, reduced fuzzing, and improved the technological properties of the treated fibers, with only a slight reduction in the strength of the samples. The results obtained suggest that the aqueous emulsion based on polymethylsiloxane (PMS-200) and polyvinyl alcohol is the most effective oiling agent for coreless silicon carbide fiber.

ZrBN coatings were deposited by reactive pulsed magnetron sputtering using a ZrB₂ target while varying the pulse duration. The composition and structure of the coatings were studied using scanning and transmission electron microscopy, energy dispersive, optical emission and glow discharge Raman spectroscopy, as well as X-ray diffraction. Optical properties were studied by spectrophotometry. Erosion resistance was determined under laser exposure. All coatings were amorphous, had a dense, defect-free structure and a uniform distribution of elements throughout the thickness. According to Raman spectroscopy, the coatings contain B–N and Zr–N bonds. The coatings were characterized by high optical transmittance of 70–90 % in the wavelength range 450–1300 nm. The reflectivity of coatings was 9–26 %. The refractive index value increases from 1.7 to 3.0 as the wavelength increases from 200 to 1200 nm. The glass substrate is fragilely destroyed during erosion at a power of 20–60 W. All coatings successfully protect the glass substrate from erosive wear: the application of ZrBN coatings leads to a reduction in the width and depth of the erosion zone of the glass substrate by 1.3 and 4.5 times, respectively. The coating obtained at the optimal pulse duration has better erosion resistance, which may be due to its higher adhesive strength.

The study focuses on investigating the influence of ultrasonic vibrations introduced into the crystallizing metal of the weld pool through filler wire during automated electric arc surfacing with flux-cored wire, on the formation characteristics of a wear-resistant coating made from the 280Cr14Mn6Ni6Mo3Ti2Nb2 alloy. The effect of ultrasonic vibrations on the structural-phase composition, hardness, and wear resistance of the surfaced coating is analyzed, particularly under normal and elevated temperatures up to 600 °C in conditions of exposure to a gas-abrasive flow. The failure pattern of the thin surface layers of the worn coatings is also studied. It was established that the microstructure of the coating consists of a carbide eutectic based on austenite, which possesses increased ductility and sufficiently high strength due to alloying with chromium and molybdenum. This ensures reliable retention of reinforcing phases represented by Мо₂С, (Ti,Nb,Mo)_xC_y, and Me_xC_y carbides. It is shown that under the influence of high-frequency acoustic vibrations, large primary Me_xC_y carbides disappear from the alloy structure, the volume fraction of austenite increases by 25 %, and the proportion of Me_xC_y-type carbides decreases. Additionally, a redistribution of alloying elements between the austenite and carbide phases is observed. The formation of a fine lamellar eutectic leads to changes in the wear mechanism of the alloy: hard solution layers dampen shear deformations caused by impacts of abrasive particles, while the plastic flow of the austenitic matrix forms a metallic binder around the broken carbide fragments, reducing the likelihood of their detachment. This results in an 18 % increase in the alloy’s resistance to high-temperature gas-abrasive wear, surpassing the performance of an international industrial counterpart.

Cutting inserts made from the WC–5TiC–10Co hard alloy were produced by sintering blanks that were pressed in a plastic mold made from polylactide on a 3D printer using a layer-by-layer deposition method. The effect of pressing pressure and plasticizer (rubber) content in the powder mixture on the density of the blanks was studied. As the pressing pressure increased from 50 to 200 MPa, the density of the blanks rose by only 2–6 %. When the plasticizer concentration in the powder mixture increased from 1 to 6 %, the blank density increased by 28–32 %. It was found that the density values of the cutting insert blanks obtained in a plastic mold differed only slightly from those of standard blanks produced in a steel mold. After sintering in a vacuum furnace at 1450 °C, the density, carbon content, porosity, microstructure, surface roughness, hardness, and fracture toughness of all the sintered cutting inserts, standard samples, and the commercial equivalent were investigated. It was shown that the formation of free carbon as a result of rubber decomposition leads to a decrease in the density of the finished products, and therefore, their hardness. The relative density (98.7 %) of the cutting insert produced in the plastic mold at a pressing pressure of 50 MPa from powder containing 1 % rubber exceeded the density of the commercial cutting insert (98.5 %). The obtained cutting insert demonstrated high hardness (1400 HV) and fracture toughness (13.5 MPa·m^1/2). The cutting insert made from the WC–5TiC–10Co alloy is not inferior to the commercial T5K10 hard alloy insert in terms of flank wear rate during turning of a steel workpiece.

Modern technologies must meet the criteria of sustainable development, taking into account economic, environmental, and social indicators. In this study, the potential use of graphite-containing sludge from the gas purification aspiration system during cryptocrystalline graphite production was investigated for its inclusion in composite anti-burn coatings for cast iron casting. The graphite-containing sludge consists of carbon, sulfur, sodium, aluminum, and silicon, with a phase composition that includes graphite, calcite, pyrite, quartz, halite, and others. The sludge is a dispersed material with an average particle size of 3.64 µm, a total surface area of 36,506 cm²/cm³, and a main fraction size of 1–8 µm. Sludge particles exhibit various shapes, ranging from irregular to isometric. Larger isometric particles can reach sizes of 1 mm or more. On the surfaces of larger particles, smaller dispersed particles are present. The structural parameters of the sludge correspond to those of hexagonal graphite. The analysis of the composition and properties of graphite-containing sludge suggests its suitability for use in composite anti-burn coating formulations. However, due to the presence of large graphite aggregates and acicular impurities in the sludge, sieving is required before use. Complete replacement of natural graphite with sludge increases the coating density from 1220 to 1750 kg/m³, viscosity from 34 to 105 s, and abrasion resistance from 175 to 245 g/mm. Due to its high dispersity, the sludge-based coating nearly completely penetrates the pores of the sand-resin mixture mold without forming a cover layer. This does not ensure consistent reduction of burn-on defects on casting surfaces. Therefore, the full substitution of graphite with graphite-containing sludge in composite coating formulations is not recommended.