This article presents the production of nanosized powders of cobalt ferrospinel through mechanochemical synthesis, resulting in an average particle size ranging from 3 to 15 nm. The elemental composition of the nanopowders, analyzed using X-ray fluorescent analysis, is found to be nonstoichiometric and can be represented by the formula: Co_0.7±0.05Fe_2.3±0.05O₄. When the duration of mechano­chemical synthesis exceeds 25 min, the spinel phase constitutes approximately 90 vol. % in the samples. Additionally, the samples contain hematite phases, the beta modification of iron hydroxide, and an X-ray amorphous phase. Natural aging at room temperature leads to significant changes in the phase composition of the nanopowders. Specifically, there is an increase in the content of spinel phase, while the content of hematite and the amorphous phase decrease significantly. Furthermore, the saturation magnetization and effective field of anisotropy of the cobalt ferrospinel nanopowders exhibit noticeable increments. Consequently, thermal aging of the powders accelerates the changes in phase composition, structural parameters, and magnetic properties, as well as enhances the transformation extent during the formation of cobalt ferrospinel.

This research focuses on investigating the ignition and thermal explosion behavior of (Ti, Zr, Hf, Nb, Ta) + 5C mixtures that have been mechanically activated. First, we mechanically activated the metal powder mixtures to produce composite particles consisting of Ti, Zr, Hf, Nb, and Ta, followed by the addition of carbon, and re-activation. An activation time of 120 min at 347 rpm resulted in the formation of solid solutions from the metals in the mixture, while large tantalum particles were preserved. The resulting mixtures were then pressed into pellets, which were heated in argon until ignition occurred. The ignition process involves multiple phases, with the first being inert heating, followed by progressive heating at t = 420÷450 °C, and a  subsequent endothermic phase transformation at 750–770 °C. The temperature then rises rapidly, resulting in a thermal explosion that forms complex carbides, leaving some unreacted tantalum behind. The (Ti, Zr, Hf, Nb, Ta)C₅ activated mixtures and high entropy solid solution are unstable and  release titanium and zirconium carbides when heated above 1300 °C, causing changes to the composition of the (Ti, Zr, Hf, Nb, Ta)C₅ final product. When diluted by adding 25 and 50 % of the final product, the effective activation energy E_a for the (Ti, Zr, Hf, Nb, Ta) + 5C reaction in the 1100–1580 °C temperature range was found to be 34 kJ/mol.

The study explored various facets of the structure of dispersed-reinforced aluminum alloy-based metal composite material (MCM) under different modes of thermomechanical treatment. Replacing traditional structural materials with MCM provides manufacturers with an opportunity to achieve higher levels of engineering superiority. The ability to choose composition, modify primary component ratios, and employ a range of MCM manufacturing techniques allows for precise tuning of the material's strength, rigidity, temperature range, and other physical and mechanical properties. Two prevalent technologies for crafting dispersed-reinforced aluminum alloy-based MCM exist: liquid-phase and powder technologies. Liquid-phase methodology entails merging the reinforcing component into the binder alloy's melt, followed by crystallization. This process guarantees the dispersion and fixation of reinforcing particles within the binder volume. In contrast, powder technology involves simultaneous processing of primary component powders in high-energy mills, with subsequent amalgamation of the resultant composite granules via pressure molding. The chief aim of thermomechanical treatment lies in yielding blanks that closely mimic the final product's geometry and reshaping the deformable material's structure to heighten its strength properties. Powder technology was employed to fabricate monolithic composite material samples. Their structures were analyzed, accompanied by tests to ascertain density and strength parameters of the MCM at room temperature. Consequently, dispersed-reinforced aluminum alloy-based MCM possessing a uniform structure, density exceeding 99.0 % of the theoretical value, and elevated mechanical attributes: σ_u = 300÷305 MPa and E = 87÷95 GPa, were successfully produced.

The study investigated the influence of La₂O₃ addition on the oxidation properties of composite ceramics with a composition of 80 vol. % ZrB2 and 20 vol. % SiC. The source materials utilized in this study included zirconium diboride (DPTP Vega LLC., Russia), grade 63C silicon carbide (Volzhsky Abrasive Works JSC, Russia), and lanthanum hydroxide concentrate (Solikamsk Magnesium Plant JSC, Russia), with the following elemental content (wt. %): La – 54.2, Nd – 4.3, Pr – 2.8, and trace amounts of other elements (<0.1). The La₂O₃ content in the charge varied between 0, 2 and 5 vol. %. The powders were mixed in a planetary mill with ethyl alcohol as the medium for 2 h, using a grinding media to powder ratio of 3:1. Consolidation of the powders was achieved through spark plasma sintering at 1700 °С, applying a pressing pressure of 30 MPa. The heating rate was 50 °С/min, and the isothermal holding time was 5 min. Oxidation was carried out in air at 1200 °С and the total oxidation time was 20 h. Oxidation experiments were conducted in air at 1200 °С, with a total oxidation time of 20 h. It was observed that the most significant weight gain occurred within the first 2–4 h of testing. Specimens containing 5 vol. % La₂O₃ exhibited the smallest weight gain after 20 h of exposure. Regardless of the presence of La₂O₃, silicon carbide was found to be the first material to undergo oxidation. In specimens without La₂O₃ addition, the oxidized layer mainly consisted of silicon monoxide and dioxide. In contrast, specimens with La₂O₃ exhibited a predominantly oxidized layer composed of ZrSiO₄ and ZrO₂. The study revealed that the introduction of La₂O₃ intensified the formation of zircon, which subsequently slowed down the oxidation processes in the material.

The thermodynamic calculations conducted using the TERRA software package for the B–Cl–N–H system revealed that the inclusion of hydrogen into the B–Cl system significantly diminishes the thermodynamic stability of BCl₃ with the possibility of boron formation in the condensed phase. On the other hand, the introduction of ammonia, which includes hydrogen, results in the synthesis of boron nitride across a broad temperature spectrum.  The analysis of kinetic relationships uncovered three distinct regions in the boron nitride deposition process: K – kinetic region (up to 1400 K), D – diffusion region (above 1800 K) and T – transition region. The activation energy for the kinetic region was calculated as E_a = 134 kJ/mol. Within the temperature range of 1023–1123 K, linear dependences were observed. The computation of the penetration depth for the boron nitride deposition process assumed a gas mixture of boron trichloride, ammonia, and argon (BCl₃ + NH₃ + 30Ar). The results indicated that boron trichloride governs the extent of penetration. The depths of penetration for the chemical vapor infiltration boron nitride (CVI-BN) process, conducted at 0.1 kPa within the temperature range of 1100–1400 K, were determined for pore diameters of 1, 10, 30, 100, 200 and 300 µm. When porosimetry data for a specific preform is available, the acquired penetration depth relationships for the CVI-BN process under specific parameters and process temperatures facilitate the estimation of essential parameters for interphase formation using pyrolytic boron nitride.

The study focused on analyzing the trajectories of powder particles within a plasma flow, a process utilized for applying functional coatings and producing powders. An overview of contemporary scientific research dedicated to modeling these processes is presented. The primary objective of this study was to ascertain how the particle size of the powder, used as a raw material, influences the path of particles within a vertically directed plasma flow. We examined three sizes of titanium powder: 1 μm, 50 μm and 100 μm. These sizes were chosen based on production practices for the considered processes and the particle size distribution of the powder material used in full-scale experiments, employing specialized CAMSIZER-XT equipment. Our study reveals the significant impact of powder particle size on various parameters, including the opening angle, length, and width of the illuminated section of the plasma torch, as well as the distance traveled by particles entrained by the plasma flow from the plasma head. To investigate these effects, we conducted computer simulations, followed by validation through full-scale experiments for each case. Specifically, we employed the MAK-10 laboratory plasma facility at the Institute of Metallurgy, Ural Branch, Russian Academy of Sciences, which is designed for powder production and functional coatings. In order to ensure the reliability of our measurements, we performed statistical data processing of the full-scale experiment results using scatter plots and determination of their average values. The comparative analysis of results from both natural and computer experiments demonstrated a satisfactory level of convergence. This comparative analysis of three particle sizes of powder enabled us to formulate practical recommendations for enhancing equipment and process technology in the context of the considered procedures. Furthermore, our article introduces a computer model capable of predicting the dimensions of the reactor (the chamber for receiving powder materials), the optimal shape of components within the plasma facility, and the positioning of the substrate on which functional coatings are applied. This model can be applied to address similar problems within the scope of this study, facilitating the control of coating application processes and powder production.

This article examines the impact of surface and near-surface layer properties of a hard alloy on the physico-mechanical and tribological properties of Mo–Ti–Ni–Si–Al–N CAPVD-coatings deposited on HG40 and HS123 cutting tools. In both cases, the coatings had similar composition, multilayer architecture, and nanograin structure, with crystallite sizes ranging from 6 to 10 nm. However, there were significant differences in the hardness, elasticity modulus, and relative work of plastic deformation between the coatings. Specifically, on HG40 substrates, the hardness, elasticity modulus, and relative work of plastic deformation were equal to 27.6 GPa, 647 GPa and 38.2 %, respectively, while on HS123 substrates, they were 34.2 GPa, 481 GPa and 46.2 %, respectively. Furthermore, coatings formed on HS123 hard alloy demonstrated superior wear resistance and stronger adhesion. This can be attributed to the presence of higher compressive macrostresses within the coating. The maximum value of this property, approximately 5.2 GPa, was achieved when deposed to HS123 hard alloy, whereas the coating applied to HG40 reached a maximum value of approximately 3.2 GPa. Additionally, a more extensive diffusion zone between the substrate and coating components, along with associated structural phase heterogeneity, was observed at the coating-substrate interface when applied to HS123 substrate.

Ta–Zr–Si–B–C coatings were deposited by magnetron sputtering (MS) of a TaSi₂–Ta₃B₄–(Ta, Zr)B₂ multi-component target in an Ar + C₂H₄ gas mixture. TaC–Cr–Mo–Ni based coatings were obtained by electro-spark deposition (ESD) using TaC–Cr–Mo–Ni electrode. The composition and structure of the coatings were studied using scanning electron microscopy, energy-dispersive spectroscopy, glow discharge optical emission spectroscopy and X-ray diffraction. Mechanical and tribological properties of coatings were determined using nanoindentation and pin-on-disk tests. The study showed that the coatings have a homogeneous and defect-free structure, with the main structural component being the fcc-TaC phase. The MS coating exhibited a 30 % higher concentration of the TaC phase compared to the ESD coating. The TaC crystallite sizes for the MS and ESD coatings were 3 and 30 nm, respectively. The presence of a high fraction of the carbide phase and small crystallite size for the MS coating resulted in superior hardness (H = 28 GPa) compared to the ESD sample (H = 10 GPa). Both coatings exhibited similar values of the friction coefficient (about 0.15) and demonstrated reduced wear rates (<10^–7 mm³/(N·m)). The deposition of coatings on a steel substrate led to a decrease in the friction coefficient by five times and the wear rate by four orders of magnitude. Pilot tests were conducted on coatings applied to wedge gate valve of shut-off devices used in the oil and gas industry for pumping liquids. The results indicated that the service life of the steel wedge gate valve increased by 25 and 70 % with deposited MS and ESD coatings, respectively.