Aluminum oxide is widely used in industry, including as a support for precious metals in three-way catalysts. For this application, the material should have a well-developed surface and high porosity and should withstand three-way catalyst operating temperatures of up to 1100 °C, i.e., it should be thermally stable. An effective way to improve these properties is to introduce lanthanum oxide as a modifying additive. This article compares the surface characteristics and thermal stability of aluminum oxide samples containing 3 wt. % lanthanum oxide, calculated relative to the final mixed oxide. The samples were prepared by different methods: mechanical mixing of aluminum and lanthanum oxides; direct, reverse, and so-called fast precipitation of aluminum and lanthanum hydroxides; incipient wetness impregnation and impregnation in excess solvent of aluminum hydroxide with lanthanum nitrate; by capacity and, and controlled double-jet coprecipitation of aluminum and lanthanum hydroxides. The article examines how the synthesis method affects the characteristics of the resulting material. The samples differed already at the synthesis stage in particle shapes and size , which ultimately led to differences in surface characteristics and porosity. Among the selected precipitation methods, the sample obtained by controlled double-jet coprecipitation had the highest specific surface area. This material can be used in three-way catalysts.

The article presents the results of studying the effect of temperature and duration of stepwise heat treatment on the modification of a copper-zinc coating of the “brass” type, applied by cold gas-dynamic spraying with a phase composition based on copper, a solid solution of the electron type based on Cu₅Zn₈ (γ-phase) and a disordered solid solution based on CuZn₃ (ε-phase) with a mass fraction of 35.6, 41.3 and 14.6 wt. %, respectively. Heat treatment at a temperature of 430 °C for 10 min is accompanied by structural and phase transformations to a composition based on two solid solutions of zinc in copper with a copper content of 94.9 and 59.8 at. % and a solid solution of the electron type based on CuZn (βʹ-phase) with a mass fraction of 8.6, 44.1 and 34.6 wt. %. An increase in temperature by 100 °C for 20 min to 530 °C (V ≈ 5 °C/min) leads to the formation of a coating structure based on a solid solution of zinc in copper with a copper content of 60.2 at. % and a solid solution of the electron type based on CuZn (βʹ-phase) with a mass fraction of 84.7 and 10.4 wt. %, respectively, which in terms of chemical and phase composition corresponds to double brass type CW509L. An increase in the total holding time in the furnace to the maximum of 60 min leads to an increase in the copper content in the α-phase to 62.8 at. %, which is associated with a change in the chemical composition of the coating (Zn = 39.9 at. % → 38.2 at. %) and the coating in terms of chemical and phase composition corresponds to double brass type CW508L. Heat treatment for 40 and 50 min is accompanied by the formation of a coating with the composition of “double brass” based on the α-phase with a copper content of 61.1 at. % and γ-hase and a solid solution of zinc in copper with a copper content of 65.9 at. % and a disordered solid solution based on CuZn₃ , which is due to the violation of the thermodynamic equilibrium between the phase and chemical composition and a change in the nature of the diffusion process. Stepwise heat treatment allows to significantly – up to 6 times reduce the time of modification of the copper-zinc coating of the “brass” type to double brass of the CW509L type.

Different plasticizers and free-carbon additives, can be used not only to improve the formability and compactability of cemented carbide blanks but also to control carbon content. This study examined the effect of plasticizer content of 1, 2, and 4 % for rubber, PEG-4000, and paraffin, as well as graphite and carbon black additives, on the phase composition, density, porosity, hardness, and fracture toughness of products obtained from a WC–6Co powder mixture with insufficient carbon content. An increase in rubber content by 1 % increased the carbon content by 0.2 %. The addition of carbon black and graphite resulted in an equivalent increase in carbon content. Graphite is unsuitable for increasing carbon content because it is distributed unevenly throughout the sample volume, which reduces the material properties. Paraffin and polyethylene glycol used as plasticizers did not cause noticeable changes in carbon content or in the phase and chemical composition of the resulting cemented carbide products. Empirical relationships were developed to predict the carbon content, phase composition, density, hardness, and fracture toughness of the resulting cemented carbide products depending on the initial carbon content and the content of plasticizers or added carbon black. Relationships were also established describing the increase in hardness with increasing η-phase content and the decrease in hardness with increasing free-carbon content. The use of 1 % rubber as a plasticizer and 0.1 % carbon black as an additive compensated for the carbon deficiency of 0.39 % in the medium-grained WC–6Co cemented carbide blanks and increased fracture toughness from 8.4 MPa·m^1/2 for the alloy without a plasticizer to 12.2 MPa·m^1/2 with rubber and 12.7 MPa·m^1/2 with carbon black. High hardness was retained in both cases, with HV values of 1420 and 1410, respectively.

High-entropy ceramics intended for thermal barrier coatings are developed to improve their performance properties, particularly by increasing their operating temperature. However, conventional synthesis of high-entropy ceramics is time-consuming. This study explores a nonconventional approach to reducing synthesis time by processing ceramic materials with a high-power beam of high-energy electrons (fast electrons). A powder mixture of the initial reactants Y₂O₃, Yb₂O₃, Lu₂O₃, Eu₂O₃, Er₂O₃, and Al₂O₃ was heated in air using 1.4 MeV electrons at different electron-beam currents. The cuvette containing the powder mixture was moved beneath the beam at 1 cm/s, while the beam was scanned across the width of the  internal volume of the cuvette. The total irradiation time was 10 s. At beam currents of 4 mA or higher, melt droplets formed within the irradiated powder mass, and their proportion relative to the unmelted powder increased with increasing current. Crystallization occured in the melt droplets during cooling. The resulted droplet-shaped ceramic product was highly porous because of the intense release of adsorbed gases from the melt. SEM images and EDS elemental maps relealed a uniform distribution of the constituent elements throughout the droplet-shaped ceramic product. XRD analysis identified the synthesized material as high-entropy (Y_0.2Yb_0.2Lu_0.2Eu_0.2Er_0.2)₃Al₅O₁₂ ceramic. The powder that did not contribute to the formation of the droplet-shaped product was an intermediate product containing Er₃Al₅O₁₂ and Y₃Al₅O₁₂ garnets, together with Er₂O₃, Yb₂O₃, Y₂O₃, Eu₂O₃, Lu₂O₃, Al₂O₃ oxides.

The effect of dispersed hexagonal boron nitride, reduced graphene oxide, and single-walled carbon nanotubes additives on the microstructure, physical, mechanical, and tribological properties of nanomodified TaN–Si₃N₄–SiAlON ceramics was investigated. Disk-shaped ceramic samples were fabricated by self-propagating high-temperature synthesis (SHS) followed by hot pressing (HP) at 1600 °C under a pressure of 35 MPa. Their microstructure and phase composition were examined using X-ray diffraction, scanning and transmission electron microscopy, and Raman spectroscopy. The results showed that, under hot-pressing conditions, no chemical interaction was occurred between the dispersed additives and the components of the TaN–Si₃N₄–Ta₅Si₃–YAG SHS reaction mixtures. The ceramics had a microstructure consisting of polyhedral h-TaN/c-TaN grains approximately 3 µm in size, surrounded by submicron Si₃N₄ grains. The introduction of dispersed additives increased the hardness till 8.8 GPa and fracture toughness till 9.5 MPa·m^1/2, while the flexural strength remained within 430–484 MPa and the thermal conductivity within 13.2–13.5 W/(m·K). Tribological tests under dry sliding conditions showed that the addition of carbon nanotubes reduced the specific wear rate to 7.08·10^–6 mm³/(N·m). This effect was attributed to the suppression of grain growth during hot pressing and the formation of oxidized wear products based on Ta₂O₅.

The effect of SiC-to-Ti powder ratio in the electrode on electrospark deposition and the properties of Ti–Si–C cermet coa­tings on Ti6Al4V titanium alloy was investigated. Cathode mass decreased monotonically with increasing in SiC content in the electrode. The resulting coatings were 44.7–54.6 µm thick. Under low-voltage electrical discharge conditions, silicon carbide reacted with titanium melt to form titanium carbide (TiC) and titanium silicide (Ti₅Si₃). The coating structure contained TiC and Ti₅Si₃ crystallites, together with a small amount of SiC residual inclusions. The SiC inclusions exhibited poor adhesion to α-Ti. The carbon and silicon contents of the coatings increased monotonically with increasing SiC content in the electrode. All coa­tings were highly hydrophobic, with water contact angles exceeding 120°. Their microhardness ranged from 9.2 to 12.2 GPa. The Ti–Si–C coatings had lower coefficients of friction than the uncoated titanium alloy. The coating deposited using an electrod powder mixture containing 40 vol. % SiC and 60 vol. % Ti had the highest hardness and wear resistance. This coating increased the wear resistance of Ti6Al4V alloy components by a factor of 30.

AlSi10Mg-based aluminum matrix composites (AMCs) with additives of Cu, CuNi, and multicomponent CuNiFeCo alloy additives were fabricated by selective laser melting. The additives were prepared by solution combustion synthesis, and the composite powder mixtures were produced by mechanical processing in a planetary ball mill. The study examined the powder morphology, phase composition, and properties of compact samples with particular focus on their thermophysical and electrical behavior. The Cu-containing alloy additives markedly improved the functional performance of the materials: thermal conductivity increased by up to 55 %, and heat capacity increased by up to 15 % compared with the base AlSi10Mg alloy. Electrical conductivity decreased of up to 65 %, with the strongest effect observed for the multicomponent CuNiFeCo additive. The resulting AMCs combine enhanced thermophysical properties with reduced electrical conductivity, making them suitable for heat-dissipating and heat-resistant components in electronics and aerospace applications. Lower electrical conductivity may also be beneficial in radio-frequency modules, inductive components, and shielded electronic systems, where parasitic currents and eddy-current losses should be minimized. Because they compatible with selective laser melting, these materials are promising for the additive manufacturing of complex-shaped functional components, including heat-dissipating housing, heat sinks, and weight-optimized parts.

AlSi10Mg-based aluminum matrix composites (AMCs) with additives of Cu, CuNi, and multicomponent CuNiFeCo alloy additives were fabricated by selective laser melting. The additives were prepared by solution combustion synthesis, and the composite powder mixtures were produced by mechanical processing in a planetary ball mill. The study examined the powder morphology, phase composition, and properties of compact samples with particular focus on their thermophysical and electrical behavior. The Cu-containing alloy additives markedly improved the functional performance of the materials: thermal conductivity increased by up to 55 %, and heat capacity increased by up to 15 % compared with the base AlSi10Mg alloy. Electrical conductivity decreased of up to 65 %, with the strongest effect observed for the multicomponent CuNiFeCo additive. The resulting AMCs combine enhanced thermophysical properties with reduced electrical conductivity, making them suitable for heat-dissipating and heat-resistant components in electronics and aerospace applications. Lower electrical conductivity may also be beneficial in radio-frequency modules, inductive components, and shielded electronic systems, where parasitic currents and eddy-current losses should be minimized. Because they compatible with selective laser melting, these materials are promising for the additive manufacturing of complex-shaped functional components, including heat-dissipating housing, heat sinks, and weight-optimized parts.

Metal Binder Jetting (MBJ), a layer-by-layer additive manufacturing process that uses metal powders and binding agents, is a relatively new and promising technology. Its principal advantages over other additive manufacturing methods, including selective laser sintering and stereolithography, are its high cost-effectiveness resulting from rapid printing and its compatibility with a wide range of powder materials. The wider adoption of MBJ in industry is limited by insufficient knowledge of this relatively new process. Therefore, investigating the effects of MBJ process parameters on the structure and properties of powder-based materials remains relevant. The study examined samples produced by MBJ from AISI 316L and AISI 304L stainless steel powders. The effect of powder characteristics, layer thickness, and printing and sintering parameters on the structure and physicomecha­nical properties of the materials were investigated. Samples were printed from powders with particle sizes of 25–45 μm using an Easy MFG 500 Max 3D printer (China). Moisture was then removed in a vacuum drying oven at 100–160 °C, followed by final sintering in a vacuum or a reducing atmosphere at 1350–1400 °C. The study used included particle size analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis, X-ray computed tomography and standard methods for determining density and strength properties. The Hausner ratio was shown to provide an indirect assessment of the flowability of fine powders. Materials printed from powder with a mean particle size of 25 μm were found to be essentially pore-free, whereas those printed from powder with a mean particle size of 45 μm had a porosity of 6–7 % and physicomechanical properties approximately 10 % lower. Decreasing the layer thickness from 60 to 40 μm while simultaneously reducing the printing speed decreased layerwise porosity and pore size. The proposed MBJ process parameters enabled the manufacture of an ESP impeller and diffuser from AISI 316L steel powder with the specified geometry and dimensions. Their structure and physicomechanical properties were comparable to those of cast steel of the same grade.

This study presents an experimental and mathematical investigations of the effects of Laser Powder Bed Fusion (LPBF) process parameters on the surface roughness of AlSi10Mg alloy parts. A full-factorial experiment comprising 60 combinations of the main process parameters – laser power, scanning speed, and hatch spacing – was conducted. A third-order multivariable response surface model was developed from the measured roughness data to describe nonlinear relationships and interactions among the process parameters. The model accounted for approximately 86 % of the total variance in the experimental data and yielded mean prediction errors of approximately 0.9 µm for S_a and ± 0.2 µm for R_a. The minimum roughness values, S_a ≈ 5 µm  and R_a ≈ 2 µm, were obtained at a laser power of 400 W, a scanning speed of 938 mm/s, and a hatch spacing of 80 µm. Laser power, hatch spacing, and their interaction had the greatest effect on the resulting surface roughness. The developed model can be used to predict surface quality and select optimal process parameters for the LPBF manufacturing of aluminum alloy components.