Ceramic-metal composites (cermets) based on multicomponent phases are the newest research direction in the field of high-entropy and medium-entropy materials. Like traditional cermets, they consist of ceramic grains and a metal binder, with at least one of these phases being a high- or medium-entropy solid solution of three or more components in comparable concentrations. In this work, the possibility of producing (100 – x)TiC + xCoCrNi cermet in the range of x = 0÷60 wt. % by self-propagating high-temperature synthesis (SHS) is investigated for the first time. It is shown that the size of the CoCrNi binder particles added to the powder reaction mixture significantly affects the combustion patterns and the structure formation of the material. When using large granules (~1.5 mm), the combustion rate is higher compared to the combustion of mixtures with a fine binder, while the chemical compositions and combustion temperatures are similar.The relative difference in the average combustion rate increases from 30 % to two times with an increase in the binder content from 10 to 40 wt. %. This effect occurs due to the combustion wave “slippage” between the granules and is explained by the assumption of thermal micro-heterogeneity of the reacting medium. The use of a finer CoCrNi powder (~0.2÷0.5 mm) allows obtaining homogeneous macrostructure of SHS products without large cracks and chips, and a finer-grained microstructure. In this case, the interaction of the binder with the TiC ceramic phase that is forming in the SHS wave is observed, which is expressed in the dependence of the crystal cell parameter of the carbide phase on the binder content. The results can be used to control the microstructure and phase composition of multicomponent cermets obtained by the SHS method.

The influence of mechanical activation (MA) of titanium and boron powders in a ball mill on the combustion behavior of Ti + 2B mixtures has been investigated. Experimental dependences of the combustion temperature and combustion-wave velocity on the density of compacts prepared from starting and mechanically activated powders were obtained. It was shown that the dependences of these parameters on the compact density exhibit pronounced maxima. With increasing density, the rise in combustion temperature is governed by the growth of the Ti–B reaction-interface area, whereas its subsequent decrease is associated with an increase in the Ti–Ti contact area. Mechanical activation exerts opposite effects on the reactants: it reduces the specific surface area of titanium powder, thereby decreasing the Ti–B contact area, but at the same time destroys the arch-like structure of amorphous boron and disperses its agglomerates, which increases the reaction-interface area. The overall result is an increase in the maximum combustion temperature to 2900 °C. It was experimentally established that, at compaction pressures above 30 MPa, mechanically activated boron exhibits limited plasticity, enabling consolidation of Ti + 2B mixtures to relative densities of 0.7–0.8. A correlation was found between electrical resistivity and combustion temperature: the highest combustion temperatures correspond to a resistivity range of R ≈ 10^5.0 – 10^5.5 Ω·cm, while a further decrease in resistivity – related to the growth of the Ti–Ti contact area – leads to a reduction in the combustion temperature.

This study examines how additions of Si, Al, Cu, and Cr powders to the stoichiometric 3Ti–Si–2C (at. %) charge influen­ce the formation of the Ti₃SiC₂ MAX phase during self-propagating high-temperature synthesis (SHS) performed in air within a sand bed, without a sealed reactor or controlled atmosphere. The effect of partially or fully substituting elemental Ti and Si powders with TiSi₂ on the Ti₃SiC₂ yield is also assessed. Microstructural characterization of the SHS products was conducted using scanning electron microscopy equipped with energy-dispersive spectroscopy, and the phase composition was quantified by X-ray diffraction. An addition of 0.1 mol Si to the stoichiometric mixture increases the Ti₃SiC₂ content in the product to approximately 70 vol. %. Incorporating 0.1 mol Al decreases the Ti₃SiC₂ fraction to 39 vol. % and results in the formation of TiAl. In contrast, combining a silicon excess with 0.1 mol Al in the 3Ti–1.25Si–2C + 0.1Al system markedly enhances the Ti₃SiC₂ yield, reaching ~89 vol. %. For synthesis in the TiSi₂–C system, the share of the MAX phase decreases while secondary phases become more prevalent; the maximum Ti₃SiC₂ content in this system is 56 vol. %. When TiSi₂ fully replaces elemental silicon in the 2.5Ti–0.5TiSi2–2C mixture, the Ti₃SiC₂ fraction drops to 20 vol. %.

Yttrium–aluminum garnet (YAG) ceramics doped with ruthenium atoms were synthesized in this study. The precursor powder was obtained by the coprecipitation method. The dopant, in the form of ruthenium (III) chloride, was introduced at different technological stages: during precursor powder synthesis and during deagglomeration of the ceramic powder, resulting in two series of samples. The phase composition of the sintered ceramics was examined by X-ray diffraction (XRD). According to the obtained data, no secondary or impurity phases were detected. Differential thermal analysis (DTA) revealed a decrease in the cationic homogeneity of the precursor powder. Incorporation of ruthenium into the YAG structure led to a shift of the exothermic crystallization peak toward higher temperatures. The ceramic samples were sintered at 1815 °C for 20 h, followed by annealing in air at 1500 °C for 2 h. Optical characterization of the ceramics showed that the method of dopant introduction affected both the optical transmittance and the band gap energy. The transmittance at 1100 nm for undoped YAG ceramics was 77.04 %, while for the ruthenium-containing samples it decreased to 65.1 and 74.5 %, depending on the dopant incorporation route. The band gap energy was determined from differential absorption spectra: for pure YAG it was 4.92 eV, and for the Ru-doped ceramics it decreased to a minimum of 4.4 eV.

Studies were carried out to develop aluminum matrix composites reinforced with amorphous microsilica particles. The feasibility of producing Al–5 wt. % SiO₂ materials using both stirring-assisted casting and semisolid metal processing was established. The latter method, when combined with subsequent squeeze casting, demonstrated the highest efficiency. Magnesium was shown to function as a surface-active additive that removes oxygen from the surfaces of the dispersed particles and enhances the mechanical properties of the composite during heat treatment. The resulting material exhibits a uniform distribution of microsilica particles throughout the aluminum matrix and demonstrates hardness, corrosion resistance, and reduced specific weight superior to those of the base AlSi7 alloy. Therefore, the composites produced using the developed technology are promising for applications in transport engineering as well as in the aerospace and space industries.

TiC–Cu ceramic–metal composites (cermets) have been extensively discussed in recent literature in terms of their properties and structure. However, in most cases the formation conditions considered involve the introduction of TiC particles into an overheated Cu melt. In the present work, samples were synthesized in air without crucible reactors by combining a thermite reaction to produce a copper melt for subsequent infiltration of a porous Ti + C powder charge and initiation of its combustion by self-propa­gating high-temperature synthesis (SHS) of titanium carbide. As a result, TiC–Cu cermets were formed. The effect of Cu addition to the Ti + C SHS charge and of compaction pressure on the completeness of infiltration by the copper melt genera­ted during combustion of the copper thermite mixture is analyzed. The influence of these factors on the structure of the synthesized cermets is also examined. TiC–Cu cermets were synthesized with 5, 10, and 15 wt. % Cu added to SHS charges compacted at 22, 34, 45, 56, and 69 MPa. The completeness of infiltration was evaluated from the appearance of polished sections, microstructure, and phase composition. Optimal conditions were identified that provide composites with maximum density, minimal structural defects, the desired phase composition, and enhanced mechanical properties. The microstructure, composition, and physico-mechanical properties (density, Brinell hardness, compressive strength) of the new composites were investigated. It was established that the highest infiltration completeness and density of TiC–Cu samples are achieved at 10 wt. % Cu addition to the SHS charge and a compaction pressure of 45 MPa, while increasing Cu content in the charge leads to higher mechanical properties (hardness and compressive strength).

Corrosion is one of the primary causes of failure in oil and gas equipment, affecting not only its service life but also operational safety. In the Russian Federation, crude-oil production is increasingly complicated by the high water content of produced fluids, which significantly accelerates corrosion processes. The use of internal polymer coatings in pipelines partly mitigates this problem; however, the proportion of corrosion-related failures remains high. Effective protection of oil pipelines using polymer coatings requires a clear understanding of their degradation mechanisms, including under conditions that closely approximate field operation. Such understanding enables the development of effective solutions that help maintain the operating stock of oil wells in serviceable condition. This work summarizes the principal mechanisms of degradation of polymer coatings on metallic surfaces, including under exposure to aggressive environments. The key factors governing coating failure in oil pipelines are identified: diffusion and absorption of water molecules within the polymer matrix; disruption of molecular interactions in the polymer network; delamination due to loss of adhesion between the coating and the metal; interfacial corrosion; cathodic delamination; blister formation; and erosion-driven damage. The study presents results of the examination of various epoxy–novolac-based anticorrosion coatings removed from pipelines after field service and provides representative images of coatings at different degradation stages. The aim of the work was to consolidate current knowledge on the degradation mechanisms of polymer coatings on metals under diverse conditions and to refine the staged description of coating degradation in oil pipelines.