Abstract. Coatings of the Ti–Al–C MAX-phases were obtained by plasma-assisted magnetron sputtering of a composite target with the 2Ti–1Al–1C stoichiometry. The phase composition of the coating was studied after deposition and vacuum heat treatment. In-situ studies of phase transformations were performed using synchrotron radiation in the coating upon heating in air to 1300 С. The morphology and elemental composition of the coating surface after oxidation in air were estimated. The results showed that immediately after deposition, the coating does not crystallize completely, which can be indicated by the broadening of reflections on the diffraction pattern and a change in the diffraction pattern after heat treatment. Subsequent vacuum heat treatment makes it possible to form a crystalline structure in the coating, the phase composition of which is represented mainly by a mixture of the Ti2AlC and Ti3AlC2 MAX-phases. In-situ studies showed that the phase composition of the coating remained stable up to a temperature of 1090 С; upon further heating, oxidation of the coating occurred with the formation of several mixed layers, as well as oxidation of the protected Inconel 718 alloy. Analysis of the coating surface and chipped areas showed that the coating was destabilized and several zones were formed that differed significantly in both morphology and elemental composition.

This article examines the topical issue of mathematical modeling of plant material extraction processes, where a deep understanding and analysis of these processes are important in various industries, including food, pharmaceutical, and chemical. It has been established that the mathematical model under study is a special case of a more general universal model describing heat and mass transfer in a capillary-porous body-liquid system. The solution to the boundary value problem obtained in the work using exponential Fourier series averages based on a continuous periodic function reveals the properties and approximation capabilities of this model. The theorem on the convergence of the model to the physical system describing the processes of plant material extraction under certain conditions confirms its reliability and applicability. The issues of summability of trigonometric series in the metric of the corresponding functional space are analyzed. The study provides a fundamental scientific description of the mathematical model of plant material extraction processes and a detailed analysis of its properties, opening new horizons for the development of this field of research. The presented results will be useful for specialists in fields related to extraction, as well as for those involved in the development of new methods for optimizing and controlling plant material extraction processes.

The paper examines the impact of hydrogen sulfide (H2S) on the adhesion strength of internal polymer coatings designed to safeguard oil pipelines against corrosion. The analysis focuses on the mechanisms of coating destruction in aggressive environments, including the chemical reaction of H2S with inorganic fillers such as iron oxide (Fe2O3), which leads to the formation of sulfides and a sharp decrease in adhesion. Experiments were conducted under autoclave conditions with varying H2S concentrations, temperatures, and holding times. The results showed that even minimal H2S concentrations significantly deteriorate the adhesive properties of coatings. A model of adhesion reduction is proposed that allows to predict the service life of coatings under specific operating conditions. Particular attention is given to comparing various types of coatings, including duplex, liquid, and powder systems, as well as the role of phenolic primers in their stability. The processes of diffusion and chemical interaction with the coating components were found to play a key role in durability. These findings are crucial for developing more effective anti-corrosion solutions in the oil and gas industry.

Results of a comparative study of the crystal structure of carbon components in nanodispersed liquid colloidal solutions based on natural graphite (NG) and carbon black, obtained by grinding combined with chemical cleavage (oxidation with a mixture of nitric and sulfuric acids), are presented. For the studied samples, structural features, average particle size, electrical conductivity and diffuse reflectance coefficient were determined. The studies revealed fundamental differences in both the structure of the carbon components of the colloidal solutions based on NG and carbon black, and the properties of coatings produced from them. In the case of NG, this is nanodispersed graphite, which retains the structure of the original NG even after grinding and chemical cleavage. Despite the destruction of the original crystallites along the basal planes, few-layer graphene particles were not found, and the resulting particles are NG nanocrystallites with a three-dimensionally ordered crystalline structure. The carbon component of the carbon black-based colloidal solution is also a nanodispersed polycrystalline graphite-like material, but has a turbostratic structure inherent to the original carbon black. These structural differences lead to fundamental disparities in coating properties from NG- and carbon black-based colloidal solutions, with surface electrical resistance of 5.10 and 55,600 kOhm?sq. –1, respectively. For NG, coating reflectivity at a 60 light beam incidence angle was 3.0–5.0%. However, in the case of carbon black, reflectivity at 60 was 0.2–0.3%, which is anomalously low for carbon materials.

This paper describes a circular process scheme for manufacturing painted automotive repair parts from composite materials using paint mist particles collected by a multivortex separator. The research evaluates the mechanical, chemical, and adhesion properties of the resulting composites to assess their compliance with industry standards. Paint mist particles were characterized using dispersion analysis, X-ray fluorescence spectroscopy, and elemental analysis. Composite samples with 0-20 wt. % reclaimed particles were manufactured and subjected to tensile, bending, and adhesion tests. The reclaimed particles (2.8–1445 u) contained mainly silicon dioxide (SiO2), lead dioxide (PbO2), and titanium dioxide (TiO2), known to enhance composite properties. At 20 wt. %, tensile strength increased by 13.3 %, while bending stress decreased by 18 %. Adhesion remained within control sample limits, confirming practical viability. The study demonstrates that paint mist reuse aligns with circular economy principles, offeringa technically feasible circular scheme, reducing waste while maintaining the mechanical performance of the composites.

Nanoparticles of insoluble Gd3+ compounds are considered to be a promising direction of development of multimodal contrast agents for magnetic resonance imaging and computed tomography. The surface of such nanoparticles can be functionalized by molecules or chemical groups with high affinity to specific biopolymers. In the present work, we proposed a novel approach to obtaining such selective structures. At the first stage, Gd2O3 nanoparticles of 1–2 nm size stabilized on the surface of graphene nanoflakes (GNFs) were produced. Their further graphitization produced core-shell (Gd2O3/GNFs)@C particles. Treatment of these particles with nitric acid vapor resulted in the formation of surface carboxyl groups. Further reaction with SOCl2 produced (Gd2O3/GNFs)@C-COCl particles, which were used to obtain the esters containing the allyl fragment (Gd2O3/GNFs)@C-COOAll or molecules of specific inhibitor of angiotensinconverting enzyme captopril. All products were characterized by transmission electron microscopy, thermogravimetric analysis, IR and X-ray photoelectron spectroscopy. The results of these analyses confirmed that the functionalization of the particles by carboxyl, acyl chloride or allyl groups, as well as captopril molecules, did not change their morphology or the size of Gd2O3 cores. The cytotoxicity of (Gd2O3/GNFs)@C-COOH, (Gd2O3/GNFs)@C-COOAll and (Gd2O3/GNFs)@Ccaptopril particles was assessed.

The effect of nanosized tungsten on the ignition of W–PTFE–Al compositions under shock-wave or thermal impact has been investigated. It has been found that ignition in the studied compositions occurs at 1000–1060 C with rapid temperature increase to 1700 C. The mechanism and localization of synthesis in the studied compositions under shock-wave loading in recovery ampoules depends on aluminum content. Compositions with low aluminum content (5–10 wt. %) ignite in low-pressure regions (upper part of the ampoule), whereas those with high Al content (20–30 wt. %) ignite in high-pressure regions (lower part of the ampoule). The 72W–18PTFE–10Al composition demonstrated the highest energy release, causing nearly complete ampoule destruction (70 % of length). The use of nanosized tungsten enabled shock-wave synthesis initiation in the 56W–14PTFE–30Al composition and revealed structural changes along the sample length. Following shock-wave loading of 64W–16PTFE–20Al and 56W–14PTFE–30Al compositions, the synthesized products underwent dispersion under atmospheric moisture exposure without phase composition changes.