One of the most popular and widely used is the WC – Co composite. To improve some functional properties: thermal conductivity, corrosion resistance, etc., a search is underway for alternative metal binders with the possible replacement of Co with copper to reduce sintering temperatures and provide a higher thermal conductivity of the composite. Previously, it was shown that melt impregnation of freely poured refractory powders into a crucible-mould, activated by low-frequency vibration (LFV) of their compositions, differs from the methods used in industry in the simplicity of technology, short duration, and the possibility of obtaining composites with a high content of refractory phase with its frameless packaging. 2 – 3-layer WC – Cu/Cu and Cu/WC – Cu/Cu composites with different arrangement of the working WC – Cu layer along the height of the ingot and different structural characteristics and properties of the layer have been obtained. The influence of thermal and temporal conditions, pressure of cold prepressing of WC powder, dilution of carbide powder with copper powder, geometry of stacking of alloy components on the formation of a given lamination of a composite alloy, a given composition, and a minimum porosity of the WC – Cu working layer are analyzed. The hardness and wear resistance of the WC – Cu layer were measured and their relationship with the layer structure and controlled parameters of the composite synthesis process control was established. Both the porosity of the structure and the presence of dense macroaccumulations of WC in the Cu-matrix can be reduced to a minimum by preventive small pre-pressing of freely poured powders at room temperature before loading the alloy components into the furnace, followed by processing of the vibration. Composites with a homogeneous structure and low porosity of the working layer have been obtained.

We have studied for the first time the feasibility of using Al2O3 and Al : Zn (1 : 1) coatings produced by supersonic plasma spraying for protecting GdTbDyHoSc and GdTbDyHoY high-entropy rare-earth (RE) alloys from corrosion in a salt-fog chamber. The results demonstrate that, under salt fog conditions, Al2O3 coatings break down through local surface activation, resulting in pitting corrosion, with a considerable fraction of the coating on the main material remaining intact. The alloys coated with Al : Zn (1 : 1) exhibit lower corrosion resistance under salt fog conditions as a consequence of electrochemical corrosion. Interaction of Al2O3 with NaCl limits the suitability of such coatings for protecting high-entropy RE alloys under salt fog conditions. Limitations refer to the specimen test time and coating thickness.

The paper reports the research outcomes on the structural and chemical composition of the equiatomic GdTbDyHoSc and GdTbDyHoY high-entropy alloys, which are potential materials for magnetic cold generators. The solidus and liquidus temperatures of the alloys were determined using differential scanning calorimetry. Based on these findings, an experimental mode of thermal cyclic treatment was selected. No signs of alloy destruction were observed after five test cycles for thermal resistance under exposure at a temperature of 1073 K (~0.6 of the melting point) for 15 minutes followed by quenching in room-temperature water. The applied heat treatment resulted in an increase in the hardness of alloys by 2–3 times and a decrease in wear resistance by 4–40 times depending on the alloy composition and the number of heat treatment cycles. Significant changes in the properties of alloys are associated with the formation of oxides, including REM 2 О 3 , not only on the surface but also within their volume, which is due to the high chemical activity of rare-earth metals. The data presented in this study will be beneficial in the development of thermal and thermomechanical treatment methods for studied alloys.

Впервые исследована возможность использования Al 2 O 3 - и Al : Zn (1 : 1)-покрытий, нанесенных методом сверхзвукового плазменного напыления, в качестве защитных для высокоэнтропийных сплавов (ВЭС) редкоземельных элементов (РЗМ) GdTbDyHoSc и GdTbDyHoY от коррозии в камере соляного тумана. Показано, что покрытие Al 2 O 3 в условиях соляного тумана разрушается по механизму локальной активации поверхности, появляется питтинговая коррозия и при этом сохраняется значительная доля покрытия на основном материале. Образцы с покрытием Al : Zn (1 : 1) в условиях соляного тумана показывают меньшую стойкость вследствие электрохимической коррозии. Взаимодействие Al 2 O 3 с NaCl делает данное покрытие ограниченно годным для защиты сплавов РЗМ ВЭС в условиях соляного тумана. Ограничения касаются времени испытания образцов и толщины нанесенного покрытия.

The plasma modification unit UPM MAK-10 developed in IMET UrO RAS was used for surface hardening samples of 35KhGSA steel. As a result, it leads to an increase in the tribological characteristics of products (hardness and wear resistance, etc.) and, consequently, increases the service life of various machines and mechanisms.

This paper presents the results of a research study carried out to investigate the tribological characteristics of coatings based on the Ni-B-Si-Fe and Co-Ni-Cr-B-Si-Fe powders applied onto 20Kh13 steel substrates by the supersonic plasma spraying method. These coatings are established to demonstrate high durability and wear resistance to stresses within the range of the matrix elastic strain. The experiments were performed using an SMT-1M 2070 tribotester following the scheme "fixed pin (specimen) - rigid rotating disk (counterbody)" in accordance with GOSTs 23.208-79, 30479-97 and 50740-95. A comparative analysis of the wear rates of steel and plasma-sprayed powder coating specimens was carried out under the constant tribotester operational parameters, with the counterbody rotation velocity and the specimen load being equal to 850 rpm and 200 N, respectively.

In present research are presented the results of the study and evaluation of the strength characteristics of Al and Ni-Al coatings applied by supersonic plasma spraying on plastic and aluminum substrates. The spraying of coatings with various compositions was carried out on the supersonic plasma unit. It is shown that the coating is sufficiently strong, it also has satisfactory corrosion resistance and has sufficient shielding effectiveness against electromagnetic radiation. The screening efficiency was measured by the ZVA 24 VectorNetworkAnalyzer.