Problems of Tribology = Проблеми трибології - 2025 рік
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Перегляд Problems of Tribology = Проблеми трибології - 2025 рік за Автор "Dykha, O.V."
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Документ Improving the wear resistance of guides: tribological analysis, surface texture and lubricants(Хмельницький національний університет, 2025) Dykha, O.V.; Dytyniuk, V.O.; Kovtun, O.S.; Fasolia, V.O.; Hetman, M.V.The article considers the main failure modes of guides, in particular wear and contact fatigue, which depend on friction between contact surfaces. The influence of tribological parameters, in particular surface roughness and lubricating structures, on the operational characteristics of linear guides is studied. Particular attention is paid to the dynamic behavior of guides, which determines the accuracy and stability of mechanical systems. To predict wear, mathematical models based on the Archard and Hertz theories were used, which allow estimating load distribution and contact deformations. The influence of lubricants, in particular molybdenum disulfide and hexagonal boron nitride, on reducing the friction coefficient and improving antifriction properties was separately studied. The prospects for using new materials, such as cubic boron nitride, to increase the wear resistance of guides are considered. Methods for optimizing the load between rolling elements, which contributes to increasing the durability of guides, are proposed. The results obtained can be used to improve the designs of high-precision mechanical systems and reduce operating costs.Документ Theoretical foundations of glow discharge nitriding of internal local recesses on metallic surfaces(Хмельницький національний університет, 2025) Stechyshyn, M.S.; Dykha, O.V.; Skyba, M.Ye.; Zdorenko, D.V.; Liukhovets, V.V.This paper presents a comprehensive analysis of internal local recesses on metallic surfaces during glow discharge nitriding. Various types of recesses and their geometric features are studied to evaluate their impact on electric field concentration, which in turn affects the uniformity of surface modification. A field concentration criterion is introduced to quantify these effects, and an analytical framework is developed to describe the relationship between surface geometry and electric field parameters. The influence of the dimensions of internal recesses on field concentration is examined using numerical simulations. The results provide a deeper understanding of the mechanisms leading to localized variations in current density distribution on nitrided surfaces. The developed analytical tools are applicable for predicting and controlling electric field concentration indicators in glow discharge processes used for the surface modification of metallic components, which is critical for ensuring optimal mechanical and tribological properties.Документ Wear resistance of structural steels carbonitrated by the separate method(Хмельницький національний університет, 2025) Stechyshyn , M.S.; Dykha, O.V.; Zdorenko, D.V.; Oleksandrenko, E.G.The article investigates the influence of technological modes of separate carbonitriding of carbon steels on the thickness and microhardness of the hardened layer. Two hardening variants were investigated: first, carburizing of surfaces was carried out in argon-propane, and then nitriding in argon-nitrogen mixtures and vice versa. As the conducted studies have shown, the variant of the hardening technological process significantly affects the physical and mechanical characteristics of the hardened layer. In all two variants of the technological process, the hardened layer consists of a surface carbonitride zone and a diffusion zone of internal nitriding, but the properties of these zones are different in different variants of the technological process. Thus, when hardening steels according to the first mode, the thickness of the carbonitride zone is maximum, and the internal nitriding zone has a small thickness. This is explained by the fact that the carbonitride layer created on the steel surface at the first stage of processing performs the function of shielding the surface from the penetration of nitrogen ions into the surface layer of the metal. When hardening according to the second mode, the carbonitride zone has a slightly smaller thickness, but a more developed internal nitriding zone. In addition, carbonitriding according to the first mode leads to the formation of carbonitride inclusions in the diffusion zone in the form of a mesh, which significantly reduce the plasticity of the layer and under dynamic loads are centers of microcrack nucleation. It has also been established that a carbonitride ε − phase is formed on the surface of steels, which consists of carbonitrides of the type Fe2(N,C), Fe3(N,C), Fe4(N,C). The carbonitride zone has high hardness, high corrosion resistance, and increased wear resistance. The thickness of the carbonitride zone reaches a thickness of up to 25 microns. Under the carbonitride zone is the internal nitriding zone, which has a large thickness and is the main part of the carbonitrided layer. The internal nitriding zone consists of a nitrogenous solid solution of the base metal, its nitrides and nitrides of alloying elements. The dependences of thickness and microhardness on the technological parameters of carbonitriding of carbon steels obtained in the work: temperature, saturation time, composition of the gas medium, its pressure allow them to be optimized depending on the requirements of further operation