OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 3 2025 Introduction Modern wear-resistant coatings made of self-fluxing nickel-based alloys are widely used in industry [1]. However, when operating in aggressive environments, such as seawater or chemically active solutions, these coatings are subjected not only to mechanical stress but also to corrosive degradation. In this case, the corrosion rate can significantly affect their wear resistance and durability, leading to premature failure of components and substantial economic losses [2–4]. The relevance of this work lies in the need for a comprehensive study of the corrosion behavior of wearresistant coatings, since their traditional evaluation is mainly limited to mechanical characteristics, such as hardness and abrasion resistance [5–8]. However, even high-strength coatings, for example, those based on tungsten or boron carbides, can lose their operational properties due to corrosion processes developing at particle boundaries or pores [9–12]. It is particularly important to investigate corrosion kinetics, as it determines not only the service life of the coating but also its interaction with the substrate, ultimately affecting the overall performance of the system [13–15]. In this study, the detonation spraying method was used to apply the coatings, which offers several significant advantages over alternative technologies. The key advantages of the detonation spraying method include: high particle velocity (up to 2,500 m/s), ensuring better coating adhesion to the substrate and reducing porosity [16], lower heating of the sprayed material, minimizing the risk of undesirable phase transformations and oxidation [17], and the ability to precisely control process parameters, including the gas mixture composition and explosion energy, allowing for optimization of the coating structure and properties [18]. The practical significance of this work lies in the potential application of the obtained results in the development of new wear- and corrosion-resistant coatings for equipment in the oil and gas industry, shipbuilding, and energy sectors operating under extreme conditions. The scientific novelty of the study consists in establishing quantitative relationships between the boron carbide content, detonation spraying parameters, and the corrosion resistance of nickel-chromium-boron-silicon coatings, which has not been previously addressed in the literature to such an extent. The objective of this work was to evaluate the corrosion rate of wear-resistant coatings based on the self-fluxing alloy PR-NKh17SR4 and its modified counterpart with the addition of boron carbide. The specific aims of this study were to: – mechanically blend the self-fluxing powder NiCrBSi alloy (PR-NKh17SR4) with 10 % boron carbide (B4C) and assess the uniformity of particle distribution; – compare the granulometric composition and bulk density of the initial powders and the resulting mixture; – study the microstructure of the coatings using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis; – perform electrochemical tests (potentiostatic measurements, impedance spectroscopy) in a 3.5 % NaCl solution, – compare the corrosion behavior of NiCrBSi alloy (PR-NKh17SR4), NiCrBSi (PR-NKh17SR4)+10 wt. % B4C coatings, and a commercial counterpart NiCr/WC alloy (VSNGN-85). Methods For the research, plates made of structural steel grade 0.4 C-Mn (40G) (40×40×5 mm) were used as substrates. The chemical composition of the steel complies with the requirements of GOST 1050-2013. Spectral analysis performed on an optical emission spectrometer “ISKROLINE 100” (Russia) confirmed that the steel met the declared grade. The content of the main alloying elements was as follows: 0.40 % carbon, 0.25 % silicon, and 0.78 % manganese, with the total content of sulfur and phosphorus not exceeding 0.03 % each. Substrate surface preparation involved thorough sandblasting with quartz sand (grain size 1.0±0.2 mm) at a compressed air pressure of 0.6 MPa.
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