###### Abstract  
In this paper, the oxidation behavior of the 310H alloy coated with NiCrAlY using the EB-PVD method is studied after exposure to water at a high temperature and pressure (550 \({}^{\circ}\)C and 25 MPa) for different periods (720 h, 1440 h, and 2160 h). The Electron Beam Physical Vapor Deposition (EB-PVD) method was used to obtain the NiCrAlY coating. After testing, the coating performance was carried out by gravimetric analysis, grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and the linear polarization method. GIXRD analysis highlighted the presence of chromium oxide (Cr\({}_{2}\)O\({}_{3}\)) and the Corundum phase (Al\({}_{2}\)O\({}_{3}\)) on the surface of the oxidized NiCrAlY-coated 310H samples. On the surface of the 310H alloy, the existence of the NiCrAlY coating and of the oxide film generated during oxidation are evident according to the EIS spectra, which show two capacitive semicircles in the Nyquist diagram. Furthermore, an increase in diameter semicircles with the oxidation time increasing was observed in the Nyquist diagram. Very low corrosion rates of 4.8 \(\times\) 10\({}^{-5}\) mm \(\times\) year\({}^{-1}\), which were observed for oxidization for 2160 h NiCrAlY-coated samples, indicated that the oxide films are more protective and provide better corrosion resistance, which is also evidenced by the EIS analysis. Considering the obtained results, a significant relationship between the electrochemical technique, scanning electron microscopy, and gravimetric analysis was established. c 2025, 15, 2361 20  
present a significant global challenge as a sustainable and economical mode of energy production [2]. Compared to current nuclear reactor systems, the new Gen IV reactors operate in more severe conditions and require new materials for the new performance in an aggressive environment. One of the six innovative nuclear fission reactor concepts is the Supercritical Water-Cooled Reactor (SCWR), which uses water above its critical thermodynamic point (374 \({}^{\circ}\)C, 22.1 MPa). In such an environment, the structural materials used in conventional nuclear reactors can no longer meet the operating requirements, and new selections were proposed as the material substrates and their coatings [3]. The suggested substrates come from various alloy classes, including Ni-based alloys (IN718, IN625), austenitic stainless steels (304, 304L, 316, 316L, 310), and ferrite-martensitic steels (HT-9, T91, T92, and HCM12A). Following heat treatment and exposure to high temperatures, the nonmagnetic austenitic stainless steel varieties, known as the chromium-nickel 300-series and the chromium-nickel-manganese 200-series steels, demonstrate exceptional mechanical and corrosion resistance [4]. Due to their mechanical and corrosion resistance properties, as well as their performance against radiation, austenitic stainless steels [5] have attracted special interest for applications in higher temperatures and pressures. With a crystalline structure of the FCC type, the 310H type is a 300-series chromium-nickel austenitic stainless steel material that was developed for utilization at temperatures ranging from 800 \({}^{\circ}\)C to 900\({}^{\circ}\) C. It combines exceptional high-temperature qualities with resistance to creep, weldability, and strong ductility. To improve corrosion resistance, existing alloys can be modified by applying thin protective ceramic or metallic layers on the surface using different surface modification techniques. Currently, there are several techniques for thin layers on metal surface deposition, which are as follows: physical vapor deposition (PVD) [6; 7] and chemical vapor deposition (CVD). An early technology was EB-PVD, which is still in use. The coatings obtained via such procedures have high density, remarkable oxidation resistance, and a strong bonding force [8; 9; 10]. For the EB-PVD technology, alloy targets are mostly used, and the coating composition is affected by the target content.