This paper presents the results of a study of layer gradient thermal protection coatings based on NiCrAlY and YSZ obtained by detonation spraying. Modern gas turbines and high-temperature units operate under extreme temperatures and aggressive environments, which requires effective protection of components from wear, corrosion, and thermal shocks. In this study, the use of layer gradient coatings consisting of alternating layers of NiCrAlY and YSZ was investigated with the aim of solving the problem of thermal stress accumulation due to a smooth change in the composition of the layers. Microstructural and phase analysis showed that alternating layers of NiCrAlY and YSZ formed a dense layer gradient structure with clear interphase boundaries and low porosity. Detonation spraying led to a complete transformation of the monoclinic ZrO₂ phase into a tetragonal one, which significantly increased the mechanical strength of the coating and its resistance to thermal shocks. Sample 1D1 demonstrated excellent tribological and corrosion properties in a 3.5% NaCl solution, which can be explained by its higher density and reduced number of pores. Mechanical tests revealed stable values of hardness and wear resistance of the coating, especially for the 1D1 coating. Studies have shown that coatings are resistant to thermal shocks, but thicker layers show a tendency to peel off after thermal cycling. The obtained results indicate high prospects for the use of layer gradient coatings based on NiCrAlY and YSZ for the protection of gas turbine components and other high-temperature installations operating under extreme loads and aggressive environments.

This paper presents the results of a comprehensive study of the structure, phase composition, thermal corrosion, and tribological properties of multilayer gradient coatings based on YSZ/NiCrAlY obtained using detonation spraying. X-ray phase analysis showed that the coatings consist entirely of metastable tetragonal zirconium dioxide (t’-ZrO₂) phase stabilized by high temperature and rapid cooling during spraying. SEM analysis confirmed the multilayer gradient phase distribution and high density of the structure. Wear resistance, optical profilometry, wear quantification, and coefficient of friction measurements were used to evaluate the operational stability. The results confirm that the structural parameters of the coating, such as porosity and phase gradient, play a key role in improving its resistance to thermal corrosion and CMAS melt, which makes such coatings promising for use in high-temperature applications. It is shown that a dense and thick coating effectively prevents the penetration of aggressive media, providing a high barrier effect and minimal structural damage. Tribological tests in the temperature range from 21 °C to 650 °C revealed that the best characteristics are observed at 550 °C: minimum coefficient of friction (0.63) and high stability in the stage of stable wear. At room temperature and at 650 °C, there is an increase in wear due to the absence or destabilization of the protective layer.

In this work, multilayer gradient coatings obtained by detonation spraying were studied. To obtain a multilayer gradient coating by detonation spraying, two modes with different numbers of shots of NiCrAlY and YSZ were developed. The presented results demonstrate the effectiveness of creating a gradient structure in coatings, ensuring a smooth transition from metal to ceramic materials. Morphological analysis of the coatings confirmed a layered gradient structure, consisting of a lower metallic (NiCrAlY) layer and an upper ceramic (YSZ) layer. The variation in the contents of elements along the thickness of the coatings indicates the formation of a gradient structure. X-ray analysis shows that all peaks in the X-ray diffraction patterns correspond to a single ZrO₂ phase, indicating the formation of a non-transformable tetragonal primary (t′) phase characteristic of the thermal protective coatings. This phase is known for its stability and resistance to phase transformation under changing operating temperature conditions. As the thickness of the coatings increased, an improvement in their mechanical characteristics was found, such as a decrease in the coefficient of friction, an increase in hardness, and an increase in surface roughness. These properties make such coatings more resistant to mechanical wear, especially under sliding conditions, which confirms their prospects for use in a variety of engineering applications, including aerospace and power generation.

This work studies the influence of the composition of an acetylene–oxygen explosive O₂/C₂H₂ mixture on the structure and properties of hydroxyapatite coatings obtained by detonation spraying. The molar ratios of O₂/C₂H₂ were 2.61; 3.03 and 3.35; the explosive charge was between 73 and 77%. The results of X-ray phase analysis showed partial conversion of the hydroxyapatite (HA) phase to the tricalcium phosphate (α-TCP) phase and formation of the amorphous phase during detonation sputtering. The formation of a small amount of the α-TCP phase during detonation spraying of HA is obviously due to structural transformations occurring during the heating of the material by detonation products. In addition, very rapid cooling of molten particles leads to the formation of the amorphous phase. The study results of the microstructure of the cross sections of the formed coatings, conducted using scanning electron microscopy, indicate that an increase in the O₂/C₂H₂ ratio leads to increased porosity in the coatings. Additionally, an increase in the explosive charge by 77% results in the appearance of transverse cracks in the coating.

This paper studies the coatings deposited on a 65G steel substrate by electric arc metallization using a 30KhGSA wire. The properties of the coatings obtained at 30 V, 40 V and 45 V are discussed, including their microstructure, porosity, microhardness, coefficient of friction and corrosion resistance. The experiments showed that the coatings possess a layered structure formed by sequential deposition of metal microdroplets. It was found that the increase in voltage favors the decrease in porosity, increase in layer density, increase in microhardness and improvement in wear resistance and corrosion resistance. At maximum voltage (45 V), there are optimum performance characteristics, such as minimal porosity (1.36%), high microhardness (305 HV) and improved corrosion resistance. The main defects of the coatings, including pores and oxide inclusions, which are formed during the sputtering process and depend on the kinetic energy of the microdroplets, were identified. These defects affect the mechanical and protective properties of the coatings.