## 3 Results and Discussion
Both coatings underwent thermal corrosion; however, the degree of degradation varies markedly depending on the morphology and thickness of the coating formed under different spraying regimes. The CMAS melt, which is a eutectic mixture of calcium, magnesium, aluminum, and silicon (CaO-MgO-Al\({}_{2}\)O\({}_{3}\)-SiO\({}_{2}\)), is able to penetrate into the surface layers of the coatings and interact with zirconium dioxide, which is the base of the thermal protection layer. As a result of this interaction, glassy phases and secondary  
Figure 5: Porosity of coatings according to the results of microstructure analysis. reaction products such as monoclinic ZrO\({}_{2}\), spinel structures, and silicates are formed, which leads to the destruction of the protective layer and a reduction in its wear resistance. The image on the left (sample No. 1) shows some areas of CMAS penetration, but corrosion spreading is limited, indicating an effective barrier effect of the coating. This is confirmed by the low porosity and large layer thickness, which prevents deep penetration of the aggressive phase and slows down the degradation of the material. There is an even structure without pronounced cracking. In the image on the right (sample No. 2), the situation is different: higher porosity and lower coating thickness promote rapid penetration of CMAS melt, which causes intensive cracking (indicated by red lines). These cracks are a direct consequence of the internal stresses generated by the interaction of CMAS with the coating, especially under conditions of thermal expansion and the glass transition of the surface layer. Such degradation significantly reduces the performance of the coating and leads to the loss of its protective properties. Thus, the resistance of coatings to CMAS is determined not only by chemical composition, but also by morphological parameters--primarily thickness and porosity. A denser and thicker structure ensures slower melt penetration, limiting the volume of the reaction-capable zone and thus increasing corrosion resistance. During the present work, as well as on the basis of the results of previous studies [36; 37], it was established that sample No. 1 demonstrates more stable and preferable characteristics in comparison with sample No. 2. In this regard, in this work, the main attention is paid to the study of the tribological properties of this sample at various temperatures--from room temperature to 650 \({}^{\circ}\)C.  
Figure 7 shows the dependence of the coefficient of friction (CoF) on the number of sliding cycles for sample No. 1, tested at temperatures of 21 \({}^{\circ}\)C (room temperature), 450 \({}^{\circ}\)C, 550 \({}^{\circ}\)C, and 650 \({}^{\circ}\)C. As can be seen from the graph, at the initial stage of testing at all temperatures, a short-term increase in the CoF value is observed, associated with the running-in of the contacting surfaces. At a temperature of 21 \({}^{\circ}\)C, significant instability of the friction coefficient is observed with pronounced fluctuations throughout the test, despite reaching an average level of ~0.65-0.7. At 450 \({}^{\circ}\)C, the friction coefficient reaches a stable state faster and demonstrates a smoother curve without sharp fluctuations, which may be associated with improved running-in due to thermal softening of the surface layers. At 550 \({}^{\circ}\)C, the lowest average CoF value is observed among all temperature conditions, which indicates a decrease in friction resistance due to thermally activated deformation mechanisms and, possibly, the formation of a protective oxide film. With an increase in temperature to 650 \({}^{\circ}\)C, the friction coefficient increases again and reaches maximum average values. This may be associated with increased oxidation processes on the coating  
Figure 6: Surface morphology of coatings after exposure to CMAS. surface, a change in the nature of contact interaction, and an increase in the brittleness of materials at high temperatures.