## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{3}{*}{**Layer**} & \multirow{3}{*}{**Material**} & \multicolumn{3}{c}{**Regime I (Sample No. 1)**} & **Regime II (Sample No. 2)** \\ \cline{3-6}  & & **Doser 1** & **Doser 2** & **Doser 1** & **Doser 2** \\  & & **(NiCrA1Y)** & **(YSZ)** & **(NiCrA1Y)** & **(YSZ)** \\ \cline{3-6}  & & \multicolumn{3}{c}{**Number of Shots**} \\ \hline Substrate & 12 Kh18N10T & - & - & - & - \\ Layer 1 & NiCrA1Y/YSZ & 5 & 1 & 10 & 2 \\ Layer 2 & YSZ/NiCrA1Y & 3 & 1 & 6 & 2 \\ Layer 3 & NiCrA1Y/YSZ & 2 & 1 & 4 & 2 \\ Layer 4 & YSZ/NiCrA1Y & 2 & 1 & 4 & 2 \\ Layer 5 & NiCrA1Y/YSZ & 1 & 1 & 2 & 2 \\ Layer 6 & YSZ/NiCrA1Y & 1 & 1 & 2 & 2 \\ Layer 7 & NiCrA1Y/YSZ & 1 & 1 & 2 & 2 \\ Layer 8 & YSZ/NiCrA1Y & 1 & 1 & 2 & 2 \\ Layer 9 & NiCrA1Y/YSZ & 1 & 1 & 2 & 2 \\ Layer 10 & YSZ/NiCrA1Y & 1 & 1 & 2 & 2 \\ Layer 11 & NiCrA1Y/YSZ & 1 & 1 & 2 & 2 \\ Layer 12 & YSZ/NiCrA1Y & 1 & 2 & 2 & 4 \\ Layer 13 & NiCrA1Y/YSZ & 1 & 2 & 2 & 4 \\ Layer 14 & YSZ/NiCrA1Y & 1 & 3 & 2 & 6 \\ Layer 15 & NiCrA1Y/YSZ & 1 & 20 & 2 & 40 \\ \hline \end{tabular}
\end{table} 
Table 2: Sequence of layer application and number of shots in regime 1 (sample No. 1) and regime 2 (sample No. 2). Figure 2: CCDS2000 equipment (**a**) and the operating principle (**b**) of detonation spraying of coatings. Microstructural analysis of initial powders and cross-sections of the obtained coatings was carried out using scanning electron microscopy (SEM) on a TECAN MIRA3 LMH device (TESCAN, Brno, Czech Republic) [39]. For a quantitative assessment of porosity, cross-sectional images obtained in the SEM mode were used, followed by processing according to the method described in the ASTM E2109 standard [40]. Calculations were carried out using ImageJ software (version 1.54g). To simulate the corrosive effect of silicate melts, a model CMAS mixture with a molar composition of 33 CaO-9 MgO-13 Al2O3-45 SiO2 was used, recommended in a number of previous studies [41; 42]. The starting reagents (CaO, MgO, Al2O3, SiO2) with a chemical purity of 99.9% were precisely measured in the specified molar ratios and dispersed in anhydrous ethanol. The mixture was processed in a planetary ball mill (Emax, Retsch GmbH., Haan, North Rhine-Westphalia, Germany) at 1000 rpm for 1 h. The resulting suspension was dried at 120 \({}^{\circ}\)C for 5 h, after which the dried powder was melted at 1550 \({}^{\circ}\)C for 1 h to obtain a homogeneous melt. Rapid cooling of the melt in deionized water ensured the formation of an amorphous glassy phase of CMAS. The resulting glass was additionally crushed and sieved through a sieve with a mesh size of 200 \(\upmu\)m. To simulate the effect on the coating, CMAS powder was applied to the surface of the samples, followed by heat treatment at 1200 \({}^{\circ}\)C for 1 h, followed by slow cooling to room temperature in an SNOL7.2/1100 muffle furnace (SNOL (Umega Group AB), Utena, Lithuania). Tribological tests of the coatings at room and elevated temperatures were carried out on a T-21 tribotester located at the Department of Machine Design and Tribotechnology of the AGH University (Krakow, Poland) in accordance with the international standard ISO 20808:2016 [43]. The configuration of the ball-on-disk contact pair was used. The test parameters included a normal force of 10 N, 2000 cycles, a wear scar radius of 3.5 mm, a linear velocity of 0.1 m/s, temperatures of 21 \({}^{\circ}\)C, 450 \({}^{\circ}\)C, 550 \({}^{\circ}\)C, and 650 \({}^{\circ}\)C, and the use of aluminum oxide (Al2O3). This range was chosen to evaluate the tribological behavior of coatings under conditions covering both room temperature and temperature regimes close to the actual operating conditions of thermal protection systems. Elevated temperatures allow tracking changes in the wear mechanism, as well as the effect of thermal exposure on the structure and stability of the coating. After the completion of the tests, the samples were cooled to ambient temperature and cleaned of possible contamination.