## 3 Results and Discussion  
### Structure and Mechanical Characteristics of As-Deposited Coatings  
The coatings were characterized by a dense homogeneous structure without pronounced columnar grains. The Ta-Zr-Si-B-C and Ta-Zr-Si-B-N coatings, 7.2 and 6.4 \(\upmu\)m thick, had the following composition at.%: Ta\({}_{28}\)Zr\({}_{10}\)Si\({}_{26}\)B\({}_{24}\)C\({}_{12}\) and Ta\({}_{27}\)Zr\({}_{8}\)Si\({}_{22}\)B\({}_{22}\)N\({}_{20}\). The roughness parameter (Ra) of the coatings was close and was in the range of 16-18 nm. A detailed description of the composition, structure and thickness of the as-deposited coatings is presented in [19; 20; 21].  
According to the XRD data (Figure 1a), the coatings were X-ray amorphous. According to SAED patterns and BF TEM images (Figure 1b,c), the coatings are characterized by an amorphous structure.  
On the SAED patterns of the Ta-Zr-Si-B-C and Ta-Zr-Si-B-N coatings, a broad reflection is observed, close to the position of the (110) and (111) lines of the h-TaSi\({}_{2}\) crystalline phase (JCPDS 38-0483) with d/n = 0.239 and 0.224 nm, respectively.  
In this work, the chemical and phase composition of the coatings was additionally studied using the XPS method. Figure 2 shows the Ta4f, Zr3d, C1s and Si2p spectra of the Ta-Zr-Si-B-C coating after etching.  
In the Ta4f spectra, two doublets are observed at positions 22.7 and 24.7 eV and 23.4 and 25.5 eV, related to the Ta-Si and Ta-C bonds, respectively [34]. The low intensity peak at position 26.5 eV can be attributed to Ta-O bonds [34]. The high intensity of the Ta-Si peaks indicates the predominance of this bond in the coating. According to the Zr3d spectra, the doublet at binding energies of 179.5 and 181.9 eV indicates a Zr-B bond [35]. Peaks at 181.0 and 183.3 eV correspond to the bond of zirconium with oxygen [35]. Peaks in the C1s spectrum in the range of 282-284 eV indicate the presence of Ta-C and Si-C bonds; there is also a low-intensity C-C peak [34]. The Si2p spectrum confirms the presence of Si-C and Ta-Si bonds [36].  
Figure 1: XRD patterns (**a**), SAED patterns and BF TEM images of the structure (**b**) of Ta-Zr-Si-B-N and Ta-Zr-Si-B-C as-deposited coatings.  
The spectra of Ta4f, Zr3d, N1s and Si2p for the Ta-Zr-Si-B-N coatings after etching are shown in Figure 3.  
A doublet was found in the Ta4f spectrum at positions 22.7 and 24.7 eV, corresponding to the Ta-Si bond [34]. Low-intensity peaks at positions 23.7 and 25.7 eV correspond to the chemical state of Ta in the cubic or hexagonal Ta-N phase [37]. Also, the presence of Ta-Si-N bonds cannot be excluded. Three doublets were revealed in the spectrum of Zr3d, which can be attributed to the Zr-B, Zr-N and Zr-O-N bonds, respectively [38]. The spectra of N1s show an intense peak at 397.3 eV, which appeared as a result of the overlap of the Ta-N [39] and Si-N [40] peaks. It is also impossible to exclude the presence of B-N bonds at 396.7-397.5 eV [41]. Peaks at 99.3 and 101.6 eV in the Si2p spectrum correspond to Si-Si and Si-N bonds [40].  
Thus, the XPS data showed that in the coatings, tantalum is predominantly bonded to silicon, and zirconium is bonded to boron. In addition, Ta-C and Si-C bonds were found for the carbon-containing coating, and Ta-N, Zr-N and Si-N bonds were found for the nitrogen-containing coating.  
Figure 2: XPS spectra of Ta4f (**a**), Zr3d (**b**), C1s (**c**) and Si2p (**d**) for Ta-Zr-Si-B-C as-deposited coatings after etching for 5 min.  
The Ta-Zr-Si-B-C coating had a hardness of 25 GPa, an elastic modulus of 259 GPa and an elastic recovery of 71%. For the Ta-Zr-Si-B-N coating: H = 23 GPa, E = 229 GPa and W = 74%. The high mechanical characteristics of the carbon-containing coating can be explained by the higher hardness of the TaC and SiC carbide phases compared to the TaN and Si\({}_{3}\)N\({}_{4}\) phases [42; 43; 44].