## 3 Results  
The nitrogen content in the coating is 51.4 \(\pm\) 2.1 at.% and is practically identical for all three coatings. In what follows, we will consider only the metal content in nitride coatings; the total content of the metal component of the coating is taken as 100 at.%. The aluminum content in the coatings decreases from 94.2 at.% for sample T2, located directly opposite the evaporator with an Al cathode, to 10.3 at.% for sample T12, located opposite the evaporator with a Ti cathode (Figure 2a). Simultaneously with this, the titanium content increases from 7.6 at.% to 89.7 at.%. The slightly higher aluminum content in sample T12 compared to the titanium content in sample T2 can be explained by the significantly lower weight of aluminum atoms and, accordingly, a greater dispersion of these atoms in the chamber space. Sample T7, which occupies an intermediate position between the aluminum and titanium plasma flows, has a dominant titanium content (69.5 at.%) and a lower aluminum content (30.5 at.%). This disproportion can be explained by a wider angle of the titanium plasma flow compared to the more focused aluminum plasma flow in the FCVAD system [23]. An approximation of the obtained data shows that both elements are characterized by a polynomial (second-order) function, which allows for achieving an approximation accuracy of R2 = one (Figure 2b). The results of coating thickness measurements are presented in Table 1. The obtained data show a significant difference in the coating thicknesses depending on the sample location in the chamber. The T2 coating thickness is in the range of 0.8-1.5 \(\upmu\)m, which is significantly less than the T12 coating thickness (2.8-3.4 \(\upmu\)m), given that the duration of the deposition process for all samples was identical and was 30 min. Such a difference in thicknesses is associated with the features of the PVD process in general and FCVAD technology in particular. It is known that the PVD method, unlike CVD methods, does not allow for a completely unified coating thickness, since the coating thickness depends on the sample location in the chamber [5]. This is because aluminum forms a high amount of the microparticle phase during evaporation, and FCVAD technology allows for filtering the plasma flow from these microparticles, but this reduces the flow density and, accordingly, the coating deposition rate [5,30]. Accordingly, with identical parameters of the deposition process, the growth rate of the coating for the sample located opposite the CAA-PVD evaporator with a titanium cathode is significantly higher compared to the sample located opposite the FCVAD evaporator with an aluminum cathode. When measuring the hardness of coatings, it is usually assumed that the indentation depth should not exceed 10% of the total coating thickness [32,33]. This condition allows one to obtain an adequate value for the hardness of a coating deposited on a substrate with significantly different properties (in this case, a significantly softer and more plastic one). When working with nanoindentation data, the relative indentation depth should be determined by the contact depth normalized by the coating thickness [34]. Available data show that the adequate measurement of coating hardness with nanoindentation is possible with a coating thickness of more than 100 nm and an indenter indentation depth of more than 20 nm [34]. In general, the results of the nanoindentation of hard coatings on a soft substrate are completely adequate with coating thicknesses of about 1 \(\upmu\)m, even if the indentation depth exceeds 10% of the coating thickness [35]. Other works contain data showing that in the case of a sufficiently thick (more than 1 \(\upmu\)m) and hard coating on a relatively soft and plastic substrate, the plastic deformation of the substrate, affecting the accuracy of measuring the hardness of the coating, is observed at an indentation depth of about 20% of the coating thickness [36].