## 3 Results and Discussions
### Application Possibilities in Stationary Gas Turbine Equipment  
The possibility of modifying the surface of a gas-dynamic seal made of silicon carbide-based ceramics by microstructuring to decrease the friction coefficient in stationary gas turbine equipment is determined. It is known that the main problems arising during the creation of new and modernization of existing stationary gas turbine equipment are associated primarily with the requirements of improving efficiency and increasing its service life. The operating parameters of such gas turbine units depend on the permissible pressure levels, temperatures, and rotation speeds for them. The limits of these parameters are often determined by the capabilities of the applied sealing assemblies. At present, there is a tendency to reconstruct land-based units, involving the use of high-tech assemblies, which significantly reduce the operating costs and increase their reliability. One of the most prominent examples is the use of face gas dynamic seals. In centrifugal compressors for natural gas, in order to prevent the leakage of compressed gas from the flow part of the compressor into the cavity of the bearing chambers, a hydraulic shutter with an oil sealing solution is used. This shutter consists of two graphite rings pressed against each other, one of which rotates directly with the compressor shaft. The cavity between the bearing and the graphite rings is filled with oil at a pressure higher than the pressure of the transported gas. The oil traps the gas, provides lubrication and cooling of the friction pair, which determines the oil consumption depending on the pressure drop and the geometry of the ring surfaces in this friction pair. It is expected that the gas compression rate in the compressor, gas temperature before the turbine, and rotor speed will further increase in the future, which in turn will increase the load on the seal assemblies. It should be taken into account that along with the improvement of the engine parameters, the engine service life will increase. The implementation of new equipment is hindered by the lack of advanced highly reliable sealing assemblies, which would be operable in more severe operating conditions. Failures of sealing systems are among the leading causes of emergency shutdowns of gas pumping units. In this regard, the greatest success in the reconstruction of gas pumping units was achieved by replacing hydraulic shutters with \"dry\" face gas dynamic seals. Rotor seals must provide the required sealability during the entire service life, the minimum possible friction, wear, and heat generation. The advantages of face gas dynamic seals are reduced power loss due to friction and lack of the necessity to lubricate the friction pair with oil or other liquid due to the use of gas lubrication. If the rules of operation and on-time maintenance are respected, such a seal should work with low leakage without wear of the friction pair for a long service life. The implementation efficiency of face gas dynamic seals in gas pumping units is determined by the costs of the seal design and manufacture, as well as the costs of the re-equipment and operating costs. The investment costs for gas dynamic seals are higher than for traditional turbomachinery sealing units. However, the system of functioning and parameter control requires considerably lower costs. Furthermore, the operating costs for gas dynamic seals are significantly lower. Therefore, high-performance gas dynamic face sealing systems from ceramics based on silicon carbide with reduced friction coefficient are becoming the standard for newly built compressors. The design, manufacture, and operation of sealing systems in land-based compressor systems require the consideration of many factors that are not usually critical in other areas of engineering. Many technical problems are associated with the materials used in such installations.