## 1 Introduction
This takes place despite the significant disadvantages of SiC that are its low tensile strength and fragility. The friction pair \"SiC-SiC\" works reliably in a liquid medium; however, when working in a gaseous medium, the friction torque can be high enough, which leads to the destruction of the sealing rings due to local overheating. In this case, in order to reduce the friction coefficient in contact when starting and stopping the turbomachine, when the gas-dynamic force is insufficient to create a lubricant layer in the contact and the sealing ring does not \"float\", it is necessary to apply a special antifriction coating to the contact surface of the sealing ring. The application of a thin layer of wear-resistant diamond-like or graphite coating reduces dry friction during start-up and shutdown. For example, a friction pair with a hard and, at the same time, chemically resistant and high sliding diamond coating (DLC technology) applied to both SiC rings has shown good performance [36]. However, the application of such a coating is a very complicated and expensive process. Therefore, it is appropriate to use more competitive laser technologies to reduce the friction coefficient in the \"SiC-SiC\" contact pair when developing seals. Ultraviolet lasers provide a highly localized effect that is characterized by a small beam size. The spatial resolution of an optical image is directly proportional to the wavelength of the radiation; therefore, lasers with shorter wavelengths generating ultraviolet irradiation are quite commonly used for surface structuring [37]. A precise local exposure on the surface of the material is achieved, which corresponds to the size of the laser spot and its scanning step. The use of controlled scanning with a laser beam over the sample surface at a high pulse repetition rate opens up the possibility of structuring extended surface areas with arbitrary shapes and ensures the achievement of a high spatial resolution. It is known that the results of laser exposure depend on the power absorbed by a unit of the surface area. When the applied power is low, it is possible to ensure the required impact due to the short pulse duration, which determines the threshold pulse energy and depth of the removed layer. With a small heat-affected zone, the heat load is minimized, which also reduces the formation of microcracks when treating brittle materials. A nanosecond laser is assumed to be used to provide a high-accuracy processing and low mechanical stresses in the material under treatment, combined with reliability and stability. Surface scanning by a laser beam with a sufficiently high pulse frequency will allow to process extended surfaces with high spatial resolution [38]. Shortening the pulse duration is known to be accompanied by a reduction of the heat affected zone and an increase in the processing accuracy [39]. In this case, the possible advantages of using ultrashort pulses [40] are completely offset by the higher complexity, cost, and specific maintenance difficulties of such laser systems. It should be noted that the application of femtosecond lasers does not solve the problem of precision laser treatment of materials. In particular, it does not completely avoid the undesirable thermal effects of laser-induced plasma at intensities high enough to provide acceptable ablation rates. A nanosecond laser source is used to perform surface modifications, as it is more affordable and easier to operate than pico- and femtosecond lasers. The determination of the possibility of modifying the surface of a gas-dynamic seal made of silicon carbide-based ceramics by microstructuring to obtain a decrease in the friction coefficient is the purpose of this article. The microstructuring is performed by pulse-periodic ultraviolet irradiation with the duration of a pulse in the nanosecond range.