The paper summarizes the results of studies of the structure, phase composition and operational properties of gears made of steel type 38Kh2MYuA, which are observed in the modified layer, after the nitriding process. Much attention is paid to the process of ion nitriding in a glow discharge. The study of the hardened layer showed that there are some differences depending on the temperature of the process. Frequently used methods for the protection of non-aerated surfaces are considered.