Most failures of machine parts occur due to degradation processes such as fatigue, corrosion and wear occurring on the surface of the materials. Currently, there are various methods to modify the surface layer. For modification, concentrated heating sources, technological lasers, plasma and electron beam installations are used. In this work, plasma alloying of the surface of low-carbon steel was carried out. It has been established that borated layers on steel 20 can be obtained by plasma alloying. An increase in boron content in the melting zone makes it possible to move from a hypoeutectic microstructure to a hypereutectic one, consisting of primary Fe2B borides and a small amount of eutectic ferrite-Fe2B. The highest level of microhardness is characteristic of the boride alloyed layer obtained by alloying using a powder mixture of 40% B + 10% Fe, and amounts to 1000...1300 HV. Compared to samples obtained using carburizing technology, we recorded an approximately threefold increase in the resistance of the alloy.