The technology of powder metallurgy makes it possible to develop fundamentally new structural and instrumental materials. This is precisely the type of materials from the Fe-C-Cu system. Copper is an alloying element that is not used in conventional technological processes but is a major alloying element in powder metallurgy. It has several advantages, but the main one is that it guarantees the sintering process in the presence of a liquid phase in the iron matrix. This favours the coagulation of the pores and helps to reduce the amount of residual porosity in the final product, thus achieving an increase in its operational characteristics. The publication examines the peculiarities of surface strengthening of materials from the Fe-C-Cu ternary system with boron. The research was done on semi-permeable powder materials with a density of 5.80–7.00g/cm3 (with a porosity of 5–10%) in semi-permeable saturating environment containing elemental boron. The formation mechanism of the boride coating, as well as the structure and phase composition of the diffusion layer after saturation for 2–4 h at temperatures of 900–1000 °C, were monitored. Graphic dependences of the experimental results in the X-ray phase analysis, as well as metallographic images of the obtained coatings are presented.