(V) Electron-beam surface modification of boron-based diffusion layers obtained of the surface of steel H21

The development of new protective coatings is of great fundamental and applied importance for increasing operational properties of surface layers in machine parts, increasing their durability, and expanding their functionality. The study is devoted to the creation of coatings based on boron and aluminum on the surface of alloyed steel using a method, combining diffusion saturation (DS) and subsequent electron beam processing (EBP). DS was carried out in saturating pastes based on boron carbide and aluminum at a temperature of 950 °C for 2 hours. As a result of processing, a diffusion layer with a thickness of up to (5.6–5.8) × 10² μm and a complex structure with depth-heterogeneous composition was formed on the steel surface. The subsequent EBP led to a complete transformation of the primary diffusion layer and an increase in its thickness to 10³ μm. XRD analysis showed significant differences in composition before and after EBP: after EBP tungsten borides (WB, W₂B₉) and iron (Fe₂B) were detected. In addition, it was determined that the distribution of microhardness and elemental composition (B, Al, W) over the depth of the layer after EBP have a more favorable profile without significant fluctuations compared to the sample after DS.