OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 1 2023 The maximum concentration of 96.9 % is observed in unalloyed, low-carbon steel St3. On the surface of other coatings, formed on alloy steels 40-Cr, 20-Cr13, 12-Cr18-Ni10-Ti, the concentration of chromium decreases by almost 6 %. Such decrease in the concentration of chromium in the coating indicates the steels’ alloying elements influence. The smallest coating thickness of 8 µm is observed on steels 20-Cr13 and 12-Cr18-Ni10-Ti. The thickness of the coatings on 40-Cr and St3 steels is greater and amounts to 10–12 µm. There is a dependence of the chromium distribution on the composition of the coated steel, which is especially evident for steel 20-Cr13. A significantly faster drop of chromium concentration in the coating surface/base material area is observed on 20-Cr13 steel. So the chromium concentration in the amount of 60 % in the coating formed on this steel corresponds to a distance from the surface equal to 3 µm, and in steels 12-Cr18-Ni10-Ti, St3, 40-Cr 60 % chromium concentration is observed in the coatings of these steels at distances: 6.5, 8 and 10 µm, respectively. This feature during the coating formation can be explained by the presence in steel 20-Cr13 of a sufficiently large amount of chromium not bound by carbon in steel. a b с d Fig. 2. Results of electron microprobe analysis of diffusion-saturated chromium coatings formed by DSLMMS, temperature 1 025 °C, duration 5 h: a – St3; b – 40-Cr; c – 20-Cr13; d – 12-Cr18-Ni10-Ti
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