OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 1 2023 Results and discussion It is found that the coatings formed by the DSLMMS process significantly differ from the CDA coatings. CDA leaded to the formation of diffusion-alloyed coatings of much greater thickness, other elemental composition and operational properties, in particular, mechanical and physicochemical. After DSLMMS and CDA multilayer coatings, at least – the main layer and transition layers are formed; but coatings structures differs. The micrographs of the surface layers of St3 and 40-Cr steels are showed in figure 1. Fig 1. Coating on the surface of steels: a – St3 CDS; b – 40-Cr CDS; c – St3 DSLMMS; d – 40-Cr DSLMMS a b c d Analyzing the data of micrographs, it can be concluded that TCT makes it possible to obtain coatings of a greater thickness than DSLMMS. More details about the thickness and elemental composition of the layers are provided by X-ray microanalysis. The elemental composition and distribution of elements in the coatings being formed using DSLMMS and TCT technologies differ in many respects not only in the thickness of the resulting diffusion coatings, but also in the elemental composition, and, consequently, in the properties. The results of electron microprobe analysis made it possible to compare the elemental composition of the coatings, formed by the DSLMMS and TCT in order to further reveal the features of the formation of diffusion-alloyed coatings. The diffusion penetration depth of chromium and its concentration in different areas of the formed diffusionalloyed coating is compared. The results of X-ray microanalysis of diffusion-alloyed chromium DSLMMS coatings are shown in figure 2. As follows from the X-ray microanalysis of the chromium distribution in the coating, despite the different composition of the coated steels, the chromium content at the surface layers is from 96.9 to 91.1 %.
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