OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 2 2023 Fig. 3. X-ray pattern of the first specimen after plasma-jet hard-facing a b Fig. 2. Micrograph (a) and scheme (b) of the 1st specimen cross section structure after plasma-jet hard-facing: 1 – hypereutectic zone with iron borides of various structures; 2 – eutectic zone; 3 – heat affected zone; 4 – base metal A heterogeneous structure of the surface layer of the second specimen after plasma-jet hard-facing was also obtained (Fig. 5). But it is noted that the proportion of primary borides in the hard-faced layer is much smaller. The boron content in the hard-faced layer decreases and amounts to 9.23%. The microstructure of the coating layer consists of primary iron borides FeB and Fe2B located in a eutectic matrix consisting of Fe2B and α-Fe, as shown in figure 5. X-ray analysis shows the presence of primary FeB and Fe2B borides on the steel surface after plasma-jet hard-facing (figure 6). In the lower part of the coating near the boundary with the base metal (figure 5, d),
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