Fig. 1. X-ray diffraction patterns of surface layers before (a) and after anode PEN/C in a solution of carbamide (10%) and ammonium chloride (10%) for 5 min at 650 °С (b), 750 °С (c), 850 °С (d), and 950 °С (e).Figure optionsDownload full-size imageDownload high-quality image (513 K)Download as PowerPoint slide
3.2. Microstructure of the surface layer and formation of the RJR-2403 layers
According to SEM analysis, the structure of the treated steel surface is composed of the following layers (Fig. 2):–oxide layer that contained the FeO, γ-Fe2O3 and Fe3O4 iron oxides,–external nitrocarburised layer that contained nitrides FeN0.05, perlite or martensite and remained austenite depending on the treatment temperature and cooling conditions,–external nitrocarburised layer that contained nitrides FeN0.05, martensite and remained austenite when the sample is quenched in the electrolyte or nitrides and perlite after cooling in air,–internal diffusion layer that contained solid solution of nitrogen and/ or carbon depending on the treatment temperature and cooling conditions,and initial pearlite–ferrite structure.