Abstract
The study investigates the spectral, structural, and phase changes occurring in austenitic steel 12Kh18N10T during cathodic electrolytic plasma nitriding (EPN) in a Na2CO3–CO(NH2)2–NH4Cl electrolyte at 550 °C for 10 min. Emission spectroscopy revealed active plasma components: N2+, N I, Hα, and O I. The electron density, calculated from the Hα line broadening, was approximately 8.5 × 1018 cm−3. X-ray phase analysis revealed the formation of CrN, Fe3N phases, and a solid solution of nitrogen in γ-Fe. SEM analysis revealed a three-layer structure of the nitrided layer: a nitride zone, a transition region, and the austenitic matrix. The EDS profile confirmed a decrease in nitrogen concentration, accompanied by a reduction in microhardness from a maximum of 480 HV at the surface, both gradually decreasing with depth. The friction coefficient decreased from ~0.8 (in the initial state) to ~0.6 after EPN. The results confirm the effectiveness of EPN in strengthening and improving the wear resistance of stainless steel.