Plasma Electrolytic Polishing Effect on Steel’s Surface Roughness after Cathodic Saturation with Nitrogen and Carbon

— Some characteristics of the modified layers after the structural steels' cathodic saturation with nitrogen and carbon were studied. The structure of the layers was examined using scanning electron and optical microscopes; the layer’s elemental composition was determined by energy dispersive analysis. Microhardness and roughness were measured using standard methods. The formation of oxide layers was found during the cathodic processes of carburizing, nitriding, and nitrocarburizing comparable to those observed during the anodic treatment. A certain nitrogen potential of the cathode vapor-gaseous envelope formed in solutions containing ammonium chloride was noted. It was shown that the maximum microhardness of the layer on steel 20 after cathodic carburizing in a glycerol and ammonium chloride solution reached 900 HV, which exceeds that obtained during the anodic carburizing. The steel 20 surface roughness nitrocarburized in the solution of ammonium nitrate and glycerol can be reduced by 1.3 times using subsequent anodic polishing in the ammonium chloride solution.