Abstract
UDC 544.558+66.088
DOI https://doi.org/10.52577/eom.2021.57.2.1
Some characteristics of modified layers after cathodic saturation of structural steels with nitrogen and carbon have been studied. The structure of the layers was investigated using a scanning electron and optical microscopes; the elemental composition of the layer was determined by the energy dispersive analysis. Microhardness and roughness were measured by standard methods. The formation of oxide layers during cathodic processes of carburizing, nitriding, and nitrocarburizing, comparable to those observed during anodic treatment was found. A certain nitrogen potential of the cathode vapour-gaseous envelope formed in solutions containing ammonium chloride was noted. It is shown that the maximum microhardness of the layer on steel 20 after cathodic carburizing in a solution of glycerol and ammonium chloride reaches 900 HV, which exceeds that obtained during anodic carburizing. The roughness of the surface of steel 20 nitrocarburized in a solution of ammonium nitrate and glycerol can be reduced by a factor of 1.3 by subsequent anodic polishing in a solution of ammonium chloride.
Keywords: plasma electrolytic treatment, diffusion saturation, polishing, microstructure, surface roughness, microhardness.