The Influence of the Conditions of Local Plasma-Electrolytic Carbonitriding of 45# Steel on Tribological and Corrosion Properties

Abstract The characteristics of local plasma-electrolytic treatment of a rotating shaft are examined. Changes are studied in the structural and phase composition of the surface layer, as well as in the tribological and corrosion properties in the contact zone of the electrolyte jet with the surface being treated and in adjacent areas of 45# medium-carbon steel. The formation of a gradient of structural and phase changes is demonstrated, which is determined by changes in temperature and diffusion intensity, as well as the cooling rate during quenching. The tribological effectiveness of local treatment is revealed, caused by the oxide layers acting as a lubricant in combination with a high-hardness matrix and increased load-bearing capacity of the surface profile after treatment. The presented treatment method reduces mass and volume wear by up to 32 times in the contact zone of the electrolyte jet with the surface. The polarization resistance in the sodium chloride medium after local treatment of the steel surface is found to increase, which is due to the influence of nitride and oxide phases.