Cathodic Boronitrocarburizing and Anodic Polishing of Low-Carbon Steel in Plasma Electrolysis

Abstract—

The possibility of increasing the wear resistance and corrosion resistance of the surface of low-carbon steel after cathodic plasma electrolytic boronitrocarburizing in a solution of boric acid, glycerin, and ammonium chloride, and subsequent anodic plasma electrolytic polishing in a solution of ammonium sulfate through the formation of a modified structure has been demonstrated. The modified structure consists of a dense oxide layer and a diffusion layer underneath, which contains up to 0.87% carbon, 0.80% nitrogen, and 0.87% boron, achieving a microhardness of 970 ± 20 HV. The competing effects of surface erosion due to discharge and high-temperature oxidation on surface morphology and roughness were identified. The positive effect of reducing surface roughness during the formation of a dense oxide layer on the surface and a solid diffusion layer underneath on reducing the coefficient of friction and mass wear, as well as reducing surface roughness and additional oxidation during polishing on reducing the corrosion current density, was established.