THE EFFECT OF THE ELECTROLYTE COMPOSITION ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF STEEL 45 AFTER CATHODIC ELECTROLYTE-PLASMA NITRIDING

This research offers an in-depth exploration of the impact of cathodic nitriding on the structural and mechanical characteristics of 45 steel treated in different aqueous electrolytes. Through a combination of Xray diffraction and electron microscopy analyses, it was determined that the nitriding process facilitates the development of a multilayered surface structure, which includes oxide, nitride, and martensitic layers. The composition of the electrolyte plays a crucial role in determining the phase composition and thickness of the modified layers, directly influencing the steel's mechanical properties, as reflected by variations in hardness and wear resistance post-treatment. Notably, an electrolyte containing sodium carbonate (Na₂CO₃) and urea (CH₄N₂O) achieved a maximum microhardness of 986 HV due to the formation of a dense nitride layer. On the other hand, introducing ammonium nitrate to the electrolyte, while slightly decreasing the microhardness to 882 HV, resulted in the formation of a more intricate and stable phase structure, including additional nitrides and oxides, which contributed to enhanced corrosion resistance. These findings underscore the critical importance of optimizing electrolyte composition to improve the performance characteristics of steel, such as hardness, wear resistance, and corrosion resistance. This study underscores the effectiveness of cathodic nitriding as a method for significantly enhancing the mechanical and surface properties of 45 steel, thereby expanding its potential for use in high-load and aggressive environments.