Enhancement in Corrosion Resistance of Low-Carbon Steel via Surface Modification

Abstract

This research investigated the corrosion resistance of surface layers on low-carbon steel exposed to a chloride environment at room temperature. This study systematically evaluated the effects of varying pack compositions, coating temperatures, and application durations on the characteristics of the deposited coatings. The potentiodynamic polarization corrosion test was employed to assess the wet corrosion behavior of the specimens. Elemental compositions and microstructural features were analyzed using energy-dispersive X-ray spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM), providing insights into phase distribution. The chromizing, titanizing, and chromotitanizing treatments were conducted at temperatures of 900 °C, 1000 °C, and 1100 °C, respectively, with varying coating times. X-ray diffraction analysis revealed a complex arrangement of elements and compounds within the coatings, including Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, Cr1.36Fe0.52, and (Ti0.86)3.58. The study found that as the deposition duration increased, the coating thickness increased, comprising a thin inner layer and a substantially thicker outer layer. This layered structure resulted from the outward diffusion of Fe atoms and the inward diffusion of Cr and Ti atoms. Electrochemical analysis in a 3.5% NaCl aqueous solution indicated a marked enhancement in the corrosion resistance of the coated specimens compared to their uncoated counterparts. The potentiodynamic polarization tests confirmed that the protective coatings significantly reduced the corrosion rate, with performance influenced by both the temperature and duration of the deposition process. These findings highlighted the potential of tailored coating techniques to improve the durability and performance of low-carbon steel in corrosive environments.