Microstructure and Corrosion Resistance of Ni-Cr-Mo-Si/Cr3C2 Coatings Prepared by Laser Cladding

Abstract

This paper enhances the corrosion resistance of Q235A steel in a seawater environment by employing laser cladding technology to prepare Ni-Cr-Mo-Si/x Cr₃C₂ (x = 0, 5, 15 wt%) hydrophobic coatings on its surface. The results indicate that the introduction of Cr₃C₂ substantially refines the microstructure of the coating and forms additional reinforcing phases, primarily including Cr₂₃C₆, Ni₃C, and Cr_1.12Ni_2.88. The addition of an appropriate amount of Cr₃C₂ significantly contributed to the enhanced formation of hard phases. Specifically, when the Cr₃C₂ content is 15%, the average hardness reached a maximum of 395.2 HV_0.5. Combining wettability tests with electrochemical results, the Ni-Cr-Mo-Si/Cr₃C₂ coatings show lower surface energy, improved hydrophobicity, and reduced corrosion rates. When the Cr₃C₂ content reaches 15%, the synergistic effect of hydrophobicity and carbides optimized the corrosion resistance of the coating. Therefore, this paper reveals the multifaceted roles of Cr₃C₂ in refining the microstructure and improving corrosion resistance.