Background 316L stainless steel faces challenges of wear and corrosion in marine environments. Laser cladding offers an effective surface modification technique to enhance its service performance.
Purpose This study aims to improve the wear and corrosion resistance of 316L stainless steel by in-situ synthesizing Ni-based (Ti,V)C composite coatings via laser cladding. The focus is on investigating the influence of the Ti/V molar ratio on the coating's microstructure, mechanical properties, and service behavior.
Methods Coatings with different Ti/V molar ratios (3∶1, 1∶1, 1∶3) were fabricated. Their phase composition, microstructure, and elemental distribution were characterized using XRD, SEM, and EDS. Microhardness, wear resistance (via a tribometer), and corrosion resistance in a simulated marine environment (via electrochemical workstation) were systematically evaluated.
Results The Ti/V ratio critically controlled the reinforcing phase morphology. (Ti,V)C solid solutions were successfully synthesized at ratios of 1∶1 and 1∶3, while TiC predominated at 3∶1. All coatings exhibited typical solidification gradient structures, with the Ti/V ratio affecting grain morphology. The coating with Ti/V=3∶1 showed the highest microhardness (603.2 HV). However, the Ti/V=1∶1 coating demonstrated the optimal overall performance, featuring the lowest wear rate (wear volume of 0.0182 mm3) and the best corrosion resistance, evidenced by the lowest corrosion current density (36.0 μA·cm−2) and the highest charge transfer resistance (281.4 Ω·cm2).
Conclusions The Ti/V molar ratio is a key factor governing the in-situ formation of carbides and the resulting properties of laser-clad Ni-based coatings. The Ti/V=1∶1 ratio yields a superior combination of wear and corrosion resistance due to the synergistic effect of Ti and V in forming (Ti,V)C solid solutions. This work reveals the regulation mechanism of Ti-V bimetal synergy on coating performance and provides guidance for designing high-performance composite carbide coatings.
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