Synergy of laser metal deposition and CeO2 nanoparticles: A novel strategy for fabricating superior corrosion-resistant 316L stainless steel coatings for harsh oil and gas environments

This study explores the synergistic effects of laser metal deposition (LMD) and CeO 2 nanoparticles in fabricating corrosion-resistant 316L stainless steel (SS) coatings for severe oil and gas operating conditions. The results show that an LMD-fabricated 316L SS coating containing 0.20 wt.% CeO 2 possesses the best electrochemical performance, involving a decrease in passivation current density ( i pass ), an increase in pitting potential ( E p ), an increase in charge transfer resistance ( R ct ), a double-logarithmic slope close to −1 and a decrease in point defect concentrations ( N D and N A ), suggesting further inhibition of electrochemical reactions and enhanced corrosion resistance of passivation films. In addition, XPS analysis reveals that the LMD-processed sample with 0.20 wt.% CeO 2 obtains the highest fraction of Cr 2 O 3 associated with a lower defect density, higher thermodynamic and chemical stability instead of the hydrated/soluble component dominated by Cr(OH) 3 , thereby enhancing corrosion resistance of passivation films under harsh oil and gas environments, particularly in the presence of high Cl − concentrations. Our focus on developing coatings for demanding oil and gas environments, characterized by concentrated chlorides, provides a crucial practical relevance. The observed improvements in pitting potential and charge transfer resistance directly address critical failure mechanisms in this industry.