Corrosion protection of stainless steel by Nanocomposite coating prepared by Pulsed laser ablation in liquid

Stainless steels remain indispensable in various engineering and biomedical applications due to their favorable combination of mechanical strength and intrinsic corrosion resistance. However, in aggressive environments such as the oral cavity, additional surface protection is often required. This study introduces a novel dual-layer coating strategy for 316L stainless steel to enhance its resistance to corrosion and microbial colonization. The first layer consists of platinum nanoparticles (PtNPs) deposited via radio-frequency (RF) plasma sputtering, forming a conductive and stable base. The second layer—a Pt-based nanocomposite—is synthesized and directly deposited using pulsed laser ablation in liquid (PLAL) with polyvinylpyrrolidone (PVP) as a stabilizer and natural tannins as a reducing and bioactive agent. Importantly, the PLAL process enables the simultaneous synthesis and in-situ coating of the multifunctional nanocomposite in a single, integrated step, offering a clean, rapid, and scalable fabrication approach. Electrochemical characterizations, including potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), were conducted in artificial saliva to assess corrosion performance. The coated samples exhibited a significant decrease in corrosion current density and a marked increase in polarization resistance compared to uncoated stainless steel. Furthermore, antibacterial tests against Streptococcus mutans revealed inhibition zones up to 42 mm, demonstrating strong antibacterial activity. This synergistic dual-layer system, combining RF-deposited PtNPs with a laser-fabricated organic–inorganic nanocomposite, shows excellent potential for next-generation biomedical coatings.