• • The optimal laser micro-additive parameter (800 mm/s, double-layer coating) reduced corrosion current by one order of magnitude and increased corrosion potential by 0.04 V, directly extending the service life of SS304L components in chloride-rich breeding environments where pitting corrosion typically initiates at inclusions.
• • Surface height difference increased from 0.1 µm (untreated) to 3.8 µm (double-pass coating), creating mechanical interlocking sites that anchor Cu particles; this texture also disrupts continuous electrolyte films, reducing active corrosion area by an estimated 30–40% based on Rct enhancement.
• • XPS confirmed the formation of CuO and Cu2O layers on embedded Cu particles, providing a dual barrier: the oxide film stifles oxygen reduction, while Cu2+ release is suppressed, yielding a charge transfer resistance (Rct) of 6954 Ω·cm²—a 5.2-fold improvement over untreated SS304L (typical Rct ~1330 Ω·cm²).
• • The double-pass coating achieved the maximum height difference (3.8 µm) but did not yield the best corrosion performance; the double-layer coating at 800 mm/s balanced Cu deposition and oxide continuity, indicating that excessive texturing can compromise film integrity and accelerate localized corrosion.