Corrosion behaviour and mechanism of high-velocity-arc-sprayed Fe-based amorphous coating in 3.5 % NaCl solution

A novel FeMnCrNiBNb amorphous coating (AC) was synthesised in situ using high-velocity arc spraying. The coating demonstrated significantly improved corrosion resistance during long-term immersion in a 3.5 % NaCl solution. After 35 days of immersion, the coating still maintained a stable passive film with a thickness of 0.83 nm; its optimal performance was reached after 14 days, as indicated by a low corrosion current density (Icorr = 0.31 μA·cm−2) and high charge transfer resistance (Rct = 9333.4 Ω·cm2). This study highlights the critical role of passive film integrity and self-repair mechanisms in enhancing long-term performance: the cyclic regeneration of the passive film provides extended protection against chloride-ion penetration. These findings offer a new perspective on the application of in-situ-synthesised ACs to enhance the durability of mechanical components in harsh marine environments.