Study on the Corrosion Behavior and Mechanism of Supersonic Flame Sprayed C276 Coating in Simulated Seawater Environment

In this study, a Hastelloy C276 coating was fabricated on the surface of Q345B steel using high-velocity oxy-fuel (HVOF) spraying technology, and the corrosion behavior and mechanism of the coating in a simulated seawater environment were investigated through electrochemical measurements and immersion tests. Studies have shown that C276 coatings fabricated using HVOF technology exhibit dense microstructures and high microhardness. The corrosion rate of the coating initially increased and then decreased with prolonged immersion time, reaching a maximum at 720 h, followed by a reduction to 0.259 mm/year at 1440 h. Corrosion morphology analysis indicated that the decreased corrosion resistance of the C276 coating was primarily due to pitting initiation and propagation at the pores of the coating. With increasing immersion time, the corrosion products accumulated at the surface defects of the C276 coating, forming a dense covering layer that effectively hindered corrosion.