Corrosion mechanism and behavior of high-velocity arc-sprayed Al-Ti-Si-RE coating in a simulated deep sea

The corrosion protection of deep-sea equipment using the economical method of thermal spraying has become a research hotspot. This study investigated the corrosion behavior of high-velocity arc-sprayed Al-Ti-Si-RE coating in a simulated deep sea with regard to microstructures, compositions, and electrochemical measurements. Results showed that the Al-Ti-Si-RE coating has excellent corrosion resistance at high hydrostatic pressure (HP). HP plays an important role in the anodic reaction of the coating, whereas dissolved oxygen (DO) mainly affects the cathodic reaction. HP accelerates the dissolution of the coating's passive film, which results in steady corrosion. The amount of corrosion products depends on DO. The corrosion of the self-sealing coating is inhibited in low DO when steady corrosion is achieved.