Effects of Cu²⁺ on Corrosion Behavior of Materials in Seawater

The corrosion behaviors of A106B carbon steel and 304L stainless steel in artificial seawater solution containing different content of Cu²⁺ were studied by immersion test, electrochemical test, stereo microscopy and scanning electron microscopy (SEM) observation. The results of immersion test showed that with the increase of Cu²⁺ content, the corrosion rate of A106B carbon steel increased, and the corrosion morphology showed uniform corrosion. The 304L stainless steel had obvious pitting, and the pitting resistance decreased with the increase of Cu²⁺ content. The results of electrochemical tests showed that the self-corrosion potential of A106B carbon steel shifted negatively with the increase of Cu²⁺ content. When the Cu²⁺ content increased to 100 mg/L and above, the polarization curve shifted to the upper right, and both the self-corrosion potential and the self-corrosion current density were significantly increased. The polarization curve of 304L stainless steel moved to the upper right with the increase of Cu²⁺ content, the self-corrosion potential was obviously improved, the range of the passivation zone was shortened, and the pitting sensitivity increased.