Numerical simulation and deep-sea experiment validation for the cathodic protection design of aluminum alloy framework

Aiming at the deep-sea corrosion protection problem of aluminum alloy framework, the cooperative scheme of sacrificial anode cathodic protection and anticorrosive coating protection was designed, the boundary element numerical simulation was used and subsequently the deep-sea field exposure experiment were carried out to verify the protection effect. The simulation results show that the overall protection potential ranges between -961 mV (vs. Ag/AgCl) and -1004 mV (vs. Ag/AgCl) for the initial stage, indicating a good protective effect of cooperative project. And the 0.5-year protective potential ranges between -959 mV and -1004 mV. On the other hand, the 1000m deep-sea field exposure experiment with 0.5 year was carried out with the in-situ electrochemical monitoring equipment recording the real-time potential variation and the result shows that the overall protective potential displays a range of -996 mV similar to -1046 mV (vs. Ag/AgCl), showing a protection potential difference value of 39 mV from the simulation prediction. The average adhesion strength of deep-sea anticorrosive coating reaches above 8 MPa, remaining the same level as that before the deep-sea experiment. These results prove that the cooperative protective scheme gets a high reliability and can meet the corrosion protection requirement of deep-sea 5A06 aluminum alloy structure.