Activation Mechanism of New Al Anode in Tidal and Coastal Environment

Aiming at the problem that the national standard aluminum anode cannot meet the requirements of cathodic protection in the tidal and coastal environment, a test device for simulating tidal and coastal soil environment was established, and the working characteristics and activation mechanism of three new Al anodes in tidal and coastal environment were studied. The results showed that the actual capacitance of Al-1 anode and Al-3 anode was greater than 1 500 A ·h ·kg^-1, and the current efficiency was greater than 50 %, which was better than the national standard aluminum anode performance. At -1.10 V polarization potential, the stable anode current densities of the three new anodes were 128 μA ·cm^-2 ( Al-1 anode ) and 70 μA ·cm^-2 ( Al-2 anode and Al-3 anode ), respectively. The Al-1 anode was more suitable for the beach and coastal environment, because the reduction process of Sn-In solid solution and GaO^3-₃ in the Al-1 anode promoted the continuous dissolution of corrosion product layer on the surface of aluminum anode in tidal and coastal environment.