Effect of Seawater Static Pressure on Cathodic Protection of DH36 Ocean Platform Steel

The cathodic protection situations were simulated using an autoclave at atmospheric pressure, 2.0 MPa, 5.0 MPa and 10 MPa. The initial cathodic protection was simulated using galvanostatic control method and the cathodic protection situations were evaluated by the change of potential, the macro-morphology of the electrode and the formation situation of calcareous deposit layer. The results showed that the effect of simulated seawater static pressure on cathodic protection was not significant. The polarization resistance zoomed obviously and the scale coverage of calcareous deposit layer could form on the electrode when the current density was 100 mA/m2. The principal deposit layer constituent was aragonite CaCO3. The calcite having magnesium would form and grow together with aragonite when the current density was relatively high.