The most common solution for Marine engineering corrosion protection is the installation of sacrificial anodes. Aluminum anodes are most commonly used, but in water with low salinity (brackish water), magnesium anodes have higher driving voltages and can also be applied.
The most common solution for Marine engineering corrosion protection is the installation of sacrificial anodes. Aluminum anodes are most commonly used, but in water with low salinity (brackish water), magnesium anodes have higher driving voltages and can also be applied.
Although there are many considerations for dealing with extreme environmental conditions at sea, sacrificial anodes combined with protective coatings are still suitable for protecting immersed steel surfaces from corrosion. Cathodic protection is designed individually for each seafloor structure. Design considerations typically include environmental parameters, harmful effects, fastening devices, coating breakdown factor (coating class), and anode life requirements.
| Types | Zn | In | Cd | Sn | Mg | Si | Ti | Impurities, not more than | Al | ||
| Si | Fe | Cu | |||||||||
| Al-Zn-In-Cd | 2.5-4.5 | 0.018-0.050 | 0.005-0.02 | — | — | — | — | 0.1 | 0.15 | 0.01 | Balance |
| Al-Zn-In-Sn | 2.2-5.2 | 0.020-0.045 | — | 0.018-0.035 | — | — | — | 0.1 | 0.15 | 0.01 | Balance |
| Al-Zn-In-Si | 5.5-7.0 | 0.025-0.035 | — | — | — | 0.10-0.15 | — | 0.1 | 0.15 | 0.01 | Balance |
| Al-Zn-In-Sn-Mg | 2.5-4.0 | 0.020-0.050 | — | 0.025-0.075 | 0.50-1.00 | — | — | 0.1 | 0.15 | 0.01 | Balance |
| Al-Zn-In-Mg-Ti | 4.0-7.0 | 0.020-0.050 | — | — | 0.50-1.50 | — | 0.01-0.08 | 0.1 | 0.15 | 0.01 | Balance |
| Performance, types, indicators | Open circuit potential -V(SCE) | Working potential -V(SCE) | Actual capacitance A · h/kg | Current efficiency % | condition |
| Ordinary aluminum alloy anode | 1.10-1.18 | 1.05-1.12 | ≥2400 | ≥85 | Corrosion products are easy to fall off and dissolve evenly on the surface. |
| High-efficiency aluminum alloy anode | 1.10-1.18 | 1.05-1.12 | ≥2600 | ≥90 | |
| Highly activated aluminum alloy anode | 1.45-1.50 | 1.40-1.45 | ≥2080 | ≥70 |
