The galvanic series ranks metals and alloys based on their electrical potential in seawater. Metals at the top (anodic) are more active and corrode preferentially when coupled with metals at the bottom (cathodic/noble).
| Metal / Alloy | Potential (V) | Category | Type | Note |
|---|---|---|---|---|
| Magnesium | -1.60 | Very Active | Anodic | — |
| Magnesium Alloys | -1.60 | Very Active | Anodic | — |
| Zinc | -1.03 | Active | Anodic | Galvanized steel |
| Aluminum 1100 | -0.75 | Active | Active | — |
| Aluminum 2024-T4 | -0.60 | Active | Active | — |
| Aluminum 7075-T6 | -0.60 | Active | Active | — |
| Cadmium | -0.82 | Active | Active | — |
| Carbon Steel (1010) | -0.60 | Active | Active | — |
| Cast Iron | -0.60 | Active | Active | — |
| Low Alloy Steel (4140) | -0.60 | Active | Active | — |
| Stainless Steel (Active) | -0.50 | Stainless Steel | Active | — |
| Lead | -0.40 | Active | Active | — |
| Tin | -0.40 | Active | Active | — |
| Brass | -0.35 | Copper Alloys | Active | — |
| Copper | -0.35 | Copper Alloys | Active | — |
| Bronze | -0.30 | Copper Alloys | Active | — |
| Nickel (Active) | -0.30 | Nickel Alloys | Active | — |
| Monel 400 | -0.20 | Nickel Alloys | Active | — |
| Titanium (Active) | -0.10 | Titanium | Active | — |
| Stainless Steel (Passive) | +0.10 | Stainless Steel | Passive | 316, 304 passive |
| Nickel (Passive) | +0.15 | Nickel Alloys | Passive | — |
| Monel 400 (Passive) | +0.20 | Nickel Alloys | Passive | — |
| Titanium (Passive) | +0.30 | Titanium | Passive | — |
| Silver | +0.45 | Noble Metals | Noble | — |
| Gold | +0.80 | Noble Metals | Noble | — |
| Platinum | +0.95 | Noble Metals | Noble | — |
| Graphite | +1.00 | Non-Metal | Noble | — |
| Metal 1 | Metal 2 | Compatibility | Recommendation |
|---|---|---|---|
| Aluminum | Carbon Steel | Unsafe | Use insulation or coating |
| Aluminum | Stainless Steel | Caution | Use zinc anodes or coating |
| Aluminum | Copper | Unsafe | Avoid direct contact |
| Aluminum | Titanium | Unsafe | Avoid direct contact |
| Carbon Steel | Stainless Steel | Caution | Use coating or cathodic protection |
| Carbon Steel | Copper | Caution | Use insulation or coating |
| Carbon Steel | Brass | Caution | Use insulation or coating |
| Carbon Steel | Zinc | Safe | Zinc acts as sacrificial anode |
| Stainless Steel | Copper | Caution | Acceptable in some applications |
| Stainless Steel | Titanium | Caution | Use insulation |
| Stainless Steel | Nickel Alloy | Safe | Close in galvanic series |
| Copper | Brass | Safe | Similar materials |
| Copper | Bronze | Safe | Similar materials |
| Zinc | Carbon Steel | Safe | Zinc protects steel |
| Zinc | Copper | Unsafe | Rapid zinc corrosion |