Zinc alloy sacrificial anode is a material that prevents corrosion through cathodic protection. It is also classified as an electrochemical anode, and other sacrificial anodes include aluminum alloy sacrificial anode and magnesium alloy sacrificial anode. The protective performance of zinc anode benefits from a strong negative reduction potential, which is more negative than the metal potential it protects. The oxidant that corrodes the metal will oxidize the zinc alloy sacrificial anode instead of the protected metal, thus preventing the structure from being corroded.
Zinc anode model specifications
Product name | Model | Specifications/mm | Weight/kg |
A×（B1+B2）×C |
Zinc anode | ZE-1 | 500×（115+135）×130 | 56.0 |
Zinc anode | ZE-2 | 1000×（80+100）×80 | 50.0 |
Zinc anode | ZE-3 | 500×（105+135）×100 | 40.0 |
Zinc anode | ZE-4 | 500×（80+100）×80 | 25.0 |
Zinc anode | ZE-5 | 400×（110+120）×50 | 16.0 |
Zinc anode | ZE-6 | 300×（140+160）×40 | 12.5 |
Zinc anode | ZE-7 | 200×（90+110）×40 | 5.5 |
Chemical composition of zinc anode
Chemical elements | Al | Cd | Impurities, not more than |
Fe | Cu | Pb | Si | Zn |
Content% | 0.3-0.6 | 0.05-0.12 | 0.005 | 0.005 | 0.006 | 0.125 | Balance |
Electrochemical performance of zinc anode
Performance indicators | Open circuit potential-V (SCE) | Working potential-V (SCE) | Actual capacitance A · h/kg | Current efficiency% | condition |
In seawater | -1.09~-1.05 | -1.05~-1.00 | ≥780 | ≥95 | Corrosion products are easy to fall off and dissolve evenly on the surface |
In the soil | ≤-1.05 | ≤-1.03 | ≥530 | ≥65 |
Note 1: Reference electrode - saturated calomel electrodeNote 2: Medium - The seawater medium is artificial seawater; the soil medium is moist soil with filler added around the anode. |
Zinc anode is a material that prevents corrosion through cathodic protection . It is also classified as an electrochemical anode, and other sacrificial anodes include aluminum alloy sacrificial anodes and magnesium alloy sacrificial anodes. The protective properties of zinc anodes benefit from a strong negative reduction potential, which is more negative than the metal potential it protects. Oxidants that corrode metals will oxidize the zinc anode instead of the protected metal, preventing the structure from being corroded. Zinc anodes are commonly used in brine, most commonly in marine applications such as hulls, tanks, rudders, and docks. They are also commonly used in underground tanks and pipelines. Corrosion Lingo: Zinc Anode
Zinc anodes use their characteristics of potential, current capacity, and alloy quality to protect metal surfaces from corrosion. When immersed in water, zinc anodes have a reduction potential of -1.05V compared to the reference electrode. When the zinc anode is close to another metal with a larger reduction potential, it makes the other metal the cathode of the electrochemical system. When oxidants erode the metal surface, electrons flow through the system and are removed from the zinc anode instead of the protected metal, as shown in the formula:
Zn → Zn 2 ++ 2e -
Therefore, the zinc anode is oxidized and corroded, rather than the surface of the protected metal being corroded. The higher the quality of the zinc anode, the longer it will provide protective current before it runs out on its own. An important indicator of the zinc anode is its utilization rate, which specifies how much the anode can be used before losing its protective performance. With these indicators, we can calculate the demand for the anode according to the formula. The quality of the zinc anode material is also important because impurities in the zinc metal can weaken its protective performance.
In fresh water, the zinc anode produces a thin film of zinc hydroxide on the surface, preventing the flow of electricity. Therefore, the zinc anode is ineffective in fresh water and is used in saltwater.
Like other sacrificial anodes, zinc anodes offer the following advantages:
1. No external power supply is required.
2. Easy to install.
3. Low voltage;
4. Low maintenance costs.
5. The risk of overprotection is low.
Zinc anode disadvantages include:
1. Cannot work in high-resistance environments.
2. High electrical isolation requirements from other structures.
3. The capacitance is small.
4. High density;
5. Potential interference with water flow.
