03 / CATHODIC PROTECTION · SACRIFICIAL ANODE
Zinc Anode
Zinc sacrificial anodes for ship hulls, marine structures and submerged pipelines — stable, well-understood seawater performance in Type I and Type II grades.
ZINC SACRIFICIAL ANODE
Zinc Anodes
Zinc anodes give stable, reliable and well-understood performance in seawater, brackish water and saline mud. Capacity is lower than aluminium, but the predictable potential and long service record make zinc a default choice for ship hulls and marine structures. A service-temperature limit applies to avoid passivation. ซิงค์แอโนด (zinc anode) ใช้ป้องกันการกัดกร่อนของตัวเรือและโครงสร้างในน้ำทะเล.
- Stable, predictable performance with a long service record
- High current efficiency in seawater and brackish water
- Reliable, well-understood potential — low maintenance
- Effective in saline mud and immersed conditions
- Type I and Type II compositions for different electrolytes
- Robust forms for hull, structure and pipeline mounting
Applications: ship hulls, rudders & ballast tanks, offshore platforms, jetties & harbour structures, submerged pipelines (bracelet), condenser / heat-exchanger water boxes, buried structures (Type II)
Documentation
Catalogs and technical documentation are available upon request. Please contact our team for product information, specifications, and documentation.
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Applicable standards
ELECTROCHEMICAL PROPERTIES
Electrochemical Properties
| Parameter | Typical value |
|---|---|
| Design electrochemical capacity | ~780 Ah/kg (seawater) |
| Current efficiency | ≥ 95 % |
| Closed-circuit potential | −1.00 to −1.05 V (Ag/AgCl) |
| Soil capacity (with backfill) | ~530 Ah/kg |
| Service temperature limit | ≤ 50 °C (seawater) |
Typical values to ASTM B418 / DNV-RP-B401.
CHEMICAL COMPOSITION
Chemical Composition (% by weight)
| Element | Type I (Z32120) | Type II (Z13000) |
|---|---|---|
| Aluminium | 0.10–0.50 | ≤ 0.005 |
| Cadmium | 0.025–0.07 | ≤ 0.003 |
| Iron (max) | 0.005 | 0.0014 |
| Lead (max) | 0.006 | 0.003 |
| Copper (max) | 0.005 | 0.002 |
| Zinc | remainder | remainder |
To ASTM B418. Type I ≈ MIL-A-18001 (seawater); Type II high-purity (soil / freshwater).
AVAILABLE FORMS
Available Forms
Block / Slab Anode
Hulls · platforms · jetties
Cast blocks and slabs with steel cores or straps, bolted or welded on — the general-purpose form for seawater structures.
Bracelet Anode
Submerged pipelines
Half-shell segments clamped around a pipeline, distributing protection evenly without interrupting the line.
Ribbon Anode
Tanks · continuous bonding
Continuous zinc ribbon over a steel core, for tank interiors and runs needing uniform, close current distribution.
Hull / Disc Anode
Ship hulls · rudders
Low-profile disc and hull anodes for vessels and appendages, protecting hull plating, rudders and trim tabs.
Choose Type I (MIL-A-18001) for seawater and brackish water, and Type II high-purity zinc for soil and freshwater with suitable backfill; avoid continuous service above the temperature limit, where zinc can passivate. Most products are made to customer drawings and project specifications.
Frequently Asked Questions
What is a zinc sacrificial anode?
A zinc anode is a galvanic anode cast from a high-purity zinc alloy that corrodes preferentially to protect steel with no external power. Zinc gives stable, predictable and well-understood performance in seawater, brackish water and saline mud, with a long service record — making it a default choice for ship hulls and marine structures. A service-temperature limit applies to avoid passivation.
Zinc Type I or Type II — which do I need?
Type I (Z32120, ≈ MIL-A-18001) is for seawater and brackish water. Type II (Z13000) is a high-purity grade for soil and freshwater with suitable backfill. Choose Type I for marine service and Type II for buried structures, and avoid continuous service above the temperature limit, where zinc can passivate.
Zinc or aluminium anode for a ship hull?
Zinc is the traditional, well-understood choice for ship hulls, with a stable potential and long track record. Aluminium (Al-Zn-In) gives more capacity per unit weight and is increasingly used offshore. Both are supplied — send us the vessel or structure and water type and we will recommend the alloy and form.
Which forms of zinc anode are available?
Cast block and slab anodes with steel cores for hulls, platforms and jetties; bracelet anodes for submerged pipelines; ribbon anodes for tank interiors and continuous bonding; and low-profile hull and disc anodes for vessels, rudders and trim tabs. Most anodes are cast to customer drawings and specification.
Do you supply zinc anodes in Thailand, and how do I get a quotation?
Yes. PCX supplies Type I and Type II zinc sacrificial anodes across Thailand, sourced from qualified international manufacturers and supplied to ASTM B418 and your project specification. Send us the anode form, size or mass and quantity — or your structure and water type — and we will return a quotation.
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