Anodes are the core of every cathodic protection system, but not all are created equal. The right anode alloy can make the difference between long-term corrosion control and premature system failure. Whether protecting offshore platforms, underground pipelines, or concrete structures, selecting the appropriate anode material requires understanding environmental conditions, current demand, and project life expectancy.
At Corrpro Europe, we supply and advise on a full spectrum of anode types, from galvanic materials like magnesium and aluminium to impressed current options like MMO and Silicon Iron. Our materials are manufactured and assembled in the UK to meet specifications and matched to each project’s unique needs.
Galvanic Anodes: Sacrificial but Strategic
Magnesium (Mg) is highly active, delivering strong protective current even in high-resistivity environments like dry soil or freshwater. Its high driving voltage makes it ideal for onshore pipelines, tank bottoms, and remote structures. However, its relatively low electrochemical efficiency means it depletes faster and is not suited to low-resistivity environments like seawater.
Zinc (Zn) offers stable, reliable protection in seawater, brackish water, and low-resistivity soils. It is well understood and self-regulating, with consistent output. Zinc is commonly used in marine applications such as ship hulls and pier piles.
Aluminium (Al) is the modern standard for seawater applications. With a high capacity and low weight, it’s ideal for large offshore assets, subsea pipelines, and FPSOs. Corrpro’s proprietary Aloline® alloys deliver reliable performance. Aluminium anodes require some chloride to activate and may not be suitable for freshwater.
Impressed Current Anodes: Durable and Controllable
For larger structures or high-demand systems, impressed current cathodic protection (ICCP) is often more economical and effective.
Mixed Metal Oxide (MMO) anodes are used for ICCP systems, are durable, low-consumption options suitable for all environments. They offer long service life and stable output when operated within design current densities.
High Silicon Cast Iron (HSCI) is traditionally used in soil or freshwater groundbeds. It’s cost-effective and reliable, though brittle. Graphite anodes also remain in use for certain soil applications but are more fragile and generate more gas.
Platinised Titanium and other specialty anodes remain in use for niche applications, such as condenser protection and reinforced concrete CP, but are now largely replaced by MMO due to cost and longevity.
Matching Anode to Environment and Application
Anode selection must consider factors such as resistivity, temperature, water chemistry, and design life:
- High-resistivity soils: Magnesium or ICCP
- Seawater: Aluminium or zinc for galvanic; MMO for ICCP
- Freshwater: Magnesium for galvanic; MMO or HSCI for ICCP
- High-temperature systems: Zinc or specialised MMO coatings
- Long design life: Aluminium or MMO
Corrpro tailors each system based on these variables, offering custom anode dimensions, alloy compositions, and installation formats.
FAQs
Can magnesium anodes be used in seawater?
Generally not recommended. Magnesium is too active and can overprotect, leading to hydrogen evolution or rapid consumption.
How long do HSCI anodes last?
When properly designed and installed in coke breeze, HSCI anodes can last 25+ years. MMO typically offers longer life in similar conditions.
Are all aluminium anodes the same?
No. Corrpro’s Aloline® products use proprietary Al-Zn-In alloys optimised for marine performance. Alloying ensures reliable activation and capacity.
How do I choose between galvanic and ICCP?
Galvanic systems are simple and effective for smaller, isolated structures. ICCP is better for large or complex assets, offering longer life and lower maintenance.
Corrpro Europe: Your Partner in CP Materials
As Europe’s leading manufacturer and supplier of cathodic protection materials, Corrpro Europe delivers a full range of galvanic and impressed current anodes. We guide clients through selection, design, and supply to ensure every system performs efficiently over its intended lifespan.
Contact Corrpro today for expert advice on anode materials and comprehensive CP solutions.
