At Purity Alloys we manufacture a wide variety of Pier & Piling Sacrificial Anodes providing cathodic corrosion protection for the marine environment. Purity Casting Alloys has been manufacturing Pier & Piling Sacrificial Aluminum and Zinc Anodes since 1992.
The Advantages of Aluminum Anodes – Many manufacturers and boaters prefer aluminum anodes over zinc or magnesium for several reasons.
Aluminum has become more affordable in recent years, making it a popular choice for installing sacrificial anodes on vessels, engines, and other equipment.
Aluminum anodes protect effectively in saltwater, perform better in upper brackish water, and decently in freshwater, but they tend to develop an oxide coating (passivation) faster than zinc. Regular cleaning prevents this, ensuring aluminum anodes remain effective.
EPA reports indicate that magnesium and aluminum anodes are more environmentally friendly than zinc, though the environmental impact of zinc is minimal.
The Advantages of Zinc Anodes – Zinc is the ideal sacrificial anode when a vessel is docked or anchored in seawater for extended periods.
Unlike other metals, zinc is better at shedding film buildup, continuously exposing fresh zinc to the water and keeping the anode electrochemically active. Aluminum anodes, in contrast, can develop a crust that passivates the anode, making it less effective.
The longer a vessel sits idle, the greater the risk of anode passivation. However, when the vessel is moving, the water flow helps clean off the oxide layer and reactivate the anode, regardless of the metal type.
For vessels that are regularly active in saltwater, both zinc and aluminum anodes work well. But if a boat remains stationary for extended periods in saltwater, zinc anodes are the better choice.
Whether you already have an engineered CP design or aren’t sure what anodes your structure requires, we’ll help you find the right next step.
I have an anode spec, drawing, existing design, or know what anodes I need.
I know my structure needs cathodic protection, but the anode requirements haven’t been determined.
Learn what information is needed for a CP project what Purity can help with and when a corrosion engineer is required.
If your project’s cathodic protection requirements haven’t yet been established, we can help connect you with an experienced corrosion engineering firm.
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