Aluminium anodes

Aluminium anodes are used as sacrificial anodes in cathodic protection systems and are characterised by their high electrochemical capacity and low density, resulting in a high current capacity (Ah/kg) and efficient material utilisation. Typical aluminium alloys include Al-Zn-In formulations, which are optimised to maintain a stable active potential and prevent passivation, even under varying electrolyte conditions.

Thanks to their favourable anodic dissolution characteristics, aluminium anodes provide uniform current distribution across the protected surface, with low polarisation resistance and consistent current output throughout their service life. The electrochemical reactions occur in a controlled manner, allowing the anode to be consumed uniformly without significant formation of insulating corrosion products that could interfere with its performance.

An additional advantage is the high capacity per unit mass, typically around 2,500–2,800 Ah/kg, meaning that less anode material is required to achieve the same level of protection compared with alternative materials. This enables an optimised system design with reduced weight and volume and more efficient installation, particularly in offshore and marine applications.

Aluminium anodes perform particularly well in seawater and brackish environments, where they maintain a stable potential, typically around −1.05 V vs. Ag/AgCl. Their predictable consumption rate and reliable current output make them suitable for long-term operation with minimal inspection and maintenance requirements.

Available in various alloys, geometries, and weights, tailored to specific design criteria and environmental conditions.