Limitation of Aluminum Anode in Cathodic Protection Applications

The commonly employed method for Cathodic Protection (CP) is the sacrificial anode system. This method involves protecting the metallic structure by sacrificing other metals that are more reactive. In this process, electrons are transferred from the sacrificial metal (which has more negative potential) to the protected metallic structure (which has more positive potential) through corrosive electrolytes using a connecting conductor. An aluminum (Al) anode is a sacrificial anode made of aluminum. Al alloy anodes have been utilized for several decades, mostly in large cathodic protection projects such as ports, subsea structures, ship hulls, and piling installations. This was attributed to the superior performance of Al in comparison to zinc (Zn), which surpassed the cost difference in larger projects. Nevertheless, the electrochemical characteristics of Zn are regarded as more stable than theirs. This study aims to highlight the constraints of the Al anode under different environmental and application conditions and elucidate the potential risks associated with the utilization of this particular sacrificial anode. Furthermore, it could serve as a scientific reference for the selection of a galvanic anode system.