Lead as an anode—Part 3

THE APPLICATION of cathodic protection to marine structures, using both galvanic and impressed current systems, is a well‐established technique for reducing or preventing corrosion. It has been shown, for example, that a galvanic system applied to US Navy destroyers reduced maintenance costs by $10,000– $20,000 per ship per overhaul, and it is likely that impressed current systems will effect greater savings. Lead alloy anodes, or lead‐platinum bi‐electrodes, are being increasingly used for marine cathodic protection systems since they not only have a greater robustness than platinum or graphite anodes (and a greater coulometric efficiency than graphite) as well as lower consumption rates. The long life and ease of installation of lead alloy anodes, together with their high current carrying capacity, are strong reasons for their use.