Way back in 1824, a certain Sir Humphrey Davy in the UK, noticed that the copper sheeting on warships was decaying rapidly, and made it his business to try to do something to prevent this from happening, to lengthen the life of His Majesty’s ships of war. He realized that it was due to the constant contact with seawater, which was causing the copper to corrode and, while conducting an experimental investigation, discovered that iron anodes helped tremendously, to protect the copper, and cathodic protection was born.
However, one of the side effects of this process was increased marine growth on the ships, which had an adverse affect on their performance. After some deliberation, the Royal Navy decided that it was better to allow the copper to corrode as it normally did, than have to deal with the extra marine growth on their ships, so Davy’s discovery was not used any further.
Davy carried on with his experiment, assisted by a pupil of his, Michael Faraday, who continued with these experiments after Davy’s death. Faraday discovered a connection between corrosion and electric current in 1834, which actually formed the basis of cathodic protection as we know it today.
Even Thomas Edison experimented on ships in 1890, but, because of the lack anode material and suitable current source, was not successful. It was only in 1928 that the United States started making use of cathodic protection on oil pipelines – more than one hundred years after Davy’s experiments.
Cathodic protection basically, is the technique of making a metal surface the cathode of an electrochemical cell, in order to protect that metal surface from corrosion. The simplest way to apply it, is to connect the metal that needs protecting, to another metal that is more easily corroded, a sacrificial metal in other words, making it perform as the anode of an electrochemical cell.
Sacrificial anodes are manufactured in various sizes and shapes, using alloys of zinc, aluminum and magnesium. Zinc anodes have high driving voltage, and are suitable protection for marine structures and pipelines against corrosion caused by seawater. Zinc alloy anodes can also be used in areas where sparking is a risk and needs to be avoided, such as in tanks where flammable hazards are stored.
Cathodic protection is commonly used in steel fuel or water pipelines, storage tanks, steel piers and jetties, offshore oil platforms, onshore oil well casings, as well as the metal reinforcement bars which are used the majority of the time, in concrete structures and buildings. Cathodic protection also used in some cases, to prevent stress corrosion cracking as well. Reach out to the Zinc Anode experts at Deep Blue Yacht Supply and they will ensure your vessel has the proper parts for cathodic protection. Zimar Zinc anodes is the industry leader when it comes to providing cathodic protection on your boat.