Aluminium anodes are a good example of the cathodic metals used to preserve submerged or buried metallic structures from chemical corrosion. The anodes are faster and more aggressive in chemical reactions such that they are first to respond to elements of corrosion. This means that the cathodic metals will wear down instead of the structure they are protecting. Boat hulls, for instance, are often in contact with different water environments, which accelerate corrosion due to rusting. Thanks to cathodic protection using aluminium anodes, your boat's structure can last for many years. When buying a boat, here are some of the commonly asked questions about cathodic protection using aluminium anodes:
What Water Conditions Accelerate the Corrosion of the Aluminium Anode?
The aluminium anode protects the immersed part of the boat by releasing electrical voltage. Simply, it gives up metal while protecting the material used to make the boat. Ideally, the rate at which this happens depends on the condition of the water. In some water environments, the anode will wear much faster compared to other places. For instance, salty water in most oceans and seas is more reactive compared to freshwater in rivers. Therefore, you'd expect your aluminium anodes to wear down much faster in salty water. To add on that, high temperatures make water warm and increase its electrical conductivity. For this reason, your aluminium anode will corrode faster during hot seasons when the water is warmer.
What Effect Does the Boat Material Have on the Aluminium Anode?
The material used to make the boat also affects the aluminium anode's rate of corrosion. Cathode protection is an electrical reaction that creates a difference in voltage between the two metals that are involved in the reaction. Therefore, highly reactive metals will lead to a greater difference in voltage with the anode and elicit a higher degree of protection by the anode. This increases the rate of anode corrosion. For instance, you can buy a boat whose hull is made using stainless steel instead of bronze. Stainless steel is less volatile in such reactions, and your anodes will last longer before you have to replace them.
What Else Can You Do to Prolong Anode Life?
You can also use other measures to prolong the life of your anodes and minimise the need to replace them regularly. For instance, the part of the hull that comes into contact with water should always be painted. Inspect the bottom of the hull regularly for any scratches and repaint such areas. This will slow down the rate of cathodic reactions and preserve your aluminium anode.
For more information, talk to a professional like Carman Heating.