subject: Anodes And Their Uses [print this page] Sacrificial anodes are pieces of metals that are meant to oxidize in order to protect other pieces of metals from being oxidized (rusted). The purpose for sacrificing these anodes is to protect any other expensive metals that they are affixed to such as those on ships, boats or pipelines. The most common metals used as anodes are aluminium, magnesium and zinc. As compared to other metals, they rust faster and therefore are used as sacrificial anodes. One method of sacrificing these metals can be placing them alongside with the metal to be protected. As they oxidize more easily, they end up getting rusted instead of the other metal. An example of this can be a zinc anode being connected and buried in the ground next to an iron fence. The term sacrificed is used as the zinc slowly gets eaten away by rust instead of the iron.
Anodes are very easy to use and can protect the expensive metals on your boat's underwater metals. Mariners and boat owners depend on these sacrificial anodes to counter corrosion effectively. Anodes protect metals that are lower than itself in the galvanic series of metals and alloys. When you buy anodes, ensure that they meet standards required for them to counter corrosion. Also, you would need to constantly change the anode once it gets eroded.
How Anodes Work
When the metals on the hull and propeller come into contact with each other underwater, electricity passes from one to another. As electricity can oxidize metals, the metal that is more reactive would erode faster causing damage to you boat or ship. Therefore, if an anode is attached to the propeller or hull, it would be eroded instead as it would be more active as compared to the other two. However, when attaching anodes to the metals on your boat, you need to consider the water where your boat would be sailing in and the properties of the different anodes.
If your boat is sailing in salt waters, zinc and aluminium anodes would be the best options for you to counter erosion. These anodes can also be used in waters where there is a mixture of both, salt and fresh water. However, if the water has a higher concentration of fresh water, only aluminium anodes should be used instead. For forms of water that are completely fresh, you should only use magnesium anodes. Understanding these properties is very important for proper care of you boat's metals. If you were to use magnesium in salt water, not only would it not protect the metal against erosion, it would even boost it. Learning what suitable materials to use for your boat can prove to be a big help in taking good care of it and making it last for a long time.
