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Prevent dissimilar metals form becoming electrically connected by water
Keep small anodes from contacting large cathodes. The rate of corrosion depends on the surface area of the anode with respect to the cathode. The smaller the surface area of the anode relative to the surface area of the cathode, the more concentrated the flow of electrons at the anode and the faster the rate of corrosion. The larger the anode's surface area in relation to the cathode, the more spread out of the flow of electrons and the slower the rate of the anode's corrosion.
The application of a protective metallic coating, known as a sacrificial coating, can provide galvanic protection to the base metal when the coating is measurably more anodic than the base metal. galvanic corrosion will take place with the anodic material when the base material is exposed. The extent to which a sacrificial coating can continue to protect the base metal is directly related to the thickness of the coating.
Metallic coasting that are not sacrificial, as well as paint coatings, plastic, or other non-metallic barriers can also significantly reduce galvanic corrosion. however, when using a paint coating, it is important to realize that if the base metal becomes exposed through a small scratch in the paint, the base metal could rapidly corrode if it becomes the anode in a reaction with a nearby dissimilar metal with a large surface area.
