In the case of anti-corrosion, for example, coatings, including zinc, copper, tin, aluminium and others that fit within the galvanic scale
parameters, can easily be applied directly to the substrate.
First, because dissimilar metals more readily react with moisture in the air, you should select materials that have the lowest potential voltage between them on the galvanic scale
Because the "puddled" iron is far from copper on the galvanic scale
, with the presence of an electrolyte (furnished by leadking rainwater and harbor salt), a "battery" is created, consuming the iron, the less-noble material.