ELECTRODEPOSITION OF METALLIC COATINGS has been extensively used as a means of corrosion control. In general, coatings are designed according to one of three different schemes. Electrodeposited coatings may be devised to act as corrosion-resistant barrier layers that separate the substrate from the aggressive environment. Alternatively, the well-known galvanic effects that arise from electrically coupling dissimilar metals may be used to provide active porous coatings, which cathodically or anodically protect the substrate. Electroplating a base metal with a barrier layer of gold is an example of the first strategy. Electrogalvanizing, or depositing zinc on steel, is an example of a sacrificial coating, while thin, porous, noble metal coatings such as palladium or platinum, which catalyze the proton-hydrogen reaction, may be used to anodically protect stainless steels.