A brief review of the present theories of passivity indicates that corrosion can be completely stopped by formation of a very thin oxygen containing film. This concept has not been previously used in practical control of corrosion. Using a potentiostat for maintaining a constant potential of a metal to be protected, many variables involved in the anodic control of corrosion were studied. This technique is shown to be useful in HNO3, H2SO4, H3PO4, NH4NO3, Al2SO4, NaOH and numerous other oxidizing environments being handled in mild and stainless steels. Anodic protection was possible in acid-base neutralizations and acid-hydrocarbon reactions so long as adequate conductivity is maintained. Control has been established at temperatures as high as 500 F. Electrical measurements show the film resistance to be in the order of 104–106 ohms/-cm2. This extremely high resistance allows establishment of protection in very complex geometrical vessels, and even in flow lines. A major achievement presented by this report is the development of a potential controller which allows metal passivation to become of immediate practical importance. Pilot studies using a 500 gallon 304 stainless vessel filled with 67 percent H2SO4 showed that corrosion could be completely stifled for indefinite periods by application of almost negligible currents. It is possible by laboratory studies to predict the current and voltage requirements for anodically protecting process or storage vessels. These requirements are summarized for numerous systems. 3.8.3