Protecting Buried Metals Against Corrosion

The author mentions briefly the various types of corrosion from the standpoint of methods used to combat it. His main concern, however, is with underground structures, such as pipe lines, which suffer a corrosion loss of upward of $100,000,000 yearly. Protective coatings have been developed which constitute a long step toward elimination of pipe-line corrosion, when applied to new pipe. Older lines can be protected by a cathodic process, based on correcting the galvanic differences in potential between small sections of the pipe wall, or changes in soil conditions. The process of making the pipe cathodic to the surrounding soil is described, illustrations of the practical effects of the method being given.