ABSTRACT
This chapter discusses the basic principles of the most common type of corrosion, electrolytic corrosion. Concerns about corrosion often dominate materials selection. Accordingly, understanding corrosion and the common strategies used to deal with it are central to the selection of appropriate materials. Crevice corrosion and under-deposit corrosion can be serious problems in oxide-stabilized materials such as aluminum and stainless steel. The rate of corrosion at the anode is directly proportional to the anode current density. Chemical treatment by inhibitors is a frequently used corrosion control measure, particularly for piping systems. Crevices and deposits can accelerate corrosion in metals such as carbon steel, which does not exhibit both active and passive states. However, the rate of corrosion is much slower in such materials because they lack the galvanic driving force of the active-passive metals. A basic understanding of materials engineering is helpful in differentiating among the various alloys, non-metallic materials and composite materials available for use in modern plants.
