MECHANISTICALLY BASED PREVENTION STRATEGIES OF FLOW-INDUCED CORROSION

A mechanistic approach is taken in a discussion of the control of flow -induced corrosion. An historical survey demonstrates the close intera ction of theory and practice. There are a number of mechanisms of the conjoint action of flow and corrosion that result in four types of flo w-induced corrosion: (1) mass transport controlled corrosion; (2) phas e transport controlled corrosion; (3) erosion corrosion and (4) cavita tion corrosion. Prevention strategies are dependent on the type of mec hanism concerned. A knowledge of hydromechanical conditions is a prere quisite for the proper design of equipment and a few basic rules have to be followed. In the field of materials selection there is an increa sing trend towards choosing passivating materials. If the mechanical s tability dominates, materials, such as cast alloys and duplex steels, are applied, especially in particle-containing liquids. Other protecti on methods, such as metallic, organic and ceramic coatings, inhibition and electrochemical protection, are discussed and it is shown that a number of highly interesting problems still await a solution.