TABLE OF CONTENTS It is generally accepted that ten unique types of corrosion exist. Unfortunately, identification of a specific type of corrosion mechanism often occurs only in forensic analysis after a component fails. Design considerations must account for corrosion through the use of corrosion resistant materials, or by increasing the bulk of a material with a known corrosion characteristic to account for loss during its service life. Actuarial science and economics govern this choice in the design phase, but corrosion failures often arise in service operations not anticipated in the design phase. There are numerous remedies in existence to counteract specific corrosion mechanisms and increase the service life of specific components. The goal of this chapter is to summarise each of the individual corrosion mechanisms and describe tests to identify a material's susceptibility to a specific corrosion mechanism.
Corrosion mechanisms can be divided into two categories: (1) general or uniform corrosion and (2) non-uniform or localised forms of corrosion. Though uniform corrosion accounts for the majority of metal consumed (raw tonnage), localised corrosion is much more insidious because it is difficult to detect and its rates are often larger by several orders of magnitude. Due to these accelerated rates, breach of the material and subsequent failure are rapid and most often only detected by post-mortem failure analysis.
Uniform corrosion is recognised universally as the most prevalent of all forms of corrosion, but the least damaging in terms of number of failures. Like all forms...
