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3
Forms of Metallic Corrosion
The mechanisms of metallic corrosion were discussed in Chapter 2. The
various mechanisms can result in different forms or types of corrosion, as
discussed in this chapter. The primary forms of corrosion are as follows:
General (uniform) corrosion
•
Intergranular corrosion
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Galvanic corrosion
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Crevice corrosion
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Pitting corrosion
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Erosion corrosion
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Stress corrosion cracking
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Biological corrosion
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Selective leaching
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Hydrogen damage
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Liquid metal attack
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Exfoliation
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Corrosion fatigue
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Filiform corrosion
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Each form of corrosion and the conditions responsible for its initiation
are discussed.
3.1 General (Uniform) Corrosion
Although other forms of attack must be considered in special circumstances,
uniform attack is one form most commonly confronting the user of metals
and alloys. Uniform (or general) corrosion, which is the simplest form of corrosion, is an even rate of metal loss over the exposed surface. It is generally
thought of as metal loss due to chemical attack or dissolution of the metallic
component into metallic ions. In high-temperature situations, uniform metal
loss is usually preceded by its combination with another element rather than