Corrosion is chemically induced damage to a material that results in deterioration of the material and its properties. This may result in failure of the component.

Several factors should be considered during a failure analysis to determine the affect corrosion played in a  failure. Examples are listed below:

• Type of corrosion
• Corrosion rate
• The extent of the corrosion
• Interaction between corrosion and other failure mechanisms

Corrosion is a normal, natural process. Corrosion can seldom be totally prevented, but it can be minimized or controlled by proper choice of material, design, coatings, and occasionally by changing the environment. Various types of metallic and nonmetallic coatings are regularly used to protect metal parts from corrosion.

Stress corrosion cracking necessitates a tensile stress, which may be caused by residual stresses, and a specific environment to cause progressive fracture of a metal. Aluminum and stainless steel are well known for stress corrosion cracking problems. However, all metals are susceptible to stress corrosion cracking in the right environment.

Laboratory corrosion testing is frequently used in analysis but is difficult to correlate with actual service conditions. Variations in service conditions are sometimes difficult to duplicate in laboratory testing.

Corrosion Failures Analysis
Identification of the metal or metals, environment the metal was subjected to, foreign matter and/or surface layer of the metal is beneficial in failure determination.

Examples of some common types of corrosion are listed below:

• Uniform corrosion
• Pitting corrosion
• Intergranular corrosion
• Crevice corrosion
• Galvanic corrosion
• Stress corrosion cracking