Phase Boundary Corrosion
Phase boundary corrosion is the selective attack at the boundaries between different phases in the metal structure due to different electrode potentials. This leads to material degradation.
Physical-Chemical Mechanism of Action
Interphase corrosion occurs when different electrode potentials exist at the boundaries between different phases in the metal structure. These differences can lead to electrolytic cells that absorb oxygen and water and decompose the metal.
Metallurgical Relevance & Welding Risks
This corrosion can occur during welding of steels and other metals, especially when the metal is in a humid environment or when there are chemical triggers such as salts or acids. It leads to cracks, deformation, and reduced material life.
Shop Practice & Action Items
To avoid interphase corrosion, it is important to clean the metal before welding and to apply a suitable protective coating or paint in wet environments. When choosing the welding process, make sure it does not adversely affect the metal's chemical properties.