Bimetallic Corrosion Prevention
Bimetallic corrosion is prevented by geometric shielding or coating to minimize potential differences between dissimilar metals and avoid an unacceptable cathode-to-anode ratio.
Physicochemical Mechanism of Action
In bimetallic corrosion, different metals react differently under the influence of electrolytes. This leads to potential differences where one part of the material (anode) corrodes more and the other part (cathode) remains protected. This can cause localized corrosion susceptibility and damage.
Metallurgical Relevance & Welding Risks
The use of dissimilar metals in a component can lead to bimetallic corrosion if no suitable measures for potential equalization are taken. This can result in cracks, wear, and reduced material service life.
Workshop Practice & Action Instructions
To prevent bimetallic corrosion, the following measures should be taken:
• Geometric shielding: Use barriers or insulating materials between the different metals.
• Coating: Apply a suitable coating to the surface of the metals to prevent the electrolytic reaction.
• Material selection: Use homogeneous materials or materials with similar corrosion behavior in a component.