Galvanic Corrosion
Bimetallic corrosion occurs when two metals with different electrode potentials are electrically connected in an electrolyte. The less noble metal corrodes at an accelerated rate.
Physicochemical Mechanism of Action
Two metals with different electrode potentials form a galvanic cell in an electrolyte. The less noble metal acts as the anode and corrodes at an accelerated rate, while the more noble metal is protected as the cathode.
Metallurgical Relevance & Welding Risks
Bimetallic corrosion can damage the weld, especially when dissimilar steels or alloys are joined. This can lead to cracks and loss of strength.
Workshop Practice & Action Instructions
Avoid direct contact between metals with different electrode potentials. When welding steels with different filler materials (e.g., austenitic and ferritic), careful isolation is required. Use suitable protective agents or barrier layers to prevent corrosion.