What condition is necessary for galvanic corrosion to occur?

What condition is necessary for galvanic corrosion to occur?

• A. Two different metals in contact in the presence of an electrolyte
• B. Two identical metals in contact in air
• C. Only in vacuum
• D. Only with magnetic field

Answer: (A)

Galvanic corrosion happens when two dissimilar metals are in electrical contact and a conductive electrolyte is present. The electrolyte lets ions move and completes the circuit between the metals, while their different electrochemical potentials drive electrons from the more active (anodic) metal to the less active (cathodic) one. The anodic metal then corrodes preferentially as metal ions go into solution, while the cathodic metal is protected. Without an electrolyte, or when the metals are identical, this galvanic setup can’t form. Magnetic fields don’t create the electrochemical conditions needed for galvanic corrosion.

Galvanic corrosion happens when two dissimilar metals are in electrical contact and a conductive electrolyte is present. The electrolyte lets ions move and completes the circuit between the metals, while their different electrochemical potentials drive electrons from the more active (anodic) metal to the less active (cathodic) one. The anodic metal then corrodes preferentially as metal ions go into solution, while the cathodic metal is protected. Without an electrolyte, or when the metals are identical, this galvanic setup can’t form. Magnetic fields don’t create the electrochemical conditions needed for galvanic corrosion.