What does galvanic corrosion depend on?

Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte, leading to one metal (the anode) corroding more quickly than it would alone and the other metal (the cathode) being protected. The rate and extent of galvanic corrosion are heavily influenced by the surface area ratio of the anodic and cathodic materials involved.

When the surface area of the cathodic material is significantly larger than that of the anodic material, it provides greater protection to the anodic metal and slows down the rate of corrosion. Conversely, when the anodic surface area is larger, it can lead to increased corrosion rates because the cathodic protection is less effective relative to the anode. Thus, understanding the relationship between the surface areas is vital for predicting and managing galvanic corrosion.

The other factors mentioned, such as the color of the metals, the weight of the materials, and the temperature of the environment, do not directly influence the galvanic cell formed between the two metals as much as the surface area ratio does, making that the key determinant in galvanic corrosion scenarios.