What does galvanic corrosion typically appear as?

Galvanic corrosion typically appears as white powder, which is a result of the corrosion process that occurs when two dissimilar metals are in contact in a conductive environment. This type of corrosion often manifests as a powdery residue, primarily composed of metal oxides and hydroxides, because the more anodic metal (the one that corrodes) reacts with moisture and oxygen. This white corrosion product is commonly seen in aluminum, zinc, and other metals that undergo galvanic corrosion.

The nature of galvanic corrosion is such that it occurs when two different metals establish a galvanic cell in the presence of an electrolyte, which accelerates the deterioration of the anodic metal while protecting the cathodic metal. The powdery deposits are indicative of this ongoing chemical reaction. This clarity about the visual signs is essential for proper identification and maintenance in environments where different metals may be used together.