Scientists Discover Previously Unknown Form of Corrosion That Even Raindrops May Cause

Raindrops may do more than wet metal surfaces. German scientists say electrically charged water droplets can burn microscopic holes through protective coatings in laboratory experiments, exposing the metal beneath.

The discovery offers a possible explanation for why car bodies, historic monuments and ship hulls can begin to rust despite careful treatment with anti-corrosion layers. The droplets can gather an electrical charge as they move across a surface, in a process compared with static electricity.

Researchers observed the effect under laboratory conditions. They have not yet established how much real-world rust damage the phenomenon causes, but the finding suggests that existing explanations of corrosion may not tell the whole story.

The same electrical attack could potentially occur in rain, sea waves and waterfalls. The possibility remains a question raised by the research rather than a confirmed measure of its impact in those environments.