Why can scratched paint lead to rust?
A scratch exposes iron to water and oxygen. Electrochemical reactions then transform some of the metal into rust.
- The scientific idea
- Corrosion
- Fields of science
- Chemistry
How it works
A scratch through paint exposes iron to water and oxygen. Linked reactions remove electrons from iron, eventually producing rust.
Look closer
Ordinary rust flakes away, exposing fresh metal. By contrast, chromium in stainless steel helps form a protective oxide layer. What matters is whether the reaction products shield the material underneath.