How does rust form on metal and can it be stopped?

Rust forms when iron or steel reacts with oxygen and water in a process called oxidation. Water acts as an electrolyte that allows electrons to move between iron atoms and oxygen molecules, producing iron oxide, which is the reddish-brown flaky substance we recognize as rust. The process accelerates in salty or acidic environments because these increase electrical conductivity. Rust can be stopped or significantly slowed through several methods. Painting or coating the metal creates a physical barrier against moisture and oxygen. Galvanizing, which coats steel with zinc, provides both a barrier and sacrificial protection since zinc oxidizes preferentially instead of the iron. Stainless steel resists rust because chromium in the alloy forms a stable protective oxide layer. Regular maintenance and keeping metal dry also help considerably.