Rust, say is an oxidation process that occurs when iron and oxygen come into contact with each other. Rust is a reddish-brown flaky coating that forms on the surface of iron and steel objects when they are exposed to air and moisture. Rust can cause metal objects to corrode and weaken over time, making them less durable and more prone to damage. OXIDE is the chemical compound formed when oxygen combines with another element, such as iron, and is responsible for the formation of rust.