Rusting is a very destructive process. The loss by the rusting is so high that if considered with a natural calamity or disaster then there is nothing wrong with the statement. Rusting can break down a well-constructed bridge, can rust down a complete Car into ashes and can sink the monster ship under the sea.
Rusting is very simple chemical process involve in decaying of Iron ore and its alloy metals including steel. In chemistry rusting is called as oxidation. Oxidation is a chemical process where metal gains oxygen and become oxide.
In rusting the Iron ore make a chemical reaction with the oxygen in the presence of water and environmental or atmospheric moisture to produce an Iron oxide. Iron oxide is otherwise called as rust. Rust has two different chemical composition Fe2O3nH2O (hydrated Iron Oxide) and (FeO (OH), Fe(OH)3) Iron oxide-hydroxide. This reddish residue out from Iron has the ability to completely destroy the iron and the Iron made structures and instruments.
Rusting is an electro-chemical process. The rate of oxidation of iron occurs more quickly in the presence of some electrolytes like saltwater and other acidic or alkaline substances.
The oxidation or rusting of the iron ore reduced or completely stopped by mixing or coated with other metals like aluminum, silver etc. Coating with other metals over the rusting iron is also very helpful and banned further rusting. The protective layer is called passivation layer.
(Growing Image Courtesy: Growing with Science Blog)