What is Rust?
Rust is the substance that is formed when iron begins returning to its natural state (iron ore) by combining with oxygen to become ferric oxide. This chemical combining of metal and oxygen is called oxidation. The oxidation of any metal generates corrosion, and the corrosion of iron specifically is what we commonly call rust. The steel from which cars are made is iron alloyed with a small amount of carbon and therefore may rust. Wherever iron or steel is exposed to air (oxygen), rust is likely to occur eventually. The oxidation process is accelerated by moisture, acid rain, salt and dirt, all of which act as catalysts to speed up the rust process. Do today’s cars still rust? Yes. Rust can begin in any area of the body, inside or out, that is exposed to the elements. A recent study conducted by Ziebart International Corp. involving 240 vehicles manufactured in the 1990s determined that 105 of the vehicles (44%) showed signs that rust had formed on the inside of metal panels. The predomi
Rust is the result of the reaction between a metal and a non-metal. To have the clearest view possible of this process we will take the example of metallic Iron reacting with Oxygen to form the brownish, flaky rust we are all used to seeing on our cars and drain pipes. The Metal Lattice We have previously seen how metals come to form lattices that consist of alternating layers of positively charged ions and free electrons. This layered structure of metal is presented below: Oxygen Gas Oxygen gas, O2, consists of two atoms of Oxygen covalently bonded together. This is a fairly stable state for Oxygen but given the opportunity each Oxygen atom will absorb two electrons from elsewhere and have a full outer shell of 8 electrons without having to share. This is the most stable state for any Oxygen atom. What is Rust? It’s The Reaction Between the Two We know that the metal Iron has loose electrons. We also know that each of the atoms in the oxygen molecule would prefer to have 8 electrons w
Rust is the result of a conversion process that takes place when oxygen and moisture come in contact with metal. The oxygen and water combine with iron to create a brown coating (hydrated ferric oxide) on the surface of the metal. The interaction between the water and iron is accelerated if salts are added to the mix. Because the oxide that is created is bulky and porous, it allows oxygen access to the iron below, causing additional oxidation. If allowed to continue, the iron metal will be completely converted to ferric oxide or solid rust, which is weak and flaky.
Simply put, rust is the common term for iron or iron alloy corrosion. Though most of the metals present on Earth eventually go through a corrosion phase, we only refer to the iron metal corrosion when we say the word rust. Iron corrosion represents a set of chemical reactions between iron, water and oxygen, which end with the transformation of the whole mass of metal into a mix of iron oxides and water that leads to the disintegration of the respective iron structure.
