Rust
(→What is rust?) |
(→What is rust?) |
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Rust is the common name for iron oxide. An oxide is a chemical compound containing an oxygen atom and other elements. Oxides are formed when elements come into contact with air, through a process known as oxidation. Oxides are common, forming most of the earth's crust. When iron (or steel, which contains mostly iron) is exposed to air, it combines with the oxygen in the air, and forms iron oxide -- rust. | Rust is the common name for iron oxide. An oxide is a chemical compound containing an oxygen atom and other elements. Oxides are formed when elements come into contact with air, through a process known as oxidation. Oxides are common, forming most of the earth's crust. When iron (or steel, which contains mostly iron) is exposed to air, it combines with the oxygen in the air, and forms iron oxide -- rust. | ||
| − | Other metals oxidize, but their oxidation is not referred to as rust. For example, when aluminum oxidates, it forms a protective, corrosion-resistant coating that looks a lot like un-oxidized aluminum. | + | Other metals oxidize, but their oxidation is not referred to as rust. For example, when aluminum oxidates, it forms a protective, corrosion-resistant coating that looks a lot like un-oxidized aluminum. Zinc's oxide is similar, which is why it is used for galvanizing. |
Only the oxidation of iron and steel (iron oxide) is known as "rust". Why? Because iron oxide takes up more physical space than iron. It's bigger. So, when iron pulls oxygen atoms from the air, to make iron oxide, it "puffs out", exposing even more of the original steel to the elements. And, it has a distinct color, that is very different from steel: it's red. | Only the oxidation of iron and steel (iron oxide) is known as "rust". Why? Because iron oxide takes up more physical space than iron. It's bigger. So, when iron pulls oxygen atoms from the air, to make iron oxide, it "puffs out", exposing even more of the original steel to the elements. And, it has a distinct color, that is very different from steel: it's red. | ||
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