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Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture.Rust consists of hydrous iron(III) oxides (Fe 2 O 3 ·nH 2 O) and iron(III) oxide-hydroxide (FeO(OH), Fe(OH) 3), and is typically associated with the corrosion of refined iron.
Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe 2 O 3. It occurs in nature as the mineral hematite , which serves as the primary source of iron for the steel industry. It is also known as red iron oxide , especially when used in pigments .
Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion: it forms as a result of the oxidation of iron metal. Common rust often refers to iron(III) oxide, formed in the following chemical reaction: 4 Fe + 3 O 2 → 2 Fe 2 O 3. The oxidation of iron(II) to iron(III) by hydrogen peroxide in the presence of an acid:
Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. [1] Iron oxides and oxyhydroxides are widespread in nature and play an important role in many geological and biological processes. They are used as iron ores, pigments, catalysts ...
Rust was also an important factor in the Silver Bridge disaster of 1967 in West Virginia, when a steel suspension bridge collapsed within a minute, killing 46 drivers and passengers who were on the bridge at the time. Similarly, corrosion of concrete-covered steel and iron can cause the concrete to spall, creating
Many steel objects are coated with a layer of zinc, which is more electronegative than iron, and thus oxidises in preference to the iron, preventing the iron from rusting. [4] Similarly, sacrificial bars of a metal such as aluminium or aluminium alloys can be attached to an oil rig or to the hull of a ship to prevent it from rusting and ...
Iron(III) oxide hydrate is known as rust. The concentration of water associated with iron oxide varies, thus the chemical formula is represented by Fe 2 O 3 · x H 2 O. An electric circuit is formed as passage of electrons and ions occurs; thus if an electrolyte is present it will facilitate oxidation, explaining why rusting is quicker in salt ...
Painting, galvanization, passivation, plastic coating and bluing are all used to protect iron from rust by excluding water and oxygen or by cathodic protection. The mechanism of the rusting of iron is as follows: [140] Cathode: 3 O 2 + 6 H 2 O + 12 e − → 12 OH − Anode: 4 Fe → 4 Fe 2+ + 8 e −; 4 Fe 2+ → 4 Fe 3+ + 4 e −