Brief of Iron Oxide
Iron oxide, also known as Pink, ferric oxide, iron oxide red, iron oxide, chemical formula Fe2O3, is anhydrous crystalline, with Pink can be extremely bright polished surface, manufacture of optical components, precision instrument manufacturing and jewelery in widely used, it is considered the best polishing material. But with Pink sample preparation prone to deformation disrupt layer, and will be pulled out inclusions. Although can get very bright grinding, polishing operations often inadvertently, can not show the real organization, it is subject to certain restrictions.
General traits: reddish brown powder
Melting point: 1565 ℃
Relative density (water = 1): 5.24
Solubility: insoluble in water, soluble in acid.
Molecular Weight: 160
Minerals: hematite, ocher
Enthalpy of Formation and Standard: -824.2 kJ / mol
Burning in the air and other ferrous or ferric compounds can be obtained ferric oxide.
In humid air, steel surface with a thin layer of adsorbed water film, this layer of water film contains a small amount of H + and OH-, also dissolved oxygen, resulting in the steel surface to form a layer of electrolyte solution, it is with steel in iron and small amounts of carbon (due to steel impure) is just the formation of numerous small primary battery. In these primary battery, the negative electrode is iron, carbon is positive. Iron lose electrons and is oxidized:
Negative: 2Fe-4e- = 2Fe2 +
Cathode: 2H2O + O2 + 4e- = 4OH-
Electrochemical corrosion is the main cause of corrosion of steel.
1. Its reddish brown powder is a lower pigment, iron oxide red called on the industry, used in paint, ink, rubber and other industries
2. do catalyst
3. glass, stones, metal polishing agent
4. The reaction for refining pig iron and CO (H2 also available) Fe2O3 + 3CO = 2Fe + 3CO2 (high temperature) Fe2O3 + 3H2 = 2Fe + 3H2O (high temperature)