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Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula Al 2 O 3. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, or alundum in various forms and ...
Pure cryolite has a melting point of 1009 ± 1 °C (1848°F). With a small percentage of alumina dissolved in it, its melting point drops to about 1000 °C (1832°F). Besides having a relatively low melting point, cryolite is used as an electrolyte because, among other things, it also dissolves alumina well, conducts electricity, dissociates electrolytically at higher voltage than alumina, and ...
This page provides supplementary chemical data on aluminium oxide. Material Safety Data Sheet ... data relate to Standard temperature and pressure. Reliability of ...
The melting point of aluminium oxide is 2050°C (2323K), much higher than pure aluminium's 658°C (931K). [6] This and the insulativity of aluminium oxide can make welding more difficult. In typical commercial aluminium anodizing processes, the aluminium oxide is grown down into the surface and out from the surface by equal amounts. [7]
The cryolite ratio (NaF/AlF 3) in pure cryolite is 3, with a melting temperature of 1010 °C, and it forms a eutectic with 11% alumina at 960 °C. In industrial cells the cryolite ratio is kept between 2 and 3 to decrease its melting temperature to 940–980 °C. [5] [6]
Oxygen-balanced iron thermite 2Al + Fe 2 O 3 has theoretical maximum density of 4.175 g/cm 3 an adiabatic burn temperature of 3135 K or 2862 °C or 5183 °F (with phase transitions included, limited by iron, which boils at 3135 K), the aluminium oxide is (briefly) molten and the produced iron is mostly liquid with part of it being in gaseous ...
Aluminium(I) oxide is formed by heating Al and Al 2 O 3 in a vacuum while in the presence of SiO 2 and C, and only by condensing the products. [2] Information is not commonly available on this compound; it is unstable, has complex high-temperature spectra, and is difficult to detect and identify. In reduction, Al 2 O is a major component of ...
2. The decomposition of fresh chemically-synthesized AlOOH or Al(OH) 3 to aluminium oxide in the rapid achievement of the temperature of decomposition 175 °C and use for it the pressure of 5 bars within thirty minutes. The sooner of the temperature of decomposition of the hydroxo-compounds of aluminium is achieved, the smaller the resulting ...