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The Hall–Héroult process is the major industrial process for smelting aluminium.It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell.
Aluminium smelting is the process of extracting aluminium from its oxide, alumina, generally by the Hall-Héroult process.Alumina is extracted from the ore bauxite by means of the Bayer process at an alumina refinery.
The superscript Plimsoll on this symbol indicates that the process has occurred under standard conditions at the specified temperature (usually 25 °C or 298.15 K). Standard states are defined for various types of substances. For a gas, it is the hypothetical state the gas would assume if it obeyed the ideal gas equation at a pressure of 1 bar.
During atomic layer deposition, a film is grown on a substrate by exposing its surface to alternate gaseous species (typically referred to as precursors or reactants). In contrast to chemical vapor deposition, the precursors are never present simultaneously in the reactor, but they are inserted as a series of sequential, non-overlapping pulses.
Nitric oxide (nitrogen oxide or nitrogen monoxide [1]) is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen . Nitric oxide is a free radical : it has an unpaired electron , which is sometimes denoted by a dot in its chemical formula ( • N=O or • NO).
[better source needed] [14] This layer protects the metal from further oxidation. The thickness and properties of this oxide layer can be enhanced using a process called anodising . A number of alloys , such as aluminium bronzes , exploit this property by including a proportion of aluminium in the alloy to enhance corrosion resistance.
Aluminium(II) oxide or aluminium monoxide is a compound of aluminium and oxygen with the chemical formula AlO. It has been detected in the gas phase after explosion of aluminized grenades in the upper atmosphere [ 1 ] [ 2 ] [ 3 ] and in stellar absorption spectra.
The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).