Aluminum or Aluminium?

History
The ancient Greeks and Romans used alum in medicine as an astringent, and in dyeing processes. In 1761 de Morveau proposed the name "alumine" for the base in alum. In 1807, Davy proposed the name alumium for the metal, undiscovered at that time, and later agreed to change it to aluminum. Shortly thereafter, the name aluminium was adopted by IUPAC to conform with the "ium" ending of most elements. Aluminium is the IUPAC spelling and therefore the international standard. Aluminium was also the accepted spelling in the U.S.A. until 1925, at which time the American Chemical Society decided to revert back to aluminum, and to this day Americans still refer to aluminium as "aluminum".
The first isolation of aluminum was by Hans Christian Oersted in 1825 who reacted aluminium chloride (AlCl₃) with potassium amalgam (an alloy of potassium and mercury). Heating the resulting aluminium amalgam under reduced pressure caused the mercury to boil away leaving aluminium metal.
Aluminium is one of the elements which has an alchemical symbol, shown below (alchemy is an ancient pursuit concerned with, for instance, the transformation of other metals into gold).

General (click here for a lovely description of aluminium) Real audio
Pure aluminium is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and nonsparking. It is somewhat decorative. It is easily formed, machined, and cast. Pure aluminium is soft and lacks strength, but alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties. Aluminium is an abundant element in the earth's crust, but it is not found free in nature.

Aluminium is mined in huge scales as bauxite (typically Al₂O₃.2H₂O). Bauxite contains Fe₂O₃, SiO₂, and other impurities. In order to isolate pure aluminium, these impurities must be removed from the bauxite. This is accomplished utilizing the Bayer process. This involves treatment with sodium hydroxide (NaOH) solution, which results in a solution of sodium aluminate and sodium silicate. The iron remains behind as a solid. When CO₂ is blown through the resulting solution, the sodium silicate stays in solution while the aluminium is precipitated out as aluminium hydroxide. The hydroxide can be filtered off, washed, and heated to form pure alumina, Al₂O₃.
The next stage is formation of pure aluminium. This is obtained from the pure Al₂O₃ by an electrolytic method. Electrolysis is required because aluminium exceedingly electropositive. Electrolysis of the hot oxide in a carbon lined steel cell cathode with carbon anodes is most common.

Uses
Besides the everyday cans and foils, aluminum is often used for exterior building fixtures and utility applications such as streetlights. Anywhere there is a need for strong, light, economical and easily fabricated material you will usually find an aluminum application.
Although its electrical conductivity is only about 60% that of copper, it is used in electrical transmission lines because of its lightness and price point.
Alloys of aluminum are of vital importance in the aerospace industry because of their strength to weight properties.
Evaporated in a vacuum, it forms a highly reflective coating for both visible light and radiant heat hence their use in telescope mirrors.
These coatings soon form a thin layer of the protective oxide and do not deteriorate as do silver coatings.
The oxide, alumina, occurs naturally as ruby, sapphire, corundum, and emery, and is used in glass making and refractories. Synthetic ruby and sapphire are used in the construction of lasers

Alloys
Wrought and cast alloys are identified by a four-digit number, the first digit of which generally identifies the major alloying element as shown in the table below. For casting alloys, the fourth digit is separated from the first three digits by a decimal point and indicates the form, i.e., casting or ingot.

Number / Alloying Element
lXXX 997. Mm. Aluminum
2XXX Copper
3XXX Manganese
3XX.X Silicon with added copper and/or magnesium
4XXX Silicon
5XXX Magnesium
6XXX Magnesium and Silicon
7XXX Zinc
8XX.X Tin
9XXX Unused series

The most common alloys used for fasteners
2024-T4
This alloy provides a good combination of strength, corrosion resistance and economy. Rivets of this alloy are very strong but are difficult to drive.
COMPOSITION: Cu 3.8% - 4.9%. Mn .30% -.90% Mg 1.2% - 1.8%. Zn.25%. Cr.1 %. Fe.5%. Si .5%. Al remainder.
TENSILE (PSI): 68,000

6061-T6
Used for applications requiring maximum corrosion resistance. Rivets of this alloy can be cold driven as received.
COMPOSITION: Cu . 1 5% -.40%. Mg .8% - 1.2%. Mn . 1 5%. Zn .25%. Cr .04% -.35%. Ti . 1 5%. Fe .7%. Si .4% -.8%. AJ remainder.
TENSILE (PSI): 45,000

7075-T73
Has good resistance to stress corrosion. Stronger than 2024-T4.
COMPOSITION: Cu 1.2% - 2.0%. Mg 2.1% - 2.9%. Mn.30% Zn 5.1% - 6.1 %. Cr. 1 8% -.35%. Ti .20% Fe .5% Si .4%. Al remainder.
TENSILE (PSI): 75,000

Temper Designations
The temper designation appears as a hyphenated suffix to the basic alloy number. An example would be 7075-T73 where -T73 is the temper designation. Four basic temper designations are used for aluminum alloys. They are -F: as fabricated; -0: annealed; -H: strain hardened and -T: thermally treated. A fifth designation, -W, is used to describe an as-quenched condition between solution heat treatment and artificial or room temperature aging. Following is a list of tempers that define aluminum alloys.

• H1ll: Applies to products That are strain-hardened less than the amount required for a controlled Hll temper.
• H112: Applies to products which acquire some temper from shaping processes not having special control over the amount of strain-hardening or thermal treatment, but for which there are mechanical property limits.

The following H temper designations have been assigned for wrought products in alloys containing over a nominal 4 percent magnesium.

• H311: Applies to products that are strain-hardened less than the amount for a controlled H31 temper.
• H321: Applies to products that are strain-hardened less than the amount for a controlled H32 temper.
• H323: Applies to products that are specially fabricated to have acceptable resistance to stress corrosion cracking.

Products that are thermally treated with or without supplementary strain hardening are designated with a -T temper. The "T" is followed by a digit(s) that designate the specific thermal treatment. Temper designations for aluminum alloys are as follows:

• Tl: Cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition.
• T2: Annealed (cast products only).
• T3: Solution heat-treated and then cold worked. Applies to products which are cold worked to improve strength or in which the effect of cold work in flattening or straightening is recognized in mechanical property limits.
• T31: Solution heat treated and then cold worked by flattening or stretching. Applies to 2219 and 2024 sheet and plate per MIL-A-8920. Also applies to rivets driven cold immediately after solution heat treatment or cold storage. 2024 rivets are an example.
• T351: Solution heat-treatment and stress relieved by stretching. This is equivalent to -T4 condition. It applies to 2024 plate and rolled bar and 2219 plate per MIL-A-8920.
• T3511: Solution heat-treated and stress relieved by stretching with minor stretching allowed. This is equivalent to -T4 condition and applies to 2024 extrusions.
• T36: Solution heat-treated and then cold worked by a reduction of 6 percent. Applies to 2024 sheet and plate.
• T37: Solution heat-treated and then cold worked by a reduction of 8 percent. Applies to 2219 sheet and plate.
• T4: Solution heat-treated and naturally aged to a substantially stable condition. Applies to products which are not cold worked after solution heat treatment, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.
• T42: Solution heat-treated and naturally aged by the user to a substantially stable condition. Applies to 2014-0 and 2024-0 plate and extrusions that are heat treated by the user from the annealed condition.
• T451: Solution heat-treated and stress relieved by stretching. Equivalent to -T4 and applies to plate and rolled bar stock except 2024 and 2219.
• T4511: Solution heat-treated and stress relieved by stretching with minor straightening allowed. Equivalent to -T4 and applies to all extrusions except 2024 and 2219.
• T5: Cooled from an elevated temperature shaping process and then artificially aged.
• T51: Cooled from an elevated temperature shaping process, stress-relieved by stretching and then artificially aged.
• T52: Cooled from an elevated temperature shaping process, stress-relieved by compressing and then artificially aged.
• T54: Cooled from an elevated temperature shaping process, stress-relived by stretching and compressing and then artificially aged. Applies to die forgings that are stress-relieved by restriking cold in the finish die.
• T6: Solution heat-treated and then artificially aged. Mechanical property limits not affected by cold working. Most alloys in the -w and -T4 conditions artificially aged to -T6.
• T61: Solution heat-treated and then artificially aged. Applies to forgings which receive a boiling water quench to avoid internal quenching stress. Applies to solution heat treated and artificially aged castings when more than one aging cycle is available for that alloy.
• T611: Solution heat-treated and artificially aged. Applies only to 7079 forgings that are quenched in 1750 to 1850F water.
• T62: Solution heat-treated and then artificially aged by the user. Applies to any temper that has been heat treated and aged by user which attains mechanical properties different from those of the -T6 condition.
• T651: Solution heat-treated, stress-relieved by stretching and artificially aged. Equivalent to -T6 and applies to plate and rolled bar' except 2219.
• T6510: Solution heat-treated, stress-relieved by stretching and artificially aged with no hard straightening after aging. Applies to extruded rod, bar and shapes except 2024.
• T6511: Solution heat-treated, stress-relieved by stretching and artificially aged with minor straightening. Equivalent to -Tb and applies to extruded rod, bar and shapes except 2024.
• T652: Solution heat-treated, stress-relieved by compressive deformation and artificially aged. Equivalent to -T6 and applies to hard forged squares, rectangles and simply shaped die forgings except 2219.
• T7: Solution heat-treated and then stabilized. Applies to products that are stabilized to carry them beyond the point of maximum strength to provide control of growth and residual stress.
• T73: Solution heat-treated and then artificially aged. Applies to 7075 alloys that have been specially aged to make the material resistant to stress-corrosion.
• T7351: Solution heat treated and specially artificially aged. Applies to 7075 alloy sheet and plate which have been specially aged to make the material resistant to stress-corrosion.
• T73511: Solution heat treatment and specially artificially aged. Applies to 7075 alloy extrusions which have been specially aged to make the material resistant to stress-corrosion.
• T7352: Solution heat treated and specially artificially aged. Applies to 7075 alloy forgings which have both compression-stress relief and special aging to make the material resistant to stress-corrosion.
• T8: Solution heat treated, cold worked and then artificially aged. Applies to products which are cold worked to improve strength, or in which the effect of cold work in flattening or straightening is recognized in the mechanical property limits.
• T81: Solution heat treated, cold worked and then artificially aged. Applies to 2024-T3 artificially aged to T-81.
• T851: Solution heat treated, stress-relieved by stretching and artificially aged. Applicable to plate, rolled bar and rod.
• T8511: Solution heat treated, stress-relieved by stretching and artificially aged. Applies to 2024 extrusions and 2219.
• T86: Solution heat treated, cold worked by a thickness reduction of 6 percent and then artificially aged. Applies to 2024 sheet and plate.
• T87: Solution -heat treated, cold worked by a thickness reduction of 10 percent and then artificially aged. Applies to 2219 sheet and plate.
• T9: Solution heat treated, artificially aged and then cold worked. Applies to products which are cold worked to improve strength.
• TlO: Cooled from an elevated temperature shaping process, artificially aged and then cold worked. Applies to products which are artificially aged after cooling from an elevated temperature shaping process, such as casting or extrusion and then cold worked to further improve strength.

For Geeks Only

Atomic Number: 13
Atomic Mass: 26.981539
Electronic Configuration: (Ne)3s²p¹
Melting Point: 660.37 °C
Boiling Point: 2467.0 °C
Density @ 293 K: 2.702 g/cm3

Chemical reactions of the elements
The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, alumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack, even by water.
It will burn in oxygen with a brilliant white flame to form the trioxide aluminum (III) oxide, Al₂O₃.
4Al(s) + 3O₂(l) 2Al₂O₃(s)

Aluminium metal reacts vigorously with all the halogens to form aluminium halides. So, it reacts with chlorine, Cl₂, bromine, I₂, and iodine, I₂, to form respectively aluminium (III) chloride, AlCl₃, aluminium (III) bromide, AlBr₃, and aluminium (III) iodide, AlI₃.
2Al(s) + 3Cl₂(l) 2AlCl₃(s)
2Al(s) + 3Br₂(l) Al2Br₆(s)
2Al(s) + 3I₂(l) Al2I₆(s)

The metal dissolves readily in dilute sulfuric acid to form solutions containing the aquated Al (III) ion together with hydrogen gas, H2. The corresponding reactions with dilute hydrochloric acid also give the aquated Al (III) ion. Concentrated nitric acid passivates aluminium metal.
2Al(s) + 3H₂SO₄(aq) 2Al³⁺(aq) + 2SO₄^2-(aq) + 3H₂(g)
2Al(s) + 6HCl(aq) 2Al³⁺(aq) + 6Cl^-(aq) + 3H₂(g)

Aluminium dissolves in sodium hydroxide (strong base) with the evolution of hydrogen gas, H₂, and the formation of aluminates of the type [Al(OH)₄]^-.
2Al(s) + 2NaOH(aq) + 6H₂O 2Na⁺(aq) + 2[Al(OH)₄]^- + 3H₂(g)