Aluminium

Properties of aluminium

There’s hardly anyone in the world today who could imagine everyday’s life without aluminium being involved, and this involvement shall be affecting the mankind even more in the days to come, and, today, it is one of the elements to measure our standard of living.

PHYSICAL AND CHEMICAL CHARACTERISTICS OF ALUMINIUM

Diffusion: 7,28% of all elements

Position in the natural system of elements: III A group

Discovered: in 1827 (Fridrich Weller)

Colour: silvery white

Atomic number: 13

Thickness: 2700 kg/m3

Atomic mass: 26,981 U

Atomic radius: 125 pm

Crystalline structure: superficially centralized

Melting point: 933,47 K / 660,320oC

Boiling temperature: 2792K / 25190oC

Molal volume: 10 x 10 – 3 m3/mol

Evaporation heat: 293,4 KJ/mol

Melting heat: 10,79 KJ/mol

Sound velocity: 5100 m/s (933K)

Electric negativity: 1,61

Specific heat: 900 J/kg K

Conductivity: 37,7 x 106 S/U

Heat conductivity: 237 W/mK

Oxidation number: +3

Its behaviour in:
- the air: gets covered with an Al2O3 oxide film
- boiling water: converts into aluminium hydroxide
- strong bases: gets dissolved easily
- hydrochloric and diluted sulphur acids: gets dissolved, and presses out hydrogen
- concentrated sulphur acid: sulphur separation
- diluted nitrogen acid: ammonia separation
- concentrated nitrogen acid: gets passivized

The comparative advantages of aluminium:

- light metal

- corrosion-resistant

- good heat conductivity

- good electric conductance

- does not magnetize

- good heat and heat reflectivities

- uninflammable

- does not produce sparks

- good weldability

- non-toxic

- does not affect taste and odour of food

- not brittle at low temperatures

- shapable through all procedures applied

- attractive appearance

- simple and inexpensive maintenance

- durability

- fast and easy installation

- wide scope of products

- wide range of applications