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Refinement of aluminium

The material
  • Base material of Al  =  Bauxite and Laterite
  • The melting point of pure Al  =  658°C
  • The specific gravity of aluminium  =  2,7 kg / dm3
  • With which materials Al is alloyed?  =  Mainly with Si, Zn, Mn, Mg, Cu
  • Al alloys which can be hardened  =  Al Cu Mg, Al Mg Si, Al Cu Ni, G Al Si Mg
Fortes of the material
  • The specific gravity
  • High mechanical strength because of suitable alloy forming and thermal treatment
  • Corrosion resistance
  • High reflecting power
  • Good thermal and electric conductivity
  • Magnetic neutrality
  • High cold working aptitude
Galvanisierung von Aluminium
Weaknesses of the material
  • Low strength and strain limit
  • Instability against alkalis and alkaline matters
  • Welding and soldering only possible with fluxing agent
  • Because of its high affinity to oxygen in the air aluminium forms a thin but dense oxide coating which constructs its space lattice on the aluminium and so protects it against further attacks.

Criteria when galvanizing aluminium

  • Aluminium protects itself by a relatively stable oxide coat which must be removed before any galvanic treatment (high affinity to oxygen).
  • Aluminium has got a high affinity to react in the alkali as well as in the acidic area and to build up compounds (amphoteric behaviour).
  • Because of its position in the electrochemical series of the elements aluminium strongly reacts with other metals, a fact which is important for the corrosion process as well as for the selection of the electrolytes for the galvanic treatment.
  • The great number of aluminium qualities which are available requires an indispensable partnership between the producing and the processing companies.