Aluminium does not rust! Right?

The use of aluminium has many advantages. However, an advantage mistakenly attributed to aluminium is that it does not rust.

That’s unfortunately not true, aluminium does corrode.

When using our materials, it is therefore useful to take precautions to prevent or minimize corrosion.

Corroded aluminium component used in the fluid industry

What is corrosion?

Like any metal, aluminium forms a natural oxide layer when it comes into contact with oxygen. In contrast to steel, the corrosive layer comes to a halt after approximately 2.5-4 nm, thus protecting the underlying metal from corrosive destruction. This layer remains stable in the pH range of 4.5 to 8.5, which means that it is not attacked by corrosive gaseous or liquid media. In this state, aluminium has clear advantages over steel.

Most important tips to avoid aluminium corrosion:

  • do not bring into contact with materials having an electrochemical voltage potential of > 50 mV
  • avoid contact with media outside the pH range of 4.5 to 8.5
  • seal crevices ≤0. 5 mm (connected to component)
  • do not allow moist parts to come into contact with steel, copper, brass or bronze
  • avoid direct contact of parts when stacked vertically
  • always use interlayers that are completely dry and free of acid residues
  • do not store parts directly on wet or contaminated wood (e.g. pallets)
  • never use rags that have been previously used to clean/dry steel, brass, copper, etc. or that are dirty
  • never use abrasives (pads paper, etc.) with which other metals have been previously processed
  • process only a single material on the machine. If you do change, however, then change the emulsion beforehand.
  • even the most elaborate filtration systems cannot separate finest foreign metal particles
  • immediately remove machined components and clean and dry them thoroughly
  • use only cooling emulsions with a pH range between 4.5 to 8.5
  • perform weekly check of pH value of the emulsion
  • do not use cleaners with a pH value >8.5
  • do not store aluminium in areas with changing climatic conditions

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