Glossary "Anodising aluminium"

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Aluminium:
Aluminium is a silver-white coloured light metal with the element symbol Al and is the third most common element after oxygen and silicon. It is important to know that when describing working material, the term "aluminium" describes every substance based on aluminium, which means also their alloys. It is not at all a precious metal, which means that it reacts on cut parts immediately with air and water to aluminium oxide - already at room temperature. It is one of the few metals that, through anodic oxidation, creates an oxide layer than can be dyed (colour anodisation). The most known aluminium product is the aluminium foil.

Anodising:
Anodising (or anodizing) is an electrochemical process to create protective oxide layers on metals. The anodisation of aluminum is what we are focusing on when using this term. Magnesium, zinc and titanium can be anodized relatively well as well.

Aluminium casting:
Aluminium casting describes the melting and casting of aluminium alloys and the adding of certain substances to change the material's specifications and behaviour. In general, it is more difficult to anodise aluminium castings. You can find a selection of aluminium casting alloys that can be anodised in our anodisation manual.

Anode:
An anode is an electrode in electrochemical procedures that discharges anions in electrolytic solutions (e.g. anodising baths) absorbing electrons or creates cations to run oxidation reactions. The anode is therefore an "electron absorber" and therefore behaves like an oxidation agent. For the anodisation process, the aluminium workpiece serves as anode (positive electrode) and aluminium oxidizes to Al (III) cations and finally a further reaction to aluminium oxide.

Aluminium oxide:
The oxidation compound of aluminium. Pure aluminum has a thin aluminium oxide layer on its surface when exposed to air. This can be reinforced by the anodizing process.

Anodic oxidation:
Oxidation of substances, e.g. metals like aluminium or titanium, by flow of electric current in an external circuit. It is especially used to create oxidic protection layers on light metals (anodising).

Anodising dye:
Dyes for anodising porous aluminium oxide layers created by the anodisation process. The most important characteristic is a high UV-resistance and with it a high durability of the intense colouration of the aluminium. These anodising dyes can be purchased in different colours in our Tifoo anodisation shop and an overview of the possible shades can be found in our Tifoo Anodisation colour chart.
Anodising bath:
The electrolyte or liquid in which, after having prepared the aluminium, the creation of the porous aluminium oxide layer takes place.
Activator for anodisation:
Alkaline cleaning agent for preparation of the aluminium and the majority of its alloys.
Aluminizing by  a third party:
Anodisation carried out by a specialized company on commission. Especially reasonable for big lines and industrial production. Instead of having your small aluminium pieces anodised by someone else, we recommend anodising them by yourself to avoid high costs and waiting times. This is possible with the different anodising products by Tifoo. They allow you to easily achieve professional results for small parts or small lines with just a few precautions and by respecting the safety indications. Ideal for construction companies, workshops, model makers and every technically experienced user.

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Colour anodising:
Dyeing the fresh and porous or spongy anodised layer with colours. You can purchase the Tifoo Anodising dyes here >>>

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Hard anodising / hard anodizing:
Normal anodising is carried out at room temperature and relatively low current intensities and achieves layer thicknesses of 10 to 50 µm. This layer thickness is enough for a sufficient corrosion protection in most applications. It may happen that in industrial of particularly corrosive places, thicker layers of over 100 µm are needed. This is when hard anodising with significantly higher current intensities comes into play. Due to the high current densities, the pieces contacted as anode of course get very hot. This is why one has to work with sufficient cooling of the anodising bath when hard anodising. 

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Sealing:
Compressing the created anodising layer and with that hydrating the oxide layer. This closes the pores and therefore seals the surface completely and locks the dyes into the layer. The temperature of the water or the sealing solution should always be at least 96 °C. The pH-value should be between 5.5 and 6.