Surface Protection
"Anodising is an electrochemical process used to produce durable and decorative finishes on components made of aluminium or aluminium based alloys."
Untreated aluminium naturally produces a protective oxide coating on exposure to the atmosphere. Whilst this natural oxidisation offers some protection from corrosion, it is very thin and therefore should not be considered suitable for long term protection. This coating can however be replicated and improved by anodising.
There are three types of anodising, two of which are available here at Alpha Anodising UK Ltd.
Sulphuric Acid Anodising
This type of anodising is used extensively for general industrial, household and architectural applications. The Company has also used this type of anodising to create artwork due the fact that the resulting anodic film can be dyed to produce an attractive quality finish to any anodised component.
The standard colours on offer are:
(pictures of colours – perhaps actual pictures of dyed components?)
Additional non standard colours are also available. Speak to Alpha for more information.
As the anodic film produced during this type of anodising is translucent, it also means that the components can be pre treated to produce different textures which show through the anodic film.
Hard Anodising
Hard anodising covers a number of processes which are based on the use of specialist acid solutions, high voltage and current density electrical conditions, to produce a particularly hard anodic coating with excellent wear and corrosion resistant properties. These coatings have particular advantages on aluminium used for specialist engineering components where the properties of light weight plus a hard surface are of particular benefit.
The hard anodising process at Alpha is available to BS5599/DEF STAN 03-26 and MIL-A-8625 with typical coatings of 35-50 microns, although thicker coatings are available if required. Please speak to the team at Alpha for further advice and information.
Chromic Acid Anodising (not offered by Alpha)
This type of anodising is normally used by the aviation industry and for engineering components that only require a thin anodic coating.
Chromate Conversion Finishes
Chromate conversion is a non-electrolytic method of protecting the surface of aluminium and its alloys by a chemical immersion process. These finishes are particularly suitable as paint primers and also where electrical conductivity plus protection is required. The two processes most widely used in industry are available at Alpha.
Alocrom 1000
A colourless conversion coating that was developed to satisfy a requirement for good chemical treatment of aluminium and its alloys without significantly changing the surface.
Alocrom 1000 is not suitable for foodstuffs and water containers.
Alocrom 1200
Produces gold to orange conversion coatings and is ideal for coating all types of aluminium and its alloys, including high silicon pressure die castings. It is recommended for use on aluminium wherever maximum corrosion resistance is required. Coatings are flexible and will withstand bending and inserts of brass , steel or copper are not affected by the process. Alocom 1200 is approved to DEF-STAN 03-18 and to MIL-C-05541.
Alcrom 1200 must not be used to treat foodstuff containers as it contains Hexavekent chromium.
As with all the processes and services offered by Alpha Anodising UK Ltd we are happy to advise you on the best technique for your application. Don't forget we can project manage your whole products design and build if requried. Contact us with your questions about any aspect of our services.
