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Aluminium Processes


The quality of any finish applied to aluminium strongly depends on the preparation stages. Due to  the many varied alloys of aluminium the chemicals for this need to be selected to suit the job.To cover all the variations MacDermid have a comprehensive range of pretreatment chemicals to prepare your aluminium for whatever finish you require.

For any given job, Macdermid technical experts can advise on the correct pretreatment required.

However as a general guide the following stages should be considered:
Soak clean - Minco or Alprep 230 will effectively clean without etching, avoiding a patchy etch later
Cold Water Rinse - optional
Etch/deoxidize - Aluminium Etch ELE Aluclean 245 SA will provide an even, satin etch to remove oxide, embedded soils and light tooling marks.
Cold Water Rinse
Deoxidize/Desmut - The Deox range of acid deoxidizers will remove smuts and oxide without the use of Nitric acid
Cold Water Rinse

Chromates and Chrome Free Passivates

Chrome based passivates have long been used to provide a good base for paint on aluminium and corrosion resistance to unpainted surfaces. MacDermid can supply all of the required finishes.

Iridite 201 will provide the traditional green phosphochrome conversion coating, whilst Iridite 14-2 (sold in the UK as Alibond 802) gives the typical yellow finish.

As chrome is becoming less and less acceptable Macdermid have developed a range of chromium free processes for use in these applications. Iridite NR2-I offers a 'dry in place' replacement for chromates, for use under paint scheme and can be applied by spray or immersion.

For the most demanding applications the Chemidize range of products has been specially formulated. Chemidize 720 will provide the maximum adhesion of organic coatings and is used on several Boeing aircraft designs. Application is simple and it uses no restricted or controlled substances.

For corrosion resistance on unpainted surfaces without chromium Chemidize NCP is the choice. Chemidize NCP will provide salt spray resistance to rival conventional chromating and can also be used to provide a base for paint or other organic coatings. Chemidize NCP is not effected by high temperatures and no curing is required before painting.

Paint pretreatments

The Iridite and Chemidize ranges of products will provide efficient pretreatment under paint, whether you need chrome or chrome free products. For multi-metal use where steel, aluminium and perhaps zinc have to be processed our Keykote I/M3 (a cleaner/iron phosphate) may be a better choice. Use the link above to find our range of pre-paint phosphate treatments and post phosphate adhesion enhancers.


MacDermid supply a comprehensive range of products to prepare aluminium for anodizing. Non-etch cleaners such as Minco or Alprep 230 will remove oils and general shop soils. Long life etches such as Aluminium Etch ELE will then provide a consistent quality of etch throughout their life. Following the etch with one of the Deox or Alprep range of nitric acid free deoxidizers/desmuts will ensure a clean, smut and oxide free surface ready to be anodized.

After the anodizing process our Fox AGA cold seal is a money saving, reliable way to seal the anodized coating. Fox AGA will save considerable amount of energy in comparison to using boiling water and, as the seal goes on working after the initial treatment, a full seal is always achieved.