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Sulphuric and Chromic Acid Anodising

Poeton Sulphuric and Chromic Acid Anodising

As well as Hard Anodising and Anodic Polymer Composites, Poeton offer Chromic Acid Anodising and Sulphuric Acid Anodising, mainly for aluminium Aerospace and Defence parts. Chromic acid anodising is typically 1 to 2 thick, often used as a pre-treatment prior to painting, as well as for some corrosion protection. Sulphuric acid anodising produces layers 10 to 15 for corrosion protection and dying in a wide range of colours.

Our aluminium anodising capacity is huge, with automated lines capable of processing volume parts quickly and efficiently, as well as long, deep tanks for your biggest (even 5 meters!) Aerospace and Defence parts.

With an eye on environmental issues associated with Chromic Acid, we now offer Tartaric Sulphuric Acid Anodising as an alternative, with a plant and treatment procedure that conforms to the latest Aerospace and Defence specifications.


Typical applications of chromic acid anodising on aluminium are:

And typical applications of sulphuric acid anodising on aluminium are:


For maximum corrosion protection, aluminium anodised layers are usually sealed, immediately after the main coating process, filling the micro-columns in the layer and preventing access to the substrate.

The main techniques are:

It is also possible to infuse the layer with a polymer, a procedure more commonly used with Hard Anodising, but we do offer that facility with Apticote 300su.

Corrosion resistance

Corrosion protection is the main purpose of aluminium anodising. Typical salt mist endurance results (on 6082 aluminium alloy, ASTM B117-97 and ISO 9227) are less than 5 spots per panel. (Pass criteria vary with different end-users and specifications)


Salt mist endurance

Sulphuric anodised

> 300 hrs

Chromic anodised

> 300 hrs

Chromic anodised + di-chromate seal

> 500 hrs


Apticote sulphuric and chromic acid anodising can be applied to most aluminium alloys, including those commonly used in aerospace and defence applications - 2124 (T3), 7175 and 6082.

Alloys with silicon greater than 10% are unsuitable, as are alloys with more than 5% copper.

Technical Data Sheet

Click here to download a printer friendly version for your retention (PDF = 760B).

For details of all our processing capabilities, size and capacity, please follow this link.

More info about anodising