Chromic Acid Anodising
Anodising is a very popular protective treatment for aluminium. Like all types of aluminium anodising, chromic acid anodising forms a corrosion resistant, amorphous layer of aluminium oxide. Anodising is performed by passing a current through parts (attached to the anode), in this case, in an electrolyte of chromic acid.
Chromic anodising was the original method of anodising and is sometimes referred to as the Bengough-Stuart process. Chromic acid anodising can produce films between 1µm and 6µm. Chromic acid anodising produces films that are considerably more opaque than other types of anodising.
Due to the use of hexavalent chromium, chromic acid anodising is gradually being phased out wherever possible. Laws and regulations are being enacted around the world both restricting its use and in some cases banning it outright. If you are designing a new product or updating an existing one, you may wish to consider using sulphuric acid anodising instead. Our technical staff will be able to assist you with any decisions about this, so please do contact us.
Specifications/Standards
Our chromic anodising process conforms to:
- Def Stan 03-24 (replaces NWS 1005/2-2 and NES 1005/2-2)
- Def Stan 21-005/2-2
- MIL-A-8625 Type I
- MIL-STD-171 7.1.1
- TS 112/DS 26.00 D1
- JP 213-2
- BS EN 2101