Sulphuric Acid Anodising

Sulphuric acid anodising is the most common protective treatment for aluminium and leaves a clear ("natural") silver coloured finish, which can be subsequently dyed. The anodising process involves the oxidation of the aluminium surface to form a thin layer of aluminium oxide under controlled chemical conditions - this process occurs naturally at a much slower rate for aluminium exposed to oxygen in the air. As anodising does not involve the coating of the aluminium with a different metal (or other man made coating), the process will not hide any surface imperfections or blemishes in the aluminium substrate. In fact, the vigorous nature of the process will generally degrade the surface finish of the aluminium - this should be taken into account when considering the quality of the surface material to be treated if a highly decorative finish is required.

Anodising is an electrolytic process which requires an electrical contact point at all times during the treatment - this means that a very small set of jig marks will always appear after treatment. It is important that we are made aware of any specific jigging requirements where certain surfaces must be free from jig marks for decorative purposes or for critical bores and sealing surfaces.

Sulphuric acid anodising is generally used where a decorative and corrosion resistant finish is required. The resulting anodic film is usually between 5 and 20 microns thick and is electrically insulating. We typically treat components in all industry areas with special emphasis in the electronics, motorsport, aerospace, medical and general engineering sectors.