Chromic anodising refers to the process of anodising using a chromic acid solution which forms a relatively soft, thin coating (usually between two-five microns in thickness) and offers general protection against corrosion under mild conditions.
The process of chromic anodising can help to minimise the loss of fatigue strength in work-pieces (compared to sulphuric anodising). It provides maximum protection with the minimum loss of metal section.
Chromic anodising is a highly specialised process and is particularly useful when the item to be anodised contains small blind holes, from which it may be difficult to remove electrolyte. Any trace of the solution left in these crevices after treatment is easily highly visible which makes its removal far easier. The product is also completely non-corrosive to the aluminium, and this combined with the visibility of the chemicals (which are a bright orange colour) makes the chromic solution perfect for use in crack detection.