Hard Anodising is a high-tech, extreme engineering finish. It is extensively used in the aerospace and marine industry on components which are subject to extreme heat, abrasion and corrosive conditions.
The finish is ultimately is the thickest form of anodising, creating an oxide layer which is between 20 to 100 Microns thick, depending on the base alloy being treated. It offers the highest increases in hardness, wear resistance and electrical resistance and is primarily a functional coating. It is also performed in a sulfuric acid solution, but with higher acid concentration, low temperature and a higher voltage applied.
DEF STAN 151-3 25-50µm
DEF 03-26 25-50µm
BS 5599 25-50µm
Ordinarilly, up to 75 microns (µ)