Hard Anodising (HAP) is an electro-chemically produced thin layer of pure aluminium on the surface of almost all metals. The final thickness can be achieved from just a few nanometres to 120 nanometers depending on the metal used. Hard Anodising is a complex, specialist process where millions of tiny particles are sprayed or brazed onto the surface with a high voltage laser, under a pulsed beam of electricity. One of the most proficient at it is Poeton.

The application and thickness of the coating depends upon many factors such as the type of surface to be treated, the type of coating to be applied, the operating conditions during the treatment and the exact properties desired of the final thickness. There are many different methods and products available for hard anodising. There are two types of Hard Anodising, these are: Hard Coat and Hard Nitriding. Hard coat finishes provide a higher gloss finish; Hard Nitriding produces a glossier finish than Hard Anodising.

Both Hard Coat and Hard Anodising are required in high performance areas such as engines, pumps, turbines, shaft seals, hydraulic fittings, tank wear and corrosive water treatment and even dent repair. Both Hard Anodising and Hard Coat finishes can provide both long term corrosion resistance and long term wear resistance and are used in a wide range of applications including marine applications, where high wear resistance is essential to ensure that pumps and turbines are always operating at maximum efficiency. Hard Anodising also provides an extra layer of defence against carbon fibres, providing increased protection against carbon ingress.