DECO are proud to be the only commercial hard anodisers in New South Wales.
For extra longevity and durability, hard anodising or hard coat anodising is a tough and thick coat finish ideal for aluminium applications where high wear resistance is required. As with regular anodising, hard anodising converts the base metal itself into a protective oxide, making it scratch and chip resistant. Hard anodising is suitable for uses such as tough engineering applications, high-speed machine parts, and cookware and aerospace applications.
By lowering the temperature of the acid baths, we can anodise parts from 20 – 100 microns in thickness. For standard anodising under 20 microns, click here.
Hard anodised parts have a surface thickness/hardness 400 – 600HV – Alloy 6082 (equates approximately to 65 – 70 Rockwell C).
DECO can hard anodise products up to 2800mm long, 800mm high and 350mm wide.
Due to the density of the hard protective coating formed during this process, it is difficult to apply dye to the finished product. However, the alloying ingredients will affect the final colour of your product. Hard anodising films are commonly dark grey, yellowish-brown or black. To create a ‘naturally’ black look, it is possible to increase the microns of the anodic coating.
Standard anodising offers more colour selection.
Alloyed aluminium can compromise the hard anodised finish as it contains impurities. The surface finish may be less effective, or discoloured, or may not form properly on the metal’s surface. The purer grade of aluminium being hard anodised, the better. Generally alloy grades of around 5000 – 6000 are preferable, especially the 6061 series or higher. Alloy grades lower than 3000 will usually result in a poorer quality finish.
Hard coat anodising protects aluminium from mild acids, but they can still be attacked by alkali such as lime mortars and cement. Contact us to find out more about our special sealing processes, which can greatly increase your products’ resistance to alkali attack.
Anodising is heat resistant up to 800C. After this temperature it may craze, which can affect corrosion resistance.
Hard anodised aluminium is extremely abrasion resistant, which means it stands up well against scratches from steel cooking utensils, scrapes when used in high-speed machinery and other scratches and forms of wear. Bear in mind that this protective coating is very hard and glass-like, making it relatively inflexible. This means it could crack or craze when bent under high pressure.
Hard anodised components are non-conductors of electricity and have excellent electrical insulation characteristics. That said, be aware that if using your hard anodised components as part of an electrical circuit, you must make provisions for masking the component, to prevent coating or removal of the coating post-processing.