Colorbond ® is the brand name of the most widely used pre-fab exterior sheet metal in the Australian building industry. The process and name Colorbond are owned by BlueScope Steel, the company previously known as BHP Steel. Colorbond sheeting begins as a sheet of iron galvanised with a zinc/aluminium alloy. First a pre-primer is applied, then a polyester primer is baked on, lastly BHP's "specially developed" exterior grade top coat is baked on.
Colorbond steel was first produced in 1966 at Port Kembla in New South Wales. It is currently available in twenty different colours, and if you have seen a coloured corrugated iron roof, fence, shed or water tank in Australia constructed since the '70s you have probably seen some Colorbond. For corrosion reasons, BHP recommend against placing copper, lead or stainless steel against Colorbond.
Official site: http://www.colorbond.com/