Introduction to alloy classification
These are alloys of copper with 5-12% aluminium, some having additions of iron, nickel, manganese and silicon, available in cast and wrought form. They are stronger than brasses or tin bronzes with better corrosion resistance due to a hard, adherent, protective alumina film (Al203). They have an attractive golden colour, with very little tarnishing with time.
Special alloy characteristics
The major use for aluminium bronzes is in seawater applications, such as:
- Fasteners
- Pumps and valve components
- Pipe fittings
- Heat exchangers
- Bearings
- Propellers
For marine applications they meet exacting Def Stan (Defence Standard) specifications (previously Naval Engineering Standard – NES), and are widely used for MOD applications.
The durability and golden colour makes aluminium bronze an attractive proposition for architects, for example as cast upright balustrades for the Sackler Crossing in Kew Gardens, London. The alloy used for this project was CuAl8Fe3; the balustrades were polished to the required finish and waxed in situ.
Equivalent Specifications