Copper alloys

About the material

Copper alloys are indispensable for many applications – from watchmaking and electronics to membrane production. Thanks to their electrical conductivity, formability and corrosion resistance, they are used in many technical fields.

Brass (Cu-Zn)

Brass is an alloy of copper and up to 45% zinc, often supplemented by lead, tin, nickel, manganese or aluminium. It offers a good combination of mechanical strength, good workability and non-magnetic properties.

The higher the zinc content, the better the strength – but at the expense of cold formability. Above zinc content of more than 36% the beta phase occurs, which further restricts formability.

Grades containing lead are characterised by their excellent machinability. Nevertheless, brass is not suitable for every application: relaxation resistance when exposed to heat is limited, especially in the case of plug-in connectors.

Bronze (Cu-Sn)

Bronze primarily refers to alloys made of copper and tin – often used in connection technology. This is often referred to as phosphor bronze, since some phosphorus content remains as a reducing agent during production.

To ensure good cold formability, bronze is worked only in the alpha phase – i.e. with a tin content of 4-9%. Higher tin content would lead to the formation of the brittle delta phase.

Bronze has better mechanical properties than brass, but its resistance to relaxation under thermal stress is only slightly higher.

Nickel silver (Cu-Ni-Zn)

Nickel silver is a ternary alloy of copper, nickel and zinc – sometimes also with lead to improve machinability.

It offers higher corrosion resistance than brass and is characterised by good cold formability, especially in single-phase grades. Mechanically, nickel silver is more robust than conventional brass alloys.