List of copper alloys



Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. Of the large number of different types, the best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both of these are imprecise terms. Latten is a further term, mostly used for coins with a very high copper content. Today the term copper alloy tends to be substituted for all of these, especially by museums.

Copper deposits are abundant in most parts of the world (globally 70 parts per million), and it has therefore always been a relatively cheap metal. By contrast, tin is relatively rare (2 parts per million), and in Europe and the Mediterranean region, and even in prehistoric times had to be traded considerable distances, and was expensive, sometimes virtually unobtainable. Zinc was somewhere between these two in terms of rarity at 75 parts per million, but often harder to extract from its ores. Bronze with the ideal percentage of tin was therefore expensive and the proportion of tin often reduced to save cost. The discovery and exploitation of the Bolivian tin belt in the 19th century made tin far cheaper, although forecasts for future supplies are less positive.

There are as many as 400 different copper and copper alloy compositions loosely grouped into the categories: copper, high copper alloy, brasses, bronzes, copper nickels, copper–nickel–zinc (nickel silver), leaded copper, and special alloys.

Composition
The similarity in external appearance of the various alloys, along with the different combinations of elements used when making each alloy, can lead to confusion when categorizing the different compositions. The following table lists the principal alloying element for four of the more common types used in modern industry, along with the name for each type. Historical types, such as those that characterize the Bronze Age, are vaguer as the mixtures were generally variable.

The following table outlines the chemical composition of various grades of copper alloys.

Brasses


A brass is an alloy of copper with zinc. Brasses are usually yellow in colour. The zinc content can vary between few % to about 40%; as long as it is kept under 15%, it does not markedly decrease corrosion resistance of copper.

Brasses can be sensitive to selective leaching corrosion under certain conditions, when zinc is leached from the alloy (dezincification), leaving behind a spongy copper structure.
 * Nordic Gold

Bronzes
A bronze is an alloy of copper and other metals, most often tin, but also aluminium and silicon.


 * Aluminium bronzes are alloys of copper and aluminium. The content of aluminium ranges mostly between 5% and 11%. Iron, nickel, manganese and silicon are sometimes added. They have higher strength and corrosion resistance than other bronzes, especially in marine environment, and have low reactivity to sulphur compounds. Aluminium forms a thin passivation layer on the surface of the metal.
 * Bell metal
 * Brastil
 * Phosphor bronze
 * Nickel bronzes, e.g. nickel silver and cupronickel
 * Speculum metal
 * UNS C69100

Precious metal alloys
Copper is often alloyed with precious metals like gold (Au) and silver (Ag).

† amount unspecified