In the wake of the recent announcement of a new £1 coin to be introduced in 2017, today’s post looks at some of the metals present in the coins of the United Kingdom. All of these coins are produced using alloys, or mixtures of metals; the main metals used include copper, nickel, zinc and iron. The composition of some of the coins has also changed since their original introduction, for reasons which are examined below.
The three main alloys used in the manufacture of coins are nickel-brass (mainly copper, with zinc and nickel), cupronickel (mainly copper, with nickel), and bronze (mainly copper, with zinc and tin). Copper and its alloys can be easily made into coins, and also show good resistance to corrosion. Additionally, they are also natural antimicrobial materials, due to their toxic effect on moulds, viruses & fungi, a characteristic which is highly beneficial considering that currency changes hands frequently.
Until recent years, copper was also chosen due to its relative cheapness. However, as its wide range of applications has increased demand, the price of copper has risen in recent years, to the point where some low value coins have become worth less in monetary terms than their copper content. As a consequence, several British coins have undergone changes in composition since their introduction, in order to minimise copper content.
1p & 2p coins, formerly composed of 97% copper content, have, since 1992, been made from copper-plated steel. Steel is an alloy of iron with small amounts of carbon (and trace amounts of manganese). The coating of copper on the steel core is just 0.025mm thick, vastly reducing the percentage of copper contained within the coin. Similarly, 10p and 5p coins, formerly fashioned from cupro-nickel, are now made from nickel-plated steel, cutting out the inclusion of copper entirely.
Another coin whose copper composition could change is the £1. With the treasury announcing a new £1 coin to be introduced in 2017 to combat forgeries, the precise metal composition is yet to be decided on, and will be subject to a public consultation in the summer of 2014.
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References & Further Reading