The alloy of copper and nickel, called cupro-nickel, is used in low-denomination coins, often for the outer cladding.
The successful use of cupro-nickel in coinage is due to its corrosion resistance, electrical conductivity, durability, malleability, low allergy risk, ease of stamping (metalworking), antimicrobial properties and recyclability. Switzerland pioneered the nickel billon coinage in 1850, with the addition of silver. In 1968, Switzerland adopted the far cheaper 75:25 copper to nickel ratio then being used by the Belgians, the United States, and Germany. From 1947 to 2012, all “silver” coinage in the UK was made from cupronickel, but from 2012 onwards the two smallest cupronickel denominations were replaced with lower-cost nickel-plated steel coins.