It depends on the country. For a long time Canadian nickels were made of 99% nickel. However in the US the nickel only has 25% nickel in it and the rest is copper.
The 'copper' (1p & 2p coins) are made from 97% copper - and 3& trace elements. The 'silver' coins are made from nickel-plated sheet steel.
Cupronickel or copper-nickel or "cupernickel" is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese.
Nickel
Coins are a mixture because they are made up of multiple elements like metals such as copper, nickel, and zinc. These metals are physically mixed together to create the coin.
Copper - nickel
Coins are made of a combination of elements, typically metals like copper, nickel, and zinc. These metals are mixed together in specific proportions to create the material from which coins are minted. Therefore, coins are not elements themselves but are composed of a mixture of different elements.
The Iraqi coins made for general use since 1960 are made of nickel, copper-nickel, stainless steel, copper plated steel and nickel plated steel.
U.S. coins used to be made with silver, typically a blend of 90% silver with 10% copper. Then modern dimes, quarters, and half dollars are nickel-coated copper. Nickels are made with 25% nickel and 75% copper. There aren't any coins made of a silver/nickel blend.
20p coins in the United Kingdom are made from a combination of 84% copper, 5.5% nickel, and 10.5% zinc.
two pound coins are made out of copper/zinc/brass/and nickel not gold
Today in 2012 the series of coin that we presently use is the contemporary coins where coins are made up of copper+nickel (cupro-nickel alloy).
For the same reason any other nickel was made - to provide coins for commerce.