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IYPT Elements

IYPT 2019 Elements 028: Nickel: Toasters and coins

Nickel is element 28 in our International Year of the Periodic Table elements series. One of a select number of magnetic elements, it’s found in many of the coins of various currencies, and is also found in the heating elements in your oven and toaster.

Nickel is one of those elements that you encounter a whole lot more than you might realise. For starters, it’s almost certainly found in your kitchen. If you have an electric oven, or a toaster, the heating element will be made of nichrome alloy. This is composed of around 80% nickel and 20% chromium; it’s chosen for its high electrical resistance and also for the fact that when it heats up a layer of chromium oxide forms on the surface, preventing further oxidation of the alloy.

Nickel is also one of only a small number of the 118 elements which are magnetic around room temperature. In fact, there are only three others that are magnetic at 20˚C: iron, cobalt, and gadolinium. Gadolinium, the most unfamiliar of these, is only just magnetic at 20˚C – raise the temperature even a little high and this ceases to be the case.

Finally, many of the coins of many currencies contain nickel in varying amounts. All of the UK coins in current circulation, with the exception of the 1p and 2p coins, contain nickel, as do all U.S. coins with the exception of the penny.

Nickel can also cause allergic skin reactions for some – there’s more detail on that in this feature from Chemistry World.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.