A heating element converts electricity into heat through the process of Joule heating and, therefore, requires wire of high resistivity. Heating elements are usually constructed from resistance wire or tape, and will be either embedded within an insulating material, supported on the surface of the insulating material or suspended under its own spring force.
The primary material used for heating elements is Nichrome, or Nickel Chrome alloy – due to its relatively high resistivity and resistance to oxidation. (On first heating, a layer of chromium oxide forms which prevents oxidation throughout the element thereby preventing failure).
Other materials are also used: ICA alloys (Iron Chrome Aluminium alloy) due to its relatively high resistivity and lower cost, but reduced oxidation resistance, and the Cupro Nickel alloys which are useful for low temperature heating.