In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster, etc. an alloy such as Nichrome is used, not pure metals.

Explanation

i. The heating devices such as iron, electric heater, toaster, boiler etc. works on the principle of heating effect of electric current.
ii. Alloys (such as nichrome) as compared to metals have higher resistivity.
iii. Unlike metals they can be heated to higher temperature.
Hence, heating devices like electric heater, boiler, toaster etc., are made of alloys rather than a pure metal.