Why are electric coils made of alloy rather than pure metal?« Back to Questions List

Alloys are combination of one or two metals. Though metals possess useful properties like good conductivity and high strength, alloys combine these properties making a metal useful for a particular application. When metals are alloyed, properties like their melting point, conductivity etc are affected. 

electrical coil, alloy

There are coils inside electrical appliances that take part in electrical heating. Electrical heating is a process in which electrical energy gets converted to heat energy. The size and shape of the coil varies according to its use. Modern home appliances use nichrome which is wound in coils that produce heat when current passes through the coil.

Nichrome is an alloy of nickel (80%) and chromium (20%). It is silver grey in color, resistant to corrosion and has high melting point of about 1400 degree centigrade. They do not oxidize (burn) readily at high temperatures and is quite stable at such a temperature.


The resistivity of alloys is generally differs from its constituent metals. Nichrome has a very low resistivity in the range of 10–8 Ωm to 10–6 Ωm and are good conductors of electricity. Both the resistance of a material varies with temperature. The properties like no oxidation at high temperature, low resistivity and high melting point makes nichrome very much suitable for their use as coils in electrical appliances like electric iron, toasters etc.


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