Nickel chrome alloys, or Nichrome as they are commonly known, are alloys that contain nickel, chromium and sometimes iron. The chemical formula is NiCr, or sometimes NiFeCr if iron is included.
Nichrome alloys are usually composed of 80% nickel and 20% chromium (Nichrome 80/20), although other compositions can be found in different ratios. Nichrome is characterised by a silver-grey colour and has a high resistance to electrical flow and heat. It is also very resistant to corrosion and wear, is very durable and has a very high melting point at around 1,400oC.
Its resistance to oxidation make nichrome a popular material for use in heating elements. For example, the heating elements in a household toaster are most commonly made of thick nichrome wire. When used in this way the nichrome is typically wound in coils to a certain electrical resistance before a current is passed through to produce the heat that is emitted. When nichrome is heated to high temperatures it develops an outer layer of chromium oxide, unlike other metals which may begin to oxidise when heated in air. This means it is mostly impervious to oxygen and the heating element is therefore protected from oxidation.
Another popular use of nichrome is in fireworks and explosives as an electrical ignition. When current flows through it, the nichrome glows red hot and heats up extremely quickly even with a small voltage. This makes it an excellent choice for igniting fireworks and other pyrotechnics as it can be activated from a safe distance at the push of a button.
As nichrome is very wear resistant it is also a popular for creating hard wearing coatings both for decorative and engineering purposes. Nickel chrome alloys are commonly used in aircraft engine turbines, for example, due to their durability, resistance to heat and general toughness.
William Rowland is one of the world’s leading suppliers of nickel products, including high purity nickel and nickel powders. We supply nickel chromium in both lumps and powder form, of various sizes.