What is cobalt?

Cobalt, with chemical symbol Co and atomic number 27, is a lustrous grey metal and not found in its pure form in nature. The word cobalt is taken from German word Kobold, which means “goblin”, a name used by miner to refer to cobalt ore. Mostly yielded from Democratic Republic of the Congo, cobalt ore is mainly a by-product of copper and nickel mining. It can also be found in meteoric iron and vitamin B-12.

Alloys

Superalloys made from cobalt consume most of the cobalt mined worldwide. The strength and stability of cobalt alloys make them the perfect material for building turbine blades and jet engines for aircrafts. The corrosion and wear-resistant characteristics make cobalt based superalloys widely used in medical industries for replacing body parts such as knee and joint bones. Another reason that cobalt alloys are suitable for prosthetics part is being hypoallergenic as well. High speed steel drill bits are also made from cobalt alloys due to their superior heat-resistance.

Other Applications

Other applications of cobalt include pigmenting glass and ceramic with green and blue color and manufacturing paint. The use of cobalt in coloring can be traced back to ancient Egypt and China civilizations. Cobalt is also used in making of lithium batteries and chemical catalysts.

One of the variations of cobalt, called Cobalt-60 isotope, is used widely in treating cancer and killing cancer cells.

Physical properties

Cobalt is very hard, very ductile and moderately malleable. It is also one of the only three naturally magnetic metal found on Earth, among iron and nickel. The melting point of cobalt metal is 1,493°C (2,719°F), and the boiling point is about 3,100°C (5,600°F).

Cobalt Chrome

The specific type of cobalt alloy used to create cobalt rings is call cobalt chrome (CoCr). The chemical composition of CoCr is as follows

Chromium: 25-30%
Molybdenum: <1%
Tungsten: 2-15%
Carbon: 0.25-3.3%
Iron: <3%
Silicone: <2%
Manganese: <1%
Cobalt: rest of the balance