Kobalt

Kobalt is a chemical element with the symbol Co and atomic number 27. It is found in the Earth's crust in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

Properties

Kobalt is a ferromagnetic metal, with a specific gravity of 8.9. The Curie temperature is 1,115 °C (2,039 °F) and the magnetic moment is 1.6–1.7 Bohr magnetons per atom. Kobalt has a relative permeability two-thirds that of iron. Metallic kobalt is not a health hazard.

Occurrence

Kobalt is a relatively rare element, it is only found in the Earth's crust to the extent of about 20 to 30 parts per million (ppm). The main source of kobalt is as a by-product of copper and nickel mining.

Uses

Kobalt is used in many industrial applications that capitalize on its unique properties, such as good resistance to wear and oxidation. It is used in high-speed and high-temperature alloys, in cemented carbides, and in magnetic alloys.

Health effects

Exposure to kobalt metal dust is harmful and can lead to a potentially fatal condition known as "hard metal lung disease". However, small amounts of kobalt are essential for human health, as it is a part of vitamin B12.

See also

• Chemical element
• Earth's crust
• Copper
• Nickel
• Vitamin B12