Glossary

Cobalt is a hard, lustrous, silver-gray metal with the chemical symbol Co and atomic number 27. It is a transition metal known for its magnetic properties, wear resistance, and ability to form strong, heat-resistant alloys. Cobalt is chemically similar to iron and nickel, and it plays an essential role in both industrial manufacturing and biological systems.

In metallurgy, cobalt is most valued for its use in superalloys—high-performance alloys that retain strength and stability at extreme temperatures. These alloys are used in jet engines, gas turbines, cutting tools, and space applications. Cobalt improves hardness, tensile strength, and resistance to oxidation and corrosion, especially under high stress and heat.

Cobalt compounds also have important uses. Cobalt oxide and cobalt aluminate provide vivid blue pigments known as cobalt blue, used in ceramics, glass, and paints since ancient times. Cobalt salts are used as catalysts in chemical industries and in electroplating, providing a hard, attractive, and corrosion-resistant surface finish.

In modern technology, cobalt is critical in rechargeable batteries, particularly lithium-ion batteries, where it stabilizes the cathode and improves energy density and lifespan. This makes cobalt a key material for electric vehicles, smartphones, and renewable energy storage.

Biologically, cobalt is an essential trace element as part of vitamin B₁₂ (cobalamin), which is necessary for red blood cell production and neurological function. However, excessive exposure to cobalt (such as dust or fumes in industrial settings) can be toxic, leading to respiratory or cardiac issues.

Cobalt is typically obtained as a byproduct of nickel and copper mining, with major producers including the Democratic Republic of the Congo, Russia, Canada, and Australia.