Dirk Coster, a Danish chemist, and Charles de Hevesy, a Hungarian chemist, jointly discovered hafnium in 1923 in the mineral zircon. The element's name stems from the Latin word for the city of Copenhagen, Hafnia.
Hafnium is a ductile metal with a brilliant silver lustre. Its properties are influenced considerably by any impurities of zirconium present. Of all the elements, zirconium and hafnium are two of the most difficult to separate. It has a good absorption cross section for thermal neutrons, excellent mechanical properties and is extremely corrosion resistant.
Applications of Hafnium:
- Energy: Hafnium's excellent mechanical, corrosion-resistance and nuclear absorption properties make it ideal for use in the harsh environment of pressurized water nuclear reactors, in particular in fission control rods.
- Alloys: Small additions of hafnium increase the adherence of protective oxide scales on nickel based alloys. It improves the corrosion resistance, especially under cyclic temperature conditions that tend to break oxide scales by inducing thermal stresses between the bulk material and the oxide layer. Hafnium is also used in iron, titanium, niobium, tantalum and other metal alloys. For example, the hafnium C103 alloy was used in the engine of the Apollo Lunar Lander Modules.
- Electronics: Hafnium-based compounds can be employed in gate insulators in the 45 nm generation of integrated circuits from Intel, IBM and others. It is also being substituted for silicon in computer chips, allowing for smaller sizes and faster functioning.
- Other uses: Hafnium is a good scavenger for oxygen and nitrogen in gas-filled and incandescent lamps. Hafnium is also used as the electrode in plasma cutting.