Hafnium

Hafnium is a ductile metal with a brilliant silver lustre. It is found in all minerals containing zirconium. These two metals show greater similarities in properties than between any other metals in the periodic table, and hence are difficult to separate. Hafnium shows good absorption for thermal neutrons, is very corrosion resistant and has impressive mechanical properties.

Due to these properties it is used in nuclear reactor control rods. Hafnium is also used in gas filled and incandescent lamps, and to control the recrystallisation of tungsten filaments. The ability of hafnium to absorb thermal neutrons is conversely inconvenient when present as a zirconium impurity, since zirconium is used in the nuclear industry for cladding fuel elements due to its low absorption for thermal neutrons.