Piece of Hafnium

Hafnium can be found along with zirconium, in zircons, at a ratio of 50:1. The principal uses of hafnium are in high-temperature ceramics, nickelbase superalloys, nozzles for plasma arc metal cutting, and nuclear control rods.  Hafnium is used in nuclear control rods because of its high thermal neutron absorption cross section. Commercial-grade zirconium, unlike nuclear grade, contains hafnium and is used in chemical process industries because of its excellent corrosion resistance. Hafnium metal also is used as an additive in superalloys. Image credit: By Deglr6328 at the English language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6875345