Introduction
Terbium (atomic number 65) is a very rare Heavy Rare Earth Element. It is another of the elements named after Ytterby, Sweden. It serves dual critical roles: creating brilliant green light in electronics and stabilizing high-powered magnets against heat.
Chemical & Physical Properties
A silvery-grey metal that is relatively stable in air compared to lighter lanthanides. It is malleable, ductile, and soft enough to be cut with a knife.
Occurrence & Production
One of the rarer lanthanides. It is found in minerals like cerite, gadolinite, and monazite, often recovered from ion-adsorption clays which are rich in heavy rare earths.
Key Applications & Uses
- Phosphors (Green): Terbium is the premier component for green phosphors used in fluorescent lamps and color TV tubes. In combination with divalent Europium (blue) and trivalent Europium (red), it creates trichromatic lighting.
- High-Temperature Magnet Additive: A crucial use today is as an additive to Neodymium-Iron-Boron (NdFeB) magnets. Adding small amounts of Terbium allows these magnets to operate at much higher temperatures without losing their magnetism, which is essential for electric vehicle motors.
- Terfenol-D: An alloy of terbium, dysprosium, and iron that expands or contracts in a magnetic field (magnetostriction). Used in sonar systems and high-precision actuators.
Future Outlook & Significance
Terbium is highly critical due to its scarcity and its role in enabling high-performance electric motors. Reducing reliance on Terbium (and Dysprosium) in magnets is a major goal of materials research due to its high cost and supply constraints.