Rare Earth Metals and Alloys
Terbium (Tb) and Cerium (Ce) phosphors in your computer screen allow you to see GREEN.
Europium (Eu) is the source of the RED light and BLUE emitted by our display.
The Ames Laboratory has been actively involved in the preparation of very pure rare earth metals since the early 1940's when Dr. Frank H. Spedding and his group of pioneers developed the ion-exchange process, a technique that separates the "fraternal fifteen" plus yttrium and scandium. As a result of this and subsequent work, high-purity oxides are available from which high-purity rare earth metals can be prepared.
In most cases, the rare earth oxides are first converted to their respective fluorides and are then reduced metallothermicaly on a kilogram scale, using pure calcium metal specially sublimed for this purpose, this is call the Ames Process. The resulting metals are very pure. Nonetheless, many are further refined at the MPC by one of the following processes:
- vacuum casting
- zone refining
- electro-transport processing
Quantities of high-purity rare earth metals and alloys in single and polycrystalline forms are available to scientists outside of Ames Laboratory. Complete chemical analyses, obtained by mass spectrometry, inert gas fusion and combustion analysis, accompany the materials. Special preparations of high-purity alloys and compounds are also available in small quantities.
For more historical persepective on the importance of the rare earths please download "1787-1987 Two Hundred Years of Rare Earths."
Below is a video of one of the processing steps used to purify the rare earth metals:
[link takes you to the Ames Laboratory Youtube Channel]