Yttrium
Yttrium was discovered in 1789 by Johan Gadolin, a Finnish chemist, who analyzed the composition of a new mineral from a quarry near the Swedish village of Ytterby. Yttrium is primarily obtained through solvent extraction processes from a type of clay deposit found in China.
Yttrium is a silvery, metallic element with chemical properties similar to the lanthanide elements. It has historically been classified as a rare earth element; it is almost always found combined with the lanthanides in rare earth minerals, and is never found in nature as a free element.
Yttrium is highly crystalline. The pure element is relatively stable in air in a solid form.
Applications of Yttrium:
- Materials and Chemicals: Small quantities of yttrium are added to alloys to reduce the grain size in chromium, molybdenum, zirconium and titanium, and to increase strength of aluminum and magnesium alloys. Yttrium’s addition to alloys further improves their workability, adds resistance to high-temperature recrystallization and significantly enhances resistance to high-temperature oxidation. As a metal, it is used on the electrodes of some high-performance spark plugs.
- Electronics: The most important use of yttrium is in making phosphors providing the white and grey colours in television cathode ray tubes and in LEDs. It is also used in tri-chromatic fluorescent lighting where it helps produce brilliant white light with significant energy savings. Yttrium iron garnets are used to filter microwaves and as transmitters and transducers of acoustic energy. Yttrium, iron, aluminum and gadolinium are used in combination with dopants such as neodymium, erbium and ytterbium in near-infrared lasers.
- Energy and Superconductors: Yttrium is used in the mix of yttrium barium copper oxide in the development of superconducting materials for the transmission of electricity.
- Jewellery: Yttrium aluminum garnets are used to simulate diamond gemstones and yttrium oxide is used to stabilize the cubic form of zirconia for use in jewellery.
- Ceramics and Specialty Glass: Yttrium oxide is used in some ceramic and glass formulas, since it has a high melting point and imparts shock resistance and low thermal expansion characteristics. The same cubic zirconia, or yttrium stabilized zirconia, is found in optical glasses and camera lenses.
- Medical: Yttrium stabilized zirconia will take a sharper edge than conventional scalpels and is used in fabrication of needles that are used to sever pain-transmitting nerves in the spinal cord. The stabilized ceramics are also used in artificial joints and other prosthetic devices. Neodymium-doped yttrium-aluminium-garnet lasers have been used in experimental radical prostatectomies and erbium-doped lasers are starting to be used in cosmetic skin resurfacing. The radioactive isotope yttrium-90 is used in drugs the treatment of various cancers, including lymphoma, leukemia, ovarian, colorectal, pancreatic and bone cancers. Yttrium-90 is also finding new use in the treatment of inflamed joints, especially knees, in sufferers of conditions such as rheumatoid arthritis.
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