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Yttrium

Figure 1  

Yttrium location

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. The element yttrium was subsequently given its name after the village of Ytterby by another chemist, Ekeberg, who also named the new mineral gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10). Today, yttrium is primarily obtained through solvent extraction processes from a type of clay deposit in China that is a primary source of heavy rare earth elements.

Yttrium is a silvery-metallic transition element with chemical properties similar to the lanthanide elements and  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, because of a  passivation resulting from the formation of a protective oxide (Y2O3) film on its surface. Yttrium cuttings will ignite in air if their temperature exceeds 400°C.

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.  Its 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. Yttrium is also used in the manufacturing of gas mantles for propane lanterns as a replacement for thorium; the latter being radioactive. Yttrium is used as a deoxidizer for vanadium and other nonferrous metals, and as a catalyst in the polymerization of ethylene.

Developing uses include yttrium-stabilized zirconia as a solid electrolyte. Yttrium stabilized zirconia has long been used as an oxygen sensor in automobile exhaust systems, substrates in automotive catalytic converters, turbocharger components, and piston rings.

Electronics:  The most important use of yttrium is in making phosphors providing the white and grey coloursin 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. Cerium-doped yttrium aluminum garnet (YAG:Ce) crystals are used in phosphors to make white LEDs.Yttrium, iron, aluminum and gadolinium are used in combination with dopants such as neodymium, erbium, ytterbium in near-infrared lasers. YAG lasers have the ability to operate at high powers as well, and are used for drilling  and cutting of metals.

Energy and Superconductors: Yttrium is used in the mix of yttrium barium copper oxide (YBCO) in the development of superconducting materials for the transmission of electricity.

Jewellery: Yttrium aluminum garnets (YAG), with a hardness of 8.5, are used to simulate diamond gemstones and yttrium oxide is used to stabilize the cubic form of zirconia for use in jewelry.

Ceramics and Specialty Glass:  Yttrium oxide 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 robot-assisted 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.

LINKS:
For chemical and physical properties: www.webelements.com or http://education.jlab.org/itselemental/ele039.html

YBCO Superconductor    Yttrium Metal     
Figure 2   Figure 3    
         
Medical Applications    Yttrium Stabilized Zirconia   Catalytic Converter
Figure 4   Figure 5   Figure 6