Rare Earth Elements Explained
Lanthanum is a key component in batteries for hybrid vehicles, computers and electronic devices. Lanthanum is utilized in hydrogen fuel storage cells, special optical glasses, electronic vacuums, carbon lighting applications, as doping agents in camera and telescope lenses, and in polishing glass and gemstones. It also has major applications in petroleum cracking and as an alloy for many different metals.
Praseodymium is used as an alloying agent with magnesium for high-strength metal applications in aircraft engines. It is also used in super magnets, catalytic converters, UV protective glasses, carbon arc lights and CAT scan scintillators. The element is additionally used as a doping agent in fibre optic cables and in several metal alloys.
Neodymium is essential in the production of the world's strongest super magnets, which are present in hybrid cars, state-of-the-art wind and tidal turbines, industrial motors, air conditioners, elevators, microphones, loudspeakers, computer hard drives, in-ear headphones and guitar pick-ups. When combined with dysprosium (or terbium) a neodymium magnet can withstand high temperatures, allowing the element to be used in electric cars. Neodymium has many additional uses. It is utilized in incandescent light bulbs, cathode ray tubes, as a glass filter and colourant, as a doping agent in yttrium-aluminium-garnet lasers and for glare-reduction in rear-view mirrors.
Samarium -cobalt alloys are used to make permanent magnets that are extremely difficult to demagnetize and work at high temperatures. Samarium-cobalt magnets have been used by the US defence industry since the 1970s. They also have additional applications in the music industry but are primarily used as precise pickups. The element can be found in many other compounds used for such products as neodymium-yttrium-aluminium garnet laser glass and infrared absorption glass, capacitors for microwave frequencies, as well as in the cancer drug 'Quadramet'.
Europium is used as a phosphor in all TVs and computer screens to create red and blue light, and when combined with green terbium phosphors, trichromatic fluorescent lighting is created. Europium isotopes are the best known neutron absorbers and therefore the element is ideal for control rods in nuclear reactors. The element is also used in fluorescent light bulbs, alloys, as an agent in fluorescent glass and to dope plastic and glass to make lasers.
Gadolinium when added to chromium, iron or related alloys, greatly improves the workability and raises resistance to high temperature oxidization. It is also utilized in microwave applications, CDs, computer memory devices, MRI image enhancing, neutron radiography and for making phosphors in TV tubes. One final use of gadolinium comes in nuclear reactors as an emergency shut-down mechanism.
Terbium is used in colour TV tubes and fluorescent lamps as a green phosphor. In combination with europium blue and red phosphors the three create trichromatic fluorescent lighting, which is much brighter than conventional fluorescent lighting. Another green application for terbium can be found in combination with neodymium in the production of super magnets. The element is also used in alloys, crystal stabilizers in fuel cells that operate at high temperatures, specialty lasers and to dope calcium fluoride, sodium borate and strontium molybdate materials. Terbium is a component of Terfenol-D, a material that is used in transducers, high-precision liquid fuel injectors and in a new form of audio equipment that has the potential to revolutionize the speaker industry.
Dysprosium's thermal neutron absorption cross-section and high melting point enables it to be used in nuclear control applications. The element can be added to neodymium-iron-boron magnets to raise the strength and corrosion resistance of applications like drive motors for hybrid electric vehicles. Like terbium, dysprosium is a component of terfenol-D; a very promising material for future technology applications. It is also used in CDs, chemical reaction testing, laser materials and dosimeters.
Holmium has one of the highest known magnetic moments (force and torque on electric currents). The element is imperative in the creation of the strongest, artificially generated magnetic fields. Holmium is also used in nuclear control rods, solid-state lasers in eye-safe medical and dental microwave equipment, as a yellow and red glass and a cubic zirconia colorant.
Erbium is used in neutron-absorbing control rods, creating lasers for cutting and welding and as a doping agent for optical fibers. As an alloy additive, erbium lowers the hardness and improves the workability of numerous metals. In oxide form, the element is used as a pink colorant in glass and porcelain enamel glazes and it is often used in photographic filters.
Thulium is the second rarest element after promethium and does not occur naturally in the earths crust. Because of its scarcity and high price, there are few widely-used thulium applications. Its current uses are mainly scientific experimentation and in portable x-ray devices use for areas where electric power is not available.
Ytterbium is used in solar cells, optical glasses, crystals and ceramics. It can be utilized as a doping material for high power solid-state lasers and as an alloy that helps to strengthen stainless steel. Like thulium, ytterbium is employed in portable x-ray machines where electricity is not available.
Lutetium is mainly used as a catalyst in refining petroleum, hydrogenation and polymerization processes, and in organic LEDs. Lutetium is currently being investigated as an agent for possible cancer treatments. It is also used in x-ray phosphors and computer memory devices.
Yttrium is most widely used in phosphors for white and grey colours in LEDs and in tri-chromatic fluorescent lighting. Yttrium is regularly alloyed with chromium, molybdenum, zirconium, titanium, aluminium and magnesium. Yttrium is used as a deoxidizer for vanadium and other nonferrous metals and as a catalyst in the polymerization of ethylene. It has medical applications in cancer treatment, arthritis and joint inflammation, artificial joints, prosthetic devices and needles. The element can also be found in optical and camera lenses, cubic zirconia jewellery, super conductor materials, high performance spark plugs, yttrium-stabilized zirconia, solid electrolytes, exhaust systems, catalytic converters, turbocharger components and piston rings.
Scandium's main application by weight is in aluminium-scandium alloys for minor aerospace industry components. These alloys contain between 0.1% and 0.5% of scandium. Some items of sports equipment, which rely on high performance materials, have been made with scandium-aluminium alloys, including baseball bats and bicycle frames. Lacrosse sticks are made with scandium-titanium alloys to take advantage of the strength of titanium. The American gunmaking company Smith & Wesson produces revolvers with frames composed of scandium alloy and cylinders of titanium. Scandium is also used to make high-intensity discharge lamps.