Specifications: Neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. Neodymium, a rare earth metal, is present in Mischmetal to the extent of about 18%. The metal has a bright, silvery metallic luster, however, as one of the more reactive rare earth metals, it quickly tarnishes in air. The tarnishing forms an oxide layer that falls off, which exposes the metal to further oxidation. Although it belongs to "rare earth metals," neodymium is not rare at all. It constitutes 38 ppm of EarthÕs crust.
Characteristics
Neodymium, a rare earth metal, is present in Mischmetal to the extent of about 18%. The metal has a bright, silvery metallic luster, however, as one of the more reactive rare earth (Lanthanoid) metals, it quickly oxidizes in air. The oxide layer then falls off, which exposes the metal to further oxidation. Although it belongs to "rare earth metals," neodymium is not rare at all. It constitutes 38 ppm of the Earth’s crust.
[edit] Applications
* Neodymium magnets are the strongest permanent magnets known - Nd2Fe14B. These magnets are cheaper, lighter, and stronger than samarium-cobalt magnets. Neodymium magnets appear in products such as microphones, professional loudspeakers, in-ear headphones, Dokodemo Magnets, guitar and bass guitar pick-ups and computer hard disks where low mass, small volume, or strong magnetic fields are required.
* Neodymium is a component of didymium used for coloring glass to make welder's and glass-blower's goggles. The sharp absorption bands obliterate the strong sodium emission at 589 nm.
* Neodymium has an unusually large specific heat capacity at liquid-helium temperatures, so is useful in cryocoolers
* Neodymium lamps are incandescent lamps containing neodymium in the glass to filter out yellow light, resulting in a whiter light more like sunlight
* Neodymium colors glass in delicate shades ranging from pure violet through wine-red and warm grey. Light transmitted through such glass shows unusually sharp absorption bands; the glass is used in astronomical work to produce sharp bands by which spectral lines may be calibrated. Neodymium is also used to remove the green colour caused by iron contaminants from glass.
* Neodymium salts are used as a colourant for enamels.
* Probably because of similarities to Ca2+, Nd3+ has been reported [1] to promote plant growth. Rare earth element compounds are frequently used in China as fertilizer.
* Samarium-neodymium dating is useful for determining the age relationships of rocks and meteorites.
* Size and strength of volcanic eruption can be predicted by scanning for neodymium isotopes. Small and large volcanic eruptions produce lava with different neodymium isotope composition. From the composition of isotopes, scientists predict how big the coming eruption will be, and use this information to warn residents of the intensity of the eruption.
* Certain transparent materials with a small concentration of neodymium ions can be used in lasers as gain media for infrared wavelengths (1054-1064 nm), e.g. Nd:YAG (yttrium aluminium garnet), Nd:YLF (yttrium lithium fluoride), Nd:YVO4 (yttrium orthovanadate), and Nd:glass. The current laser at the UK Atomic Weapons Establishment (AWE), the HELEN 1-TW neodymium-glass laser, can access the midpoints of pressure and temperature regions and is used to acquire data for modeling on how density, temperature and pressure interact inside warheads. HELEN can create plasmas of around 106 K, from which opacity and transmission of radiation are measured.
[edit] Neodymium glass
Neodymium doped glass slabs used in extremely powerful lasers for inertial confinement fusion.
Neodymium doped glass slabs used in extremely powerful lasers for inertial confinement fusion.
Neodymium glass (Nd:Glass) is produced by the inclusion of neodymium oxide (Nd2O3) in the glass melt. In daylight or incandescent light neodymium glass appears lavender, but it appears pale blue under fluorescent lighting.
Neodymium glass solid-state lasers are used in extremely high power (terawatt scale), high energy (megajoules) multiple beam systems for inertial confinement fusion. Nd:Glass lasers are usually frequency tripled to the third harmonic at 351 nm in laser fusion devices.
Neodymium glass is becoming widely used in incandescent light bulbs, to provide a more "natural" light.
Neodymium glass has been patented for use in automobile rear-view mirrors, to reduce the glare at night.
The first commercial use of purified neodymium was in glass coloration, starting with experiments by Leo Moser in November 1927. The resulting "Alexandrite" glass remains a signature color of the Moser glassworks to this day. Neodymium glass was widely emulated in the early 1930s by American glasshouses, most notably Heisey, Fostoria ("wisteria"), Cambridge ("heatherbloom"), and Steuben ("wisteria"), and elsewhere (e.g. Lalique, in France, or Murano). Tiffin's "twilight" remained in production from about 1950 to about 1980. Current sources include glassmakers in the Czech Republic, the USA, and China; Caithness Glass in Scotland has also used the colorant extensively. The sharp absorption bands of neodymium cause the glass color to change under different lighting conditions, being reddish-purple under daylight or yellow incandescent light, but blue under white fluorescent lighting, or greenish under trichromatic lighting. This color-change phenomenon is highly prized by collectors. Neodymium in combination with praseodymium gave Moser's "Heliolite" glass. In combination with gold or selenium, beautiful red colors result, such as Moser's "Royalite" or Tiffin's "Wistaria" or some of the colors achieved by Fenton. Since neodymium coloration depends upon "forbidden" f-f transitions deep within the atom, there is relatively little influence on the color from the chemical environment, so the color is impervious to the thermal history of the glass. However, for the best color, iron-containing impurities need to be minimized in the silica used to make the glass. The same "forbiddenness" of the f-f transitions makes rare earth colorants less intense than those provided by most d-transition elements, so more has to be used in a glass to achieve the desired color intensity. The original Moser recipe used about 5% of neodymium oxide in the glass melt, a sufficient quantity such that Moser referred to these as being "Rare Earth Doped" glasses. Being a strong base, that level of neodymium would have affected the melting properties of the glass, and the lime content of the glass might have had to be adjusted accordingly.
