Neodymium Metal Characteristics
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Notable characteristics

Neodymium, a rare earth metal, is present in Misch metal 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 Earth’s crust.

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 high-quality 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 lamps are incandescent lamps containing neodymium in the glass to filter out yellow light, resulting in a whiter light more like sunlight

• Didymium glass was used during World War I to send Morse Code across the battlefields. The glass filter caused only imperceptible fluctuation in the overall light intensity, but the intended receiver had a set of binoculars fitted with a spectroscope wherewith to see the neodymium absorption bands flashing on and off.

• 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 color 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 to promote plant growth. Rare earth element compounds are frequently used in China as fertilizer.

• 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.