Neodymium is the protagonist of the modern permanent-magnet industry; without it, today's compact high-torque magnetic motors would not exist. The neodymium-iron-boron magnet (Nd2Fe14B), introduced in 1983, is the highest-energy-product practical permanent-magnet material currently available. Cut into thin strips and bonded onto a motor rotor, it delivers large torque from very small volume and weight, which is why it is so widely used in electric-vehicle traction motors, wind-turbine generators, hard-disk voice-coil motors, phone vibration motors, headphone speakers, and all kinds of servo motors. The neodymium ion is also one of the most classic active ions in solid-state lasers: neodymium-doped yttrium aluminum garnet (Nd:YAG) emits near-infrared light at 1064 nm and is widely used in industrial marking and cutting, ophthalmic surgery, laser ranging, and military target designation. In the glass industry, neodymium oxide acts as a colorant that makes glass shift in hue from purplish-red to blue-violet under different light sources, and is used in imitation-gemstone glass and special color filters; paired with praseodymium, the resulting Pr-Nd glass remains the standard lens material for welding goggles.
Nd2O3 (neodymium(III) oxide) is the most important industrial oxide of neodymium. It is a pale blue-violet powder and one of the direct raw materials for NdFeB magnets, with the bulk of worldwide neodymium oxide output going to magnet makers; it is also the dopant feedstock for laser crystals and laser glasses, and serves as a colorant for glass and ceramics as well as an additive in capacitors. NdCl3 (neodymium trichloride) is an intermediate in the rare-earth extraction and separation flowsheet, yielding neodymium metal or Pr-Nd metal via molten-salt electrolysis; it is not a terminal material in its own right. Strictly speaking, NdFeB is the intermetallic compound Nd2Fe14B, which combines the high magnetocrystalline anisotropy of neodymium with the high saturation magnetization of iron—the fundamental reason neodymium became a strategic metal. Industrially, to raise its high-temperature coercivity, dysprosium or terbium is additionally incorporated, and after the magnet is formed it is electroplated with nickel or zinc to prevent corrosion.
