Neodymium magnet
[7][8] General Motors (GM) and Sumitomo Special Metals independently discovered the Nd2Fe14B compound almost simultaneously in 1984.
[3] The research was initially driven by the high raw materials cost of samarium-cobalt permanent magnets (SmCo), which had been developed earlier.
The Sumitomo facility became part of Hitachi, and has manufactured but also licensed other companies to produce sintered Nd2Fe14B magnets.
[9] Chinese manufacturers have become a dominant force in neodymium magnet production, based on their control of much of the world's rare-earth mines.
[10] The United States Department of Energy has identified a need to find substitutes for rare-earth metals in permanent magnet technology and has funded such research.
[11] Because of its role in permanent magnets used for wind turbines, it has been argued that neodymium will be one of the main objects of geopolitical competition in a world running on renewable energy.
This perspective has been criticized for failing to recognize that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production.
[3] The diamagnetic boron atoms do not contribute directly to the magnetism but improve cohesion by strong covalent bonding.
This vulnerability is addressed in many commercial products by adding a protective coating to prevent exposure to the atmosphere.
[18] Neodymium has a negative coefficient, meaning the coercivity along with the magnetic energy density (BHmax) decreases as temperature increases.
This fall in coercivity limits the efficiency of the magnet under high-temperature conditions, such as in wind turbines and hybrid vehicle motors.
Dysprosium (Dy) or terbium (Tb) is added to curb the fall in performance from temperature changes.
The first letter N before the values is short for neodymium, meaning sintered NdFeB magnets.
[26][27] In 2015, Nitto Denko of Japan announced their development of a new method of sintering neodymium magnet material.
The method exploits an "organic/inorganic hybrid technology" to form a clay-like mixture that can be fashioned into various shapes for sintering.
[34] They are the main metal in the formerly popular desk-toy magnets, "Buckyballs" and "Buckycubes", though some U.S. retailers have chosen not to sell them because of child-safety concerns,[35] and they have been banned in Canada for the same reason.
[40] They have also been implanted in the fingertips in order to provide sensory perception of magnetic fields,[41] though this is an experimental procedure only popular among biohackers and grinders.
