Rare-Earth Permanent Magnet (NdFeB)

稀土永磁（钕铁硼）NdFeBAdvanced

A strong magnetic material made mainly of neodymium, iron, and boron, core to robot joint motors.

NdFeB (neodymium-iron-boron) is a permanent-magnet material made primarily of neodymium, iron, and boron, with a main phase of Nd2Fe14B, developed independently in the early 1980s by Japan's Sumitomo Special Metals and America's General Motors; it remains the strongest commercially available permanent magnet today. The permanent magnet synchronous motors, brushless motors, and coreless motors used in robot joints almost all use NdFeB magnets in their rotors, since they deliver more torque for the same size, which directly determines a joint's torque density and power density. Its weakness is that it demagnetizes at high temperature, so heavy rare earths like dysprosium and terbium are commonly added to improve heat tolerance. China holds the majority of the world's rare-earth mining and magnet-processing capacity, and starting in April 2025 imposed export controls on dysprosium, terbium, and some other medium and heavy rare earths and related products, affecting overseas motor supply chains.

Also called: Neodymium Magnet, Neodymium-Iron-Boron
Related: Permanent Magnet Synchronous Motor (PMSM) · Brushless DC Motor · Torque Density · Power Density (W/kg) · Motor Thermal Derating / Overheat Protection · Core Components
Sources: Neodymium magnet - Wikipedia
As of: 2025-04