Neodymium Iron Boron
Properties
| State | Solid (sintered or bonded ceramic-metallic) |
| Color | Metallic gray (dark after protective coating) |
| Solubility | Insoluble in water; slowly oxidizes in humid air |
| Melting Point | 1185 °C (decomposes to other phases before melting) |
About Neodymium Iron Boron
Nd2Fe14B (1081.125 g/mol) is the hard magnetic intermetallic that holds the highest room-temperature maximum energy product of any commercial permanent magnet — up to 64 MGOe (512 kJ/m³) in the highest-grade N52 sintered material — and that single property explains why every electric vehicle, every offshore wind turbine, and every hard disk drive on the planet contains some of it. The compound was discovered independently in 1984 by Masato Sagawa at Sumitomo Special Metals (sintered route) and John Croat at General Motors (melt-spun route), and the patent fight that followed shaped the magnet industry for two decades. The crystal structure is tetragonal P4₂/mnm with Nd and Fe atoms layered along the c-axis and boron sitting in the basal plane — the geometry creates an enormous magnetocrystalline anisotropy with the easy magnetization axis locked along c, which is what produces the high coercivity. Saturation magnetization comes from the Fe sublattice (Js around 1.6 T at room temperature), the Curie temperature is 312 °C — workable but the limiting factor in motor design — and the coercivity in finished magnets reaches about 1 T. Annual global production now exceeds 200,000 tonnes, with China holding roughly 90% of that capacity. A single Tesla Model 3 rear motor uses about 2 kg of NdFeB; a 6 MW offshore direct-drive wind turbine uses up to 4 tonnes per nacelle.
Where you'll encounter it
If you've ever pried a small silver disk magnet off the back of a hard drive or cracked open a pair of Bluetooth earbuds to find the tiny driver magnet, you've handled NdFeB. They are the magnets that snap dangerously hard onto each other — the 50 mm cube grade can develop pinch forces high enough to break fingers, which is why anyone who has worked in a magnet lab has war stories about K&J Magnetics demos gone wrong. In the EV world, anyone teardown-ing a Tesla Model 3 or BYD motor stator finds them embedded as buried magnets in the rotor lamination stack. In the wind sector, a single direct-drive nacelle from Goldwind or Siemens Gamesa needs a couple of tonnes of NdFeB sintered into curved arc segments. And in any consumer electronics teardown, the speaker driver, the haptic vibration motor, and the camera autofocus actuator are all NdFeB.
Common Uses
- Permanent-magnet rotors in EV traction motors (Tesla, BYD, Hyundai)
- Direct-drive generators in offshore wind turbines (Goldwind, Siemens Gamesa)
- Voice-coil actuators and spindle motors in 3.5" and 2.5" hard disk drives
- Driver magnets in earbud speakers, haptic vibration motors, and lens autofocus
- Magnetic couplings for sealed-shaft pumps in chemical and pharma processing
- MRI gradient and shim assemblies in 1.5 T and 3 T clinical scanners
- Industrial servo motors for robotic arms and CNC machine-tool spindles
Safety Information
Not classified for acute chemical toxicity (GHS). The hazards are mechanical and biological. Magnets above about 25 mm develop pinch forces that can crush fingers, shatter on impact (the material is brittle and chips at high speed), and slam into ferromagnetic tools across a benchtop without warning. Keep at least 30 cm from pacemakers, ICDs, and insulin pumps; small disk magnets swallowed by children cause bowel necrosis when two pieces attract through tissue and have killed multiple toddlers. Uncoated NdFeB oxidizes in humid air — commercial magnets are Ni-Cu-Ni triple-plated or epoxy-coated. Do not heat above 150 °C without checking the grade's working temperature limit; above 312 °C the Curie point is exceeded and magnetization is lost permanently. Wear cut-resistant gloves and safety glasses when handling stacks above 1 kg.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals. We deliberately do not publish occupational exposure limits or other regulatory thresholds: those values are revised over time and differ between jurisdictions, so the only correct source is the current SDS and the regulations that apply where you work.