Neodymium magnet

The neodymium-iron-boron (NdFeB) permanent magnet emerged from one of technology's great races: General Motors in the United States and Sumitomo Special Metals in Japan independently conceived the same breakthrough in late 1982, worked in secret, and surprised each other by announcing their results at the same Pittsburgh conference in 1983. The resulting magnets became the strongest permanent magnets ever made, enabling everything from electric vehicle motors to wind turbines to the miniaturized speakers in smartphones.

The adjacent possible opened through the economics of rare earth elements. Samarium-cobalt magnets, developed in the 1970s, were the strongest permanent magnets available but depended on expensive cobalt. Researchers at both GM and Sumitomo sought alternatives using more abundant rare earth elements. The breakthrough came when both teams discovered that neodymium, iron, and boron could form an intermetallic phase (Nd2Fe14B) with extraordinary magnetic properties.

John Croat at General Motors and Masato Sagawa at Sumitomo followed completely different routes to the same discovery. GM's approach grew from attempts to produce metastable compounds from rapidly solidified rare earth-iron materials. Sumitomo's discovery emerged from systematic searches for ternary compounds using powder metallurgy processes originally developed for samarium-cobalt magnets. Both teams filed patents in early 1982, apparently within weeks of each other.

The convergent emergence was striking. Neither team knew of the other's work until the 1983 Pittsburgh conference, when both Sagawa and Croat presented their findings. The magnetic community was astonished: the strongest permanent magnets ever discovered had been invented twice, independently, at nearly the same moment.

General Motors commercialized through Magnequench (founded 1986), focusing on melt-spun nanocrystalline magnets. Sumitomo developed sintered magnets through a different manufacturing process. The two approaches served different applications, with sintered magnets dominating high-performance uses.

The cascade from NdFeB magnets reshaped modern technology. Computer hard drives used NdFeB magnets in their read/write heads and voice coils. Electric vehicle motors became practical because NdFeB magnets provided the power density needed for automotive applications. Wind turbine generators adopted NdFeB permanent magnets for direct-drive designs. Every smartphone contains NdFeB magnets in speakers, vibration motors, and sensors.

In 2022, IEEE honored Sagawa and Croat with its Medal for Environmental and Safety Technologies, recognizing that their magnets had become essential infrastructure for renewable energy and electric transportation. The material discovered independently in Michigan and Japan in 1982 had become indispensable to the energy transition.