The World’s Strongest Permanent Magnet

In this special episode, we speak to 2022 QEPrize winner, Dr Masato Sagawa, who received the award in recognition for his work in the discovery, development and global commercialisation of the world’s most powerful permanent magnet— the sintered neodymium-iron-boron (Nd-Fe-B) magnet.

Dr Sagawa’s innovation has been transformational in its contribution to multiple applications globally, including: medical imaging; electric vehicles; wind turbines; audio systems; spacecraft; robots and computers.

Sagawa’s breakthrough was the creation of a new compound formed by replacing the scarce and expensive elements used in previous permanent magnets, with more abundant and cheaper elements—iron and neodymium. By introducing boron and dysprosium to improve the magnetic properties and heat resistance, the resulting material was a new high-performance magnet ready for the mass market that almost doubled the performance of the previous best and successfully turned Nd-Fe-B magnets into a viable industrial material with countless applications.

About the guest

Dr Sagawa has a BS and Masters in electrical engineering from Kobe University (1966) in Japan and a doctoral degree in materials science from Tohoku University (1972). He began his career as a research engineer at Fujitsu Ltd, in 1972, working on magnetic materials for electric relays. He worked on the Nd-Fe-B magnet as private research for five years, patenting it in the early 80s, before joining Sumitomo Special Metals Co in 1982.

In 1988 he founded Intermetallics Co. Ltd in Kyoto and became its president. He also founded NDFEB Corporation in 2013 for consultation services. Dr Sagawa is now retired but works as consultant for Daido Steel in order to put his latest new technology - which improves magnetic energy density and reduces the use of dysprosium for the thermal stability part of the process - into industrial production.

Dr Sagawa has received a number of awards for his work including the 2012 Japan Prize for “developing the world’s highest performing Nd-Fe-B type permanent magnet and contributing to energy conservation.” He is also the recipient of the Osaka Prize (1984) and the American Physical Society International Prize for New Materials (1986).

Episode highlights

• “I feel very happy and honoured to have received such a prestigious engineering prize and I have nothing but respect and gratitude.”
• “One happy outcome of the invention of the neodymium magnets was the computer hard drive. Before the invention of neodymium magnets, they weighed 30 kilograms. Now you can carry them in the palm of your hand.”
• “After my PhD, I got a role to try and improve the samarium-cobalt magnet. That was really when I started taking an interest in permanent magnets.”
• “The composition of the neodymium-iron-boron magnet is 31% neodymium, 61% iron, and 1% boron. We came up with this composition after some trial and error. Having come up with this composition, we were able to create the world's number one magnet. We filed for the patent in July 1982.”
• “Neodymium is quite elastic in nature so the resulting magnet has very high durability.”
• “I really like the cycle of making and repeating experiments. I think that was one of the keys that led me to my success. Whatever materials I have at hand, I think about how those materials work inside my head. Once I come to a viable idea, then I try to make samples and measure how they perform.”
• “What we want to do eventually, is to have a magnet used in electric vehicles which has the world's highest performance.”
• “What I would say to the younger engineers is to have a look around you. There are needs within society that are unmet. Find those and try to think of a way to find solutions […] Keep thinking and once you get an idea, experiment and try to realise those goals. There will be a moment when you think ‘I am so happy that I went through the engineering journey and became an engineer’. There is no greater joy in the world.”
• “As the interatomic distances between iron atoms is small, previous magnets didn’t perform well. So I started looking at introducing atoms and elements like carbon and boron between those iron atoms, because they have a small atomic radius. I started performing experiments and was able to discover the compound within a year. It took me another three years of trial and error to come to the correct alloy microstructure.”