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Jeremy Hsu
TechNewsDaily Contributor
LiveScience.com Jeremy Hsu
technewsdaily Contributor
livescience.com Sat Apr 10, 1:55 pm ET
A magnet at the heart of high-tech products such as cell phones and hybrid cars
relies upon an increasingly scarce supply of the rare earth element known as
neodymium. Now one of the original inventors of that magnet hopes to create a
new generation of magnetic materials that can ease or break free of that
dependence.
The neodymium-iron-boron magnet represents the most powerful commercial magnet
available today, and has a starring role in many technologies crucial to the
U.S. economy and defense. But the U.S. overwhelmingly relies upon China for its
supply of neodymium and other rare earth minerals, and China has warned that
its own domestic demand may soon force it to cut off that supply.
That means the U.S. may face a shortage of neodymium and other rare earths,
unless it spends the time and money to begin mining its own fairly untapped
reserves. The possibility of a shortage has also led to renewed research aimed
at developing magnets less dependent upon neodymium.
"It's been 27 or 28 years since the discovery of neodymium-iron-boron
(Nd-Fe-B), and we have not yet found a better magnet," said George
Hadjipanayis, a physicist at the University of Delaware and co-inventor of the
Nd-Fe-B magnet.
Hadjipanayis leads a collaborative research effort with $4.6 million in funding
from ARPA-E, the U.S. Department of Energy's agency that backs high-risk but
potentially high-payoff projects.
Nd-Fe-B magnets have worked well for everything from computer hard drives to
wind turbines and Toyota's Prius because of their exceptional magnetic strength
- the energy product of such magnets can reach 50 million or even 60 million
megagauss-oersteds (MGOe). By comparison, the energy product of the more common
ferrite magnets is just 4 million to 5 million MGOe.
"The higher the strength of the magnet, the smaller the amount of magnet you
need for a particular application," Hadjipanayis told TechNewsDaily. He added
that Nd-Fe-B magnets play a crucial part in building ever-smaller electronic
devices. (Read "The Common Elements of Innovation.")
Three routes to a better magnet
Hadjipanayis and his fellow researchers plan to pursue three different routes
to possibly achieving a next-gen magnet breakthrough.
First, the U.S. Department of Energy's Ames Laboratory in Iowa plans to
investigate new materials based on combinations of rare earths, transition
metal elements and some elements that have not been studied before in magnets.
Many such elements require special working lab conditions under high pressures
or temperatures, and create additional challenges because they have high
reactivity or toxicity.
Second, an approach headed by the University of Nebraska will try to develop a
rare earth-free magnet. This has proven a challenge because existing magnets
without rare earths have much lower magnetic strength, but there are some
theoretical ideas about changing the crystal symmetry of iron-cobalt alloys by
using some non-magnetic elements as substitutes.
Third, Hadjipanayis and the University of Delaware will try to create a new
magnetic material that combines the best properties of Nd-Fe-B and iron. The
material would ideally end up with high magnetization, and also strongly resist
demagnetization.
Simulations have predicted that a next-gen magnet built this way could have a
magnetic strength of more than 100 million MGOe, and might also slash neodymium
use in magnets by 30 or 40 percent.
Feeling the pressure
All efforts to create such magnetic material have faltered over the past few
decades, but Hadjipanayis sees hope in a new bottom-up approach that mixes
nanoparticles of Nd-Fe-B at the incredibly tiny scale of just billionths of a
meter, or far smaller than the width of a human hair.
Other research participants include Northeastern University, Virginia
Commonwealth University and the Electron Energy Corporation - one of the last
U.S. companies making rare-earth magnets.
The group has put together an ambitious timeline that involves two years for
experimenting with materials, before hopefully putting together a new magnet
prototype in the third year.
"It's a fast-moving program, so I already started feeling the pressure,"
Hadjipanayis said. "Hopefully we'll have a breakthrough that leads to some
permanent magnets."