March 27, 2023

Researchers are finding substitutes for rare earth metals in magnets

Researchers at the University of Cambridge, in collaboration with Austrian colleagues, report that tetrathenite, a “cosmic magnet” that takes millions of years to develop naturally in meteorites, could potentially be used as a replacement for rare earth metals in magnets.

Previous attempts to make tetrathenite in the lab have depended on extreme and impractical methods, but researchers say they have found a way to bypass these previous techniques by using phosphorus. In a research paper published in the journal Advanced scienceThey suggest that it is possible to produce tetrataenite artificially and on a large scale without special processing or expensive techniques.

“Rare earth” is a misleading term that is something of an inside joke among organic chemistry enthusiasts. It refers to a group of elements in the periodic table. “Noble gases” is another term that has little meaning except to organic chemists. In reality, “rare earths” aren’t very rare in the grand scheme of things, but separating and purifying them is a challenge.

Rare earth metals and permanent magnets

The real reason this news is important is that rare earth materials are critical in the manufacture of permanent magnets, an integral part of the electric motors on which the transition to a zero-emissions economy depends.

The problem is that China controls more than 80 percent of the global rare earth market because it controls so many of the manufacturing processes for electric vehicles, solar panels, and other critical technologies needed to tackle a overheating planet.

We know the danger of allowing the tyrants of Saudi Arabia and Russia to control our access to fossil fuels. This experience suggests that letting China be the gatekeeper for the new technologies we need to move away from fossil fuels may be just as dangerous in the future.

Professor Lindsay Greer from the University of Cambridge’s Department of Materials Science and Metallurgy explains Innovation News NetworkThere are deposits of rare earths elsewhere, but mining is very disruptive because you have to mine a huge amount of material to get a small amount of rare earths. Between the environmental impacts and the strong dependence on China, there has been an urgent search for alternative materials that do not require rare earth metals.

One of the most promising alternatives for permanent magnets is tetrathenite, an iron-nickel alloy with an ordered atomic structure. The substance is formed over millions of years as the meteorite slowly cools. This gives the iron and nickel atoms enough time to arrange themselves into a specific stacking order within the crystal structure, resulting in a material with magnetic properties similar to those of rare earth magnets.

In the 1960s, tetrathenite was artificially formed by blasting iron-nickel alloys with neutrons, allowing the atoms to form the desired order. However, this technology is not suitable for mass production. “Since then, scientists have been interested in getting that ordered structure, but it’s always seemed like something that was very far away,” says Greer.

Over the years, many researchers have tried to produce tetrathenite on an industrial scale, but the results have been disappointing. Now, Greer and his colleagues at the Austrian Academy of Sciences and Montanuniversität in Leoben have found a possible alternative that avoids these extreme methods.

Let’s take a closer look

The team studied the mechanical properties of iron-nickel alloys containing small amounts of phosphorus found in meteorites. Inside these materials was a phase pattern that showed the expected tree-like growth structure called dendrites.

“For most people, it would have ended here: there was nothing interesting to see in the dendrites, but when I looked more closely, I saw an interesting diffraction pattern that shows an ordered atomic structure,” said first author Dr. Yuri Ivanov, who graduated during the work. in Cambridge and now works at the Italian Institute of Technology in Genoa.

At first, the diffraction pattern of tetrataenite looks like the structure expected for iron-nickel alloys, namely a disordered crystal that is of no interest to high-performance magnets. But when Ivanov looked more closely, he recognized tetrathenite.

According to the team, phosphorus allows iron and nickel atoms to move faster, allowing them to form the necessary ordered stack without waiting millions of years. They were able to speed up tetrathenite formation by 11 to 15 orders of magnitude by mixing iron, nickel, and phosphorus in the right amounts. This meant that the material could be formed in seconds in a simple casting.

“It was so amazing that no special treatment was needed. We just melted the alloy, poured it into a mold, and we had tetrataenite,” Greer says. formation would have to wait millions of years. This result represents a complete change in the way we think about this material.”

Although the research is promising, more work is needed to determine whether it is suitable for high-performance magnets. The team hopes to work with major magnet manufacturers to figure this out.


Why do we write about topics that are not yet in the laboratory stage? Because the breakthroughs taking place in laboratories around the world today are decisive in moving away from the burning of fossil fuels as the basis of the global economy and human existence.

New types of batteries that are lighter, more efficient, faster charging, cheaper and more environmentally friendly are being researched in hundreds of laboratories around the world as you read this. We don’t know where the breakthroughs will happen, but we know they will come, just as the first fuel oil and diesel engines became the highly sophisticated machines that power hundreds of millions of vehicles today.

There are electric motors that do not rely on permanent magnets, but they are generally more expensive than permanent magnet motors. If there is a way to duplicate their performance with inexpensive materials that are readily available to all manufacturers without any one country controlling the supply chain, that’s good news for us all.

The likelihood is that by 2030 electric cars will have taken a big leap forward as more and more new innovations become commercially available. We can’t wait!

Featured image: Tetrataenite by Rob Lavinsky (CC BY-SA 3.0)

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