Researchers from the University of Cambridge, together with Austrian colleagues, report that tetrataenite, a ‘cosmic magnet’ that takes millions of years to grow naturally in meteorites, can potentially be used instead of land rare in magnets.
Previously, attempts to make tetrataenite in the lab depended on extreme and impractical methods, but researchers say they have found a way around these earlier techniques by using phosphorus. In a research article published in the journal Advanced sciencesthey suggest that there is a possibility of producing tetrataenite artificially and on a large scale without any specialized processing or expensive techniques.
“Rare Earth” is a misleading term that is kind of a joke among organic chemistry aficionados. 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 truth, “rare earth” elements are not that rare in the grand scheme of things, but extracting and purifying them is a challenge.
Rare earth materials and permanent magnets
The real reason this news matters is that rare-earth materials are essential to making the permanent magnets that are a critical component of electric motors on which the transition to a zero-emissions economy depends.
The sticking point is that China, with its predilection for dominating so many manufacturing processes for electric vehicles, solar panels and other critical technologies needed to cope with an overheated planet, controls more than 80% of the global market. rare earth elements.
We know the danger of letting tyrants in Saudi Arabia and Russia control our access to fossil fuels. This experience suggests that letting China be the guardian of the new technologies we need to shift our dependence on fossil fuels could be just as dangerous in the future.
Professor Lindsay Greer from the Department of Materials Science and Metallurgy at the University of Cambridge tells Innovation News Network, “Rare earth deposits exist elsewhere, but mining operations are very disruptive, because you have to extract a huge amount of material to obtain a small volume of rare earths. Between the environmental impacts and the heavy reliance on China, there has been an urgent search for alternative materials that do not require rare earths.
One of the most promising alternatives for permanent magnets is tetrataenite, an iron-nickel alloy with an ordered atomic structure. The material forms over millions of years as a meteorite slowly cools. This gives the iron and nickel atoms enough time to order themselves into a particular stacking sequence within the crystal structure, resulting in a material with magnetic properties similar to those of rare-earth magnets.
In the 1960s, tetrataenite was artificially formed by blasting iron-nickel alloys with neutrons, which allowed the atoms to form the desired ordered packing. However, this technique is unsuitable for mass production. “Since then, scientists have been fascinated with getting this orderly structure, but it always seemed like something very far off,” Greer says.
Over the years, many scientists have attempted to manufacture tetrataenite on an industrial scale, but the results have been disappointing. Now Greer and his colleagues at the Austrian Academy of Sciences and Montanuniversität Leoben have found a potential alternative that avoids these extreme methods.
To look closer
The team studied the mechanical properties of iron-nickel alloys containing small amounts of phosphorus, present in meteorites. Inside these materials was a pattern of phases that indicated the expected tree-like growth structure called dendrites.
“For most people it would have ended there: nothing interesting to see in the dendrites, but when I looked closer I saw an interesting diffraction pattern indicating an ordered atomic structure,” said said first author Dr Yurii Ivanov, who completed the work while at Cambridge and is now based at the Italian Institute of Technology in Genoa.
Initially, the diffraction pattern of tetrataenite resembles the structure expected for iron-nickel alloys, namely a disordered crystal of no interest as a high-performance magnet. But when Ivanov looked closer, he identified tetrataenite.
According to the team, phosphorus allows iron and nickel atoms to move faster, allowing them to form the necessary ordered packing without waiting millions of years. They were able to accelerate the formation of tetrataenite by 11 to 15 orders of magnitude by mixing iron, nickel and phosphorus in the right amounts. This meant the material could form in seconds in a single pour.
“What was so amazing was that no special treatment was needed. We just melted the alloy, poured it into a mold and we had tetrataenite,” says Greer. Previous opinion in the field was that you couldn’t get tetrataenite unless you did something extreme, because otherwise it would have to wait millions of years for it to form. the way we think about this material.
Although the research is promising, more work is needed to decide if it will be suitable for high performance magnets. The team hopes to work with major magnet manufacturers to determine this.
Takeaway meals
Why do we write about subjects that have not yet come out of the laboratory stage? Because the breakthroughs happening in labs around the world today will be critical to transitioning fossil fuel combustion as the basis of the global economy and human existence.
New types of batteries that are lighter, more powerful, faster to charge, cheaper, and more environmentally friendly are being researched in hundreds of labs around the world as you read this. We don’t know where the breakthroughs will happen, but we know they will come, just as those early crude gasoline and diesel internal combustion engines became the ultra-sophisticated machines that power hundreds of millions of vehicles today.
There are electric motors that do not rely on permanent magnets, but in general they are 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 one country dominating the supply chain, that’s good news for all of us.
Chances are that by 2030, electric cars will have taken a leap forward as more and more new innovations become available in the market. We can’t wait!
The featured image: Tetrataenite, by Rob Lavinsky (CC BY-SA 3.0)
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