Cerium. Chances are when you think of the elements in the international spotlight right now for use in rare-earth magnets, the rare-earth element cerium doesn’t come to mind. But in the future, cerium may occupy a rather large seat at the rare-earth magnet table as a substitute for its more famous cousin, neodymium.
Rare earths are of high interest because they are key components, of among other things, the lightweight, permanent magnets that are used in nearly every modern-day electronic device from televisions to cell phones and computer hard drives to electric and hybrid automobile drivetrains to generators in wind turbines. Neodymium is so significant to our nation’s energy future that it is one of five rare earths identified in the Department of Energy’s “Critical Materials Strategy” report as being vital to the nation’s “clean energy economy.”
So you might ask what this has to do with cerium. It turns out that cerium has the potential to be a substitute for neodymium in today’s permanent magnets. This is big not because cerium is a better rare-earth material than neodymium for making permanent magnets, but simply because there’s more of it. Cerium, it seems, is four times more abundant in the earth’s crust than neodymium. Imagine the potential then for cerium, particularly in light of our nation’s growing quest to become energy independent.
In an effort to further rare-earth research in many areas, including cerium as a replacement for neodynium, the federal government last fall introduced the Rare Earth Alternatives in Critical Technologies (REACT) program through the DOE’s Advanced Research Projects Agency-Energy’s (ARPA-E). One of the projects takes advantage of the Ames Laboratory’s scientific expertise in rare earths. As part of a $2.2 million, potentially three-year project (the program is renewed after 18 months) Bill McCallum, an Ames Laboratory metallurgist, has been leading a project researching the use of cerium as a replacement for neodymium in magnets.
The Ames Lab research will look at combining other metallic elements with cerium to create a new powerful magnet with high-temperature stability for electric vehicle motors. Partners in the project are General Motors, NovaTorque and Molycorp Minerals – a “dream team” of worldwide leaders, says McCallum. General Motors will take an active role in alloy development, and along with NovaTorque, will provide the evaluation of the material for traction motors in vehicles. Molycorp, the only U.S. producer of rare-earth materials, will provide the important supply chain and development path for commercialization of these materials.
Ames Laboratory scientist Bill McCallum will
During the past three months, McCallum has been ramping up the Ames Laboratory project by hiring additional scientists and staff.
“We’ve mostly been doing baseline experiments and theoretical calculations,” says McCallum, who adds the current work is helping scientists better understand challenges like the role of the hybridization of cerium electrons, crystal structure, and the symmetry of neighboring atoms. The result, he says, should be a better understanding of the best crystalographic environment for having cerium behave the way in which scientists want it to. In layman’s terms, McCallum says, “We first have to determine what’s wrong with cerium before we can find out how to make it behave.”