Scientist Arjun Pathak. Source: AMES
A team at the U.S. Department of Energy’s AMES Laboratory, led by Arjun Pathak and Mahmud Khan, discovered that an alloy comprised of neodymium, iron and boron co-doped with cobalt and cerium is cheaper than dysprosium and functions similarly to magnets made with the rare-earth element.
The alloy’s intrinsic coercivity (its ability to resist demagnitization) is higher at elevated temperatures compared to dysprosium magnets. Furthermore, the materials used in the researcher’s magnet are up to 40 percent cheaper than those containing the rare-earth element.
“This is quite [an] exciting result; we found that this material works better than anything out there at temperatures above 150° C,” said researcher Karl A. Gschneidner. “It’s an important consideration for high-temperature applications.”
Issues with using cerium
Up until now, scientists and engineers have largely been unsuccessful at using cerium in rare-earth magnets. The main reason is that cerium tends to reduce the Curie temperature (the temperature that leads an alloy’s permanent magnetic properties to shift). However, the AMES researchers found that co-doping cerium with cobalt maintained those properties and allowed the team to replace dysprosium.
The group’s findings were recently published in the journal Advanced Materials, in an article titled “Cerium: An Unlikely Replacement of Dysprosium in High Performance Nd-Fe-B Permanent Magnets.”
There is a lot of work to be done before the magnet can hit the market. Still, this finding is significant for the automotive industry, which has been reliant on dysprosium-containing magnets for decades.
For more information, visit the AMES Laboratory website.