As automakers explore alternative motors, researchers in the U.S. and elsewhere are also trying to devise replacements for rare-earth materials, and political efforts are advancing to boost supplies of rare earths from outside of China.
In the U.S., the Chinese dominance of rare-earth mineral production has prompted a surge of funding focused on developing permanent magnets that use less, if any, rare-earth materials, such as nearly $7 million from the Advanced Research Projects Agency for Energy (ARPA-E). In one of these projects, University of Nebraska researchers are working to enhance permanent magnets made with an alloy iron and cobalt, or FeCo. This class of materials is sold today, but delivers half or less of the power of the best rare-earth-based magnets. The Nebraska researchers will focus on ways to dope the structural matrix of these alloys with traces of other elements, thereby rearranging their molecular geometry to create stronger, more durable permanent magnetic materials.
Working alongside the Nebraska researchers in the same ARPA-E program, researchers at the University of Delaware are advancing nanocomposites that use far less of the valuable rare-earth materials, but that have been shown theoretically to generate magnetic strengths twice as powerful as today’s best permanent magnets. The lab is mixing particles, just 20 to 30 nanometers in size, of rare-earth magnetic materials with a non-rare-earth complement (tin cobalt). Prior efforts to make this material have been unable to precisely align the nanoparticles, diminishing their magnetic performance substantially. Instead of concocting the material in bulk, like mixing batter, the team is developing a process to control the particles’ alignment by assembling them in regular arrays.
GE Global Research, in Niskayuna, New York, is pursuing nanocomposites similar to those being developed in Delaware, also with ARPA-E funding. Using methods developed in-house, the project aims to build a new material through the alignment of nanopowders. “These materials are intrinsically unstable,” so controlling their assembly is at the frontier of nanoscale manufacturing processes, says Luana Iorio, a manager at GE’s High Temperature Alloys and Processing Laboratory, who leads the research. GE estimates its nanocomposites could deliver 35 percent greater magnetic strength than today’s best permanent magnets, while using 40 percent of the rare earths, by volume. Within two years, Iorio hopes, the project will be able to create samples of the new material a few centimeters in diameter.
Yet since it may take years for these efforts to bear fruit, the hunt for non-Chinese sources of the minerals is attracting attention in the near term. In California, Molycorp Minerals is looking to reopen rare-earth mines that closed in 2002, amidst low pricing and environmental concerns. In recent weeks, bills have been floated in the U.S. House and Senate aimed at reviving the rare-earth supply chain in the U.S., including mining, refining, and manufacturing. A third bill, in the House, is narrower, focusing on offering loan guarantees to restart mining.