Cheaper magnetic material for cars, wind turbines

Washington: Scientists, including one of Indian-origin, have created a new magnetic alloy that could be an inexpensive alternative to high-performance permanent magnets found in automobile engines and wind turbines.

The new alloy eliminates the use of one of the scarcest and costliest rare earth elements, dysprosium, and instead uses cerium, the most abundant rare earth.

The result, an alloy of neodymium, iron and boron co-doped with cerium and cobalt, is a less expensive material with properties that are competitive with traditional sintered magnets containing dysprosium, the study noted.

The materials are at least 20 to 40 percent cheaper than the dysprosium-containing magnets according to the scientists.

Arjun Pathak and fellow scientists at the US Department of Energy's Ames Laboratory demonstrated that the cerium-containing alloy's intrinsic coercivity -- the ability of a magnetic material to resist demagnetisation -- far exceeds that of dysprosium-containing magnets at high temperatures.

"This is quite exciting result, we found that this material works better than anything out there at temperatures above 150 degrees celsius," said one of the researchers Karl Gschneidner and fellow scientists at the U.S. Department of Energy's Ames Laboratory.

"It is an important consideration for high-temperature applications," Gschneidner noted.

Previous attempts to use cerium in rare-earth magnets failed because it reduces the Curie temperature -- the temperature above which an alloy loses its permanent magnet properties.

But the research team discovered that co-doping with cobalt allowed them to substitute cerium for dysprosium without losing desired magnetic properties.

Finding a comparable substitute material is key to reducing manufacturing reliance on dysprosium; the current demand for it far outpaces mining and recycling sources for it, said the study published in the journal Advanced Materials.