High Performance Permanent Magnets for Advanced Motors

There is a high interest in developing advanced motors for hybrid electric vehicles that can provide improved performance at an affordable price. One approach to achieving this goal is to improve the magnetic performance of the permanent magnets used in electric motors, while maintaining a good thermal stability at lower cost. Because variable external magnetic fields in motors cause eddy current losses in magnets, a high resistivity magnet would improve motor efficiency. Therefore, this project will develop high performance permanent magnets with improved BH max at temperatures up to 240 degrees C, reduced eddy current losses, and low cost. Two approaches to enhance magnetic performance will be explored: (1) partial substitution of Sm with Pr, Nd, Y and/or La to increase residual induction; and (2) die-upsetting to develop Sm(Co,Fe,Cu,Zr)z/Nd-Fe-B hybrid magnets, in order to take advantage of the high residual induction of Nd-Fe-B magnets and the superior thermal stability of Sm(Co,Fe,Cu,Zr)z . Magnet cost will be reduced by using light rare earth elements, which are less expensive. Cost reduction will also be addressed by shortening the thermal cycle length through careful tuning of the Sm(Co,Fe,Cu,Zr)z stoichiometry. Different approaches to the production of Sm-Co/ceramic composite magnets ¿ where the ceramics insulate the magnet powder particles and increase electrical resistivity ¿ will be explored. These approaches include blending, co-milling, deposition from solution, and atomization. Commercial Applications and other Benefits as described by the awardee: The technology should lead to a new class of permanent magnets with high magnetic performance, high resistivity, superior thermal stability, and low cost. In addition to DOE applications, markets may exist in the aerospace and military sectors, especially for motor and generator applications.