New magnetizing procedure for bonded-magnets with enhanced surface flux density

It has been widely recognized that Nd-Fe-B sintered permanent magnets are indispensable for highly efficient electromagnetic devices as well as mechanic devices, which are electric motors, tape recorders and undulators at synchrotron radiation facilities. On the other hand, due to downsizing of such the devices, the demand for small and multiplex magnets rapidly increases in recent years. To overcome the issues, Nd bonded-magnets are considered one candidate, due to not only the cost efficiency but also the advantages in molding small and multiplex magnets. However, our previous report revealed that the bonded-magnets still have the essential issues that the flux density (B) is much smaller than that for the Nd-Fe-B sintered conventional magnets. Therefore, we have focused on enhancing the B of the bonded-magnets by Halbach-type magnet arrangement, and have achieved the improvement up to the B of Nd-Fe-B sintered magnets, which was the target value for our development. However, such the Halbach arrayed magnet involves essential difficulties in the production, so that we investigated the alternative technology to enhance the B by means of magnetizing procedures.