A NEW METHOD FOR THE PREPARATION OF ANISOTROPIC ND-FE-B-BASED MAGNETS

A new hot-forming process has been studied to produce anisotropic Nd-F e-B-based magnets from melt-spun ribbons. The ribbon fragments were in serted in a Cu tube and hot-deformed together with one-stroke. At a he ight reduction ratio of 0.44, the melt-spun ribbons were densified int o a magnet with a density of 7.14 g/cm(3), and showed a (BH)(max) of14 .6 MGOe. With further deformation, the magnets were plastically deform ed with Cu tubes in the lateral direction, and crystallographic anisot ropy was introduced. The magnets with a height reduction ratio of 0.75 exhibited magnetic properties of (BH)(max) = 32.1 MGOe, B-r = 11.7 kG , and H-i(c) = 10.6 kOe. This process shows the possibility that the c onventional hot-pressing and subsequent die-upsetting for anisotropic magnets can be simplified into a one-step process.