PrFe and NdFebased Materials: A New Class of High Performance Permanent Magnets

We report the properties of a new class of high performance permanent magnets prepared from NdFe B and PrFeB alloys. Magnetic hardening is achieved by rapid solidification. Energy products of these isotropic materials can exceed 14 MGOe with intrinsic coercivi ties of ~15 kOe. Xray and microstructural analyses indi cate that the alloys exhibiting optimum characteristics are comprised of roughly spherical crystallites, strongly suggesting that the coercivity mechanism is of the singledomain particle type. The crystallites are com posed of an equilibrium RFeB intermetallic phase hav ing tetragonal symmetry, and the stability of this phase with respect to other rare earths and other metalloids has been investigated