Preparation of SmCo5 Permanent Magnets

The technology of making SmCo5 magnets with energy products of 20 × 106 GOe is described. This technology consists of the preparation of a powder by grinding, aligning the powder particles in a magnetic field, and cold pressing by applying a uniaxial deformation at 20 kbar. The permanent magnetic properties of the SmCo5 powders are shown to vary appreciably with various applied chemical treatments and with the composition of the alloy. The intrinsic coercive force appears to decrease with time but remains so large that the demagnetization of the induction is hardly affected. Some properties of the magnets are discussed.