METHOD TO PRODUCE IRON-RARE EARTH METALS-BORON ANISOTROPIC PERMANENT MAGNETIC SYSTEMS Russian patent published in 1994 - IPC

FIELD: mechanical engineering, aeronautics, electronics. SUBSTANCE: magnet ingot of iron- rare earth metals-boron produced by directed crystallization if covered with a shell, in particular, of non-magnetic materials of 0Cr18Ni10Ti alloy type. Workpiece is rolled for several runs at temperature of about 1000 C. First the rolling starts in the direction being perpendicular to one of crystals arrangement, and then in the direction being parallel to crystals arrangement. Strain pattern for the last stage is the same as for the first stage. The process is run up to achievement of 60 - 95 per cent of total strain degree. Then the workpiece is subjected to thermal treatment at 1000± 5 C during 24 h, and cooled in permanent magnetic field of 10 kOe with 10 to 20 C/min speed in 400 - 200 C interval. Properties of the magnet: H_c≥ 12 кOe, В_g= 1,1-1,2 T, (BН)_max= 35-40 MGs·Oe, 4.0 - 3.5 magnetic anisotropy coefficient. EFFECT: permanent magnets of improved properties. 4 cl