METHOD OF PRODUCTION OF MATERIAL FOR ANISOTROPIC MAGNETO-PLASTICS Russian patent published in 2006 - IPC B22F3/12 H01F1/57 

FIELD: powder metallurgy; production of polymer magnetic materials for permanent magnets on base of rare-earth alloys.

SUBSTANCE: proposed method is used for production of magneto-plastic on base of neodymium-iron-boron system at the following content of components, mass-%: neodymium, 27-32; boron, 1-1.5; M, 0.1-1.5; the remainder being iron, where M is zirconium, cobalt, niobium, hafnium, aluminum, indium, gallium, terbium, deuterium, praseodymium, manganese, zinc, uranium. Ingot thus obtained is crushed and is annealed in vacuum furnace for 20-40 h at five stages: at first stage, furnace is evacuated at 25-130°C to residual pressure of P=10^-3 mm Hg, after which hydrogen is fed to pressure of P₁=700-980 mm Hg; at second stage, heating to 750-940°C at rate of 300-400°C/h at P₂=700-980 mm Hg; at third stage isothermal holding is carried out at 750-940°C and P₃=700-980 mm Hg continued for 120-180 min; at fourth stage isothermal holding is carried out for 5-30 min at 750-940°C and P₄=kP₃, where k =0.1-0.05; at fifth stage furnace is evacuated at 750-940°C to pressure P₅=10^-3 mm Hg ensuring growth of anisotropic phase Nd₂Fe₁₄B in form of small crystals and is cooled in vacuum to room temperature at rate of 50-100°C/h. Then, lumps of alloy are ground to obtain powder which is compacted in oriented magnetic field and is sintered.

EFFECT: increased residual induction at retained high coercive force; improved physico-chemical characteristics; facilitated procedure.

2 cl, 1 dwg