METHOD FOR PRODUCING SINTERED RARE-EARTH MAGNETS FROM SECONDARY RAW MATERIALS Russian patent published in 2022 - IPC C22C1/05 H01F1/57 B22F3/16 

FIELD: metallurgy.

SUBSTANCE: invention relates to powder metallurgy, particularly, to production of sintered rare-earth permanent magnets based on Nd-Fe-B system from secondary raw materials. Powder of magnetic material from secondary raw material based on permanent magnets of Nd-Fe-B system is demagnetised in vacuum furnace and subjected to hydrogenation with provision of surface cleaning and preliminary grinding to 350 mcm. Powder of magnetic material is mixed with additives in form of hydrides of rare-earth metals or alloys on their basis and subjected to grinding in ball vibration mill in medium of acetone with obtaining of initial mixture of fine powders with particle size of 3.5–4 mcm. Then, perpendicular pressing is performed in magnetic field to produce billet, sintering and heat treatment.

EFFECT: reduced number of process steps and possibility of controlling hysteresis characteristics.

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