Patent ID: 6368551
Filing Date: 2002-04-09
Classification: H01F

Abstract:
A method for preparation of sintered permanent magnets comprising the steps of:mixing fully fine powder of a crystalline mother alloy for permanent magnet containing a rare-earth element, Fe and B as the essential components with fine powder of zinc oxide, compaction molding the resulted mixture in the presence of a magnetic field, sintering the compacted mixture in vacuum to cause generation of oxygen and metallic zinc by thermal decomposition of the zinc oxide; segregation of a part of metallic component in the mother alloy at the boundary and inside of the mother alloy crystal; formation of amorphous metallic oxide by forced oxidation of the segregated metal with the generated oxygen; crystallization of the amorphous metallic oxide; formation of an epitaxial junction between the crystallized metallic oxide and the mother alloy crystal; and evaporation of the metallic zinc into the vacuum, and quenching the sintered compact.