NdFeB sintered magnet production method and production device, and NdFeB sintered magnet produced with said production method

Abstract

Disclosed are a production method and production device for producing a thin-shaped NdFeB sintered magnet with superior magnetic properties, particularly coercive force and degree of orientation, and an NdFeB sintered magnet produced with said production method and production device. The NdFeB sintered magnet production device is provided with a filling unit (1) that supplies an alloy powder (11) comprising a prescribed amount of Dy to molds (10) and fills the powder to a density in the range of 3.0 to 4.2 g/cm3, an orienting unit (3) that orients the molds (10) filled with the alloy powder (11) in a magnetic field, a sintering furnace (not shown) that with each mold (10) sinters the alloy powder (11) within the molds (10) that have been oriented by the orienting unit (3), and a conveying unit that comprises a belt conveyor and a manipulator (not shown) and conveys the molds (10); to each unit and the sintering furnace. The production device is also provided with coils for thermal orientation (20) that reduce the coercive force of each particle in the alloy powder (11) by heating the alloy powder (11) filled within the molds (10) before and/or after applying the magnetic field in the orienting unit (3).

Description

technical field [0001] The present invention relates to a manufacturing method and manufacturing apparatus for manufacturing a thin NdFeB-based sintered magnet excellent in magnetic properties, especially coercive force and degree of orientation, and a NdFeB-based sintered magnet manufactured by the manufacturing method. Background technique [0002] The sintered magnet of the NdFeB (neodymium iron boron) system was discovered by Sagawa (the inventor of the present application) and others in 1982. (a type of rare earth), iron and boron such as relatively abundant and cheap raw materials to manufacture. Therefore, NdFeB-based sintered magnets are used in voice coil motors such as hard disks, driving motors for hybrid vehicles or electric vehicles, battery-backed bicycle motors, industrial motors, high-end speakers, headphones, and permanent magnet magnetic resonance diagnostics. devices and other products. [0003] As methods for producing NdFeB-based sintered magnets, thre...

AI Technical Summary

Problems solved by technology

However, the chips generated in the cutting process cannot be reused as magnets, which reduces the utilization efficiency of materials and increases the production cost.

In addition, the mechanical damage caused by cutting makes the squareness of the demagnetization curve (H K / H CJ ) and other problems of magnetic property degradation also exist

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