Alloy powder for rare-earth magnet, methods for manufacturing alloy powder and rare-earth magnet and powder manufacturing device

The invention discloses alloy powder for a rare-earth magnet, methods for manufacturing the alloy powder and the rare-earth magnet and a powder manufacturing device. The method for manufacturing the alloy powder includes acquiring all powder with the grain size smaller than 50 micrometers in working procedures for finely crushing at least one type of alloy for the rare-earth magnet and at least one type of alloy coarse powder for the rare-earth magnet by the aid of high-speed inert gas flow with the oxygen content lower than 1000ppm. By the aid of the alloy powder, the methods and the powder manufacturing device, ultrafine powder with the grain size smaller than 1 micrometer does not need to be separated from crushed powder which is transmitted from a crushing device and has a low oxygen content, the oxygen content of atmosphere of the crushing device is reduced and is lower than 1000ppm when the crushing device is used for crushing, and accordingly abnormal grain growth (AGG) can be prevented in a follow-up sintering procedure for acquiring a sintered magnet with a low oxygen content. The alloy powder, the methods and the powder manufacturing device have the advantages that working procedures can be simplified, and the manufacturing cost can be reduced.