Patent ID: 9048014
Filing Date: 2015-06-02
Classification: C22C,H01F

Abstract:
1. A manufacturing method of a permanent magnet comprising steps of milling magnet material into magnet powder; adding an organometallic compound expressed with a structural formula of M representing Dy or Tb, R representing a substituent group consisting of a straight-chain or branched-chain hydrocarbon, and calcining the magnet powder of which particle surfaces have got adhesion of the organometallic compound in hydrogen atmosphere so as to obtain a calcined body of which carbon residue is reduced in comparison with before calcining the magnetic powder, wherein the step of calcining causes thermal decomposition of the organometallic compound and removes R so as to reduce carbon residue; performing a dehydrogenation process by applying heat to the calcined body in vacuum atmosphere so that activity level is decreased with respect to the calcined body activated in the step of calcining the magnetic powder; compacting the calcined body after the dehydrogenation process so as to obtain a compact body; and sintering the compact body, wherein carbon residue after sintering is under 0.2 wt %, and wherein, in the step of calcining the magnet powder, the magnet powder is held for a predetermined length of time within a temperature range higher than 600° C. and equal to or lower than 900° C.