Patent ID: 9005374
Filing Date: 2015-04-14
Classification: B22F,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 V, Mo, Zr, Ta, Ti, W or Nb, 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 magnet powder; performing a dehydrogenation process by applying heat to the calcined body in vacuum atmosphere so that an activity level is decreased with respect to the calcined body activated in the step of calcining the magnet powder; compacting the calcined body after the dehydrogenation process so as to obtain a compact body; and sintering the compact body while applying pressure uniaxially, wherein the permanent magnet is Nd—Fe—B based.