METHOD OF PREPARING MANGANESE-BISMUTH ALLOY NANOPARTICLE, MnBi NANOPARTICLE AND HARD MAGNET CONTAINING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a wet synthesis method for producing MnBi nanoparticle having a particle diameter of less than 20 nm and a low temperature phase MnBi nanoparticle having a particle diameter of less than 20 nm.SOLUTION: There is provided a method of producing magnetic MnBi powder for obtaining MnBi nanoparticle suitable as a permanent magnet material by annealing a MnBi nanoparticle at 550 to 600K in a magnetic field of 0 to 3 TB, the MnBi nanoparticle being prepared by a method comprising a step of treating Mn powder with a hydride reductant in an ether solvent with agitation, a step of adding a solution of bismuth salt of long chain carboxylate to a Mn- hydride reductant mixture while continuing agitation, a step of adding organic amine while continuing agitation after completion of addition of the bismuth salt solution and a step of continuing agitation to form aggregated MnBi nanoparticle.