Study On The Copper Mold Suction Casting Nd₂Fe₁₄B/Fe₃B Type Nanocomposite Magnets

In this paper, the bulk alloy of the middle content of B elements of Nd₉Fe_83-xTi₄C₄B_x（x=10¹5） were prepared by copper mold suction casting. We analysed the effect of the content ofB elements and the annealing conditions on the phase composition, microstructure and magneticproperties by XRD, SEM, VSM and PPMS.The results showed that: the phases of the copper mold suction casting Nd₉Fe_83-xTi₄C₄B_x（x=10¹5） alloy with the thickness of0.5¹.2mm mainly included Nd₂Fe₁₄B, α–Fe, Fe₃B,unknown phase and a small amount of TiC phase and metastable phase Nd_1.1Fe₄B₄. In themicrostructure of these samples, there was a part of the crystalline grains adhering together, thisphenomenon made the magnetic properties bad;Besides, there was a small amount amorphousphases in Nd₉Fe₆₈Ti₄C₄B₁₅alloy. As-cast Nd₉Fe_83-xTi₄C₄B_x（x=10¹5） alloy showed the hardmagnetic properties, the B content of13at%of Nd₉Fe₇₀Ti₄C₄B₁₃had the best magnetic properties:the maximum magnetic energy was6.005kJ/m³, the coercive force was28.572kA/m, theremanence was0.435T.The Nd₉Fe_83-xTi₄C₄B_x（x=10¹5） alloy with the thickness of0.5¹.2mm through the differentannealing showed: The magnetic properties of Nd₉Fe₇₃Ti₄C₄B10magnet after annealing wasdecreased slightly. the best annealing for alloy of Nd₉Fe_83-xTi₄C₄B_x（x=10¹4） was600℃for5min,but the best annealing for the alloy of Nd₉Fe₆₈Ti₄C₄B₁₅magnet was670℃for10min. TheNd₉Fe71Ti₄C₄B12magnet with the thickness about0.5mm showed the the best magnetic propertiesafter600℃for5min annealing treatment: the maximum magnetic energywas11.827kJ/m³, thecoercive force was98.119kA/m, the remanence was0.417T. The Nd₉Fe₆₈Ti₄C₄B₁₅magnet withthe thickness about0.6mm showed the the best magnetic properties after670℃for10minannealing treatment: the maximum magnetic energy was5.411kJ/m³, the coercive force was74.166kA/m, the remanence was0.299T.In this paper, we compared the copper mold suction casting Nd₉Fe_83-xTi₄C₄B_x（x=10¹5）alloy with the copper mold suction Nd₆Fe_58.8Co₁₀Zr_1.6C_1.6B₂₂alloy. We also studied the magneticproperties of Nd₆Fe_58.8Co₁₀Zr_1.6C_1.6B₂₂alloy with600℃for5min and670℃for10min annealingtreatment. The results showed that: The Nd₆Fe_58.8Co₁₀Zr_1.6C_1.6B₂₂alloy after600℃for5min and670℃for10min annealing treatment showed the hard magnetic properties, but its value was very low.The magnetic properties which obtained by600℃for5min annealing treatment was better thanthat obtained by670℃for10min, its valuewas the maximum magnetic energy of0.581kJ/m³, thecoercive force of17.905kA/m, the remanence of0.127T.