Microstructure and magnetic properties of hot-deformed anisotropic Nd–Fe–B magnets prepared from amorphous precursors with different crystallization proportions  

作　　者：Wei Zhao Ying Liu Jun Li Ren-Quan Wang Yu-Chong Qiu 

机构地区：[1]School of Materials Science and Engineering, Sichuan University [2]Key Laboratory of Advanced Special Material and Technology,Ministry of Education

出　　处：《Rare Metals》2017年第4期268-276,共9页稀有金属（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51171122);the Sichuan Province Science and Technology Support Program (Nos. 2014GZ0090 and 2016GZ0262)

摘　　要：Anisotropic magnets were obtained by hot deformation with the partial crystallized precursor prepared via spark-plasma sintering （SPS）. Amorphous powders with the nominal composition of Nd_28.72Fe_balCo_5.66 Ga_0.59B_0.92 （wt%） were used as the starting material. The results show that the amorphous powders would suffer varying degrees of crystallization even below the crystal- lization point during the SPS process under high pressure. And the pre-crystallized grains in precursors have great impacts on the microstructure and magnetic properties of the hot-deformed magnets. The final obtained anisotropic magnets exhibit homogeneous microstructure consisting of well-aligned and platelet-shaped Nd_2Fe_14B grains without abnormal growth. It can be found that a reasonable pro- portion of pre-crystallized gains could promote the pref- erential orientation in the magnet, leading to the achievement of optimal magnetic properties among the magnets with identical composition and best magnetic performance is achieved in the magnet hot deformed from the 490 ℃ high-pressure hot-pressed precursor.Anisotropic magnets were obtained by hot deformation with the partial crystallized precursor prepared via spark-plasma sintering （SPS）. Amorphous powders with the nominal composition of Nd_28.72Fe_balCo_5.66 Ga_0.59B_0.92 （wt%） were used as the starting material. The results show that the amorphous powders would suffer varying degrees of crystallization even below the crystal- lization point during the SPS process under high pressure. And the pre-crystallized grains in precursors have great impacts on the microstructure and magnetic properties of the hot-deformed magnets. The final obtained anisotropic magnets exhibit homogeneous microstructure consisting of well-aligned and platelet-shaped Nd_2Fe_14B grains without abnormal growth. It can be found that a reasonable pro- portion of pre-crystallized gains could promote the pref- erential orientation in the magnet, leading to the achievement of optimal magnetic properties among the magnets with identical composition and best magnetic performance is achieved in the magnet hot deformed from the 490 ℃ high-pressure hot-pressed precursor.

关 键 词：Nd-Fe-B magnets Amorphous precursors Pre-crystallized grains Hot deformation MICROSTRUCTURE 

分 类 号：TM27[一般工业技术—材料科学与工程]