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采用X射线衍射(XRD)、扫描电镜(SEM)分析了热变形Nd_(10.5)Pr_(2.5)Fe_(80)Nb_1B_6磁体断口等显微组织,并用磁滞回线仪测量了磁体的磁性能,系统研究了磁体显微组织、磁性能与取向度的变化规律。估算了250~380μm和<250μm Nd_(10.5)Pr_(2.5)Fe_(80)Nb_1B_6粉、变形量60%的热变形磁体等效易磁化轴与热变形压力方向夹角α,随α从26.0°降至9.1°,磁体密度从7.04 g·cm~(-3)增加至7.49 g·cm-3,M_r/M_s(M_r为剩余磁化强度,Ms为饱和磁化强度)从0.78增大到0.91,磁能积持续增加,矫顽力先从1346 k A·m~(-1)增加至1499 k A·m~(-1),然后矫顽力下降到1216 k A·m~(-1),矫顽力增加的原因是磁体单位体积内磁性主相体积分数增加导致对矫顽力的贡献增大,更多的等轴晶参与热变形、晶粒发生碎化、晶粒尺寸细化;随着α的继续降低,热变形磁体的剩磁、矫顽力将分别进一步增加、减小,矫顽力减小的原因是片状晶的比例增加,片状晶的晶粒尺寸增大,单畴晶粒占总磁畴晶粒比例减小,片状晶出现退磁场。实验统计热变形Nd_(10.5)Pr_(2.5)Fe_(80)Nb_1B_6矫顽力与等效平均晶粒尺寸的关系拟合曲线为Hci=1523.3786+0.3280D-0.0031D2,矫顽力随等效平均晶粒尺寸的增大而降低。
The microstructure of Nd_ (10.5) Pr_ (2.5) Fe_ (80) Nb_1B_6 magnet was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The magnetic properties of the magnet were measured with a hysteresis loopmeter. The changes of the microstructure, magnetic properties and orientation of the magnet were studied systematically. The angle α between the effective magnetization axis and the direction of hot deformation pressure in the range of 250 ~ 380μm and <250μm Nd_ (10.5) Pr_ (2.5) Fe_ (80) Nb_1B_6 powders with a deformation of 60% To 9.1 °, the density of the magnet increased from 7.04 g · cm -3 to 7.49 g · cm -3, and M_r / M_s (M_r is the remanent magnetization and Ms is the saturation magnetization) increased from 0.78 to 0.91. The magnetic energy The coercive force increases from 1346 kA · m -1 to 1499 kA · m -1 and then decreases to 1216 kA · m -1 The reason for the increased force is that the increase of the volume fraction of the magnetic main phase in the unit volume of the magnet leads to the increase of the contribution to the coercive force. More equiaxed grains are involved in the thermal deformation, the grain breakage and the grain size refinement. α continues to decrease, the remanence and coercivity of the hot deformed magnet will further increase and decrease, respectively. The reason for the decrease of coercivity is that the proportion of lamellar crystals increases, the grain size of lamellar crystals increases, The proportion of grains in the total magnetic domain grains decreases, and the delaminated field appears in the lamellar grains. Experimental statistics The relationship between the coercivity of Nd_ (10.5) Pr_ (2.5) Fe_ (80) Nb_1B_6 and the equivalent average grain size is Hci = 1523.3786 + 0.3280D-0.0031D2. The coercive force follows the equivalent mean The grain size increases and decreases.