Development of High-performance Magnetic Coupling Composite-type Rare Earth Magnets

Sm_2Fe_<17>N_x和Nd-Fe-B HDDR材料等具有优异磁性能的金属间化合物制备的稀土永磁体有助于制造便携式高性能OA、音频播放器。特别是，这些材料可以模压成粘结磁铁，具有良好的尺寸控制精度。因此，本文采用锌金属气相吸附和/或自组装单层（SAM）涂层（Zn/Nd-Fe-B和SAM/Sm_2Fe_<17>N_x）的表面涂覆方法，对Sm_2Fe_<17 bbb_n_x和Nd-Fe-B HDDR粉末制备了良好的抗氧化粘结磁体。所得结合磁体对Zn/Nd-Fe-B和SAM/Sm_2Fe_<17>N_x分别提供了166和183 kJ/m^3的高（BH）最大值。此外，将Nd-Fe-B HDDR与SAM/Sm_2Fe_<17>N_x粉末混合制备了高性能磁耦合复合型粘结磁体。所观察到的（BH）最大值约为200 kJ/m^3，磁体对空气或水的氧化是稳定的。

Rare earth permanent magnets produced from intermetallic compounds with excellent magnetic property such as Sm_2Fe_<17>N_x and Nd-Fe-B HDDR materials contribute to fabricate the portable-type high-performance OA, audio players. Particularly, these materials can be molded as bonded magnets with good accuracy for the dimension control.From the above point of view, this work was made to prepare the good oxidation-resistant bonded magnets from the Sm_2Fe_<17>N_x and Nd-Fe-B HDDR powders by surface coating methods of zinc metal vapor sorption and/or Self Assemble Monolayer (SAM) coating (Zn/Nd-Fe-B and SAM/Sm_2Fe_<17>N_x). The resultant bonded magnets provide high (BH)max values of 166 and 183 kJ/m^3 for Zn/Nd-Fe-B and SAM/Sm_2Fe_<17>N_x, respectively. In addition, the high-performance magnetic coupling composite-type bonded magnets were prepared from the mixture of Nd-Fe-B HDDR and SAM/Sm_2Fe_<17>N_x powders. The (BH)max values observed were around 200 kJ/m^3 and the magnets were stable toward the oxidation by air or water.