微氧化温度对NdFeB粉体微波吸收特性的影响

Effects of partial oxidation temperature on microwave absorbingproperties of NdFeB material

采用熔炼-高能球磨-微氧化-晶化热处理的工艺，制备了NdFeB磁粉，借助X射线衍射仪和网络矢量分析仪等，研究了不同微氧化温度下制备的NdFeB粉体的相组成和微波吸收特性。结果发现：经100℃氧化后再晶化的NdFeB粉体由α-Fe、Nd2O3、Fe2O3相组成，而经200℃氧化后再晶化的NdFeB粉体由。α-Fe、Nd2O3相组成；在6～18GHz频段上100℃氧化后再晶化的粉体的微波吸收效果较好，而在2～6GHz低频段上200℃氧化后再晶化的粉体的微波吸收效果较好；经200℃氧化后再晶化的NdFeB粉体的磁损耗和介电损耗较大。

NdFeB magnetic powder was prepared according to the process flows of smelting, high-energy ball-milling, partial oxidation and recrystallization. The phase and microwave absorbing properties of the prepared powders were analysed by using the X-ray diffraction and vector network analyzer at different partial oxidiation temperatures. The results show that the NdFeB powder, which is crystallized after being oxidized at 100 ℃, is consisted of α-Fe, Nd2O3 and Fe2O3 phases, in which the Fe2O3 phase disappears when the oxidation temperature turned to be 200 ℃. The powder oxidized at 100 ℃ has a better absorbing properties in the range of 6-18 GHz, whereas it is in the range of 2-6 GHz that the powder oxidized at 200 ℃ has a better absorbing properties; the magnetic loss and dielectric loss of the powder oxidized at 200 ℃ are higher than those of being oxidized at 100 ℃.