工艺参数对注射成型铁氧体塑料粘结磁体性能的影响

Influence of processing parameters on the properties of injection molded rubber bonded ferrite magnet

采用尼龙作为粘结剂,与锶铁氧体磁粉和添加剂经过双螺杆挤出机加热混炼,并注射成型得到塑料粘结磁体,研究了含粉量、配方体系、模具磁路设计和取向励磁电流对磁体性能的影响。结果表明,提高含粉量使得塑料粘结磁体密度变大,表面磁通密度、Br和(BH)max呈显著上升趋势,但是磁粉之间摩擦增大导致Hcj和机械强度呈下降趋势。通过配方调整可以改善材料的磁性能和机械性能,制备不同性能的磁体,改变励磁电流亦可调节磁体表面磁通密度(表面场强)。在磁路模拟的基础上对模具进行优化设计,采用表面场强均匀的模具设计方案制备了模具,实验结果与模拟结果一致,得到了两面场强均匀的塑料粘结磁体。

In this paper,nylon as the binder,along with strontium ferrite magnetic powder and additives were heated and mixed together through the twin-screw extruder to get injection molded magnetic parts.The effects of powder content,formulation system,magnetic circuit design of mold and alignment current on the properties of magnetic parts were studied.The results show that the surface magnetic induction intensity,Br and(BH)max increase significantly with increasing the powder content.But the friction between the powders increases also,resulting in decrease in Hcj and mechanical strength.The magnetic and mechanical properties can be improved by adjusting the formula to produce magnets with different performance.By change magnetizing current the surface magnetic induction intensity of the product can be adjusted.Based on the simulation technique,the mold is designed and the magnets with uniform surface field were prepared.The results show that the experimental results are consistent with the simulation results,and the magnets with uniform magnetic field on both surfaces are obtained.