Development of Polymer Bonded Magnets with Enhanced Magnetic Properties for High Temperature and Aggressive Environments

9712688 Otaigbe这个目标研究计划调查磁性颗粒的形态、浓度和分布对粘结磁体的加工和磁化行为的影响。选择耐热粘结剂和高温聚合物可以提高粘结磁体的耐热性。然而，高温工程聚合物的使用受到磁性合金粉末在聚合物加工温度下的氧化行为的限制。通过适当的表面处理可以提高稀土磁粉在所需温度范围内的热稳定性。通过优化磁粉的含量，仔细控制颗粒的形貌和粒度分布，可以提高能量积。基本了解聚合物基质与磁性粉末之间的相互作用对于开发合适的粉末涂料以提高粉末的热稳定性是至关重要的。研究了与聚合物粘结剂化学相容的表面涂层。这项研究的重点是评估各种类型的聚合物粘结剂，如聚苯硫醚(PPS)和液晶聚合物(LCP)。此外，还研究了聚合物粘结剂/粉末混合物的流变行为，以改善其加工性能。在实验数据的基础上，建立了预测最佳磁粉浓度和分布的理论模型。该项目涉及爱荷华州立大学和阿诺德工程公司的合作，阿诺德工程公司是美国领先的磁性材料制造商。这位研究生将在阿诺德工程公司度过三个夏天的时间，协助对样品进行高温测试。该项目由MPS多学科活动办公室和材料研究部共同资助。聚合物粘结磁体广泛应用于汽车和非汽车领域。有必要开发具有更高能量产品的粘结磁体，这些磁体可以承受至少180摄氏度或更高的工作温度。一个关键问题是识别合适的磁粉和聚合物基质，它们可以在所需的较高温度下令人满意地执行。***

9712688 Otaigbe This GOALI research program investigates the role of magnetic particle morphology, concentration and distribution on the processing, and magnetization behavior of bonded magnets. The heat resistance of bonded magnets can be improved by selecting heat resistant binders and high temperature polymers. However, the use of high temperature engineering polymers is limited by the oxidizing behavior of the magnetic alloy powders at the polymer processing temperatures. Thermal stability of the rare earth magnetic powders at the desired temperature ranges can be improved by suitable surface treatments. The energy product can be improved by optimizing the fraction of magnetic powders and careful control of the particle morphology and particle size distribution. A fundamental understanding of the interaction between the polymer matrix and magnetic powders is essential in developing suitable powder coatings to improve the thermal stability of the powders. Surface coatings which are chemically compatible with the polymer binder are investigated. The study focuses on evaluating various types of polymer binders, such as polyphenylene sulphide (PPS) and liquid crystal polymers (LCP). In addition the rheological behavior of the polymer binder/powder mixtures is studied for improving processability. Based on the experimental data obtained, theoretical models are developed to predict the optimal concentrations and distributions of magnetic powders. The project involves a collaboration between Iowa State University and Arnold Engineering Company, a leading manufacturer of magnetic materials in the United States. The graduate student will spend three summer months at Arnold Engineering assisting in elevated temperature testing of the samples. This project is jointly funded by the MPS Office of Multidisciplinary Activities and the Division of Materials Research. %%% Polymer bonded magnets are widely being used in many automotive and nonautomotive appli cations. A need exists to develop bonded magnets with higher energy products that can withstand operating temperatures of at least 180 C and higher. A key issue is the identification of suitable magnetic powders and polymer matrices which can perform satisfactorily at the desired higher temperatures. ***