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

小行星9712688 该GOALI研究计划调查了磁性颗粒形态，浓度和分布对加工的作用，以及粘结磁体的磁化行为。粘结磁体的耐热性可以通过选择耐热粘结剂和高温聚合物来提高。 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。 稀土磁粉在所需温度范围内的热稳定性可以通过适当的表面处理来改善。 可以通过优化磁粉的分数和仔细控制颗粒形态和粒度分布来提高能量积。 对聚合物基体和磁性粉末之间相互作用的基本理解对于开发合适的粉末涂料以提高粉末的热稳定性至关重要。 研究了与聚合物粘合剂化学相容的表面涂层。 该研究的重点是评估各种类型的聚合物粘合剂，如聚苯硫醚（PPS）和液晶聚合物（LCP）。 此外，研究了聚合物粘合剂/粉末混合物的流变行为以改善加工性能。 基于实验数据，理论模型被开发来预测磁性粉末的最佳浓度和分布。 该项目涉及爱荷华州州立大学和美国领先的磁性材料制造商阿诺德工程公司之间的合作。 研究生将在阿诺德工程公司度过三个夏季，协助样品的高温测试。 该项目由MPS多学科活动办公室和材料研究部共同资助。 聚合物粘结磁体被广泛用于许多汽车和非汽车应用。 需要开发具有更高能量积的粘结磁体，其可以承受至少180 ℃和更高的操作温度。 一个关键问题是确定合适的磁粉和聚合物基体，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. ***