Permanent Rare Earth magnets are becoming more and more important in efficient motors and generators with high energy density. Among them NdFeB magnets are the most employed, with NdFeB having higher remanence, high coercivity and energy product. Nevertheless,their poor corrosion resistance makes them susceptible to degradation of the magnetic properties. One possible solution is the development of innovative polymeric composite magnetic materials. The preparation of NdFeB powders filled polymeric matrix (PEEK), with a double goal of protecting the magnetic alloy is proposed, thus preventing it from corrosion, and to realize a new material that can be shaped in the form of filaments. This material was used as feedstock in the 3D printing process to produce high performance magnets with customized and optimized design. The PEEK-NdFeB filaments were produced with three percentages of filler amount(i.e. 25, 50 and 75 wt%). PEEK neat filaments were produced as reference. The influence of the filler on the main thermomechanical properties of the resulting composites, as well as its effect onthe 3D printing process were evaluated by means of different investigation techniques (DSC, DMTA, XRD, tensile testing). The magnetic properties exhibited by Fused Filament Fabrication (FFF) printed parts confirmed the feasibility of employing such a combination of an innovative manufacturing technique and high-performance PEEK-NdFeB compounds. The characterization carried out on both neat and composite filaments evidenced that the presence of the filler slightly decreased the thermal stability, increased the elastic modulus while decreasing ductility and maximum tensile strength. By means of DSC analysis, it was confirmed that the crystallinity is influenced by the presence of the filler. Magnetic measurement performed on the 3D printed parts demonstrate that interesting magnetic properties were achieved, confirming the feasibility of the magnetic 3D printed composite with PEEK.

中文翻译：

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高性能聚合物键合PEEK-NdFeB磁性复合材料的3D打印

永磁稀土在具有高能量密度的高效电动机和发电机中正变得越来越重要。其中钕铁硼磁体使用最多，钕铁硼具有更高的剩磁，高矫顽力和能量积。然而，它们差的耐腐蚀性使它们易于磁性能下降。一种可能的解决方案是开发创新的聚合物复合磁性材料。提出了一种NdFeB粉末填充聚合物基体（PEEK）的制备方法，其双重目的是保护磁性合金，从而防止其腐蚀，从而实现一种可以制成长丝形式的新型材料。这种材料在3D打印过程中用作原料，以生产具有定制和优化设计的高性能磁体。PEEK-NdFeB长丝以三种百分比的填料量（即25、50和75 wt％）生产。生产PEEK纯净的长丝作为参考。通过不同的研究技术（DSC，DMTA，XRD，拉伸试验）评估了填料对所得复合材料主要热机械性能的影响及其对3D打印过程的影响。熔融长丝制造（FFF）印刷零件所表现出的磁性，证实了将创新制造技术与高性能PEEK-NdFeB化合物结合使用的可行性。对纯净纤维丝和复合纤维丝进行的表征证明，填料的存在会稍微降低热稳定性，增加了弹性模量，同时降低了延展性和最大拉伸强度。通过DSC分析，证实了结晶度受填料的存在影响。在3D打印部件上进行的磁性测量表明，实现了令人感兴趣的磁性，从而证实了用PEEK磁性3D打印复合材料的可行性。