The performance of electric sensors is continuously improving due to the demands of modern vehicles and electronic devices. Magnetic sensors are used in a wide field of applications. However, handling and mounting the typical high-performance rare earth permanent magnets are challenging due to their brittleness. A constant magnetic flux is a key property of the magnetic setup in many devices. State-of-the-art adhesive bonding of magnets in devices can cause problems due to the low durability and viscous behaviour of adhesive polymers, as the magnet may change its position and hence, the magnetic flux distribution in the magnetic setup changes. Ultrasonic welding is a powerful technique to join hybrid material systems quickly and reliably, providing high joint strength, even for brittle materials such as glasses, ceramics and rare earth permanent magnets. The latter is being investigated in this work for the first time. The ultrasonic welding process was adapted to join 316L stainless steel, representing potential components of magnetic devices, to Ni/Cu/Ni-coated Nd2Fe14B. In addition to directly joined steel/magnet-hybrids, ductile aluminium and nickel interlayers were used in order to enhance the joint strength. Process parameters were developed and evaluated considering the resulting shear strength of the joints. The highest shear strength of 35 MPa was achieved for 316L/Nd2Fe14B and 316L/Al/Nd2Fe14B, which is more than twice the shear strength of adhesively bonded joints of up to 20 MPa, according to the literature. The functional performance of the hybrid material systems, evaluated by the magnetic flux density of the hybrid material systems was the highest for directly bonded joints, and those with a nickel interlayer, which did not show any losses in comparison to the single magnet in its initial state. Joints with an aluminium interlayer showed losses of 3% and adhesively bonded joints showed losses of 7% of the magnetic flux density. In summary, the results of this work indicate that ultrasonic welding is a suitable technique to improve the production process and performance of magnetic devices.

中文翻译：

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超声混合材料系统– 316L不锈钢与Ni / Cu / Ni涂层Nd ₂ Fe ₁₄ B磁体的超声波焊接

由于现代车辆和电子设备的需求，电传感器的性能正在不断提高。磁传感器被广泛地应用。但是，由于其易碎性，典型的高性能稀土永磁体的处理和安装具有挑战性。恒定的磁通量是许多设备中磁设置的关键属性。由于粘合剂聚合物的低耐用性和粘性行为，导致设备中磁体的最新粘合剂粘合会引起问题，因为磁体可能会改变其位置，因此，磁性装置中的磁通量分布会发生变化。超声波焊接是一项强大的技术，可快速可靠地加入混合材料系统，即使对于玻璃等脆性材料，陶瓷和稀土永磁体。后者正在这项工作中进行首次调查。超声焊接工艺适用于将代表磁性设备潜在组件的316L不锈钢连接到Ni / Cu / Ni涂层Nd2Fe14B上。除了直接连接的钢/磁铁混合体之外，还使用了韧性的铝和镍中间层，以提高连接强度。考虑到接头的剪切强度，开发并评估了工艺参数。根据文献报道，对于316L / Nd2Fe14B和316L / Al / Nd2Fe14B，可获得35 MPa的最高剪切强度，这是高达20 MPa的胶粘接头的剪切强度的两倍以上。混合材料系统的功能性能，通过混合材料系统的磁通密度评估的结果是，对于直接结合的接头以及具有镍夹层的接头，与在初始状态下的单个磁铁相比，没有任何损耗。带有铝夹层的接头的损耗为3％，而粘结接头的损耗为磁通密度的7％。总而言之，这项工作的结果表明，超声焊接是一种改善磁性器件生产工艺和性能的合适技术。