| 引用本文: | 余红雅,袁涵,李竞舟,刘仲武,郭宝春,杨建民,陈榕寅.通过优化偶联剂含量改善磁粉芯综合性能[J].中国表面工程,2024,37(2):260~268 |
| YU Hongya,YUAN Han,LI Jingzhou,LIU Zhongwu,GUO Baochun,YANG Jianmin,CHEN Rongyin.Improvement of the Overall Performance of Magnetic Powder Cores by Optimising the Coupling Agent Content[J].China Surface Engineering,2024,37(2):260~268 |
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| 通过优化偶联剂含量改善磁粉芯综合性能 |
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余红雅1,2,3, 袁涵2,3, 李竞舟1, 刘仲武2,3, 郭宝春1,2,3, 杨建民1, 陈榕寅1
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1.东莞铭普光磁股份有限公司 东莞 523330;2.华南理工大学材料科学与工程学院 广州 510640;3.华南协同创新研究院 东莞 523808
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| 摘要: |
| 磁粉芯在工程应用中会遇到体积变化引起的开裂、磁性能低等问题，目前未见关于这方面的研究。通过在羰基铁粉磁粉芯（包含磁环、磁片和一体成型电感）中加入不同含量 KH550 硅烷偶联剂，研究其成型性、磁性能和力学性能，并利用 SEM、TMA 和 LCR 等测试分析偶联剂对磁粉芯性能影响的作用机理。研究表明偶联剂能将树脂“约束”在磁粉表面，并在固化过程中带动磁粉颗粒重排，从而增加磁粉芯的膨胀系数。添加 0 wt.%和 0.1 wt.%偶联剂的磁粉芯具有负的膨胀系数，容易收缩开裂。当偶联剂含量达到 0.3 wt.%、0.5 wt.%和 0.7 wt.%时，树脂固化过程中磁粉芯的膨胀系数升高，从而增加磁粉芯的体积，有效抑制磁粉芯的开裂倾向。但是，体积的增加会降低磁粉芯的密度、磁导率、Q 值和力学性能，增加损耗。综合考虑磁粉芯的成型性和其他性能，偶联剂添加的最佳比例是 0.3 wt.%。揭示了偶联剂对磁粉芯膨胀系数等综合性能的影响规律，可为高性能磁粉芯的工程化应用提供重要理论依据。 |
| 关键词: 羰基铁粉 KH550 偶联剂 膨胀系数 磁粉芯 一体成型电感 |
| DOI：10.11933/j.issn.1007-9289.20230420001 |
| 分类号:TF123；TM272 |
| 基金项目:东莞市引进创新科研团队项目（2020607231010）；广东省自然科学基金（2021A1515012464） |
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| Improvement of the Overall Performance of Magnetic Powder Cores by Optimising the Coupling Agent Content |
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YU Hongya1,2,3, YUAN Han2,3, LI Jingzhou1, LIU Zhongwu2,3, GUO Baochun1,2,3, YANG Jianmin1, CHEN Rongyin1
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1.Dongguan Mentech Optical & Magnetic Co., Ltd., Dongguan 523330 , China;2.School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 , China;3.South China Institute of Collaborative Innovation, Dongguan 523808 , China
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| Abstract: |
| Magnetic powder cores, also known as soft magnetic composite materials (SMCs), consist of metal magnetic powders coated with an insulating layer formed through a specific pressing process. In engineering applications, magnetic powder cores may be subjected to issues such as cracking, reduced magnetic permeability, and diminished mechanical strength. The insulation coating of the magnetic powder core includes inorganic and organic coatings. Coupling agents, a type of polymer composite additive, have both inorganic and organophilic molecular groups, allowing them to modify the surface of the magnetic powder and serve as a “bridge” between the inorganic and organic coating layers. The gap between academic and industrial research on the cracking and expansion coefficients of magnetic powder cores leads to a poor understanding of the underlying mechanisms. The moldability, magnetic properties, and mechanical properties of carbonyl iron powder (CIP) magnetic powder cores (including magnetic rings, magnetic discs, and molding inductors) with different contents of the KH550 silane coupling agent were investigated in this study. Scanning electron microscopy (SEM), thermomechanical analysis (TMA), and LCR techniques were used for analysis. The SEM images of the magnetic powder core sections indicate that increasing the amount of coupling agent reduces powder agglomeration, which increases the area percentage of the nonmagnetic phase and porosity. With an increase in the coupling agent content, the area percentage of the nonmagnetic phase increased from 18.4% to 31.4%. Notably, the magnetic disc experimental outcomes, influenced by the coupling agent content, thickness, molding pressure, and curing rate, revealed that a higher curing rate, increased thickness, and higher molding pressure made the magnetic discs more susceptible to cracking. However, coupling agents can reduce the cracking tendency of the molding inductors and magnetic rings, thereby enhancing their moldability. The density of the magnetic discs is influenced by both the molding pressure and coupling agent content. When the coupling agent content remains constant, an increase in the molding pressure results in increased density. However, for discs subjected to identical molding pressures, a higher coupling agent content corresponded to a reduced density. Density of the magnetic discs with 0.1 wt.% coupling agent content are abnormal. The TMA showed that the coupling agent can stabilize the resin on the magnetic powder surface and facilitate powder particle rearrangement during curing, thereby increasing the core expansion coefficient. Magnetic powder cores with 0 wt.% and 0.1 wt.% coupling agents have negative expansion coefficients, leading to potential shrinkage and cracking. In contrast, the cores with 0.3 wt. %, 0.5 wt.%, and 0.7 wt.% coupling agents yielded an increased expansion coefficient during resin curing, thereby effectively reducing the core's cracking tendency. However, increasing the coupling agent content can affect the magnetic properties of the core. As the non-magnetic phase and porosity change, the density and magnetic permeability of the magnetic powder core initially increase and subsequently decrease. Similarly, the core loss and quality factors exhibit opposite trends. As the porosity increases, it induces additional coercivity proportional to the square root of the specific pore surface area, consequently leading to increased core loss. The core loss first decreases and then increases, and the quality factor increases before eventually decreasing. This paper also demonstrates that the meshing capability of magnetic powders directly affects their mechanical properties. As the coupling agent content increases, the mechanical strength of the magnetic powder core improves and then declines. Given the moldability of the core and other characteristics, the ideal coupling agent content is 0.3 wt.%. This study explored the effect of the coupling agent on the expansion coefficient of magnetic powder core during curing and unveiled its influence on other properties, laying a robust theoretical foundation for the application of high-performance magnetic powder cores. |
| Key words: carbonyl iron powder KH550 coupling agent expansion coefficient magnetic powder core molding inductor |
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