软磁复合材料界面设计及其对高频损耗抑制作用研究

Soft magnetic materials with unitary system can not meet the requirements of miniaturization and high frequency of magnetic components with the rapid development of information and industrialization. soft magnetic composite materials with excellent comprehensive performance is of current interest. Based on the dual anisotropy model, the scattering theory of high-frequency loss and the mechanism of magnetic exchange at the heterogeneous interface, Fe based amorphous alloy and ferrite soft magnetic composites are synthesized by wet chemical coating method. The mechanism of in situ growth of ferrite on Fe based amorphous matrix and the behavior of atomic transport, defect evolution, grain growth and slip rotation in the process of densification is investigated. Preparation conditions for the interface regulation between iron base amorphous / ferrite are obtained. The scattering process of eddy current with high frequency is analyzed by the lattice distortion, stress and defect in the interface. The mechanism of dynamic magnetization of composite magnet and its mechanism about the two-magnon and inhomogeneous scattering under high frequency excitation is revealed. The influence of interface composition and structure on magnetic exchange and soft magnetic properties is clarified. The relationship between the Fe based amorphous / ferrite interface and the high frequency loss inhibition mechanism is proposed. It will provide the basis for the industrial production of soft magnetic composites with high frequency and low loss.

随着信息化与工业化的飞速发展，单一体系软磁材料已不能满足磁性元件小型化及高频化的要求，研发综合性能优异的高频低损耗软磁复合材料成为信息社会发展的趋势。项目依据高频损耗界面散射理论及异质界面磁交换作用机理，采用湿化学方法原位合成铁氧体绝缘层以制备铁基非晶/铁氧体软磁复合材料。研究铁基非晶基体上铁氧体原位生长机制以及致密化过程中原子输运、缺陷演化、晶粒生长及滑移转动行为，获得铁基非晶/铁氧体界面可控的制备条件。分析界面晶格畸变、应力、缺陷等对高频电子的散射作用，揭示高频激励条件下动态磁化响应机制和双磁子散射、非均匀散射机理，阐明界面成分与结构对磁交换作用及软磁特性的影响规律，建立铁基非晶/铁氧体界面与磁导率、饱和磁通密度及高频损耗的映射关系，指导高频低损耗软磁复合材料的工业化生产，推动浙江省和我国磁性材料的自主创新和产业升级。

随着信息化与工业化的飞速发展，单一体系软磁材料已不能满足磁性元件小型化及高频化的要求，研发综合性能优异的高频低损耗软磁复合材料成为信息社会发展的趋势。项目基于铁基合金的“骨架结构”模型，开展了铁基非晶合金成分设计、非晶形成能力及温度稳定性研究，开发了Fe79Si3B4P10C4、FeSiBCCr成分体系以及多级雾化超细球粉的制备工艺。依据高频损耗界面散射理论及异质界面磁交换作用机理，采用湿化学方法原位合成铁氧体绝缘层，制备了铁基非晶/铁氧体软磁复合材料，其中FeSiBPC/Fe3O4@Epoxy resin双绝缘层核壳结构在100 kHz@0.05 T时具有极低的损耗187 mW/cm3。基于高磁导率和高电阻率的界面绝缘层设计原则，开发了尖晶石铁氧体MnZn、NiZn，平面六角型磁铅石铁氧体Co2Z、Co2Y，石榴石型铁氧体YIG等亚铁磁性氧化物以及LaNiMnO等铁磁性氧化物，从软磁复合材料的组成上优化了工作磁路，降低了磁阻和退磁效应，显著优化了复合材料的磁导率和磁损耗，其中1wt.%Co2Z@Fe软磁复合材料的典型性能为: 600kHz，5mT，μ=41.2，Pcv=210kW/m3。基于优化软磁合金粉末的组分与性能，进而对绝缘层进行替代并优化工艺路线的思路，采用NH3/H2气相氮化技术开发了Fe4N/Fe、Fe3N/Fe和Fe3N/Fe4N等多元体系，显著降低了磁损耗，尤其是涡流损耗。在成型压制过程中，利用外磁场对球形、片状合金体系的粒子排布进行重构，进而形成一种各向异性磁有序结构，牺牲其他方向的磁性，提高工作磁路方向的磁性，其中平行有序结构FeSiBCCr@NiZn体系在600kHz、10mT条件下的磁损耗仅为取向之前的85.2%，磁导率较好提升。在上述研究的基础上，系统分析了界面晶格畸变、应力、缺陷等对高频电子的散射作用，揭示了高频激励条件下动态磁化响应机制和双磁子散射、非均匀散射机理，阐述了界面成分与结构对磁交换作用及软磁特性的影响规律，建立了铁基非晶/铁氧体界面与磁导率、饱和磁通密度及高频损耗的映射关系，指导高频低损耗软磁复合材料的工业化生产，推动浙江省和我国磁性材料的自主创新和产业升级。