同质纤维和强磁场调控大长径比MnZn铁氧体轴向结晶与性能

Extrusion molding can realize low cost and high efficiency preparation of large length-diameter ratio members, but there were problems of poor structural density and unstable grain boundaries. To meet the needs of diverse engineering applications, complex service environments and high frequency, high power applications for high performance, high reliability large length-diameter ratio MnZn ferrite cores. A new idea of the axial crystallization and properties of large length-diameter ratio MnZn ferrite controlled by homogenous fiber and strong magnetic field was proposed..Through the regulation of the grain growth direction and crystal orientation degree of the core, the axial orientation characteristics of the grain were explored, the grain orientation regulation law was clarified, and the regulation mechanism of the axial texture structure of the magnetic core enhanced by the homogenous fiber and the strong magnetic field was revealed. Through the study of crystallization kinetics, controlled the grain growth process and growth characteristics, analyzed the grain growth law, clarified the grain boundary regulation law, and the regulation mechanism of grain boundary structure enhanced by homogenous fibers and strong magnetic fields was revealed. By understanding the control law of the core axial texture structure on the mechanical properties and magnetic properties of the magnetic core, the synergistic strengthening mechanism of the mechanical properties and magnetic properties of the magnetic core was indicated. The method of controlling the axial crystallization and properties of the magnetic core by the homogenous fiber and the strong magnetic field was mastered. The structural orientation, compactness and grain boundary stability were improved, and the mechanical properties and magnetic properties of the magnetic core were improved, which provides a scientific basis for the preparation of high performance, high reliability large length-diameter ratio MnZn ferrite cores by extrusion molding.

挤出成型可以实现大长径比构件低成本高效率制备，但存在结构致密性差、晶界不稳定的问题。为满足多样化工程应用，复杂服役环境和高频率、高功率应用方向对高性能高可靠性大长径比MnZn铁氧体磁芯的需求，项目提出同质纤维和强磁场调控大长径比MnZn铁氧体轴向结晶与性能新思路。 .通过磁芯晶粒生长方向和取向度调控，探索晶粒轴向取向特性，阐明晶粒取向调控规律，揭示同质纤维和强磁场强化磁芯轴向织构结构调控机制。通过结晶动力学研究，控制晶粒生长过程和生长特征，解析晶粒生长规律，阐明晶界调控规律，揭示同质纤维和强磁场强化晶粒界面结构调控机制。通过理解磁芯轴向织构结构对磁芯力学性能和磁性能的控制规律，揭示磁芯力学性能和磁性能协同强化机制，掌握同质纤维和强磁场调控磁芯轴向结晶与性能的方法，提高结构取向度、致密性和晶界稳定性，提高磁芯力学性能和磁性能，为挤出成型制备高性能高可靠性大长径比MnZn铁氧体磁芯提供科学依据

为满足多样化工程应用对高性能高可靠性大长径比MnZn铁氧体磁芯的要求，项目提出了利用同质纤维和强磁场强化挤出成型制备大长径比MnZn铁氧体磁芯技术。大长径比MnZn铁氧体磁芯磁性能和力学性能是两个重要指标，为了让两个重要性能满足使用要求，项目提出结晶结构与性能协同调控思路。通过磁芯轴向织构结构调控，强化磁芯晶粒生长方向和取向度调控；通过晶粒界面结构调控，强化结晶结构致密性和晶界稳定性。基于磁芯轴向织构结构和晶粒界面结构调控，强化大长径比MnZn铁氧体磁芯磁性能和力学性能。.通过制备方法、制备工艺条件、强磁场控制，强化同质MnZn铁氧体纤维结晶结构和性能控制，增强了MnZn铁氧体纤维磁性能和诱导结晶活性。通过同质MnZn铁氧体纤维、成型工艺、烧结工艺控制，强化大长径比MnZn铁氧体结晶结构控制，增强了大长径比MnZn铁氧体磁性能和力学性能。同质纤维增强MnZn铁氧体晶体结构更致密、孔隙率更少、晶界更少，Mn0.7Zn0.3Fe2O4型同质纤维增强MnZn铁氧体结晶结构更致密，具有更高的磁导率、更低的磁损和更高的维氏硬度和抗压强度。同质纤维含量为2 wt%的大长径比MnZn铁氧体磁芯，磁性能与力学性能最优。1T稳恒磁场可以提高纤维增强MnZn铁氧体对外加载荷的承受能力并降低其损耗。随着烧结温度升高，大长径比MnZn铁氧体磁芯电阻率、磁导率和品质因数先升高后降低，在1260℃达到最大值，损耗最小，磁性能最高。随着氧分压增大，大长径比MnZn铁氧体磁芯热导率先增大后减小。当氧分压为3%时，热导率达到最大值。同时，磁损随氧分压增加先减小后增大。3%氧分压下制备的MnZn铁氧体损耗最小。.通过解析大长径比MnZn铁氧体磁芯结晶结构与磁芯力学性能和磁性能的协同调控机制，建立大长径比MnZn铁氧体磁芯结晶结构调控方法，为挤出成型制备高性能高可靠性大长径比MnZn铁氧体磁芯提供了重要理论依据。