稀土对BaO-Fe2O3体系相关系及其相关化合物微波吸收的影响

With the rapid development of microwave technology, the absorbance absorbing materials have become an urgent demand. In the project，the crystal structures, magnetic structure and phase relationships of the RxOy-BaO-Fe2O3 system will be investigated by XRD, PND, Raman spectroscopy, EPMA, SEM and TEM. The phase diagrams will be developed to support the composition design of wave absorbing ferrite materials. After that, an emphasis will be put on the composition, temperature evolution of the crystalstructure and phase relationships in order to control the performance of wave absorbing ferrite materials. The microstructure of wave absorbing ferrite materials will be regulated by optimizing the preparation technology. Crystal structure parameters of the compounds, including cell parameters, bond lengths and bond angles between atoms, atomic positions and occupancy, will be calculated by the Rietveld program. The variation of the compounds with the composition and the element doping are analyzed. Combined with thermodynamic test and optimization, the stability and forming the phase rule of the compounds will be systematically studied. The magnetoelectric and the electromagnetic absorption properties will be tested by PPMS and vector network analyzer, so as to find the absorbing materials with excellent absorbing properties. The synergistic effect of double (multiple) main phase coupling is analyzed. The effect of the microstructure and phase composition on electromagnetic absorption properties will be illuminated, which provides a theoretical foundation for the design of microwave absorbing ferrite materials. The ultimate goal of the project is to understand the mechanism of magnetoelectric coupling and electromagnetic absorption of absorbing ferrite materials and to establish, and establish the modern design method for absorbing materials. The research results can also accelerate the development of advanced absorbing materials.

随着微波技术的发展，具有高吸收率的吸波材料已成为迫切需求。本项目拟用原位XRD、NPD、拉曼、EPMA、SEM、TEM技术，开展RxOy-BaO-Fe2O3体系的晶体结构、磁结构及相关系的研究，测定其相图，构建吸波材料设计平台。在此基础上，为解决吸波性能调控问题，重点研究晶体结构和相关系随成分、温度的演变。优化制备工艺，实现对微观结构的调控。通过Rietveld对晶体结构精修，计算晶胞参数、键长、键角、占位及占有率等参数，分析其随成分和元素掺杂的变化规律。结合热力学测试及计算，研究化合物稳定性和成相规律。采用PPMS测试其电、磁性能和VNA测量电磁吸收性能,寻找优异的吸波材料。研究多主相耦合效应，探索相组成、微观结构对电磁吸收性能影响规律，为吸波材料设计提供理论依据。通过本项目研究，深入理解吸波材料的电、磁耦合与电磁吸收的机理，建立吸波材料的现代设计方法，加速吸波材料的开发。

本项目拟采用XRD、拉曼光谱、扫描电镜SEM、光电子能谱议（XPS）等测试分析，开展RxOy-BaO-Fe2O3体系晶体结构及相关系的研究，通过晶体结构精修Rietveld程序，计算晶胞参数、原子占位、占有率、各原子间键长、键角等结构参数，结合热力学测试及优化，重点研究晶体结构和相关系随成分、温度的演变。根据相图合理设计合金材料，通过综合物性测量系统（PPMS）测试其磁电性能，结合结构相变、磁结构变化、晶体形貌变化、原子价态变化，建立结构相变和吸波性能关系。系统研究其制备工艺、成分对其形貌、结构相变、价态变化、结构稳定性对吸波性能的影响。

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