(1. 贵州大学 材料与冶金学院，贵阳 550025；
2. 贵州大学 先进光电子材料与技术研究所，贵阳 550025)
摘 要: 采用基于密度泛函理论的赝势平面波法，研究了Ni元素对Fe3Si合金电子结构及介电性能的影响。计算结果表明：添加Ni元素后体系金属性增强，电导率增大。Ni元素使体系的介电常数实部和虚部在高频段显著提高，并具有展宽吸收频带所期望的频响特性。利用机械球磨和真空退火方法制备了Fe75Si25和Fe71.875Ni3.125Si25合金粉末，测试了试样在2~18 GHz的微波介电常数和磁导率。实验结果表明：添加Ni元素后，合金体系的磁导率和介电常数都增大，且两者的虚部增大更加显著，尤其在10.6 GHz处介电常数虚部峰值达1.31，较Fe75Si25合金粉末高1.11，进一步验证了理论计算结果，并讨论了微波损耗机制。
关键字: Fe3Si合金；第一性原理；电子结构；介电性能；电磁特性
（1. College of Material and Metallurgy, Guizhou University, Guiyang 550025, China;
2. Institute of Advanced Optoelectronic Materials and Technology, Guizhou University, Guiyang 550025, China）
Abstract:The influences of Ni element on the electronic structure and dielectric properties of Fe3Si alloys were studied by the pseudopotential plane wave method based on density functional theory. The calculated results show that the metallic properties of the system are enhanced and the conductivity is increased by adding Ni element. The Ni element greatly improves the real and imaginary parts of the dielectric constant of the system in the high frequency band, and the frequency response characteristic of broadening the absorption band is obtained. The Fe75Si25 and Fe71.875Ni3.125Si25 alloy powders were prepared by mechanical ball grinding and vacuum annealing method, and the microwave dielectric constant and permeability of the samples were measured in the frequency range of 2-18 GHz by vector network analyzer. The experimental results show that the permeability and dielectric constant of the alloy increase with the addition of Ni, especially the imaginary part. The imaginary part peak value of dielectric constant at 10.6 GHz is 1.31, which is 1.11 higher than that of Fe75Si25 alloy and validates the results of theoretical calculation. The mechanism of microwave loss was discussed.
Key words: Fe3Si microwave absorber; first principles; electronic structures; dielectric properties; electromagnetic properties
