(1. 貴州大學(xué) 材料與冶金學(xué)院，貴陽 550025；
2. 貴州大學(xué) 先進光電子材料與技術(shù)研究所，貴陽 550025)
摘 要: 采用基于密度泛函理論的贗勢平面波法，研究了Ni元素對Fe3Si合金電子結(jié)構(gòu)及介電性能的影響。計算結(jié)果表明：添加Ni元素后體系金屬性增強，電導(dǎo)率增大。Ni元素使體系的介電常數(shù)實部和虛部在高頻段顯著提高，并具有展寬吸收頻帶所期望的頻響特性。利用機械球磨和真空退火方法制備了Fe75Si25和Fe71.875Ni3.125Si25合金粉末，測試了試樣在2~18 GHz的微波介電常數(shù)和磁導(dǎo)率。實驗結(jié)果表明：添加Ni元素后，合金體系的磁導(dǎo)率和介電常數(shù)都增大，且兩者的虛部增大更加顯著，尤其在10.6 GHz處介電常數(shù)虛部峰值達1.31，較Fe75Si25合金粉末高1.11，進一步驗證了理論計算結(jié)果，并討論了微波損耗機制。
關(guān)鍵字: Fe3Si合金；第一性原理；電子結(jié)構(gòu)；介電性能；電磁特性
（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
