FeBP@SiO2核壳结构纳米复合材料的可控制备及其吸波性能

提出一种简便易行的方法制备核壳型FeBP@SiO₂纳米粒子，该方法利用化学还原和溶胶凝胶相结合，实现复合粒子的核壳结构可控。通过改变SiO₂壳厚度，研究了壳层厚度对吸波性能的影响，并对微波吸收机制进行分析和解释。结果表明，随着SiO₂壳层厚度的增加，粒子微波吸收能力先增大后减小。当SiO₂壳层厚度为38 nm时，FeBP@SiO₂样品具有最强的微波吸收性能，在吸收涂层厚度为2.19 mm下反射损耗获得较好的吸收性能(-52.66 dB)，这种增强的微波吸收性能主要来自新增磁-介电界面，从而提高了材料的阻抗匹配以及介电损耗的能力，通过设计复合粒子的核壳结构，可以实现复合吸波剂的性能调控，因此本研究为设计下一代新型复合微波吸收材料提供了重要参考。

Controllable Preparation and Microwave Absorbing Properties of FeBP@SiO2 Core-shell Nanocomposites

The core-shell composite nanomaterials composed of magnetic particles and dielectric materials have excellent microwave absorption properties and have become a research hotspot in the field of microwave absorption. The absorbing mechanism of different types of absorbers in composite materials is different, so their proportion has an important influence on the comprehensive absorbing performance. In this paper, a facile method is proposed to prepare core-shell FeBP@SiO₂ nanoparticles. This method combines chemical reduction and sol-gel to realize the controllable shell-core structure of composite particles. By changing the thickness of SiO₂ shell, the effect of shell thickness on microwave absorption performance was studied, and the microwave absorption mechanism was analyzed and explained. With the increase of SiO₂ shell thickness, the microwave absorption capacity of the particles increases first and then decreases. When the thickness of the SiO₂ shell is 38 nm, the FeBP@SiO₂ sample has a nice microwave absorption performance, and the reflection loss at a thickness of 2.19 mm obtains better absorption performance ( -52.66 dB ). This enhanced microwave absorption performance mainly comes from the new magnetic-dielectric interface, thereby improving the impedance matching and dielectric loss of the material. By designing the shell-core structure of the composite particles, the performance regulation of the composite absorber can be achieved. Therefore, this work might provide an important reference for the design of the next generation of new composite microwave absorbing materials.