Department of Chemical Engineering, National Chung Cheng University, 168 University Rd., Min-Hsiung, Chia-Yi, 621, Taiwan.
Dalton Trans. 2012 Jan 21;41(3):723-6. doi: 10.1039/c1dt11012h. Epub 2011 Aug 25.
An α-Fe(2)O(3) nanoflake urchin-like structure is formed via the thermal oxidation of micrometre-sized iron spheres in air at temperatures of 300-400 °C. The material consists of α-Fe(2)O(3) nanoflakes grown perpendicularly to the sphere surface, a layer of a mixture of α-Fe(2)O(3) and Fe(3)O(4) as the oxidation shell, and an iron core. The ranges of the tip diameters of the nanoflakes are 20-30 nm (300 °C), 30-50 nm (350 °C), and 60-100 nm (400 °C). A composite consisting of the α-Fe(2)O(3) nanoflake urchin-like structure and an epoxy resin exhibits an excellent electromagnetic (EM) wave absorption ability. A small tip diameter (20-30 nm) and a high density (3 × 10(13) nanoflakes m(-2)) lead to a good network structure and good EM wave absorption. A minimum reflection loss (RL) of -33.8 dB (99.93% of EM wave absorption) at 7.8 GHz can be achieved using a 70 wt% urchin-like material as the filler in the resin matrix. In addition, a composite containing 60 wt% unchin-like material exhibits dual-frequency EM wave absorption. The peaks of the minimum RL values are located at 9.7 GHz (-26.2 dB) and 25.2 GHz (-21.0 dB). The unique morphology of the α-Fe(2)O(3) nanoflake urchin-like material is believed to be a key factor in the enhancement of the EM wave absorption.
一种α-Fe(2)O(3)纳米片刺猬状结构是通过在 300-400°C 的空气中对微米级铁球进行热氧化而形成的。该材料由垂直于球表面生长的α-Fe(2)O(3)纳米片组成，氧化壳为α-Fe(2)O(3)和 Fe(3)O(4)的混合物层，以及一个铁核。纳米片尖端直径的范围为 20-30nm（300°C）、30-50nm（350°C）和 60-100nm（400°C）。由α-Fe(2)O(3)纳米片刺猬状结构和环氧树脂组成的复合材料表现出优异的电磁波（EM）波吸收能力。小的尖端直径（20-30nm）和高密度（3×10(13)纳米片 m(-2))导致良好的网络结构和良好的 EM 波吸收。在树脂基体中使用 70wt%的刺猬状材料作为填料，可以实现 7.8GHz 时最小反射损耗（RL）为-33.8dB（99.93%的 EM 波吸收）。此外，含有 60wt%刺猬状材料的复合材料表现出双频 EM 波吸收。最小 RL 值的峰值位于 9.7GHz（-26.2dB）和 25.2GHz（-21.0dB）。α-Fe(2)O(3)纳米片刺猬状材料的独特形态被认为是增强 EM 波吸收的关键因素。
