Abstract In this work, we prepared a core-shell carbonyl iron powder (CIP) SiO2 binary composite (CIP@SiO2) by sol-gel method, in which L-lysine was firstly used as a catalyst to synthesize CIP@SiO2. The structure, chemical composition and morphology of the obtained composite and its microwave absorption performance were analyzed in detail. The electron microscopy images results show that the surface of the spherical CIP is distributed with an island-shaped connected rough SiO2 shell, which we propose is due to the different bonding modes of SiO2 and CIP surface and discuss it in details. In addition, the thickness of SiO2 can be adjusted by the ratio of reactant amount. The electromagnetic parameters show that the coating of SiO2 greatly improve the impedance matching of original CIP. The minimum reflection loss of CIP@SiO2 under the optimum reaction condition can reach -49.39 dB, and the widest effective absorption bandwidth can reach 7.12 GHz (10.88-18.00 GHz) only at the thickness of 1.5 mm. Its microwave absorption performance is significantly better than that of original CIP. Taken together, core-shell CIP@SiO2 binary composite has great potential as excellent microwave absorbers.

中文翻译：

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一种新型催化剂允许羰基铁粉涂覆SiO2以调节微波吸收

摘要 在这项工作中，我们通过溶胶-凝胶法制备了核壳羰基铁粉（CIP）SiO2 二元复合材料（CIP@SiO2），其中首先使用 L-赖氨酸作为催化剂合成 CIP@SiO2。对所得复合材料的结构、化学成分、形貌及其微波吸收性能进行了详细分析。电子显微镜图像结果表明，球形CIP 表面分布有岛状连接的粗糙SiO2 壳，我们认为这是由于SiO2 和CIP 表面的不同键合模式，并对其进行了详细讨论。另外，SiO2的厚度可以通过反应物量的比例来调整。电磁参数表明，SiO2涂层大大提高了原CIP的阻抗匹配。CIP@SiO2在最佳反应条件下的最小反射损耗可达-49.39 dB，最宽的有效吸收带宽仅在1.5 mm厚度处可达7.12 GHz（10.88-18.00 GHz）。其微波吸收性能明显优于原CIP。总之，核壳 CIP@SiO2 二元复合材料作为优良的微波吸收剂具有巨大的潜力。