To develop a novel utilization avenue for fly ash (FA), the Co‐loaded FA (CoFA) was constructed utilizing FA as raw material to acquire the enhanced microwave absorption (MA) performance. In this study, the CoFA composites were fabricated by a two‐step method, including the construction of FA‐based ceramic matrix and a subsequent loading of magnetic components. The results of XRD, SEM, and elemental mapping images revealed that Co particles generated from the carbothermal reduction were well dispersed over the interior and surface of matrix. Compared with pure FA, the as‐prepared CoFA composites demonstrated the impressive MA performances, which were attributed to the good impedance matching, conduction loss, and interfacial polarization effect between the matrix and Co. When the annealing temperature kept at 700°C, the minimum reflection loss (RL_min) of as‐prepared CoFA700 reached up to −40.5 dB and the broad absorption band was measured to be 4.7 GHz with a thickness of 2.0 mm, which was superior to pure FA. Our strategy might provide a new direction to the fabrication of high‐efficient MA materials derived from FA.

中文翻译：

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分两步制备粉煤灰基复合材料用于微波吸收

为了开发一种新的粉煤灰（FA）利用途径，以FA为原料构建了共载FA（CoFA），以获得增强的微波吸收（MA）性能。在这项研究中，CoFA复合材料是通过两步法制造的，包括基于FA的陶瓷基体的构造和随后的磁性成分加载。X射线衍射，扫描电镜和元素映射图像的结果表明，碳热还原产生的钴颗粒很好地分散在基质的内部和表面。与纯FA相比，所制备的CoFA复合材料表现出令人印象深刻的MA性能，这归因于基体与Co之间的良好阻抗匹配，传导损耗和界面极化效应。当退火温度保持在700°C时，最小反射损耗（RL所制备的CoFA700的_min）达到了-40.5 dB，测量的宽吸收带为4.7 GHz，厚度为2.0 mm，优于纯FA。我们的策略可能为制造源自FA的高效MA材料提供新的方向。