Developing\nRobust FeSiAl/PEEK Composites for Wide-Temperature-Range\nElectromagnetic Wave Absorption

Presently,\nresearchers are placing emphasis on microwave absorption\ncoating design while neglecting the research on materials that integrate\nboth microwave absorption performance and mechanical properties. Here,\nrobust FeSiAl/PEEK composites were prepared by a series process, including\npost ball-milling annealing, sol–gel method, and hot pressing.\nA detailed analysis of the electromagnetic (EM) parameters reveals\nthe significant effects of morphology, filling ratio, and microstructure\nof FeSiAl on EM losses under a wide-temperature range. With 20 vol\n% filler loading, flaky-FeSiAl@SiO<sub>2</sub>/PEEK composite exhibits\nexcellent performance for wide-temperature-range microwave absorption\nin the X-band. At room temperature, the minimal reflection loss (RL<sub>min</sub>) reaches −28.6 dB at 10.8 GHz and the effective\nabsorption bandwidth (EAB) is up to 3.26 GHz at 1.8 mm. As the temperature\nrises to 573 K, the RL<sub>min</sub> reaches −25.8 dB at 11.2\nGHz, and the EAB decreases to 2.04 GHz at a thickness of only 1.3\nmm. The good performance is maintained over a wide-temperature range\ndue to the SiO<sub>2</sub> shell, which serves as an intermediate\nlayer between FeSiAl and PEEK, not only improving impedance matching\nbut also mitigating adverse eddy current losses at elevated temperatures.\nIn addition, the SiO<sub>2</sub> shell enhances the mechanical properties\nof the flaky-FeSiAl@SiO<sub>2</sub>/PEEK composite, with tensile strength\nreaching 84.38 MPa at 298 K, and remaining at 16.33 MPa at 573 K.\nTherefore, the flaky-FeSiAl@SiO<sub>2</sub>/PEEK composite emerges\nas a promising candidate for materials that integrate both superior\nmicrowave absorption performance and robust mechanical properties\nunder wide-temperature-range conditions.