Microwave absorption enhancement by SiC nanowire aerogels through heat treatment-based oxidation modulation

SiC nanowire aerogels (SNWA) emerge as a promising category of electromagnetic wave absorbers (EMA) that can be applicable to extreme environments since they possess exceptional dielectric loss properties and superior ceramic characteristics. However, obtaining high-performance microwave absorption (MA) with a single SiC nanowire component poses a formidable challenge, such that the intrinsic MA potential in SNWA should be analyzed in depth. In this study, SNWAs were synthesized as a foundational matrix, of which the nanowire diameters were uniformly distributed, by adopting a straightforward and simple chemical vapor deposition (CVD) method. Subsequently, the SiO₂ sheath thickness on the external surface of SiC nanowires was modified through controlled oxidation modulation. Noteworthily, the above-described precise control over the SiO₂ sheath thickness served a dual purpose: it enables optimal impedance matching in the SNWA while substantially augmenting its dielectric loss capacity. To the best of our knowledge, this study has underscored the significance of optimizing the SiC/SiO₂ heterointerface for enhancing MA in SNWA for the first time. Such optimization is promising to significantly facilitate the design and synthesis of SiC nanowire-based EMA.