Remarkably Enhance the Stealth/Resistance/Mechanical Properties of Silica‐Zirconia Ceramic Aerogel by Phase Transitions and Interface Evolution

Abstract Multifunctionality and high‐temperature resistance are crucial for ceramic fiber aerogels (CFAs) used in extreme thermal environments. However, integrating multi‐functional elements into a cohesive assembly is complex and costly. Moreover, the brittleness of nanoceramic fibers and grain growth at elevated temperatures have long limited their high‐temperature stability. This study proposes a method to coordinately optimize the performance of stealth, high‐temperature resistance, and mechanical properties by regulating the configurational entropy values (CEVs) and electrical properties of individual ceramic nanofibers. Additionally, these parameters can be simply adjusted by controlling the phase transitions and interface evolution within silicon‐zirconium ceramic fibers induced by thermal effects. The relationship between induced temperature, CEVs, and the resultant properties is discussed in detail. Furthermore, by optimizing the fineness, aspect ratio, and stacking configuration of fibers through a pressure‐assisted collection method, finely tuned multiscale structured CFAs are achieved. The resulting CFAs exhibit excellent performance in mechanical strength (compressive strength 335.5 kPa, energy loss coefficient 0.45), acoustics (SAC 0.87, STL 34.8 dB), thermal insulation (λ = 0.034 W·m −1 ·K −1 ), and electromagnetic wave absorption (−26.6 dB at 3.5 mm). This study paves a novel way to design lightweight, high‐temperature‐resistant ceramic fiber aerogels with multifunctional integration for use in extreme high‐temperature environments.