Non-silica fiber and enabled stratified fiber doping for high temperature aerogel insulation

Ultralight Ceramic Fiber Aerogel for High-Temperature Thermal Superinsulation

“…The complex refractive indexes of ZrO 2 , Al 2 O 3 and SiO 2 are picked by [46][47][48] in the spectral range of 0.5 to 25 µm. The maximum temperature-dependent mean extinction coefficient of fibers is calculated based on the optimal fiber diameter at that temperature [33]. The optimal diameters of fibers at various temperatures are presented in Figure 1a, and the maximum temperaturedependent mean extinction coefficient of fibers based on the optimal diameter is shown in Figure 1b.…”

“…According to Equation ( 9), kr is proportional to T 3 and increases dramatically temperature, causing radiation become the dominant heat transfer mode at high tem atures. Therefore, to suppress the thermal radiation inside the ZrO2 fiber aerogels, necessary to dope opacifier particles to further enhance the aerogel shading performa Among several common ceramics (ZrO2, TiO2 and SiC), SiC exhibits superior extin properties and is therefore chosen as an opacifier in this work [33]. However, doping opacifiers in ZrO2 fiber aerogels will also inevitably increase the solid heat transfer.…”

“…Commonly, the addition of infrared opacifiers with high specific extinction coefficients, such as SiC [27], TiO 2 [28,29] and carbon [24,30], is an effective approach to suppress the high-temperature radiation heat transfer of conventional aerogels, but this method has not been widely applied to fiber aerogels. Moreover, fiber orientation also has a crucial effect on high-temperature thermal conductivity of conventional fiber-reinforced aerogel composites [31][32][33], but this has not been verified in fiber aerogels. To the best of our knowledge, there are few reports focusing on the modulation of high-temperature thermal insulation properties of fiber aerogels so far, especially the simultaneous regulation of composition, fiber arrangement and shading agents.…”