Design and preparation of hollow SiO2 nanospheres/SiC-based nanocomposite fiber membrane for high temperature thermal insulators

Abstract

Silicon carbide (SiC) fibers are attractive for their thermal stability and chemical erosion resistance. However, the practical application of SiC fiber in the fields of thermal insulation is limited owing to its high intrinsic thermal conductivity. Herein, a novel closed cell structured SiC-based nanocomposite fiber (NCF) using hollow SiO 2 nanospheres (HSNSs) as pore forming agent were designed by precursor conversion method combined with electrospinning technology. According to the content and size of HSNSs, NCFs with different pore size and porosity could be obtained. When the content of HSNSs reached 15%, a large number of closed cells were constructed inside the fiber, which broke the continuity of solid heat transfer and endowed it with excellent thermal insulation performance (∼0.105 W m −1 K −1 at 1000 °C). Meanwhile, the NCFs showed excellent high-temperature resistance and mechanical properties, which makes it have a wide application prospect as a high temperature thermal insulator. This research also offers a new insight for the development of SiC-based fiber with multiple functions to meet various applications, such as catalyst supporters and microwave absorbers. • A new type of porous insulation material with closed cell structure is designed. • Multiple phases enhance interface thermal resistance and infrared shielding performance. • Hollow SiO 2 spheres significantly reduces the thermal conductivity of the fibers. • The nanocomposite fibers show great application prospects as high temperature thermal insulators.