Strengthened microwave absorption properties of polymer-derived carbon-rich SiCN (Ni3Si) ceramic fibers pyrolyzed at low temperature.

In this study, carbon-rich SiCN (Ni 3 Si) ceramic fibers (CSCF) were prepared through electrospinning and low-temperature (700–1000 °C) polymer derivation, and the effect of pyrolysis temperature on carbon content, carbon graphitization degree, dielectric properties and microwave (MW) absorption properties of fibers was explored. The results show that increasing pyrolysis temperature is conducive to the graphitization of carbon in fibers, but it also reduces the content of polyvinylpyrrolidone (PVP) derived carbon in the material. The synergistic relationship between the carbon content and carbon graphitization degree of CSCF obtained by pyrolysis at 800 °C was the best, benefiting from which its impedance matching ability is properly cooperated with the MW attenuation and its widest effective absorption bandwidth (EAB W) can achieve 4.6 GHz at a thickness of 1.9 mm. Compared with SiCN-based composite ceramic fibers obtained by pyrolysis at high temperature (more than 1000 °C), the ceramic fiber prepared in this study had a significantly improved EAB W even at a reduced introduction amount of metal element. In addition, the as-synthesized fiber precursor (FP) has high flexibility, based on which the macro-morphology of the material can be tailored more easily, to obtain the devices made of ceramic fibers with various complex shapes. The experimental ideas and conclusions of this work are of great significance for expanding the application of SiCN ceramic based composites in the field of MW absorption in the future. [ABSTRACT FROM AUTHOR]