Preparation of continuous Fe containing carbide silicon fibers and their structural radar-wave absorbing materials

In order to prepare carbide silicon radar-wave absorbing fibers, the continuous carbide silicon (SiC(Fe)) fibers containing Fe were prepared for the first time from a precursor polyferrocarbosilane (PFCS), which was synthesized from polydimethylsilane and ferrocene, followed by melt-spinning, curing in air, and continuous pyrolysis at 1320℃ in N₂ atmosphere. The structural materials prepared with this fibers and resin show good radar-wave absorbing properties. XPS depth analysis shows that a carbon-enriched layer of about 100nm is formed on the surface of the fiber and the atomic concentration of element Fe increases a little from edge to inner. The free carbon arranges gradually in order with increasing the temperature by Raman spectra analysis. The effect of the free carbon on the properties of the continuous SiC(Fe) fibers was studied. The results show that the free carbon is of benefit to decreasing the specific resistance but increasing the complex permittivity (ε' and ε″) and relative complex permittivity (ε_r) of the fibers.