Fabrication of continuous SiOC ceramic fibers by polyethylene oxide assisted sol-gel method

Abstract

The continuous SiOC ceramic fibers were fabricated by a novel polyethylene oxide (PEO) assisted sol-gel method. The precursor fibers were prepared by a solution which viscosity and composition can be regulated. The solution with excellent spinning performance was constituted by the optimized composition of tetraethyl orthosilicate, methyltrimethoxysilane, sucrose, and PEO. The effects of the pyrolysis temperatures and C/Si ratios on the microstructure and mechanical properties of SiOC ceramic fibers were investigated. After pyrolysis at 1200 °C, the tensile strength of SiOC ceramic fibers was 182.5 MPa and the surface was uniform and dense. Furthermore, XPS and FTIR analysis confirmed the formation of Si–O–Si and Si–C bonds, demonstrating the existence of SiO3C after pyrolysis at 1200 °C. The oxidation and high-temperature resistance of the SiOC ceramic fibers were also investigated. The results showed their ability to withstand heat treatment at 1000 °C in air and 1200 °C in Ar. The continuous SiOC ceramic fibers have broad prospects for commercial application as the thermal protection and high temperature resistant material. And the novel PEO-assisted sol-gel method can be employed to fabricate various ceramic fibers.