The effects of phenolic resin-derived PyC interlayers on microstructure and mechanical properties of Cf/SiC composites

A novel, easy and cost-effective way, infiltration and pyrolysis of phenolic resin solution, was exploited to prepare pyrolytic carbon (PyC) interlayers for carbon fiber/silicon carbide (Cf/SiC) mini-composites. X-ray photoelectron spectroscopy, dynamic contact angle measurement and scanning electron microscope were carried out to characterize chemical structure of carbon fibers (CFs), wetting properties between CFs and phenolic resin solution and microstructure of CFs and their composites, respectively. Remarkably, SEM results showed regulation of uniformity and thicknesses of PyC interlayer could be achieved through controlling the concentration of phenolic resin solution and oxidation condition of CFs. When CFs were treated by 10 min' oxidation with 40 mg/L ozone followed by dip-coating with 4 wt% phenolic solution, uniform PyC interlayer with approximately 120 nm were prepared on CFs. The corresponding Cf/SiC specimens had the largest increase in tensile strength and work of fracture with the improvement of 26.2% and 71.6% from the PyC-free case.