Effect of HfC nanowires grown on carbon fibers on the microstructure and thermophysical properties of C/C composites

One-dimensional (1D) hafnium carbide nanowires (HfCnws) were grown in situ on carbon fibers (CFs) via a Ni-assisted pyrolysis method of organometallic polymer precursor. Scanning electron microscopy (SEM), transmission electron microscope (TEM), polarized-light optical microscopy (PLM), and Raman were used to analyze the effect of HfCnws on the microstructure of pyrolytic carbon (PyC). The specific heat capacity (HC), thermal diffusivity (TD), thermal conductivity (TC), and coefficient of thermal expansion (CTE) of HfCnws-C/C composites were also investigated. Results show that HfCnws wrapped by carbon nanosheet were successfully synthesized. The diameter of HfCnws is about 30 nm and the thickness of carbon nanosheet is about 10 nm, which could induce the formation of isotropic (ISO) PyC. After introducing HfCnws, the TD and CTE of HfCnws-C/C composites were increased. Ni2HfCnws-C/C composites show a higher TC and TD, and the CTE increased with the increasing content of HfCnws.