FABRICATION AND CHARACTERISTICS OF C/C COMPOSITES DERIVED FROM WOOD

C/C composites were prepared from beech and ash as raw materials, which were firstly carbonized at 800 ℃and then deposited at 1 050 ℃for 30 h with propane as precursor by chemical vapor deposition. The microstructures of carbonized and deposited wood samples were investigated by scanning electron microscope, the mechanical properties were measured by the three-point bending testing method and their fracture mechanism was analyzed by fractographs. Results showed that the pyrocarbons were found to grow inside the pores of two composites. A C/C composite with the density of 0.713 g/cm3, flexural strength of 17.6 MPa and flexural modulus of 8.58 GPa was obtained from beech wood. These two kinds of C/C composites show brittle fracture. The fracture mecha-nism of beech sample is inter-granular fracture mechanism, while ash sample exhibits both the inter-granular fracture mechanism and void coalescence mechanism.