Microstructures and Bending Property of Mesophase Based C/C Composites withAir Oxidation Process

Carbon―carbon composites werefabricated in short period by LPIC (low pressure impregnation carbonization) processwith 225 air oxidation using mesophase pitch as precursor. The microstructureswere observed by PLM (polarizingmicroscope ). The bending property and fracture surface were tested byuniversaltesting machineand S EM (scanningelectron microscope), respectively. The results show that the carbon yield isimproved remarkably with 225 air oxidation compared withthe samples without air―oxidation. After four cycles of LPIC, the density of C/Ccomposites reaches 1.73 g/cm3. Its bending property is 152.39MPa, which is increased62.87% compared with the samples without air oxidation process. It is concludedthat the C/C composites with air oxidation exhibit pseudo―plastic failure behavior and the sampleswithout air―oxidation rupture from interlays with low bending strength.The microstructures of C/C composites without air oxidation are mainlysmall domains with few mosaic and domain textures. Nevertheless, the composites with 225 air oxidationpresent domain textures mainly with small domain and flow domain.