Binding natural graphite with mesophase pitch: A promising route to future carbon blocks

Carbon blocks with relatively high graphitization degree (>92%) were prepared by simply binding natural graphite flakes with mesophase pitch at 1300-1500 °C without the traditionally used high-temperature graphitization process (~3000 °C). The influences of pitch content, molding pressure and heat-treatment temperature on the volume density and open porosity, mechanical property, and electrical resistivity of the carbon blocks were systematically investigated. The thermal conductivity and frictional property for typical carbon blocks were tested. The microstructure of the carbon blocks was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Results showed that carbon blocks with excellent comprehensive properties could be manufactured. Carbon blocks with bending strength up to 41.98 MPa were obtained when the mesophase pitch content was 25 wt%, the molding pressure 40 MPa, and heat-treatment temperature 1300 °C. The electrical resistivity and thermal conductivity of the carbon blocks (parallel to the graphite layers) were in the range of 10-15 μΩ m and 50-60 W/(m K), respectively. The frictional coefficient of the carbon blocks was below 0.1.