Thermal Conductivity and Catalytic Mechanism of Recrystallized Graphite by Titanium

The recrystallized graphite was prepared from calcined coke, coal-tar pitch and titanium by hot-pressing progress in order to investigate the effects of the amount of titanium on the thermal conductivity, bending strength and microstructure of recrystallized graphite. Experimental results show that the recrystallized graphite exhibits higher thermal conductivity and higher bending strength than the pure graphite prepared by the same process. For the orientation of graphite layers of the present RG-15 materials, the thermal conductivity and the bending strength are 424W/(m·k) and 50.2MPa at room temperature, respectively. Microstructure analysis reveals that a little amount of titanium can increase the degree of graphitization of recrystallized graphite, but overlarge amount of titanium dopant makes basic physical properties worse. For the recrystallized graphite with titanium concentration of 15wt%, the degree of development and arrangement of graphite crystallite is the best. The degree of graphitization of the present RG-15 material is 96.4% and the value of La is 306nm. XRD analysis indicates that titanium added to carbon substrate is in the form of TiC precipitates. The catalytic role of titanium to preparing recrystallized graphite can be explained by the liquid phase transition mechanism.