Effects of Heat-Treatment Temperature and Binder Content on the Microstructure and Thermal Conductivity of Graphite Flake-Carbon Composites

Abstract

In this work, graphite flake-carbon composites were fabricated from natural graphite flake and spinning pitch by a hot-pressing technique at 500°C and 10 MPa. The X-ray pole figure measurements show that the orientation degree of graphitized composite is higher than that of hot-pressed and carbonized composite and presents a descending tendency from 74.4 to 71.2% when the pitch content increases from 4 to 14 wt.%. A reducing trend of d₀₀₂ and an increasing tendency of the average crystallite diameter (L_a), crystallite stack height (L_c) and degree of graphitization (g) can also be observed when pitch fraction increases from 4 to 16 wt.%. The apparent density and thermal conductivity in the direction perpendicular to the hot-pressing direction of graphitized composite with 16 wt.% of binder all achieve maximum values, 1.930 g/cm³ and 485 W/m K, respectively.

Keywords:

• graphite flake-carbon composites
• natural graphite flake
• spinning pitch
• pole figure
• thermal conductivity

Acknowledgments

This work was supported by the Capacity Building Program of Shanghai Local Universities (No. 12160503600), Youth Innovation Fund from Shanghai Institute of Technology (No. YJ2013-35), the First-class Discipline Construction Fund of Shanghai Municipal Education Commission (No. J201212), Nature Science Foundation of China (U1332107) and Key Discipline Construction Fund of Composite Materials of Shanghai Institute of Technology (No. 10210Q140001).