Effect of heating conditions on pore structure and performance of carbon foams

Abstract

Carbon foams were prepared from AR pitch in a high pressure/high temperature reactor under different heating conditions. Their pore structure, bulk density, porosity, compressive strength, thermal conductivity, and crystallite size parameters were measured. Foams produced using a long time at a constant foaming temperature exhibit bigger pore size (412 nm), higher porosity (83.82%), lower bulk density (0.34 g/cm 3), higher compressive strength (4.92 MPa), and more interconnected pores than that produced in a short time at the same constant foaming temperature, which exhibit high thermal conductivity (71.34 W/(m · K)) and low interlayer d-spacing (d002) (0.335 56 nm) after graphitization at 2800 °C. The specific thermal conductivity of graphite foams can reach 210 (W · (m · K) −1)/(g · cm −3), which is about five times greater than copper and four times greater than aluminum.